Synthesis and characterization of paddy straw chitosan nanocomposite as an efficient photocatalytic bio-adsorbent for the removal of rhodamine B and malachite green dye from aqueous solution

Current study deals with an agriculture waste paddy straw (PS) incorporated with chitosan (CS) to prepare photocatalytic paddy straw chitosan nanocomposite (PS-CSNC) with cross-linking agent sodium tripolyphosphate was investigated and catalysis-based photocatalytic adsorptions of Rhodamine B (RhB) and Malachite green (MG) in aqueous solution under UV irradiation were also examined. Moreover, this study examined that the factors influence the adsorption process, such as catalyst concentration, pH and temperature, using kinetic models. Additionally, the composite characterization was achieved by several analysis, such as UV–visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetry/differential thermal analysis and field effect scanning electron microscopy. The study shown that the optimized concentration of PS-CSNC catalyst (3.0 g L−1), below neutral pH (6.5) of the solution and temperature 60 °C achieved excellent removal of both dyes. Initial sorption process involved the removal mechanism of both RhB and MG followed by photocatalytic adsorption. The process of adsorption was well adapted with pseudo second-order kinetics. Overall results suggested that chitosan-based agriculture waste paddy straw nanocomposite could be an eco-friendly and cost-effective bio-adsorbent for removal of RhB and MG in wastewater treatment.