Synthesis, characterization of Ag doped CdS-WO2 nanocomposite and effects of photocatalytic degradation in RhB under visible light irradiation

In this paper, the highly stable Ag/CdS-WO2 nanocomposite was fabricated by a facile and capping agent-free hydrothermal technique. The fabricated Ag-doped CdS-WO2 nanocomposite was characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and UV-vis diffuse reflectance (DRS) spectroscopy. The photocatalytic performance of synthesized photocatalysts was evaluated for the photodegradation of rhodamine B (RhB) under visible light irradiation (VLI). The parameters used for the optimization of the photocatalyst were pH, catalyst dose, oxidant dose, and irradiation time. Based on this, a possible reaction mechanism for the enhancement of the photocatalytic activity of Ag/CdS-WO2 has been proposed. Hence, we have a tendency to believe it might be a promising material that may be used for the photodegradation of organic pollutants present in wastewater

Kinetic and equilibrium studies for cadmium biosorption from contaminated water using Cassia fistula biomass

Cadmium (Cd) contamination of the water resources is one of the serious environmental issues. The present study aims to (1) evaluate the biosorption potential of Cassia fistula biomass for the removal of Cd from contaminated water and validate the experimental results with kinetic and equilibrium sorption models, (2) assess the removal of Cd from groundwater samples in the presence of other competing ions in the solution. The C. fistula biomass was characterized using Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller technique and scanning electron microscopy to understand the role of its physical properties in Cd biosorption and removal. The effects of biosorbent dose, initial Cd concentrations, contact time and presence of competing cations in groundwater samples at constant pH and temperature (27 ± 1.5 °C) were studied. At equilibrium (90 min), Cd removal (98–16%) and biosorption (6.26–0.34 mg/g) were recorded depending on the experimental conditions. The Langmuir model yielded a better approximation of the experimental data at equilibrium (Formula presented.) rather than Freundlich model. The pseudo-second-order kinetic model explained well the kinetic behavior of Cd biosorption. Results revealed a decline in the Cd removal (12.7 and 6% at 0.25 and 1.0 g/100 mL, respectively) in the presence of cations in the water samples. The results proved that C. fistula is a very effective and environment friendly alternative adsorbent for the removal (98%) of Cd from the aqueous system