Enhancing CA-based separators with thermo-responsive ionic liquids: A path to eco-friendly membrane production and multifaceted applications

We synthesized a temperature-responsive ionic liquid, [N4444][SS], and incorporated it into an environmentally friendly cellulose acetate (CA)-based battery separator. A pore was formed in the battery separator by [N4444][SS], which pierced a plasticized part due to water pressure. Varying drying temperatures during membrane fabrication revealed that the CA/[N4444][SS] membrane dried at 50 °C exhibited greater thickness and a smaller average pore size, resulting in an asymmetric internal structure. Despite the asymmetry, this membrane demonstrated significantly higher water flux and a lower Gurley value compared to the membrane dried at 25 °C, indicating minimal tortuosity and low resistance within the internal pores. Thermal behavior analysis through TGA and DSC, as well as FT-IR spectroscopy, confirmed that [N4444][SS] remains within the CA matrix, forming coordinative bonds. The findings suggest that the CA/[N4444][SS] membrane, when used as a Li-ion battery separator, could enhance Li-ion transport properties and conductivity. Moreover, the recyclability of the IL in the membrane fabrication process contributes to a more environmentally friendly approach.

Copper oxide(I) nanoparticle-modified cellulose acetate membranes with enhanced antibacterial and antifouling properties

Cellulose acetate membranes exhibit a potential to be applied in hemodialysis. However, their performance is limited by membrane fouling and a lack of antibacterial properties. In this research, copper oxide (I) nanoparticles were fabricated in situ into a cellulose acetate matrix in the presence of polyvinylpyrrolidone (pore-forming agent) and sulfobetaine (stabilising agent) to reduce the leakage of copper ions from nano-enhanced membranes. The influence of nanoparticles on the membrane structure and their antibacterial and antifouling properties were investigated. The results showed that incorporating Cu2O NPs imparted significant antibacterial properties against Staphylococcus aureus and fouling resistance under physiological conditions. The Cu2O NPs-modified membrane could pave the way for potential dialysis applications.

Highly flexible carbon nitride-polyethylene glycol-cellulose acetate film with photocatalytic antibacterial activity for fruit preservation

Cellulose acetate film, as a biodegradable and biomass-derived material, has great potential applications in food packaging. However, the poor mechanical and antibacterial properties limit its applications. Herein, a highly flexible carbon nitride-polyethylene glycol-cellulose acetate (CN-PEG-CA) film was successfully prepared by combining graphitic carbon nitride (g-C3N4) photocatalyst with cellulose acetate (CA). The g-C3N4 enables the film with antibacterial activity, as a green photocatalyst. PEG softens the rigid polymer CA and crosslinks CA, PEG, and g-C3N4 together by hydrogen bonding, as a flexible crosslinker. X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectrum (FT-IR) characterizations confirmed the successful preparation of the CN-PEG-CA film. The mechanical property tests demonstrated that adding PEG increased the elongation at break of the film by about 4 times. The composite film had high antibacterial activity, and the bactericidal rates on Escherichia coli and Staphylococcus aureus were 99.98 % and 99.89 %, respectively. It effectively extended the shelf life of strawberries to 96 h and effectively maintained the quality of strawberries during storage. After 96 h, the weight loss rate of strawberries packaged with 15 % CN-PEG-CA film was 21.83 %, vitamin C content was 45.47 %, titratable acidity content was 0.89 %, and color, hardness and total soluble solids were well maintained. And biocompatibility test results showed that the film was safe and nontoxic. From the ecological and economic point of view, the highly flexible and biodegradable films with efficient photocatalytic antibacterial activity synthesized in this paper have great potential in the field of food packaging.

Metal nanoparticles decorated mint-cellulose acetate composite as an efficient catalyst for the reduction of methyl orange

Water contamination caused by toxic compounds has emerged as one of the most severe challenges worldwide. Biomass-based nanocomposites offer a sustainable and renewable alternative to conventional materials. In this study, a nanocomposite of mint and cellulose acetate (Mint-CA) was prepared and employed as a supportive material for Cu nanoparticles (CuNPs) and Ag nanoparticles (AgNPs). The selectivity of CuNPs@mint-CA and AgNPs@mint-CA was assessed by comparing their performance in the reduction reaction of various dyes solutions. AgNPs@mint-CA exhibited superior catalytic performance, with a removal of 95.2 % for methyl orange (MO) compared to 68 % with CuNPs@mint-CA. The absorption spectra of MO exhibited a distinct peak at 464 nm. The reduction reaction of MO by AgNPs@mint-CA followed pseudo-first-order-kinetic with a rate constant of k = 0.0063 min-1 (R2 = 0.928). The highest removal of MO was achieved under the following conditions: a catalyst weight of 40 mg, an initial MO concentration of 0.07 mM, the addition of 0.5 mL of 0.1 M NaBH4, and a temperature of 25 °C. Furthermore, the AgNPs@mint-CA catalyst exhibited exceptional reducibility even after five use cycles, highlighting its potential for efficiently removing MO.

Sequestration of Pb(II) using channel-like porous spheres of carboxylated graphene oxide-incorporated cellulose acetate@iminodiacetic acid: optimization and mechanism study

The adsorption property of the costless green cellulose acetate (CA) was boosted by the dual modifications: inner modification by incorporating carboxylated graphene oxide (COOH-GO) into the CA spheres and outer modification by the surface modification of the COOH-GO@CA spheres by iminodiacetic acid (IDA) for removing Pb(II). The adsorption experiments of the Pb(II) proceeded in a batch mode to evaluate the adsorption property of the COOH-GO@CA@IDA spheres. The maximal Pb(II) adsorption capacity attained 613.30 mg/g within 90 min at pH = 5. The removal of Pb(II) reached its equilibrium within 20 min, and the removal % was almost 100% after 30 min at the low Pb(II) concentration. The Pb(II) adsorption mechanism was proposed according to the kinetics and isotherms studies; in addition, the zeta potential (ZP) measurements and X-ray Photoelectron Spectroscopy (XPS) analysis defined the adsorption pathways. By comparing the XPS spectra of the authentic and used COOH-GO@CA@IDA, it was deduced that the contributed chemical adsorption pathways are Lewis acid-base, precipitation, and complexation. The zeta potential (ZP) measurements demonstrated the electrostatic interaction participation in adsorbing the cationic Pb(II) species onto the negatively charged spheres (ZP = 14.2 mV at pH = 5). The unique channel-like pores of the COOH-GO@CA@IDA spheres suggested the pore-filling mechanism of Pb(II). The promising adsorption results and the superb recyclability character of COOH-GO@CA@IDA enable it to extend of the bench scale to the industrial scale.

Highly transparent sustainable biogel electrolyte based on cellulose acetate for application in electrochemical devices

In this study, an easy and low-cost production method for a cellulose acetate-based gel polymer containing lithium perchlorate and propylene carbonate is described, as well as the investigation of its properties for potential use as an electrolyte in electrochemical devices. Cellulose acetate, a biopolymer derived from natural matrix, is colourless and transparent, as confirmed by the UV-Vis spectroscopy, with 85 % transparency in visible spectrum. The gels were prepared and tested at different concentrations and proportions to optimise their properties. Thermogravimetry, XRD, and FTIR analyses revealed crucial characteristics, including a substantial 90 % mass loss between 150 and 250 °C, a semi-crystalline nature with complete salt dissociation within the polymer matrix, and a decrease in intensity at 1780 cm-1 with increasing Li+ ion concentration, suggesting an improvement in ionic conduction capacity. In terms of electrochemical performance, the gel containing 10 % by mass of cellulose acetate and 1.4 M of LiClO4 emerged as the most promising. It exhibited a conductivity of 2.3 × 10-4 S.cm-1 at 25 °C and 3.0 × 10-4 S.cm-1 at 80 °C. Additionally, it demonstrated an ideal shape of cyclic voltammetry curves and stability after 400 cycles, establishing its suitability as an electrolyte in electrochemical devices.

Influence of citric acid concentrations on the porosity and performance of cellulose acetate-based porous membranes: A comprehensive study

This study investigates the influence of citric acid concentration on the fabrication of porous cellulose acetate (CA) membranes using the Non-Solvent Induced Phase Separation (NIPS) method. A notable aspect is the precise control over membrane properties, particularly pore size and porosity, achieved solely through the adjustment of citric acid concentration, serving as the additive. Higher concentrations of citric acid increase pore size by rendering polymer chains more pliable, whereas lower concentrations lead to smaller, denser pores due to improved dispersion in the CA matrix and altered water interactions during phase separation. A decrease in porosity and Gurley values with reducing citric acid concentrations (from 5 × 10-2 to 1 × 10-3 M ratios) indicates less plasticization of CA chains. However, at very low concentrations (1 × 10-4 and 1 × 10-5), porosity increases, despite the presence of smaller pores, and Gurley values approach those of pure CA in terms of gas permeability. Fourier Transform Infrared (FT-IR) spectroscopy confirms the presence of citric acid and its interaction with carbonyl groups, consistent with the pore size observations from Scanning Electron Microscopy (SEM). Spectral data deconvolution reveals weakened carbonyl bonds due to the reduced presence of citric acid, correlating with the smaller pores observed in SEM. Thermal Gravimetric Analysis (TGA) demonstrates that composite membranes are more thermally stable than pure CA, attributed to the citric acid-induced crosslinking within the polymer chains. Stability increases with decreasing citric acid concentration, with some anomalies at the lowest levels. In conclusion, this study highlights the capability of adjusting citric acid concentration to tailor membrane properties, offering valuable insights for the creation of porous materials across diverse industrial applications.

Diabetic wound healing function of PCL/cellulose acetate nanofiber engineered with chitosan/cerium oxide nanoparticles

The use of cerium oxide nanoparticles (CeO2NPs) in diabetic wound repair substances has shown promising results. Therefore, the study was conducted to introduce a novel nano-based wound dressing containing chitosan nanoparticles encapsulated with green synthesized cerium oxide nanoparticles using Thymus vulgaris extract (CeO2-CSNPs). The physical properties and structure of the nanoparticles were analyzed using XRD, DLS, FESEM and FTIR techniques. The electrospun PCL/cellulose acetate-based nanofiber was prepared and CeO2-CSNPs were integrated on the PCL/CA membrane by electrospraying. The physicochemical properties, morphology and biological characteristics of the electrospun nanocomposite were evaluated. The results showed that the nanocomposite with 0.1 % CeO2-CSNPs exhibited high antibacterial performance against S. aureus (<58.59 µg/mL). The PCL/CA/CeO2-CSNPs nanofiber showed significant antioxidant activity up to 89.59 %, cell viability improvement, and cell migration promotion up to 90.3 % after 48 h. The in vivo diabetic wound healing experiment revealed that PCL/CA/CeO2-CSNPs nanofibers can significantly increase the repair rate of diabetic wounds by up to 95.47 % after 15 days. The results of this research suggest that PCL/CA nanofiber mats functionalized with CeO2-CSNPs have the potential to be highly effective in treating diabetes-related wounds.

Porous microneedle arrays as promising tools for the quantification of drugs in the skin: a proof of concept study

This study aimed to demonstrate the potential of using porous microneedles (PMNs) as a promising tool for the noninvasive quantification of topically applied pharmaceutical products. We fabricated a porous microneedle (PMN) from a blend of cellulose acetate and dimethyl sulfoxide by casting and phase separation; it was characterized using scanning electron microscopy, Raman spectroscopy, differential scanning calorimetry, and a Texture Analyzer. An ex vivo study was conducted as a proof-of-concept study to assess whether this PMN could be used to quantify drug absorption through the skin after the topical administration of two nonequivalent products of sodium ibuprofen (gel and dissolving microneedles). Three cellulose acetate formulations (PMN1: 37.5%, PMN-2: 44.4%, and PMN-3: 50%) were used to prepare PMN patches; subsequently, these were evaluated for their morphological and insertion properties. Only PMN-2 microneedle patches were chosen to continue with the ex vivo study. The ex vivo study results demonstrated that PMNs could absorb and release sodium ibuprofen (SDIB) and differentiate between two different SDIB topical products. This can be attributed to the porous and interconnected architecture of these microneedles. This developmental study highlights the potential success of such a tool for the quantification of dermal drug concentration and supports moving to in vivo tests.

Developing high performance biodegradable film based on crosslinking of cellulose acetate and tannin using caprolactone

The use of metal catalysts during the production process of cellulose acetate (CA) film can have an impact on the environment, due to their toxicity. Diphenyl phosphate (DPP) was used instead of toxic metal catalyst to react with cellulose acetate, tannin (T) and caprolactone (CL) for preparation of cellulose acetate-caprolactone-tannin (CA-CL-T) film. The results show that DPP can produce a cross-linked network structure composed of tannin, caprolactone and cellulose acetate. The maximum molecular weight reached 113,260 Da. The introduction of tannin and caprolactone into cellulose acetate caused the resulting CA-CL-T film acquire excellent strengthening/toughening effect, in which a tensile strength of 23 MPa and elongation at break of 18 % were attained. More importantly, the resistance of the film to UV radiation was significantly improved with the tannin addition, which was corroborated by the CA-CL-T film still exhibiting a tensile strength of 13 MPa and elongation at break around 13 % after continuous exposure to UV radiation for 9 days. On the other hand, the insertion of caprolactone provoked enhancement of the overall moisture resistance. Five days treatment of the films with Penicillium sp. induced gradual drop in quality, indicating the CA-CL-T film show response to biodegradation. In all, the effective crosslinking between the components of the developed material is responsible for the acquired set of these distinct characteristics.

Development of a molecularly imprinted membrane for selective, high-sensitive, and on-site detection of antibiotics in waters and drugs: Application for sulfamethoxazole

Sulfonamides are among the widespread bacterial antibiotics. Despite this, their quick emergence constitutes a serious problem for ecosystems and human health. Therefore, there is an increased interest in developing relevant detection method for antibiotics in different matrices. In this work, a straightforward, green, and cost-effective protocol was proposed for the preparation of a selective molecularly imprinted membrane (MIM) of sulfamethoxazole (SMX), a commonly used antibiotic. Thus, cellulose acetate was used as the functional polymer, while polyethylene glycol served as a pore-former. The developed MIM was successfully characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The MIM was used as a sensing platform in conjunction with a smartphone for optical readout, enabling on-site, selective, and highly sensitive detection of SMX. In this way, a satisfactory imprinting factor of around 3.6 and a limit of detection of 2 ng mL-1 were reached after applying response surface methodologies, including Box-Behnken and central composite designs. Besides, MIM demonstrated its applicability for the accurate and selective detection of SMX in river waters, wastewater, and drugs. Additionally, the MIM was shown to be a valuable sorbent in a solid-phase extraction protocol, employing a spin column setup that offered rapid and reproducible results. Furthermore, the developed sensing platform exhibited notable regeneration properties over multiple cycles and long shelf-life in different storage conditions. The newly developed methodology is of crucial importance to overcome the limitations of classical imprinting polymers. Furthermore, the smartphone-based platform was used to surpass the typically expensive and complicated methods of detection.

Development of environmentally friendly catalyst Ag-ZnO@cellulose acetate derived from discarded cigarette butts for reduction of organic dyes and its antibacterial applications

The release of harmful organic dyes from different industries besides its degradation products is a major contributor to environmental contamination. The catalytic reduction of these organic pollutants using nanocomposites based on polymeric material presents potential advantages for the environment. In this study, novel nanocomposite based on cellulose acetate (CA)-derived from discharged cigarette butts and zinc oxide nanoparticles (ZnO NPs) was prepared utilizing a very simple and low-cost solution blending method and used as support for silver nanoparticles (Ag NPs). A simple reduction method was used to anchor different percentages of Ag NPs on the ZnO@CA nanocomposite surface via utilizing sodium borohydride as a reducing agent. The Ag-ZnO@CA nanocomposite was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The TEM analysis showed spherical Ag NPs, with an average diameter of ∼17.6 nm, were uniformly anchored on the ZnO@CA nanocomposite surface. The prepared nanocomposites were evaluated as catalysts for the reduction of organic dyes in water. It was found that 10 % Ag-ZnO@CA nanocomposite showed a remarkable reduction of Rhodamine B (RhB), Rhodamine 6G (Rh6G), Methylene Blue (MB), and Sunset Yellow (SY) dyes in short time. In the presence of this nanocomposite, the rate constant, kapp values for RhB, Rh6G, MB, and SY were 0.3498 min-1, 1.51 min-1, 0.2292 min-1, and 0.733 min-1, respectively. This nanocomposite was recovered and reused in five successive cycles, with a negligible loss of its activity. Furthermore, the nanocomposites demonstrated moderate antibacterial activity toward Staphylococcus aureus and Escherichia coli. Thus, this study directed attention on recycling of waste material to a valuable nanocomposite and its applications in environmental protection.

ZIF-8 decorated cellulose acetate mixed matrix membrane: An efficient approach for textile effluent treatment

The textile industry is the second largest water-intensive industry and generates enormous wastewater. The dyes and heavy metals present in the textile effluent, even at their lower concentrations, can cause an adverse effect on the environment and human health. Recently, mixed matrix membranes have gained massive attention due to membrane property enhancement caused by incorporating nanofillers/additives in the polymer matrix. This current study examines the efficacy of ZIF-8/CA membrane on dye removal and treatment of real-time textile industry effluent. Initially, ZIF-8 nanoparticles were synthesized using a probe sonicator. The XRD, FT-IR, and SEM analysis confirmed the formation of crystalline and hexagonal facet ZIF-8 nanoparticles. The ZIF-8 nanoparticles were dispersed into a cellulose acetate matrix, and a membrane was prepared using the "phase inversion method." The membrane was characterized using FT-IR and SEM analysis, which endorse incorporating ZIF-8 into the polymer matrix. Later, the efficacy of the ZIF-8/CA membrane was verified by dye removal studies. The dye removal studies on crystal violet, acid red 13, and reactive black 5 reveal that the membrane is ∼85% efficient in dye removal, and the studies were further extended to real-time textile effluent treatment. The studies on textile effluent prevail that ZIF-8/CA membrane is also proficient in removing chemical oxygen demand (COD) ∼70%, total organic carbon (TOC) ∼80%, and heavy metals such as lead, chromium, and cadmium from textile wastewater and proved to be efficient in treating the textile effluent.

Electrospun Tamarindus indica-loaded antimicrobial PMMA/cellulose acetate/PEO nanofibrous scaffolds for accelerated wound healing: In-vitro and in-vivo assessments

In this work, Tamarindus indica (T. indica)-loaded crosslinked poly(methyl methacrylate) (PMMA)/cellulose acetate (CA)/poly(ethylene oxide) (PEO) electrospun nanofibers were designed and fabricated for wound healing applications. T. indica is a plant extract that possesses antidiabetic, antimicrobial, antioxidant, antimalarial and wound healing properties. T. indica leaves extract of different concentrations were blended with a tuned composition of a matrix comprised of PMMA (10 %), CA (2 %) and PEO (1.5 %), and were electrospun to form smooth, dense and continuous nanofibers as illustrated by SEM investigation. In vitro evaluation of T. indica-loaded nanofibers on normal human skin fibroblasts (HBF4) revealed a high compatibility and low cytotoxicity. T. indica-loaded nanofibers significantly increased the healing activity of scratched HBF4 cells, as compared to the free plant extract, and the healing activity was significantly enhanced upon increasing the plant extract concentration. Moreover, T. indica-loaded nanofibers demonstrated significant antimicrobial activity in vitro against the tested microbes. In vivo, nanofibers resulted in a superior wound healing efficiency compared to the control untreated animals. Hence, engineered nanofibers loaded with potent phytochemicals could be exploited as an effective biocompatible and eco-friendly antimicrobial biomaterials and wound healing composites.

Enhanced porous membrane fabrication using cellulose acetate and citric acid: Improved structural integrity, thermal stability, and gas permeability

In this study, our primary objective was to enhance the properties of porous membranes by addressing the limitations associated with phase separation. We employed a non-solvent induced phase separation (NIPS) method, utilizing cellulose acetate (CA) in conjunction with citric acid to fabricate these membranes. Citric acid played a dual role: ensuring a uniform pore structure and cross-linking the CA polymer, thereby enhancing its mechanical strength. This approach resulted in the development of a more robust membrane with superior structural integrity. Thermogravimetric analysis (TGA) confirmed enhanced thermal stability, particularly up to 150 °C, as a result of citric acid's cross-linking effect. Beyond 150 °C, the decomposition temperatures of the CA/citric acid membrane were found to be comparable to those of pure CA. Remarkably, a CA/citric acid ratio of 1:0.05 exhibited the slowest decomposition rate as the temperature increased. Scanning electron microscopy (SEM) examination unveiled a sponge-like membrane structure with numerous evenly distributed fine pores. Through the use of citric acid as a plasticizer, we were able to effectively control the penetration of water molecules, preventing the formation of macrovoids and promoting the creation of fine pores. This resulted in the fabrication of a high-porosity membrane, boasting an impressive porosity measurement of 84.9 %. Furthermore, measurements of the Gurley value confirmed efficient gas permeation, a critical characteristic for applications requiring effective gas transport. Fourier transform infrared (FT-IR) spectroscopy attested to the presence of citric acid in the membrane post-phase separation, indicating its successful integration. Our work presents a novel approach to enhance porous membranes, providing improvements in mechanical strength, thermal stability, and gas permeability. These findings offer valuable insights for the development of advanced materials with diverse applications in various fields.

UiO-66-NH2 nanocomposites incorporated cellulose acetate for forward osmosis membranes of high desalination performance

In this paper, the hydrophilic UiO-66-NH2 nanomaterial was synthesized by the solvent-thermal method and characterized. Then, UiO-66-NH2 was introduced into the casting membrane solution of cellulose acetate (CA) forward osmosis (FO) membrane, and CA/UiO-66-NH2 forward osmosis membrane was prepared by the phase inversion method. The optimum preparation conditions of CA/UiO-66-NH2 mixed matrix membranes were determined as follows: the content of UiO-66-NH2 was 0.4 wt%, the coagulation bath temperature was 35°C, the mixing temperature was 50°C and the heat treatment temperature was 50°C. FTIR, SEM, water contact angle and AFM were carried out on CA/UiO-66-NH2 forward osmosis membrane prepared under the best preparation conditions. Compared to the CA forward osmosis membrane, the permeability and selectivity of the CA/UiO-66-NH2 membrane were improved. The water flux and reverse salt flux of the CA/UiO-66-NH2 forward osmosis membrane reached 52.32 L/(m2·h) and 2.43 g/(m2·h), respectively. The permeability selectivity of CA membranes and CA/UiO-66-NH2 membranes did not change much during 180 min, indicating that the two membranes had good long-term stability. This study shows a potential advantage of UiO-66-NH2 as additives for improvement in the desalination performance of forward osmosis membranes.

Activities of cellulose acetate and microcrystalline cellulose on the thermal and morphomechanical performances of a biobased hybrid composite made polybutylene succinate

Microcrystalline cellulose (MCC-30 wt%) was extruded with a blend of polybutylene succinate (PBS) and cellulose acetate (CADS=2.5-20 wt%) to produce two grades of binary (PBS/CA, PBS/MCC) and ternary (PBS/CA/MCC) specimens by injection into a mold previously thermostated at 22 °C and 78 °C. The structure-property relationships of neat PBS (n-PBS) and PBS-based blends were investigated by Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, scanning electron microscopy (SEM), rheology, differential scanning calorimetry (DSC), thermogravimetry, and mechanical (tensile, bending) tests. FTIR/DRIFT outcomes revealed physical interactions between the ingredients through hydrogen bonds. Rheology and SEM evidenced the presence of entanglements and micro-voids absent in n-PBS. Non-isothermal DSC showed that 22 °C-molded formulations displayed crystalline degrees higher than 78 °C-specimens, except for PBS/MCC. DSC-isothermal analysis showed a hindrance effect of CA on PBS/CA crystallinity and a nucleating impact of MCC on PBS/MCC. Tensile and bending moduli increased for both material grades while the elongation at break decreased. Entanglements and micro-voids had detrimental effects on stress levels because the maximum tensile strength decreased when each or both biofillers were added to PBS. These structural configurations were beneficial for bending strengths since all blends' stiffness relatively increased regardless of material grade.

Gas transport into cellulose materials for highly porous structure

To solve the low thermal stability of polyolefin membranes, our group developed porous polymers using cellulose acetate (CA) material. The formation of pores in CA involved creating plasticized regions within the CA membrane using additives. By applying gas pressure to these regions, a CA/glycolic acid membrane could be prepared with a small average pore size and high porosity. According to the porosimeter measurement, the average pore size of the membrane was 150 nm, and the porosity was 77%. SEM observations of the surface and cross-section of the CA/glycolic acid membrane confirmed the abundant distribution of fine pores. Furthermore, IR analysis revealed the removal of glycolic acid from the membrane after pore formation, indicating its interaction with CA during the process of gas permeation. Additionally, TGA analysis demonstrated a decrease in thermal stability due to the formation of numerous pores after gas permeation.

Structure, morphology, and properties of nanofibers

Cellulose acetate (CA) nanofibers are prepared using solution blow co-spinning (SBS) with poly(ethylene oxide) (PEO). The pure CA membranes are obtained by washing water-soluble PEO from the fibrous CA-PEO blend. Nanofibrous membranes are characterized using optical and scanning electron microscopy (SEM), differential scanning calorimetry (DSC), infrared spectroscopy (ATR-FTIR), and surface zeta potential measurements. Thermal transitions from DSC and ATR-FTIR spectra analysis were used to confirm the removal of the PEO. Although the characteristic signals of PEO are not observed by FTIR, an additional thermal step transition in CA nanofibers indicates the embedding of a small amount of PEO (up to 6 wt%). SEM analysis shows that CA-PEO blends are constituted by fibers with mean diameters from 671 to 857 nm (depending on the SBS parameters), while after PEO removal, diameters range from 567 to 605 nm. We propose a new method for staining CA-PEO membranes with iodine solution in absolute ethanol that allows the differentiation of CA and PEO components with an optical microscope. The microscopy results suggest that PEO assists in the spinning by enveloping CA nanofibers, allowing uninterrupted processing. The successful deacetylation to cellulose using an aqueous KOH solution is confirmed with zeta potential measurements and ATR-FTIR.

Synthesis & fabrication of O-linked polymeric hybrids for recovery of textile dyes: Closed loop economy

Dyes are an important resource employed for the production systems in textile, paper, paint and leather industry. An estimate of 200,000 tons of dyes are discharged as textile effluent each year worldwide. It becomes imperative to recover these dyes by treating the effluents using economically viable routes. The present research was undertaken with the objective to attain zero emission and zero waste through development of novel polymeric hybrids as adsorbents. For this purpose, metal moieties (Al3+, Si4+, Ti4+ and Zr4+) were hybridized with polyacrylic acid, and cellulose acetate for the uptake of selected dyes under optimized parameters. The structural elucidation of four synthesized hybrids (MP-Al, MP-Si, MP-Ti and MP-Zr) by FTIR, EDX and TGA confirmed O-linked grafting of metal moieties with polymers and thermally stable porous materials. SEM micrographic images displayed void spaces providing channels for effective adsorption. The batch experiments demonstrated removal of malachite green (77-96%) and congo red (70-82%) upon contact of initial 45 min on polymeric hybrids On the other hand, pristine polyacrylic acid and cellulose acetate showed remarkably low removal of dyes. The adsorption mechanism is proposed as physical in nature following type II isotherm. Further, Langmuir and Ho's pseudo second order fitness was evaluated. In order to determine the economic viability of the present research, the real textile dyes were recovered in three consecutive cycles of adsorption and chemical treatment of hybrids. The results propose a system with positive impact on economy by maximum utilization of hybrids as adsorbents and recovery of textile dyes for reuse in textile processing.

Cellulose Acetate-Based Wound Dressings Loaded with Bioactive Agents: Potential Scaffolds for Wound Dressing and Skin Regeneration

Wound healing and skin regeneration are major challenges in chronic wounds. Among the types of wound dressing products currently available in the market, each wound dressing material is designed for a specific wound type. Some of these products suffer from various shortcomings, such as poor antibacterial efficacy and mechanical performance, inability to provide a moist environment, poor permeability to oxygen and capability to induce cell migration and proliferation during the wound healing process. Hydrogels and nanofibers are widely reported wound dressings that have demonstrated promising capability to overcome these shortcomings. Cellulose acetate is a semisynthetic polymer that has attracted great attention in the fabrication of hydrogels and nanofibers. Loading bioactive agents such as antibiotics, essential oils, metallic nanoparticles, plant extracts, and honey into cellulose acetate-based nanofibers and hydrogels enhanced their biological effects, including antibacterial, antioxidant, and wound healing. This review reports cellulose acetate-based hydrogels and nanofibers loaded with bioactive agents for wound dressing and skin regeneration.

Hydroxyapatite and ionic liquid coupled with hybrid membranes for toxic pollutant removal and remediation

Access to clean water is the mandatory requirement for every living being to sustain life. So, membrane-based integrated approach of adsorption and separation technology has recently been preferred by scientists over other conventional techniques, for wastewater treatment. Current research focused on the synthesis of novel imidazolium (A1) based IL, which was further functionalized with hydroxyapatite (HAp; extracted from Labeo rohita scales), to create possible solutions towards environmental remediation. Cellulose acetate (CA) was used for the fabrication of three different ionic liquid membranes. All the synthesized products were characterized by FTIR, XRD and TGA. Two dyes of different nature, i.e., congo red (anionic) and crystal violet (cationic) were selected because of their highly toxic and carcinogenic effects, for batch adsorption experiments. Antibacterial activity of the synthesized membranes was also evaluated against S. aureus. Results of the study revealed that CA-HA1 1:2 acted as the best adsorbent towards the removal of crystal violet, exhibiting removal efficiency of 98% with the contact time of 24 h while in case of congo red adsorption, CA-HA1 (1:2) proved as prime adsorbent with the removal efficiency of 96% for the same preceding contact time. Considering the antibacterial character of the synthesized membranes, CA-A1 (1:1) emerged as very efficient antibacterial agent with the inhibition zone of 50 mm after 48 h. The overall behavior of monolayer and multilayer adsorption was witnessed for both dyes while kinetic studies favored the pseudo-second order reaction for all adsorbents.

Regeneration and modification of cellulose acetate from cigarette waste: Biomedical potential by encapsulation of tetracycline hydrochloride

Cigarette waste are pervasive litter on Earth, posing a major threat to organisms and ecosystems. However, these waste contain cellulose acetate (CA) and can be recycled, transforming into raw materials for new products. Polymers like CA can be used in biomedical applications as drug carriers and scaffolds for drug release. In this study, cigarette filters waste was collected, recycled and used for fabricating the nanofibrous membrane of cellulose acetate nanofibers (CFCA) through electrospinning technique. Tetracycline hydrochloride (TC) was encapsulated in the nanofibers to prevent bacterial infections. Various analyses were conducted: Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction Analysis (XRD) and Thermogravimetric analysis (TGA). CA and CFCA exhibited high water uptake properties and exhibited similar breaking stress and strain values. Both CA and CFCA effectively acted as stable drug carriers, with sustained in vitro drug release. Antibacterial activity was demonstrated by the drug-loaded CA and CFCA nanofibers against, Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. Based on their cytotoxicity evaluations on mouse fibroblast cells (L929), CA and CFCA fibrous mats demonstrated no cytotoxicity and similar cell viability results. Consequently, the TC-loaded nanofibers made from CA and CFCA exhibited suitable properties for wound healing applications.

Ammonia-sensitive cellulose acetate-based films incorporated with Co-BIT microcrystals for smart packaging application

Nowadays, there is an increasing demand for smart packaging materials capable of effectively monitoring the food freshness. In this study, new Co-based MOF (Co-BIT) microcrystals with ammonia-sensitivity and antibacterial function were constructed and then loaded within cellulose acetate (CA) matrix to create smart active packaging materials. The influences of Co-BIT loading upon structure, physical, and functional properties of the CA films were then thoroughly explored. It was observed that microcrystalline Co-BIT was uniformly integrated inside CA matrix, which caused significant promotions in mechanical strength (from 24.12 to 39.76 MPa), water barrier (from 9.32 × 10^-6 to 2.73 × 10^-6 g/m·h·Pa) and ultraviolet light protection performances of CA film. Additionally, the created CA/Co-BIT films displayed striking antibacterial efficacy (>95.0 % for both Escherichia coli and Staphylococcus aureus), favorable ammonia-sensitivity function as well as color stability. Finally, the CA/Co-BIT films were successfully applied for indicating the spoilage of shrimp through discernible color changes. These findings suggest that Co-BIT loaded CA composite films have great potential for use as smart active packaging.

Effect of degree of substitution on the microphase separation and mechanical properties of cellooligosaccharide acetate-based elastomers

Thermoplastic elastomers (TPEs) have long been used in a wide range of industries. However, most existing TPEs are petroleum-derived polymers. To realize environmentally benign alternatives to conventional TPEs, cellulose acetate is a promising TPE hard segment because of its sufficient mechanical properties, availability from renewable sources, and biodegradability in natural environments. Because the degree of substitution (DS) of cellulose acetate governs a range of physical properties, it is a useful parameter for designing novel cellulose acetate-based TPEs. In this study, we synthesized cellulose acetate-based ABA-type triblock copolymers (AcCel_x-b-PDL-b-AcCel_x) containing a celloologosaccharide acetate hard A segment (AcCel_x, where x is the DS; x = 3.0, 2.6, and 2.3) and a poly(δ-decanolactone) (PDL) soft B segment. Small-angle X-ray scattering showed that decreasing the DS of AcCel_x-b-PDL-b-AcCel_x resulted in the formation of a more ordered microphase-separated structure. Owing to the microphase separation of the hard cellulosic and soft PDL segments, all the AcCel_x-b-PDL-b-AcCel_x samples exhibited elastomer-like properties. Moreover, the decrease in DS improved toughness and suppressed stress relaxation. Furthermore, preliminary biodegradation tests in an aqueous environment revealed that the decrease in DS endowed AcCel_x-b-PDL-b-AcCel_x with greater biodegradability potential. This work demonstrates the usefulness of cellulose acetate-based TPEs as next-generation sustainable materials.

Anatase-cellulose acetate for reinforced desalination membrane with antibacterial properties

This study aimed to prepare antifouling and highly mechanical strengthening membranes for brackish and underground water desalination. It was designed from cellulose acetate (CA) loaded anatase. Anatase was prepared from tetra-iso-propylorthotitanate and carboxymethyl cellulose. Different concentrations of anatase (0.2, 0.3, 0.5, 0.6, 0.7, and 0.8)% were loaded onto CA during the inversion phase preparation of the membranes. The prepared membranes were characterized using Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM & EDX), mechanical properties, swelling ratio, porosity determination, and ion release. The analysis confirmed the formation of anatase on the surface and inside the macro-voids of the membrane. Furthermore, anatase loading improved the CA membrane's mechanical properties and decreased its swelling and porosity rate. Also, CA-loaded anatase membranes displayed a significant antibacterial potential against Gram-positive and Gram-negative bacteria. The results showed that the salt rejection of the CA/anatase films as-prepared varies considerably with the addition of nanomaterial, rising from 46%:92% with the prepared membranes under the 10-bar operation condition and 5 g/L NaCl input concentration. It can be concluded that the prepared CA-loaded anatase membranes have high mechanical properties that are safe, economical, available, and can stop membrane biofouling.

Cellulose acetate network via ion pre-anchored strategy for simultaneous regulation of uniform Mg2+ flux and ion conductivity

Hybrid LiMg batteries stand out by combining the rapid lithium diffusion kinetics and the advantages of magnesium. However, the uneven Mg deposits may result in continuous parasitic reactions and penetrate the separator. Herein, cellulose acetate (CA), with functional groups, was applied to engineer coordination with MOFs and construct the evenly-distributed and ample nucleation sites. Moreover, the hierarchical MOFs@CA network was fabricated via the metal ion pre-anchored strategy to regulate the uniform Mg²⁺ flux and improve ion-conductivity simultaneously. Furthermore, the hierarchical CA networks with well-ordered MOFs provided efficient MOF-to-MOF ion-transportation channels and served as ion sieves to inhibit anion transportation, thereby mitigating polarization. The super dendrite-inhibition and interfacial compatibility was confirmed and the assembled Mo₆S₈//Mg batteries exhibited high capacity about 105 mAh g^-1 and capacity decay of 4 % after 600 cycles at 30 C, which surpassed the state-of-the-art LMBs system employing Mo₆S₈ electrode. The fabricated GPE sheds fresh strategy for the design of CA-based GPEs and bright light on the promise of high-performance LMBs.

Valorizing industrial tobacco wastes within natural clays and chitosan nanocomposites for an ecofriendly insecticide

We report the engineering of insecticide films based on two mineral clays, montmorillonite and kaolinite, combined to chitosan and/or cellulose acetate originating from cigarette filter and subsequently impregnated with tobacco essential oil extracted from tobacco dust. Both binary composites, i.e. clay and chitosan or clay and cellulose acetate, and ternary composites containing clay, chitosan and cellulose acetate were prepared and characterized by XRD, DLS, ELS, and IR to investigate the nature of interactions within the composites. The two clay minerals showed different kinds of interaction with chitosan: intercalation in the case of Montmorillonite vs adsorption on the external surface for kaolinite. Secondly, the nicotine release from the composites films at different temperatures was studied by in-situ IR. The Montmorillonite composites, particularly the ternary one, showed a better encapsulation of nicotine which release was limited. Finally, the insecticidal activity of the composites was evaluated against the Tribolium castaneum a common wheat pest. The differences observed between montmorillonite and kaolinite composites were rationalized in relation to the nature of interaction between the components. The fumigant bioassay showed promising insecticidal effects in the case of the ternary composite cellulose acetate/chitosan/montmorillonite. Therefore, these eco-friendly nanocomposites can be used efficiently for the sustainable protection of stored cereals.

Spatio-temporal distribution of cigarette butt contamination in urban beaches with varying levels of use

This study assessed the extent of cigarette butt contamination on two urban beaches in Recife-PE (Pernambuco State, Brazil) with varying levels of use. The study considered degradation levels and evaluated whether the brands varied by time, space, and beaches use. Ten transects (1.5 m wide) and spaced 10 m apart, were delimited on the beaches investigated. Twelve collections were made between May 2021 and January 2022, and the collected cigarette butts were evaluated based on degradation level, mass, size, and brand. In total, 10,275 cigarette butts were collected on both beaches, with P1 accounting for 96.91% of the found cigarette butts. The density of cigarette butts on the beaches was directly proportional to the level of use, with 8.85 butts/m2 in P1 and 1.05 butts/m2 in P2. Eighteen brands were identified, with brand (A) being the most popular regardless of the area. Significant differences (p ≤ 0.05) were found when evaluating the amount of butts/m2; Sundays with high precipitation presented reduced values of butts; more occupied areas presented transects with higher amounts; abundance in the summer; morphometry with higher values recorded in newly discarded butts; predominance of more degraded butts and brand diversity. Despite the difference in the number of butts/m2 between the areas, it was possible to identify that their abundance is very expressive, and that the monitored beaches present a high exposure to the contaminant.

Cigarettes butt littering: The story of the world's most littered item from the perspective of pollution, remedial actions, and policy measures

Cigarettes butt (CB) is one of the most littered items on the planet. This paper critically analyzes the factors responsible for CB littering, and associated environmental ramifications, and reviews all the possible technical, behavioural, and policy-based solutions. Even while smoking has declined globally, middle-income nations have seen an increase in consumption, which may be related to increased affordability and a lack of public awareness. The smokers' individual beliefs and habits, environmental ignorance, covert littering as a result of social taboos associated with smoking, and behavioural gaps between intention and action might all be contributing factors to CBs' littering behaviour. The low biodegradability of cellulose acetate filters and toxic chemical leaching from CBs are the most important aspects of CB environmental toxicity. The small size and low economic value of CB contribute to the inefficiencies of current waste collection and management systems. The current research on CB valorisation includes fired-clay bricks, asphalt concrete, biofilms, sound absorber, cellulose pulp, pesticides, and insecticides as downstream mitigation strategies. This study highlights the urgent need for policymakers to enforce regulations enabling innovative cigarette designs, the creation of deposit-refund schemes, extended producer responsibility and stringent waste collection mechanisms. Adopting gentler marketing strategies and non-confrontational behavioural nudges could result in an overall reduction in CB pollution.

Cellulose acetate/silica composites: Physicochemical and biological characterization

Cellulose acetate is of remarkable scientific interest, becoming more useful when is used in obtaining of the composite materials containing nanoparticles, as result of its improved properties. Thus, cellulose acetate/silica composite films obtained by casting the solutions of cellulose acetate (CA)/tetraethyl orthosilicate (TEOS) in different mixing ratios were analyzed in this paper. The impact of TEOS addition, and implicitly of the silica nanoparticles on the mechanical strength, water vapor sorption properties and antimicrobial activity of the cellulose acetate/silica films were mainly monitored. The results of the tensile strength tests were discussed in correlation with data obtained from Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. It was found that samples with low TEOS content show improved mechanical strength compared to samples with high amounts of TEOS. The microstructural characteristics of the studied films affect their moisture sorption capacity so that the weight of the adsorbed water increases with the addition of TEOS. These features are complemented with the antimicrobial activity against Staphylococcus aureus and Escherichia coli bacterial species. The obtained data show that the cellulose acetate/silica films, and especially those with low silica content have improved properties that can recommend them for applications in the biomedical field.

Optimization of whole-cell bacterial bioreporter immobilization on electrospun cellulose acetate (CA) and polycaprolactone (PCL) fibers for arsenic detection

Arsenic contamination is a critical global problem, and its widespread environmental detection is becoming a prominent issue. Herein, electrospun fibers of cellulose acetate (CA) and polycaprolactone (PCL) were successfully fabricated and used as the support material for immobilization of arsenic-sensing bacterial bioreporter for the first time. To date, no attempt has been made to immobilize fluorescent whole-cell bioreporter cells on electrospun fibers for arsenic detection. CA and PCL electrospun fibers were fabricated via traditional electrospinning technique and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and contact angle meter. Following immobilization of the bacterial bioreporter cells, the immobilized bacteria were also characterized by viability assay using AlamarBlue. The effects of growth phase and cell concentration on the fluorescence response of fiber-immobilized arsenic bioreporters to arsenic were also investigated. After immobilization of arsenic bioreporters on 10 wt% PCL fiber, 91% of bacterial cells remained viable, while this value was 55.4% for cells immobilized on 12.5 wt% CA fiber. Bioreporter cells in the exponential growth phase were shown to be more sensitive to arsenic compared to aged cells. While both the electropsun PCL- and CA-immobilized bioreporters successfully detected 50 and 100 µg/L of arsenite (As (III)) concentrations, the PCL-immobilized bioreporter showed better fluorescence performance which should be investigated in future studies. This study helps to fill some gaps in the literature and demonstrates the potential for using electrospun fiber-immobilized arsenic whole-cell bioreporter for arsenic detection in water.

Life cycle assessment of end-of-life options for cellulose-based bioplastics when introduced into a municipal solid waste management system

The partial degradation of cellulose-based bioplastics in industrial treatment of organic fraction of Municipal Solid Waste (MSW) opened to the investigation of further disposal routes for bioplastics in the waste management system. For this purpose, the environmental footprint of three MSW management scenarios differing only for the bioplastics final destination (organic, plastic or mixed waste streams) was assessed through a Life Cycle Assessment (LCA) approach. Results revealed how the treatment of bioplastics with organic waste achieved the worst environmental performance (5.8 kg CO₂ eq/FU) for most impact categories. On the other hand, treatment with plastics and mixed waste achieved negative impact values (that mean avoided GHG emissions) of -9.8 and -7.7 kg CO₂ eq/FU respectively, showing comparable benefits from these scenarios. The key reason was the lower quality of compost obtained from the organic treatment route, which reduced the environmental credits achieved by the energy recovery during anaerobic digestion.

Experimental and simulated distribution and interaction of water in cellulose esters with alkyl chain substitutions

This study investigated the effect of the average length of substituted side chains in different cellulose esters on water sorption and the water association mechanism. For this purpose, a set of esters with a similar total degree of substitution was selected: cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. Dynamic vapor sorption was used to determine the effect of the side chain length on sorption, desorption, and the occurrence of water clustering. Since water association in the structure was of interest, molecular dynamics simulations were performed on cellulose acetate and cellulose acetate propionate. This study showed that cellulose acetate appears to be water-sensitive and experiences hysteresis upon water sorption, which was attributed to structural changes. The simulations also showed that water is screened out by the side chains and forms intermolecular hydrogen bonds, primarily to the carbonyl oxygen rather than the residual hydroxyl groups.

Cigarette: an unsung anthropogenic evil in the environment

The world's population is growing steadily, and this trend is mirrored by a sharp rise in the number of people who smoke cigarettes. Instead of properly disposing of their cigarette waste, most people simply toss them aside, leading to serious environmental consequences. According to previous statistics, in 2012 alone, 6.25 trillion cigarettes were consumed by 967 million chain smokers. Past studies have shown that up to 30% of global litter is made up of cigarette waste. These discarded cigarette butts are non-biodegradable and contain over 7000 toxicants such as benzene, 1,3-butadiene, nitrosamine ketone, N-Nitrosonornicotine, nicotine, formaldehyde, acrolein, ammonia, aniline, polycyclic aromatic hydrocarbons, and various heavy metals. These toxicants have a negative impact on the habitats of wildlife and can cause serious health problems such as cancer, respiratory disorders, cardiac issues, and sexual dysfunction. Although it is still unclear how littered cigarettes affect plant growth, germination, and development, it is clear that they have the potential to harm plant health. Just like single-use plastic, trashed cigarette butts are a critical new rising form of pollution that requires scientific attention for effective recycling and disposal management. It is important to properly dispose of cigarette waste to protect the environment and wildlife, as well as to prevent harm to human health.

Graphene nanoplatelet/cellulose acetate film with enhanced antistatic, thermal dissipative and mechanical properties for packaging

With the increased concern over environment protection, cellulose acetate (CA) has drawn great interests as an alternative for packaging material due to its biodegradability and abundant resources; whereas, the poor antistatic property and thermal conductivity restrict its application in packaging. In this work, we proposed a simple but effective strategy to produce high performance graphene nanoplatelet (GNP)/CA composite films via the consecutive homogenization and solvent casting processes. Relying on the spontaneous absorption of CA during homogenization, the GNP/CA produced shows an excellent dispersibility in the N,N-Dimethylformamide (DMF) solution and many fewer structural defects compared with GNPs alone. As a result, the composite films obtained exhibit simultaneously and significantly enhanced antistatic, heat dissipative and mechanical properties compared with CA. Specifically, the GNP/CA composite with the optimal formula has promising overall performances (namely, surface resistivity of 3.33 × 10⁷ Ω/sq, in-plane thermal conductivity of 5.359 W ( m · K ) , out-of-plane thermal conductivity of 0.785 W ( m · K ) , and tensile strength of 37.1 MPa). Featured by its promising overall properties, simple production processes and biodegradability, the as-prepared GNP/CA composite film shows a great potential for application in packaging.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10570-023-05155-2.

Polyphenolic-modified cellulose acetate membrane for bone regeneration through immunomodulation

To enhance the bioactivity of cellulosic derivatives has become an important strategy to promote their value for clinical applications. Herein, protocatechualdehyde (PCA), a polyphenolic molecule, was used to modify a cellulose acetate (CA) membrane by combining with metal ions to confer an immunomodulatory activity. The PCA-modified CA membrane has shown a significant radical scavenging activity, thereby suppressed the inflammatory response and created a favorable immune microenvironment for osteogenesis and mineralization. Moreover, addition of metal ions could further stimulate the osteogenic differentiation of stem cells and accelerate bone regeneration both in vitro and in vivo. This study may provide a strategy to promote the immunomodulatory activity of cellulose-based biomaterials for bone regeneration.

An optimized acidic digestion for the isolation of microplastics from biota-rich samples and cellulose acetate matrices

Plastic pollution is a growing concern. To analyze plastics in environmental samples, plastics need to be isolated. We present an acidic/oxidative method optimized to preserve plastics while digesting synthetic cellulose acetate and a range of organics encountered in environmental samples. Cellulose acetate was chosen for optimization as it can be purchased as a reference material, can co-occur with plastics in environmental samples and, if it can be completely digested, is a potential filter material for the collection of nano- and micro-plastics from natural waters. Other forms of particulate organic matter (POM) were chosen to provide a range of chemistries that might alter digestion efficiency and due to the interest in the community of isolating plastics from samples where these organics occur. For instance, microalgal POM occurs in lake and ocean waters, riverine POM in rivers, and inclusion of tuna provides a test for the suitability of the method for isolating plastics from animal tissues. The method is a one-pot overnight (16-18 h) digestion in 5 M nitric acid with 0.3 M sodium persulfate heated to 80 °C. The method provides quantitative removal of cellulose acetate (exceeding detection limits), near quantitative removal of microalgal POM and Albacore tuna tissue (>99%), but only 86% of urban river POM, all while retaining >99% by mass of C-C bonded polymers polyethylene, polypropylene, and polystyrene and >96% by mass of polyethylene terephthalate. Fourier transform infrared spectroscopy (FT-IR) and %-C content analysis confirmed plastic polymer stability during digestion. However, some additives in appear susceptible to digestion with FT-IR results indicating the loss of N,N'-ethylenebis(stearamide) from polyethylene. This method provides a simpler and more effective method than many in the literature. We present recommendations for the application of this method, as well as limitations and areas for future improvement.

Determination of properties and environmental impact due to the inclusion of cigarette fibers in mortar: a new solution to mitigate the CB pollution

Cigarette butts generated are one of the major sources of total solid waste production and lead to environmental issues. This article has the objective of evaluating the effects of cellulose acetate microfibers (CAFs) sourced from discarded cigarette filters (CFs) as fiber reinforcement on the physico-mechanical properties and thermal conductivity of cementitious materials. To do so, mortar samples were prepared using different incorporated quantities of fibers (0.5, 1, 1.5, 2, 2.5, and 5% compared to the quantity of sand added to the mixture) and subjected to different tests to characterize the influence of CAFs on the microstructure of elaborated materials, considering the changes in workability time, compressive strength, flexural strength, density, water absorption, and microstructural analysis. Furthermore, the life cycle assessment (LCA) of mortar mixes in terms of CO₂ emissions is made. The results revealed that the increasing percentages of CAFs reduced the dry density and compressive strength, by approximately 1.62-51% and 37-69.64%, respectively, and a notable enhancement of insulation characteristics by about 5-47.5% was achieved. Microstructure analysis confirmed the experimental investigation and revealed that adding more than 1% of fibers resulted in a significantly low unit weight with greater entrapped air content. The studies prove the possibility of recycling cigarette butts for insulating cementitious matrix. In addition, applying mortar containing acetate cellulose fibers is recognized as a more environmentally friendly mixture in terms of reducing CO₂ emissions and could participate significantly in the achievement of SDGs.

Time to kick the butt of the most common litter item in the world: Ban cigarette filters

Cigarette filters offer no public health benefits, are single-use plastics (cellulose acetate) and are routinely littered. Filters account for a significant proportion of plastic litter worldwide, requiring considerable public funds to remove, and are a source of microplastics. Used cigarette filters can leech toxic chemicals and pose an ecological risk to both terrestrial and aquatic ecosystems. Bottom-up measures, such as focusing on consumer behaviour, are ineffective and we need to impose top-down solutions (i.e., bans) if we are to reduce the prevalence of this number one litter item. Banning filters offers numerous ecological, socioeconomic, and public health benefits.

Improved performance of metal-organic frameworks loaded cellulose acetate based film for packaging application

Bio-nanocomposite-based packaging materials have gained significance due to their possible applications in food packaging. Cellulose acetate is a biopolymer obtained by acetylation of cellulose and has characteristics such as biocompatibility, biodegradability and high transparency. Introducing iron-based metal-organic frameworks offer good mechanical strength, unique surface area and both chemical and thermally stability, making them favourable as supporting materials in fabricating polymer-based packaging materials. Among them, Fe- (Material Institute Lavoisier) MIL-88A is an iron-based nontoxic metal-organic framework, integrated with cellulose acetate and spinach extract was added to the prepared material in different compositions and cast as film. The Spinach loaded, Fe- (Material Institute Lavoisier) MIL-88A integrated cellulose acetate film significantly enhanced the tensile strength, water vapour permeability, and anti-microbial activity. The prepared film is then characterized using a scanning electron microscope (SEM), Fourier transforms infrared spectrometer (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Further, studies on mechanical properties as well as degradation tests and real-time applications of the prepared films were carried out.

Synergistic effect of GO/ZnO loading on the performance of cellulose acetate/chitosan blended reverse osmosis membranes for NOM rejection

Declining freshwater resources along with their pollution are threatening the life existence on earth. To meet the freshwater demand, one of the most appropriate and possible ways which has been adopted all over the world is to reuse wastewater by removing its impurities. Among many water pollutants, natural organic matter (NOM) is found to be responsible as major precursor for the formation of other pollutants. Removal of NOM from wastewater is being done by using membrane filtration systems incorporated with certain nanofillers to increase membranes efficiency and permeability. In this study, novel nanocomposite reverse osmosis (RO) membranes were prepared using cellulose acetate and chitosan in N,N-Dimethyl formamide. Graphene oxide (GO) nanosheets and zinc oxide (ZnO) in different concentration were loaded to modify the membranes for tuning their RO performance. The confirmation of the functional groups is demonstrated by Fourier transform infrared spectroscopy which revealed the specific peaks indicating the formation of the nano-composite membranes. The surface morphology was studied by scanning electronic microscopy which shows a gradual transformation of the membrane surface from voids-free to macro-voids filled surface up to threshold concentration of GO and ZnO. The thermal properties of GO based membranes were analyzed using thermogravimetric analysis and differential scanning calorimetry. The uniform interaction of the GO and ZnO with polymers induced the remarkable thermal properties of the synthesized membranes. Permeate flux and contact angle measurements were considered to estimate their water content (96%) capacity and NOM rejection (96%) using 0.1 ppm humic acid solution. The permeate flux, NOM rejection and the water content changed directly with GO and inversely with ZnO wt% in the membranes up to GO5 (GO:0.14: ZnO:0.03) whereas the contact angle exhibited the inverse relationship with GO and ZnO concentration in casting solution of the synthesized membranes. Hence it can be concluded that prepared RO membranes are suitable for NOM rejection and recommended for water treatment.

CeO2@PU sandwiched in chitosan and cellulose acetate layer as Cs-CeO2@PU-CA triple-layered membrane for chromium removal

The single or blended polymer membrane lacks a few advantages based on the durability of the membrane. The novel triple-layered sandwich membrane Cs-CeO₂@PU-CA membrane is cast through the phase inversion technique for chromium removal. This approach involves an arrangement of the top layer as chitosan which acts as a protective layer, and the sandwich layer of CeO₂@PU membrane which acts as source for stability, and a supportive layer of cellulose acetate is arranged accordingly. The incorporation of cerium oxide nanoparticles into the polyurethane can create pores on the surface of the membrane due to the high aspect ratio of cerium oxide. The triple-layered arrangement shows higher porosity via water contact angle, the network of pores present on the membrane which is visible through morphology, and also the intermediate sandwich layer CeO₂@PU provided with better mechanical strength which would be significant for changes achieved in adsorption technique. The batch adsorption was carried out with various ppm of Cr(VI) solution. The effect of pH, contact time, initial concentration, and temperature were analyzed and optimized for determining efficiency of chromium removal. Furthermore, the suitable adsorption isotherm and kinetics of the system were also determined for better fit via Langmuir, Freundlich, Temkin, and Sips along with pseudo-first-order and pseudo-second-order. The efficiency in adsorption is due to the prominent presence of hydroxyl, carboxyl, and hydrophilic group in the prepared membrane. Thus, the resultant prepared membrane can act as a potential chromium removal substrate.

Preparation, optimization, and in vitro-in vivo evaluation of sorafenib-loaded polycaprolactone and cellulose acetate nanofibers for the treatment of cutaneous leishmaniasis

The most common form of leishmaniasis is cutaneous leishmaniasis (CL). The major difficulties in the treatment of leishmaniasis include emergence of resistance, toxicity, long-term treatment, and the high cost of the current drugs. Although the therapeutic effect of sorafenib (SF) has been demonstrated in both in vitro and in vivo models of Leishmania infection, the therapeutic applications are limited due to severe drug-related toxicity; this is, in turn, due to non-specific distribution in the body. Thus, topical delivery has the advantage of the site directed delivery of SF. This research study evaluated SF-loaded hybrid nanofibers (NFs) which were composed of polycaprolactone (PCL) and cellulose acetate (CA) for the CL topical treatment. Accordingly, SF-loaded hybrid NFs were prepared using the electrospinning method. Formulation variables including total polymer concentration, drug/polymer ratio, and CA concentration were optimized using a full factorial design. The prepared SF-loaded NFs were then characterized for morphology, diameter, encapsulation efficiency (EE)%, drug loading (DL) %, and percentage of release efficiency during a 24-h period (RE_24h%); the mechanical characteristics were also considered. The physical state of the drug in the optimized NF was evaluated by the X-ray diffraction analysis. Finally, its in vivo efficacy was determined in L. major-infected mice. The optimized formulation had a smooth, cylindrical, non-beaded shape fiber with a diameter of 281.44 nm, EE of 97.96%, DL of 7.48%, RE of 51.05%, ultimate tensile strength of 1.08 MPa, and Young's moduli of 74.96 MPa. The XRD analysis also demonstrated the amorphous state of SF in NF. Further, the in vivo results displayed the higher anti-leishmanial activity of the SF-loaded hybrid NF by efficiently healing lesion and successfully reducing the parasite burden. This, thus, indicated the potential of the clinical capability of the SF-loaded hybrid NF for the effective treatment of CL.

Composite nanofiber formation using a mixture of cellulose acetate and activated carbon for oil spill treatment

Oil and organic pollutants are significant disasters affecting the aquatic ecosystem and human health. A novel nanofiber composite from cellulose acetate/activated carbon (CA/AC) was successfully fabricated by the electrospinning technique. CA/AC nanofiber composites were prepared from 10% (w/v) polymer solutions dissolving in DMA/acetone ratio 1:3 (v/v) with adding three different percentages of AC (3.7, 5.5, and 6.7%) to the total weight of CA. The prepared CA/AC nanofiber composite morphology reveals randomly oriented bead-free fibers with submicron fiber diameter. CA/AC nanofiber composites were further characterized by TGA, DSC, and surface area analysis. Water uptake was investigated for fabricated fibers at different pH. Oil adsorption was conducted in both static (oil only) and dynamic (oil/water) systems to estimate the adsorption capacity of prepared composites to treat heavy and light machine oils. The results showed increased oil adsorption capacity incorporating activated carbon into CA nanofiber mats. The maximum sorption capacity reached 8.3 and 5.5 g/g for heavy and light machine oils obtained by CA/AC5.5 (AC, 5.5%). A higher oil uptake was reported for the CA/AC composite nanofibers and showed a constant sorption capacity after the second recycles in the reusability test. Of isotherm models, the most applicable model was the Freundlich isotherm model. The result of kinetic models proved the fit of the pseudo-second-order kinetic model to the adsorption system.

Properties of bacterial cellulose acetate nanocomposite with TiO(2) nanoparticle and graphene reinforcement

Agricultural waste is considered a promising source for bacterial cellulose production. This study aims to observe the influence of TiO₂ nanoparticles and graphene on the characteristic of bacterial cellulose acetate-based nanocomposite membranes for bacterial filtration in waters. Bacterial cellulose was produced from the pineapple peel waste using fermentation process. High-pressure homogenization process was applied to reduce bacterial nanocellulose size and esterification process was carried out to produce cellulose acetate. Nanocomposite membranes were synthesized with reinforcement of TiO₂ nanoparticles 1 % and graphene nanopowder 1 %. The nanocomposite membrane was characterized using an FTIR, SEM, XRD, BET, tensile testing, and bacterial filtration effectiveness using the plate count method. The results showed that the main cellulose structure was identified at the diffraction angle 22° and the cellulose structure slightly changed at the peak of diffraction angles of 14° and 16°. In addition, the crystallinity of bacterial cellulose increased from 72.5 % to 75.9 %, and the functional group analysis showed that several peak shifts indicated a change in the functional group of membrane. Similarly, the surface morphology of membrane became rougher with the structure of mesoporous membrane. Moreover, adding TiO₂ and graphene increases crystallinity and bacterial filtration effectiveness of nanocomposite membrane.

Developing strong and tough cellulose acetate/ZIF67 intelligent active films for shrimp freshness monitoring

There is a growing demand for the development of intelligent active packaging films to maintain and monitor the freshness of meat food. Herein, nano Co-based MOF (ZIF67) with ammonia-sensitive and antimicrobial functions was successfully synthesized and then integrated into cellulose acetate (CA) matrix to prepare intelligent active films. The impacts of ZIF67 incorporation on the structure, physical and functional characteristics of CA film were fully investigated. The results demonstrated that the ZIF67 nanofillers were evenly dispersed in CA matrix, resulting in remarkable improvement on tensile strength, toughness, thermal stability, UV barrier, hydrophobicity and water vapor barrier ability of CA film. Furthermore, the prepared CA/ZIF67 films exhibited superb antimicrobial and ammonia-sensitive functions. The CA/ZIF67 intelligent films turned their color from blue at beginning to brown during progressive spoilage of shrimp. These results revealed that the CA/ZIF67 films with excellent antimicrobial and ammonia-sensitive functions could be applied in intelligent active food packaging.

Co-digestion of food waste and cellulose-based bioplastic: From batch to semi-continuous scale investigation

Only few studies on the behaviour of bioplastics in anaerobic co-digestion could be found in literature and most of them are conducted in batch mode. Despite the fact that continuous experiments confirm or add new insight to the findings acquired from batch ones, there is still lack of such studies. This work aims to cover this gap, carrying out a semi-continuous anaerobic co-digestion of food waste and cellulose acetate (which its behaviour under anaerobic environment is also quite unexplored). After a first evaluation of the potential methane production from each substrate at batch scale, the semi-continuous co-digestion of food waste and cellulose acetate was carried out in three configurations. During the semi-continuous process, a methane yield of 331 NmlCH₄/gVS was generated from the co-digestion of food waste and cellulose acetate while bioplastics specimens achieved a weight loss of about 45 %. The results were both lower than the one obtained from batch co-digestion, although methane production rates were comparable regardless of being fed with or without bioplastics. An increase was registered after 65 days of semi-continuous process, due to the accumulation of CA specimens. This confirms the different degradation trends between bioplastics and food waste.

Equilibrium distribution of diethyl phthalate plasticiser in cellulose acetate-based materials: Modelling and parameter estimation of temperature and composition effects

Understanding the transport and fate of semi-volatile organic compounds (SVOCs) such as phthalates in indoor environments is fundamental for quantifying levels of human exposure and preventing adverse health effects. In this context, the partition coefficient of phthalates between indoor built materials and/or consumer goods and the surrounding atmosphere represents a key parameter for determining concentration distributions. Partition coefficients are also of fundamental importance for describing degradation phenomena associated with plasticiser loss from polymeric materials. However, this key parameter has only been determined for a limited number of systems and environmental conditions. Here, we assess the partitioning behaviour of the diethyl phthalate (DEP) plasticiser in cellulose acetate (CA)-based materials for the first time, determining the effects of temperature and plasticiser composition on equilibrium distributions at temperatures between 20 and 80 °C and using CA samples with DEP contents ranging from 6 to 22 wt%. Additionally, we propose a model to describe and quantify the effect of temperature and plasticiser composition, with model parameters being estimated using non-linear regression and measurements from 130 distinct experiments. Finally, we assess the suitability of our developed model to simulate the migration of DEP from CA-based materials.

Polycaprolactone-blended cellulose acetate thin-film composite membrane for dairy waste treatment using forward osmosis

In recent years new sustainable technology for wastewater treatment has emerged, and among them, forward osmosis (FO) has gained importance. FO utilizes osmotic pressure difference across the semipermeable membrane as the driving force to concentrate the wastewater. Further, the surface and physical properties of the semipermeable FO membrane play a crucial role during the FO process in reducing the internal concentration polarization. In general, FO membranes are prepared using cellulose acetate (CA) polymer due to their high hydrophilic nature. However, CA membranes are mechanically unstable for the FO process. Hence, to increase the mechanical strength and flexibility of CA, other polymers are blended along with it. In this present study, we have prepared a phase-inversion membrane using CA blended with polycaprolactone (PCL) polymers. Further, to increase the hydrophilicity of the membrane, a thin-film composite (TFC) layer of polyamide is coated using interfacial polymerization. To increase the antifouling properties of the membrane, graphene oxide (GO) and copper oxide (CuO) nanoparticles (NPs) are incorporated inside the TFC matrix. The prepared NPs and membrane were characterized using Fourier-transform infrared spectroscopy (FTIR), wide-angle X-ray scattering (WAXD), and contact angle. Further, the GO-CuO incorporated TFC coating has improved the hydrophilicity and antifouling properties of the membrane. It was observed that the water flux has increased up to 5 LMH, and reverse solute flux has reduced to 4 GMH. Further, the membrane was utilized to concentrate in situ prepared dairy waste. It was observed that after 60 min of the FO process, the concentration of dairy waste had increased to 23%, with a concentration factor of 0.903. Thus, a prepared TFC phase inversion membrane is potential for dairy wastewater treatment.