Physically-crosslinked hydroxyethyl cellulose-g-poly (acrylic acid-co-acrylamide)-Fe3+/silver nanoparticles for water disinfection and enhanced adsorption of basic methylene blue dye

Urea-rich sodium alginate-based hydrogel fertilizer as a water reservoir and slow-release N carrier for tomato cultivation under different water-deficit levels

In this study, a new eco-friendly urea-rich sodium alginate-based hydrogel with a slow-release nitrogen property was prepared, and its effectiveness was evaluated in the cultivation of tomato plants under different water stress levels. The structure and performance of the hydrogel were investigated by FTIR, XRD, TGA, DTG, and SEM. The swelling and release experiments showed that prepared urea-rich hydrogel exhibited a high-water holding capacity (412 ± 4 g/g) and showed a sustained and slow nitrogen release property. A greenhouse pot experiment was conducted using two hydrogel levels (0.1 and 0.5 wt%) under two water deficit levels (30 and 70 % based on required water irrigation). Germination tests indicated that the developed hydrogel fertilizer has no phytotoxicity and has a positive impact on the germination rate even under water deficit conditions. The application of hydrogel fertilizer at 0.5 wt% significantly (p > 0.05) enhanced plant growth parameters such as leaf number, chlorophyll content, stem diameter, and plant length compared to the control treatment. The magnitude of the responses to the hydrogel fertilizer application depended on the concentration of applied hydrogel fertilizer and stress severity with the most positive effects on the growth and yield of tomato observed at a level of 0.5 %. Tomato yield was significantly enhanced by 19.58 %-12.81 %, 18.58 %-22.02 %, and 39.38 %-43.18 % for the plant amended with hydrogel at 0.1-0.5 wt% and grown under water deficit levels of 0, 30, and 70 %, respectively, compared to the control treatment.

Sustained-release nitrogen fertilizer delivery systems based on carboxymethyl cellulose-grafted polyacrylamide: Swelling and release kinetics

Sustained or controlled-release delivery systems can enhance functions such as nutrient usage; minimize soil contamination, and reduce the required fertilizer dose. This paper reports the development of a carboxymethyl cellulose-g-polyacrylamide copolymer (CMC-g-PAM) as a sustained and slow-release fertilizer carrier for urea. The developed copolymer was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and thermo gravimetric analysis (TG). The grafting process increased the activation energy of CMC from 0.1521 to 0.5952 J/mol with a higher loading percentage of 72.140.85% using a 15% urea solution. The swelling ratio is significantly dependent on the pH. The maximum swelling ratio of 1199.58% at pH 9. However, Swelling follows a pseudo-first-order reaction with the maximum swelling ratio in a saline of 349.76%. The CMC-g-PAM copolymer loaded with urea exhibited sustained and slow release, with the maximum cumulative percentage of 69.12% at pH 9 and 38.94% in saline. Urea release from the CMC-g-PAM copolymer followed the first-order, Fickian, and biexponential biphasic release mechanisms. The release of the CMC-g-PAM copolymer loaded with urea is a complicated process governed by diffusion and a biphasic releasing profile.

Fe(III) cross-linked cellulose-agar hydrogel beads for efficient phosphate removal from aqueous solutions

Fe(III) cross-linked cellulose agar beads (Fe-CLCAB) were synthesized by sol-gel method and employed as adsorbents for the removal of phosphate ions from aqueous medium. The synthesized Fe-CLCAB was characterized by its swelling property, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and UV-Vis absorption spectroscopic analysis. Batch adsorption studies were carried out to find out the optimum conditions of phosphate uptake. The adsorption process was found to fit both Langmuir and Freundlich adsorption isotherm model, pseudo-second-order kinetic model, and Elovich kinetic model. Ninety-four percent phosphate adsorption was achieved with 500 beads at pH 5. Maximum monolayer adsorption capacity was 73.13 mg/g. A two-step elution process using sodium chloride solution was suitable for complete desorption of phosphate from Fe-CLCAB. Six cyclic adsorption-desorption tests were conducted using a 0.1 M NaCl solution as desorbing agent. The removal efficiency of regenerated Fe-CLCAB was 42% of its original value after six cycles, which validates good stability and effectiveness of the prepared hydrogel beads. Ion exchange plays a vital role during adsorption/desorption of phosphate.

Preparation and characterization of dextran-zein-curcumin nanoconjugate for enhancement of curcumin bioactivity

Curcumin is one of the most important polyphenolic nutrients in pharmaceutical industries. Unfortunately, its poor solubility and bioavailability have hampered its clinical application. To improve curcumin solubility and bioavailability, a natural nanocarrier made from protein-polysaccharide conjugate has been developed. Following antisolvent precipitation method, zein (Z) nanoparticles coated with dextran sulphate (DS) have been fabricated as curcumin (C) nanocarrier (DSZCNPs). The physicochemical properties of the nanoconjugate were measured using different techniques. Morphologically, DSZCNPs appeared spherical and monodispersed in scanning electron microscope (SEM) and transmission electron microscope (TEM) images. Curcumin encapsulation efficiency was ≈ 96%. DSZCNPs size was 180 nm and the polydispersity index value (PDI) 0.28. Zeta potential for DSZCNPs was -28.5 mV. DSZCNPs showed stability either for shelf storage (100 days) or at different pHs. Furthermore, DSZCNPs protected zein nanoparticles degradation in gastric environment and achieved controlled curcumin release in intestinal environment. DSZCNPs greatly enhanced the antioxidant activity of curcumin as demonstrated by DPPH assay. DSZCNPs had significant results in the reduction of colony forming unit (CFU%) against the tested microbes when compared with free curcumin. Also, the anticancer activity of DSZCNPs and free curcumin against hepatocellular carcinoma cells (HepG2) were assessed by MTT assay. IC50 for DSZCNPs was 13 µg/ml compared to 50 µg/ml for free curcumin indicating the therapeutic impact of DSZCNPs over free curcumin.Based on the above results, the developed zein-dextran nanocomplex exhibited high stability and improved the efficacy and bioactivity of curcumin suggesting its potential utility as nanovehicle for the hydrophobic drug curcumin.

Dialdehyde cellulose/gelatin hydrogel as a packaging material for manganese oxides adsorbents for wastewater remediation: Characterization and performance evaluation

The dialdehyde cellulose (DC) was used to synthesize gelatin-cellulose dialdehyde by Schiff base as a packaging material to manganese oxides nanoparticles adsorbents (Mn oxides@DC/Gel) for wastewater remediation and support the antimicrobial behavior of gelatin and DC. The crystallinity index% of microwave-synthesized DC prepared from cellulose II decreased from 43.18% to 34.11% and its oxidation degree was 143.77%. The greenly-produced Mn oxides were studied by XRD and TEM. XRD verified the presence of two different phases of α-MnO2 and α-Mn2O3 in the form of nanorods and nanocubes. Mn oxides@DC/Gel was investigated by FT-IR, XRD, XPS, SEM, swelling absorptivity, and thermal analysis. The optimal swelling ratio% of Mn oxides@DC/Gel nanocomposite was 1494.04±16.65%. The influence of pH on swelling ratios verified the instability of the imine group in acid and basic media. Mn oxides@DC/Gel nanocomposite hydrogel causes approximately two-fold greater inhibitory zones than gentamicin. The optimal adsorption conditions were adsorbent dose (0.05g), pH (9.0), contact time (120 min), and methylene blue dye concentration (30mg/L). The maximum adsorption capacity of Mn oxides@DC/Gel nanocomposite was 51.06±1.0 mg/g. The adsorption by Mn oxides@DC/Gel nanocomposite agrees with Langmuir, Redlich-Peterson, and Freundlich mechanisms.

Fabrication and evaluation of antimicrobial cellulose/Arabic gum hydrogels as potential drug delivery vehicle

This article aims to assess the highly potent antimicrobial hydrogels composed of cellulose and Arabic gum containing sulfadiazine drug (sulfadiazine-loaded Cel/AG) as drug-targeting carriers. ATR-IR, SEM/ EDS, XRD, and XPS methods were used to investigate the hydrogel. The highest water absorption % was 489.93 ± 4.5 at pH 7.4. Pseudo-second order and Fickian diffusion govern the swelling behavior. The maximal sulfadiazine loading percent was 82.291 ± 74. The in-vitro drug release exhibited significant responses in physiologically simulated pH values. The maximum cumulative release percent was 66.42 ± 0.6 % at pH 7.4. The drug release is predicted by the first order and Korsmeyer-Peppas models. The first diffusion coefficient was (D_i = 9.207 ± 47 × 10^-3 cm²/h) and the late one was (D_L = 5.64 ± 9.0 × 10^-2 cm²/h) at pH 7.4. That hydrogel is well-thought-out a potential drug delivery vehicle. The thermal stability of the Cel/AG hydrogel drug carrier has been enhanced by the incorporation of sulfadiazine which is evidenced by increasing the total activation approximately two-fold. The total activation energy of Cel/AG and sulfadiazine-loaded Cel/AG hydrogels were -0.07362 and -0.2092 J/mol. The sulfadiazine medication's inhibitory effect was markedly enhanced when it was incorporated into the Cel/AG hydrogel films.

Synthesis of Cellulose-Poly(Acrylic Acid) Using Sugarcane Bagasse Extracted Cellulose Fibres for the Removal of Heavy Metal Ions

In this study, sugarcane bagasse (SCB) was treated with sodium hydroxide and bleached to separate the non-cellulose components to obtain cellulose (CE) fibres. Cross-linked cellulose-poly(sodium acrylic acid) hydrogel (CE-PAANa) was successfully synthesised via simple free-radical graft-polymerisation to remove heavy metal ions. The structure and morphology of the hydrogel display an open interconnected porous structure on the surface of the hydrogel. Various factors influencing batch adsorption capacity, including pH, contact time, and solution concentration, were investigated. The results showed that the adsorption kinetics were in good agreement with the pseudo-second-order kinetic model and that the adsorption isotherms followed the Langmuir model. The maximum adsorption capacities calculated by the Langmuir model are 106.3, 333.3, and 163.9 mg/g for Cu(II), Pb(II), and Cd(II), respectively. Furthermore, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectrometry (EDS) results demonstrated that cationic exchange and electrostatic interaction were the main heavy metal ions adsorption mechanisms. These results demonstrate that CE-PAANa graft copolymer sorbents from cellulose-rich SCB can potentially be used for the removal of heavy metal ions.

Recoverable cellulose composite adsorbents for anionic/cationic dyes removal

GO/HEC/PGDE/Fe₃O₄ materials were successfully fabricated using environmentally-friendly hydroxyethyl cellulose (HEC), poly(ethylene glycol) diglycidyl ether (PGDE), graphene oxide (GO) and magnetic Fe₃O₄. Systematic investigations were completed to explore the influences of GO content in GO/HEC/PGDE/Fe₃O₄ and adsorption conditions on the adsorptions of cationic dyes (methylene blue (MB), crystal violet (CV)) and anionic dye acid blue 25 (AB-25). The increase of GO content can remarkably improve the adsorption capacity of GO/HEC/PGDE/Fe₃O₄ for the dyes. The three kinetic, four isothermic and three thermodynamic models were investigated to reveal the adsorption behaviors of the dyes. The formation of HEC/PGDE/Fe₃O₄ and adsorption mechanisms of the dyes by GO/HEC/PGDE/Fe₃O₄ were suggested. The GO/HEC/PGDE/Fe₃O₄ endowed with easy-fabrication, eco-friendly feature, efficient adsorption capacity of anionic/cationic dyes, convenient separation and reusability has potential applications in wastewater purification industry.

Recent developments of polysaccharide based superabsorbent nanocomposite for organic dye contamination removal from wastewater - A review

One of the main problems with water pollution is dye contamination of rivers, industrial effluents, and water sources. It has endangered the world's sources of drinking water. Several remediation strategies have been carefully developed and tested to minimize this ominous picture. Due to their appealing practical and financial benefits, adsorption methods in particular are often listed as one of the most popular solutions to remediate dye-contaminated water. Biopolymer-based hydrogel nanocomposites are a cutting-edge class of materials with a wide range of applications that are effective in removing organic dyes from the environment. Since the incorporation of various materials into hydrogel matrices generated composite materials with distinct characteristics, these unique materials were often alluded to as ideal adsorbents. The fundamental emphasis of the conceptual and critical review of the literature in this research is the significant potential of hydrogel nanocomposites (HNCs) to remediate dye-contaminated water (especially for articles from the previous five years). The review also provides knowledge for the development of biopolymer-based HNCs, prospects, and opportunities for future research. It is also focused on optimum conditions for dye adsorption processes along with their adsorption kinetics and isotherm models. In summary, the information gained in this review research may contribute to a strengthened scientific rationale for the practical and efficient application of these novel adsorbent materials.

Synthesis, optical and dielectric properties of polyacryloyloxy imino fluorophenyl acetamide and polyacryloyloxy imino fluorophenyl acetamide-co-polystyrene sulfonate

Our scope is synthesis a new poly fluorobenzamide oxime ester and study its structural, optical, and dielectric properties. Consequently, ((E)-2-((acryloyloxy)imino)-N-(4-fluorophenyl) acetamide) (AIFPA) was as-synthesized via a condensation reaction of (E)-N-(4-fluorophenyl)-2-(hydroxyimino) acetamide with acrylic acid to polymerize it via free radical polymerization (PAIFPA). over and above, the synthesized PAIFPA was inserted in more polymerization action with polystyrene sulfonate through the grafting process (PAIFPA-co-PSS). The chemical structures and morphology of AIFPA, PAIFPA, and PAIFPA-co-PSS were characterized by 1H NMR, FTIR, and XRD. The crystallinity index of PAIFPA, and PAIFPA-co-PSS was studied, affording that PAIFPA-co-PSS has the highest crystallinity. Moreover, The optical bandgap that obtained from absorbance analysis was encountered to be in the range of 2.6 eV to 3.5 eV. Ultimately, the dielectric properties of PAIFPA, and PAIFPA-co-PSS showed that electric conductivity values ranged from 6.12 × 10–8 to 7.11 × 10–7 S.cm−1, and 5.48 × 10–10 to 7.75 × 10–8 S.cm−1, respectively. It has a great deal of interest of PAIFPA-co-PSS which has wide band gap energy as short-wavelength light absorbers to be used in tandem polymer solar cells.

Synergistic sorption performance of karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ metal nanoparticle for organic pollutants

In this work, we tailor facile hydrogels nanocomposite (HNC) based on sustainable karaya gum for water treatment. Karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ silver nanoparticle (KG-cl-P(AAm-co-AN)@AgNPs) HNC were made by an aqueous free radical in situ crosslink copolymerization of acrylamide (AAm) and acrylic acid (AA) in aqueous solution of KG-stabilized AgNPs. FTIR, XRD, DTA-TGA, SEM, and TEM were used to characterize HNC. The hydrogels' swelling, diffusion, and network characteristics were investigated. The removal efficiency of HNC was found to be 99% at pH 8 for a crystal violet (CV), dose of 0.02 g after 1 h. Dye adsorption by these hydrogels was also investigated in terms of isotherms, and kinetics. The dye's exceptionally high adsorption capacity on HNC for CV removal is explained by H-bonding interactions, as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules (Qmax, 1000 mg/g). The HNC can be regenerated with 0.1 M HCl and reused at least 10 times maintaining over 68% dye removal. The loading of AgNPs into the polymeric matrix of KG-cl-P(AAm-co-AN) significantly increases the removal percentage of CV dye from its aqueous solution, according to this study.

A biodegradable film based on cellulose and thiazolidine bearing UV shielding property

The current rationale is exploring new eco-friendly UV- shielding films based on cellulose and thiazolidine. Cellulose was oxidized to dialdehyde cellulose (DAC) and tricarboxy cellulose (TCC) by periodate and TEMPO/periodate/hypochlorite, respectively. While E-3-amino-5-(phenyldiazenyl)-2-thioxothiazolidin-4-one (TH) was synthesized by coupling diazonium salt with the 5-methylene of 2-thioxo-4-thiazolidinone. DAC was then coupled with TH via Schiff base reaction and incorporated onto TCC with different ratios to get UV-shielding films. ¹HNMR, infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA) were used to investigate the chemical structure of the synthesized materials. In addition, the films' morphology, thermal, mechanical, and UV-shielding properties were investigated. The UV-shielding studies revealed that the film with 10% DAC-TH has 99.88, 99.99, and 96.19% UV-blocking (UVB), UV-absorbance (UVA), and Ultra-violet protection (UPF), respectively. Moreover, the prepared films demonstrated promising antimicrobial activity against Escherichia coli, S. aureus, P. aeruginosa, and Candida albicans. Finally, the prepared films showed no cytotoxic effects on normal human skin fibroblast's HFB-4 cell line.