Enhanced removal of Methyl Orange from aqueous solution by Chitosan-CaCl2 beads

Abstract

Use of low-cost and environmental friendly sorbents has been studied as an ideal alternative to the current costly methods of removing textile dyes especially methyl orange from wastewater. In present study, the adsorption affinity of chitosan (CS)-CaCl2 beads towards anionic acid dye, methyl orange was investigated by performing batch adsorption experiments. The surface morphology and elemental composition of CS-CaCl2 beads were examined using Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDX) respectively. The effects of initial dye concentration (20 to 100 mg/L), adsorbent dosage (0.05 g to 0.5 g), contact time (0 to 48 h), and agitation speed (0 to 300 rpm) were also studied to evaluate the efficacy of adsorption. Adsorption isotherm data of CS-CaCl2 fitted well to Langmuir (R2 = 0.9964) isotherm model, indicating that homogenous adsorbent surface. Kinetic studies showed that the sorption process followed pseudo-second-order rate that involves chemisorption process, indicating that the adsorption nature of dye on CS-CaCl2 adsorbent. Based on the results, CS-CaCl2 beads could be alternative cost effective adsorbents gaining prominence as a method for the removal of anionic acid dye from textile effluent. In conclusion, this study demonstrated a profound impact on improvement in water quality.