Powdered silk: A promising biopolymer for the treatment of dye contaminated water.

Discharge of textile dye effluents into water bodies is creating stress to aquatic life and contaminating water resources. In this study, a new biopolymer adsorbent silk fibroin (SF) was prepared from Bombyx mori silk fibroin (SF) and used for removal of Solochrome Black-T (SB-T) from water. This innovative adsorbent exhibits an exceptional adsorption capacity of 20.08 mg/g, achieving a removal efficiency of approximately 98.6 % within 60 min. Notably, the powdered SF adsorbent demonstrates rapid kinetics, surpassing the performance of previously reported similar adsorbents in adsorption capacity and reaction speed. The molecular weight and particle diameter of the material were observed to be > 1.243 kDa and 3 µm, respectively. The experimental investigations were performed on different parameters, viz., adsorbent dosage, contact time, repeatability, and desorption-adsorption study. The experimental data well fit for the Langmuir model (R2 = 0.937, qmax = 20.08 mg/g) and the pseudo-second-order kinetics (R2 = 0.921 and qe = 1.496 mg/g). Compared to the adsorbents reported in the literature, the newly prepared SF showed high adsorption capacity and faster kinetics to address real-life situations. The novelty of this work extends beyond its remarkable adsorption capabilities. The SF adsorbent offers a cost-effective, sustainable solution and regenerable adsorption material with minimal negative environmental impacts. This regenerability, with its versatility and broad applicability, positions powdered SF fibroin as a transformative technology in water treatment and environmental protection.

Arsenite removal from drinking water by bark-based magnetic iron oxide particle (BMIOP): a column study.

The removal of arsenite [As(III)] from drinking water was investigated in a column at flow rates of 2.0 and 5.0 mL/min (up-flow direction) using bark-based magnetic iron oxide particles (BMIOP) prepared by coating (Fe(NO3)3.9H2O) over Tamarindus Indica bark. The BMIOP was compared with regenerated BMIOP, commercial activated carbon, commercial activated alumina (Al2O3). At 2.0 mL/min, empty bed contact time (EBCT), breakthrough time (BT), the volume of treated water and breakthrough capacity (BC) on fresh BMIOP were found to be 6.8 min, 33.15 h, 4.380 L and 0.742 mg/g, respectively, and at 5.0 mL/min, were found to be 4.1 min, 13 h, 3.675 L and 0.453 mg/g respectively. EBCT, BT and BC were increased by 65.85%, 155% and 63.79%, respectively, as the flow rate was reduced from 5.0 to 2.0 mL/min. After regeneration of BMIOP, EBCT, BT, saturated time, BC and saturation capacity (SC) were reduced by 21.95%, 15.38%, 55.15%, 16.78% and 29.71%, respectively. The BC of fresh BMIOP was increased by factors 4.15, 3.60 and 1.20 and SC by factors 9.51, 7.88 and 1.42 compared to commercial activated carbon, commercial activated Al2O3 and regenerated BMIOP, respectively. Logit model could be used for the design of the adsorption column. Thomas model and artificial neural network (ANN) were applied to predict the characteristic column parameters useful for process design. Quality of treated water meets BIS requirements. Toxicity Characteristic Leaching Procedure (TCLP) and semi-dynamic tests show that the exhausted BMIOP is safe for disposal in a secure landfill; hence, BMIOP has been proved to separate As(III) from water.

Synthesis of Ni2P/CdS and Pt/TiO2 nanocomposite for photoreduction of CO2 into methanol.

It is a great challenge to convert thermochemically stable CO2 into value-added products such as CH4, CH3OH, CO via utilizing solar energy. It is also a difficult task to develop an efficient catalyst for the reduction of CO2. We have designed and synthesized noble metal-free photocatalytic nanostructure Ni2P/CdS and Pt/TiO2 for conversion of CO2 to methanol in the presence of sacrificial donor triethylamine (TEA) and hydrogen peroxide. The synthesised catalysts physicochemical properties were studied by using several spectroscopic techniques like; XRD, UV-DRS, XPS, TEM, SEM and PL. Quantification of methanol by GC-MS showed encouraging results of 1424.8 and 2843 µmol g-1 of catalyst for Pt/TiO2 and 5 wt% Ni2P/CdS composites, respectively. Thus, Ni2P/CdS is a promising catalyst with higher productivity and significant selectivity than in-vogue catalysts.