Cellulose powder functionalized with phenyl biguanide: Synthesis, cross-linking, metal adsorption, and molecular docking

A cellulose polymer functionalized with an amine chelating agent was designed and synthesized in a three-step process that involved oxidizing cellulose powder into dialdehyde cellulose, reacting cellulose dialdehyde with phenyl biguanide to create an imine linkage between the two reactants, and reducing the imine linkage to an amine. The cellulose amine polymer was cross-linked with glycerol digycidyl ether and evaluated as an adsorbent of toxic metal ions from wastewater. The adsorption efficiency of the cross-linked cellulose amine polymer toward Pb(II) and Cu(II) was evaluated as a function of the adsorbent dose, pH, time, temperature, and initial ion concentration. The cross-linked cellulose amine polymer showed an excellent efficiency toward over 15 metal ions present in a real sample of sewage. Thermodynamic analysis showed a spontaneous adsorption of metal ions on the polymer at room temperature. Monte Carlo and Molecular Dynamic simulations showed that the Cu(II) and Pb(II) ions adsorbed onto the cellulose amine polymer surface in a considerable amount, which agreed with the experimental and thermodynamic data. The negative free energy value confirmed the spontaneity of the adsorption process. As such, cross-linked cellulose amine polymers could be a promising alternative to current commercial adsorbents.

Sorption and desorption experiments using stable cesium: considerations for radiocesium retention by fresh plant residues in Fukushima forest soils

We conducted sorption experiments with stable cesium (133Cs) solution in different organic matter samples, aiming to understand the sorption of radiocesium (134Cs and 137Cs) in the initial throughfall by fresh plant residues (e.g., needles, wood, and bark from Japanese cedar trees) in the Oi horizon in forests in Fukushima. Among the organic matter samples, bark and wattle tannin sorbed relatively large amounts of Cs, whereas wood and cellulose powder sorbed small amounts. In contrast, samples containing clay minerals showed much higher Cs sorption. We also conducted desorption experiments, and suggested that Cs on the organic matter samples were relatively mobile.

Effect of Monochloroacetic Acid on Properties of Carboxymethyl Bacterial Cellulose Powder and Film from Nata de Coco

Nata de coco has been used as a raw material for food preparation. In this study, the production of carboxymethyl cellulose (CMC) film from nata de coco and the effect of monochloroacetic acid on carboxymethyl bacterial cellulose (CMCn) and its film were investigated. Bacterial cellulose from nata de coco was modified into CMC form via carboxymethylation using various concentrations of monochloroacetic acid (MCA) at 6, 12, 18, and 24 g per 15 g of cellulose. The results showed that different concentrations of MCA affected the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, and morphology of CMCn. The optimum treatment for carboxymethylation was found using 24 g of MCA per 15 g of cellulose, which provided the highest DS at 0.83. The morphology of CMCn was related to DS value; a higher DS value showed denser and smoother surface than nata de coco cellulose. The various MCA concentrations increased the mechanical properties (tensile strength and percentage of elongation at break) and water vapor permeability of CMCn, which were related to the DS value.

Carboxymethyl Bacterial Cellulose from Nata de Coco: Effects of NaOH

Bacterial cellulose from nata de coco was prepared from the fermentation of coconut juice with Acetobacter xylinum for 10 days at room temperature under sterile conditions. Carboxymethyl cellulose (CMC) was transformed from the bacterial cellulose from the nata de coco by carboxymethylation using different concentrations of sodium hydroxide (NaOH) and monochloroacetic acid (MCA) in an isopropyl (IPA) medium. The effects of various NaOH concentrations on the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, morphology and the thermal properties of carboxymethyl bacterial cellulose powder from nata de coco (CMCn) were evaluated. In the carboxymethylation process, the optimal condition resulted from NaOH amount of 30 g/100 mL, as this provided the highest DS value (0.92). The crystallinity of CMCn declined after synthesis but seemed to be the same in each condition. The mechanical properties (tensile strength and percentage of elongation at break), water vapor permeability (WVP) and morphology of CMCn films obtained from CMCn synthesis using different NaOH concentrations were investigated. The tensile strength of CMCn film synthesized with a NaOH concentration of 30 g/100 mL increased, however it declined when the amount of NaOH concentration was too high. This result correlated with the DS value. The highest percent elongation at break was obtained from CMCn films synthesized with 50 g/100 mL NaOH, whereas the elongation at break decreased when NaOH concentration increased to 60 g/100 mL.

Effects of ingredient proportions on the performance of α-Cellulose/PLA mixtures used for laser sintering

A new powder feedstock composed of biocompatible and degradable biomass materials was introduced and evaluated for laser sintering in this research. The goal for the material is to facilitate high-value utilization of sustainable materials and expand the variety of feedstock that can be used for laser sintering. It was mechanically mixed with polylactic acid (PLA) powder and the filler of α-cellulose powder in the content of 5 wt%, 10 wt%, 15 wt%, and 20 wt%. The effects of the ingredient proportions were evaluated relative to laser sintering performance of α-cellulose/PLA mixtures. The results revealed that the increasing cellulose loading had almost no influence on the mixtures’ glass transition temperature, the melt temperature, and the crystallization temperature; thus, the mixtures would share the same processing parameters with neat PLA during the laser sintering fabrication. Although the cellulose loading reduced the materials’ melt fluidity and mechanical properties, it decreased the dimensional deformation of the laser-sintered parts and made the mixture more feasible as the feedstock of laser sintering compared to neat PLA.