Sunlight-Induced Photocatalytic Degradation of Methyl Red Using Lignocellulosic Biomass of Ricinus communis Stem with Isotherm and Kinetic Modeling

Nowadays, Water pollution is a major global issue brought on by the mixing of effluents from various industries, such as leather, paper, printing, cosmetics, Textile etc., containing metal ions and dyes. This impact causes severe damage to the health of humans, aquatic plants and animals. In view of removing the dyes from the wastewater, several techniques available pose certain drawbacks. To combat such issues, a rapid, cost-effective, eco-friendly, and sludge-less method for removing dye from the effluent using activated Ricinus communis stem as a catalyst in the solar irradiation method is discussed and reported with results. The adsorption studies carried out, followed by degradation of methyl red onto Si-RCS, shows 86% in the presence of natural sunlight, and the optimum dye concentration was 20 ppm at 0.25 g photocatalyst dosage. It depicts that the prepared adsorbent material, Si-RCS, can be used as an effective adsorbent as well as a photo-catalyst to treat textile effluents. The best fit model was found to be pseudo-second order based on the R2 value. Among the isotherm models studied, it was found that Langmuir is the best fit model.