KAVIYA MANIKANDAN, MATHUMATHI K., HARENI R., JAI PRIYA R., DESJASVANTH S.C. AND PRATAP KUMAR G.
Abstract
Azo dyes are extensively used in the textile, leather, and food industries, resulting in the discharge of large volumes of colored wastewater that pose significant environmental and health risks due to their toxicity and recalcitrant nature. These findings investigate the biodegradation of azo dyes using chitosan gel as a sustainable and eco-friendly biosorbent. Chitosan, derived from natural biopolymers, was prepared in gel form to enhance its adsorption and catalytic capabilities. The dye removal efficiency was evaluated under different environmental conditions, and the photocatalytic activity of the chitosan gel was assessed under UV irradiation. Treated and untreated dye solutions were subjected to phyto-toxicity analysis using plant bioassays to determine the ecological impact of the degradation products. Chitosan gel exhibited effective dye removal, with a degradation efficiency of 66.71%. The photocatalytic activity was evaluated under UV light, and the absorbance spectrum was recorded using a UV-Visible spectrophotometer (Labtronics LT 291) across a wavelength range of 200â800 nm. Functional group analysis was performed using FTIR spectroscopy (Shimadzu, 4000â400 cm{¹), confirming the presence of key degradation compounds. Biochemical characterization included protein estimation for green gram and fenugreek (0.55 and 0.44 via the Lowry method at 660 nm), carbohydrate estimation for green gram and fenugreek (0.53 and 0.35 via the anthrone method at 620 nm), and chlorophyll content for Vigna radiata is 0.536 (absorbance at 663 nm) To validate the environmental remediation and safety of the degradation products, the phytotoxicity tests are indicated by reducing the toxicity of the treated dye solution. It provides an understanding of the safe disposal of industrial effluent and the development of green technologies, and supports the potential of chitosan gel in eco-friendly wastewater treatment applications.