Insight into the catalytic performances of Fe0@chitosan/cellulose green hybrid structure for enhanced photo-Fenton's oxidation of levofloxacin toxic residuals: Pathway and toxicity.

A green hybridized structure of Fe0 painted chitosan/cellulose base (Fe0@CS/CF) has been developed using cellulose extracted from sugarcane bagasse along with reduction agents sourced from Khaya senegalensis leaves. The composite was assessed as an affordable, powerful, and multifunctional catalyst for enhancing the degradation of Levofloxacin (LVX) remnants within water supplies via photo-Fenton's interactions. Using a dosage of 0.5 g/L, the Fe0@CS/CF blend demonstrated noteworthy catalytic qualities, resulting in the complete photo-Fenton's degradation of LVX at a level of 25 mg/L after 40 min. However, the complete diminution of organic carbon (TOC) occurred only after 100 min, suggesting the presence of significant intermediate residues. The identified intermediate chemicals and confirmed hydroxyl radicals as the main oxidizer suggest that the degradation pathway involves carboxylation/decarboxylation, hydroxylation, demethylation, and oxidation of quinolone rings. The toxicity properties of untreated LVX solutions and their subsequent oxidized byproducts were assessed by evaluating their inhibiting impact on Vibrio fischeri over various durations. The samples that experienced partial oxidation at initial testing demonstrated a higher level of toxicity in comparison to the parent LVX. However, the sample that was treated for 100 min demonstrated substantial biological safety and a non-toxic nature. The blend of ingredients has a synergistic impact that enhances the uptake, Fenton's, photocatalytic, and photo-Fenton's characteristics of the hosted Fe0 nanoparticles.

Transforming bio-waste lignin into amine functionalized carbon quantum dots for selective detection of trace Cu2+ in aqueous system.

Developing carbon quantum dots (CQDs) from bio-waste lignin for effectively detecting Cu2+ is of great significance for promoting the value-added utilization of lignin resources. However, the limited amount of surface-active groups and low quantum yield of lignin-based CQDs hinder their application in this regard. Herein, bio-waste lignin was converted into value-added amine functionalized CQDs using a facile two-step hydrothermal approach. The as-synthesized CQDs modified with amino groups exhibit bright green fluorescence, abundant surface functional groups, high water solubility and uniform particle size (3.9 nm). Systematic analysis demonstrates that the rich NH2 groups (~12.3 %) on the CQDs backbone improve their fluorescence properties (quantum yield increased from 3.4 % to 21.1 %) and specific detection ability for Cu2+. The developed NH2-CQDs serve as an efficient fluorescent probe, displaying high sensitivity and selectivity towards Cu2+ in aqueous system, with a detection limit of 2.42 µmol/L, which is lower than the maximum permitted amount of Cu2+ in drinking water (20 µmol/L). The detection mechanism of NH2-CQDs for Cu2+ is attributed to the synergy of static quenching and photo-induced electron transfer. This study provides a valuable reference for the synthesis of high-quality fluorescent CQDs from lignin resources and the effective detection of trace Cu2+ in aquatic environments.

Cellulose-based CoFe LDH composite as a nano-adsorbent for sulfamethoxazole and cefixime residues: Evaluation of performance, green metrics and cytotoxicity.

The increase in antibiotic residues poses a serious threat to ecological and aquatic environments, necessitating the development of cost-effective, convenient, and recyclable adsorbents. In our study, we used cellulose-based layered double hydroxide (LDH) as an efficient adsorbent and nanocarrier for both sulfamethoxazole (SMX) and cefixime (CFX) residues due to their biodegradability and biocompatibility. Chemical processes are measured according to green chemistry metrics to identify which features adhere to the principles. A GREEnness Assessment (ESA), Analytical GREEnness Preparation (AGREEprep), and Analytical Eco-Scale Assessments (ESA) were used to assess the suitability of the proposed analytical method. We extensively analyzed the synthesized CoFe LDH/cellulose before and after the adsorption processes using XRD, FTIR, and SEM. We investigated the factors affecting the adsorption process, such as pH, adsorbent dose, concentrations of SMX and CFX and time. We studied six nonlinear adsorption isotherm models at pH 5 using CoFe LDH, which showed maximum adsorption capacities (qmax) of 272.13 mg/g for SMX and 208.00 mg/g for CFX. Kinetic studies were also conducted. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was performed on Vero cells in direct contact with LDH nanocomposites to evaluate the cytotoxicity and side effects of cellulose-based CoFe LDH. The cellulose-based CoFe LDH nanocomposite demonstrated excellent cytocompatibility and less cytotoxic effects on the tested cell line. These results validate the potential use of these unique LDH-based cellulose cytocompatible biomaterials for water treatment applications. The cost of the prepared adsorbents was investigated.