Synthesis of potent chitosan beads a suitable alternative for textile dye reduction in sunlight

Photocatalytic degradation is an effective method for toxic dye decontamination of domestic wastewater and industrial effluents. For this purpose, copper sulphide nanoparticles-chitosan beads (CuS-CB) were synthesized. The synthesis of beads were confirmed using FTIR spectroscopy. The size of CuS nanoparticles were 60 nm analysed using XRD technique. The EDX technique confirms presence of CuS nanoparticles in chitosan beads (CB). SEM images showed smooth surface morphology with average bead size of 735 µm. The band gap energy of the catalyst was calculated in the visible region using Tauc relation and found to be 2.1 eV. The CuS-CB was applied for photodegradation of malachite green (MG) dye. The removal efficiency of the catalytic beads obtained was 95% (50 ppm) under the optimized conditions in the sunlight. The photocatalytic degradation of MG dye under solar light has shown enhanced degradation than UV region. Pseudo first kinetics fitted well to photocatalytic degradation of MG with rate constant of 3.3 × 10⁻² min⁻¹. The photocatalyst give excellent results after recycling and regeneration up to five times for the degradation of MG dye.