Biogenic synthesis from <Emphasis Type="Italic">Prunus</Emphasis> × <Emphasis Type="Italic">yedoensis</Emphasis> leaf extract,characterization, and photocatalytic and antibacterial activity of TiO<Subscript>2</Subscript> nanoparticles

Green synthesis of TiO₂ nanoparticles (NPs) from Prunus × yedoensis leaf extract (PYLE), and their application for removal of phosphate and their antibacterial activity, were studied for the first time. NPs were obtained using a green chemistry approach from 0.1 M TiO₂ and PYLE at ratio of 1:1 (v/w). Initial confirmation of production of TiO₂ NPs was provided by a color change from white to light yellow, then calcination was performed at 500 °C for 1 h. The TiO₂ NPs were characterized using various analytical techniques such as ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The results indicated that the optimal amount of TiO₂ NPs for removal of phosphate was 10 mg/l (10 ppm) with duration of 25 min. Furthermore, the antibacterial activity of TiO₂ NPs was also investigated using two different bacteria (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli) in aqueous medium. The results revealed highly efficient sunlight-driven photocatalytic and antibacterial activity of TiO₂ NPs.     

Synthesis, characterization and application of cellulose/polyaniline nanocomposite for the treatment of simulated textile effluent

The aim of the study was to analyze the potential application of cellulose/polyaniline (Ce/Pn) nanocomposite for the treatment of synthetic reactive dye bath effluent. The Ce/Pn composite was synthesized by chemical oxidative polymerization of aniline. A central composite experimental design, a most popular design of response surface methodology, was applied to optimize the level of variables, namely, cellulose and polyaniline, to get the best response on dye removal. Biological transmission electron microscopy studies reveal that the cellulose particles were uniformly distributed on the nanocomposite. The results of the batch experiment studies indicate that Ce/Pn nanocomposite removed 95.9, 91.9, 92.7, and 95.7 % of RBBR, RO, RV, and RBK, respectively, and it decolorized 82 % of dye bath effluent. However, the presence of the salts reduced the adsorption rate of the dyes. The Langmuir model and pseudo first-order rate expression exhibited satisfactory fit to adsorption data of single component.     

Application of polyaniline/bacterial extracellular polysaccharide nanocomposite for removal and detoxification of Cr(VI)

Polyaniline/bacterial extracellular polysaccharide (Pn/EPS) nanocomposite was prepared by in situ polymerization of aniline using ammonium peroxydisulfate as oxidant. Transmission electron micrograph showed that the surface of the nanocomposite was rough, providing good possibility for adsorption of Cr(VI). Under optimized conditions, the nanocomposite removed 97.3 % (25 mg L^?1) of Cr(VI) from aqueous solution. The Freundlich isotherm model and pseudo-first order rate expression better described the adsorption equilibrium of Pn/EPS nanocomposite. X-ray diffractogram peak for Cr₂O₃ (2θ = 24.5) in the nanocomposite confirmed the reduction of Cr(VI). Fourier transform infrared spectroscopy pattern of the nanocomposite confirmed the ionic interaction between Cr species and surface functional groups. The results of the study indicate that Pn/EPS nanocomposite could be used for the removal and detoxification of Cr(VI) from aqueous solution.     

Efficiency of various semiconductor catalysts for photodegradation of Safranin-T

Semiconductor photocatalysis often leads to partial or complete mineralization of organic pollutants. In this study, photocatalytic degradation of Safranin-T, a hazardous textile dye, has been investigated using various semiconductors such as titanium dioxide (TiO₂), zinc oxide (ZnO), bismuth oxide (Bi₂O₃), cerium oxide (CeO₂), yttrium oxide (Y₂O₃), and zirconium oxide (ZrO₂). The experiments were carried out by irradiating the aqueous solution of Safranin-T containing photocatalysts with UV and air. Maximum decolorization of Safranin-T occurred with TiO₂ (99.8%), followed by ZnO (80.3%), Bi₂O₃ (57.1%), CeO₂ (13.1%), Y₂O₃ (12.2%), and ZrO₂ (10.2%). The rate of photocatalytic degradation varied with increasing concentration of Safranin-T. The equilibrium degradation data of Safranin-T by TiO₂ and ZnO were fitted to the Langmuir and Freundlich isotherm models. The Freundlich and Langmuir model showed satisfactory fit to the equilibrium degradation data for TiO₂ and ZnO, respectively. Photocatalytic degradation of Safranin-T followed pseudo second-order kinetics.     

Bio-functionalization of cotton,silk, and leather using different in-situ silver nanoparticle synthesis modules,and their antibacterial properties

Research on Chemical Intermediates - We present a novel and in-situ strategy to synthesize silver nanoparticles (AgNPs) onto cotton, leather, and silk fabrics by three different methods: a green...