Z-type CuS/ZnS@PVP nanofibers are synthesized for the photocatalytic reduction of 4-nitrophenol and for mixed-dyes degradation under mild conditions.

No abstract

In this study, CuO–TiO2 nanofiber catalysts were fabricated by an electrospinning process, followed by thermal annealing at various temperatures ranging from 300 to 700 °C. The phase transformation from CuO to metallic Cu was carried out through immersion treatment in NaBH4 solution. The resulting CuO–TiO2 and Cu–CuO–TiO2 nanofibrous mats were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. The results revealed that the crystalline phase composition of the nanofibrous mats considerably affected the efficiency of photocatalytic reduction, where the CuO–TiO2 catalysts with a predominant anatase content was found to be more photoactive than the rutile phase. Similarly, the presence of both Cu and CuO species was more beneficial for promoting the activity of fibers by acting as an interim location for facilitating the electron transfer. The fabricated Cu–CuO–TiO2 nanofibrous mat with a ratio presented high conversion (∼99%) within several minutes with the apparent pseudo-first-order rate constant of 0.42 and 0.50 min–1 in the absence and presence of UV light irradiation as well as excellent stability in recycling runs with a stable conversion efficiency of 97% or higher over five successive catalytic cycles.

The production of Ethanol has been utilized through the process of cellulose isolation from agricultural waste such as corn husk, rice straw and rice husk. Isolation of cellulose with pretreatment delignification using, NaOH 2% to produces cellulose of corn husk 16,6921 g (22,25%), rice straw 16,9021 g (22,53%) and rice husk 16,3691 g (21,85%) then analyzed the functional groups using FT-IR and SEM analysis. Cellulose as much as 2 g is hydrolyzed using HCl 30% and cellulase enzymes to obtain sugar that is qualitatively tested with Benedict and Tollens reagent and quantitatively tested with Luff Schoorl method and produces highest sugar content of rice husk 8,64% and 10,95%. The next stage sugar of hydrolysis will be fermented using  yeast (Saccharomyces cerevisiae) with 6 days, and then distilled at a temperature of 78-80oC. Ethanol was calculated by the potassium dichromate oxidation method to gave highest result from agricultral waste of ethanol chemical 5,97% and enzymatic 6,89% is rice husk.

This study uses raw materials containing lignocellulose, namely empty fruit bunches of oil palm. Oil palm empty fruit bunches were isolated to produce cellulose, hydrolyzed into simple sugars, fermented, and distilled. From the isolation of cellulose obtained α-cellulose of 19.9612 grams (26.6149%). Then it was hydrolyzed using HCl with a concentration variation of 15%; 20%; 25%; 30%; and enzymatically hydrolyzed using cellulase to produce simple sugars which were tested qualitatively with Benedict's reagent and Tollens reagent, then quantitatively tested by the Luff Schroll method. The higher the concentration of acid used, the higher the sugar will be. The best bioethanol obtained from acid hydrolysis is using 30% HCl with ethanol content of 6.54% and enzymatic 7.32%.