Comparative study of synthesis of cellulose propionate from different sources using NIS as a new catalyst

Fabrication of cellulose acetate/cellulose nitrate/carbon black nanofiber composite for oil spill treatment

There are global challenges in addressing the oil spill treatment. Nanofiber has become a great potential in the oil spill cleaning process because of the environmental friendliness, high efficiency, low cost, and stability of the obtained nanofiber mats. This study presents a novel composite fabricated from cellulose acetate (CA) and cellulose nitrate (CN) nanofibers with the incorporation of carbon black (CA-CN/CB) for efficient oil removal. This nanofiber composite was fabricated in one-step electrospinning of 10% CA and CN solution with different concentrations of carbon black (CB). The morphology and fiber diameter of the CA-CN/CB nanofiber composite were analyzed using scanning electron microscopy (SEM), and they appeared to be smooth, uniform fibers without beads. The average fiber diameter was in nano-meter size and increased with the increasing CB amount in the composite, ranging from 327 to 755 nm. The FTIR results indicated the presence of CA and CN as characteristic peaks of C = O for CA and O-NO2 for CN. The nanofibers mats of the CA-CN, CA-CN/CB0.7, CA-CN/CB1.5, and CA-CN/CB2.2 composites had Brunauer–Emmett–Teller (BET) surface area of 15.29, 38.40, 4.08, and 6.17 m2 g−1, respectively. Under optimal conditions, CA-CN/CB nanofiber mats absorb more than their weight oil in just 30 min. The adsorption result showed that loading 1.5% of CB to CA-CN mats (CA-CN/CB1.5) was more favorable for oil adsorption. The CA-CN/CB1.5 nanofiber showed its reusability for oil adsorption. The Freundlich isotherm model was the most appropriate model among other isotherm models, including Langmuir and Temkin, with a value of correlation coefficient (R2) equal to or closer to unity, and this result was confirmed by the data obtained from studying different error function models. The adsorption kinetics showed that oil adsorption into CA-CN/CB1.5 nanofiber follows a pseudo-second-order kinetics model with R2 close to unity.

Biodegradable plastic formulated from chitosan of Aristeus antennatus shells with castor oil as a plasticizer agent and starch as a filling substrate

Biodegradable plastics are those subjected easily to a degradation process, in which they can be decomposed after disposal in the environment through microbial activity. 30 bioplastic film formulations based only on chitosan film were used in the current investigation as a positive control together with chitosan film recovered from chitin-waste of locally obtained Aristeus antennatus. Additionally, castor oil was used as a plasticizer. While the yield of chitosan was 18% with 7.65% moisture content and 32.27% ash in the shells, the isolated chitin had a degree of deacetylation (DD) of 86%. The synthesized bioplastic films were characterized via numerous criteria. Firstly, the swelling capacity of these biofilms recorded relatively high percentages compared to polypropylene as synthetic plastic. Noticeably, the FTIR profiles, besides DSC, TGA, and XRD, confirmed the acceptable characteristics of these biofilms. In addition, their SEM illustrated the homogeneity and continuity with a few straps of the chitosan film and showed the homogeneous mixes of chitosan and castor oil with 5 and 20%. Moreover, data detected the antibacterial activity of different bioplastic formulas against some common bacterial pathogens (Enterococcus feacalis, Kelbsiella pnumina, Bacillus subtilis, and Pseudomonas aeruginosa). Amazingly, our bioplastic films have conducted potent antimicrobial activities. So, they may be promising in such a direction. Further, the biodegradability efficacy of bioplastic films formed was proved in numerous environments for several weeks of incubation. However, all bioplastic films decreased in their weights and changed in their colors, while polypropylene, was very constant all the time. The current findings suggest that our biofilms may be promising for many applications, especially in the field of food package protecting the food, and preventing microbial contamination, consequently, it may help in extending the shelf life of products.

Electrospun cellulose acetate/activated carbon composite modified by EDTA (rC/AC-EDTA) for efficient methylene blue dye removal

The present study fabricated regenerated cellulose nanofiber incorporated with activated carbon and functionalized rC/AC3.7 with EDTA reagent for methylene blue (MB) dye removal. The rC/AC3.7 was fabricated by electrospinning cellulose acetate (CA) with activated carbon (AC) solution followed by deacetylation. FT-IR spectroscopy was applied to prove the chemical structures. In contrast, BET, SEM, TGA and DSC analyses were applied to study the fiber diameter and structure morphology, the thermal properties and the surface properties of rC/AC3.7-EDTA. The CA was successfully deacetylated to give regenerated cellulose nanofiber/activated carbon, and then ethylenediaminetetraacetic acid dianhydride was used to functionalize the fabricated nanofiber composite. The rC/AC3.7-EDTA, rC/AC5.5-EDTA and rC/AC6.7-EDTA were tested for adsorption of MB dye with maximum removal percentages reaching 97.48, 90.44 and 94.17%, respectively. The best circumstances for batch absorption experiments of MB dye on rC/AC3.7-EDTA were pH 7, an adsorbent dose of 2 g/L, and a starting MB dye concentration of 20 mg/L for 180 min of contact time, with a maximum removal percentage of 99.14%. The best-fit isotherm models are Temkin and Hasely. The outcome of isotherm models illustrates the applicability of the Langmuir isotherm model (LIM). The maximal monolayer capacity Q_m determined from the linear LIM is 60.61 for 0.5 g/L of rC/AC3.7-EDTA. However, based on the results from error function studies, the generalized isotherm model has the lowest accuracy. The data obtained by the kinetic models' studies exposed that the absorption system follows the pseudo-second-order kinetic model (PSOM) throughout the absorption period.

Electrospun composites nanofibers from cellulose acetate/carbon black as efficient adsorbents for heavy and light machine oil from aquatic environment

The feasibility of preparing cellulose acetate/carbon black (CA/CB) composite nanofiber in one step through electrospinning process and investigating its potential oil absorbability and application for machine oil removal from aquatic environment was reported. Different CA/CB composite nanofibers were fabricated by electrospinning of cellulose acetate (CA) solution containing different loads of 0.7, 1.5, and 2.2% CB relative to the weight of CA and labeled as CA/CB0.7, CA/CB1.5, and CA/CB2.2. The scanning electron microscope (SEM) images showed continuous and smooth fiber with submicron diameter ranging from 400–900 nm with good adhering of CB into CA nanofiber. Furthermore, the CA/CB composite nanofibers exhibited high surface area compared with CA nanofiber, which reached 3.057, 2.8718 and 8.244 m2/g for CA/CB0.7, CA/CB1.5 and CA/CB2.2, respectively. Oil adsorption tests were performed with heavy and light machine oils. The CA/CB composite nanofibers showed higher affinity for oil removal from an aqueous solution than pure CA nanofiber. The CA/CB1.5 composite nanofiber has an exceptional performance for the adsorption of both oils, and the maximum oil adsorbed reached 10.6 and 18.3 g/g for light and heavy machine oils, respectively. The kinetic of machine oils adsorption was fitted well by the pseudo-second-order model. Besides, CA/CB composite nanofiber exposed good adsorption properties and respectable reusability after regeneration for four consecutive cycles. The results advocate the excellent potential of as-fabricated CA/CB composite nanofiber as a promising reusable oil adsorbent for oil spill cleanup applications.

Ferric perchlorate hydrate as a new catalyst for highly efficient esterification of cellulose at room temperature

Ferric perchlorate was tested for the first time as a new catalyst to accelerate the esterification of microcrystalline cellulose (MCC) at room temperature in a less amount of acetic anhydride compared to the amount used in the conventional methods. It was possible to manufacture cellulose acetate (CA) with a high yield of up to 94%. The influence of changes in reaction time, catalyst amounts, and acetic anhydride on the characterization of cellulose acetate produced was investigated. The optimum condition for esterification of 2.0 g (12.34 mmol) MCC was found to be: 10 mL (105.98 mmol) AC₂O, 200 mg (0.564 mmol, anhydrous basis) of Fe(ClO₄)₃·xH₂O and 1 h reaction time at room temperature. The substitution degree of CA was investigated by FTIR and ¹H-NMR spectroscopy. Thermal stability of CA was studied using TGA, DTA and DSC analyses. The degree of polymerization and the polydispersity index (PDI) were obtained using Gel permeation chromatography (GPC). This study verified the direct and efficient synthesis of di- and tri-cellulose acetate in one-pot reaction using Fe(ClO₄)₃·xH₂O as a catalyst without using solvent.