Investigation of adsorption of organic dyes present in wastewater using chitosan beads immobilized with biofabricated CuO nanoparticles

Abstract

A novel type of polymer beads (CS/CuO nanocomposite beads) were formulated by incorporating laboratory synthesized CuO nanoparticles into pure chitosan (CS) beads. The CuO nanoparticles (NPs) used for immobilization were synthesized through simple, environment friendly and cost effective green route using plant extract of Ficus retusa. These beads were used as an adsorbent for removal of organic dyes from their aqueous solutions. Two typical organic dyes, congo red (CR) and eriochrome black T (EBT) were used to gauge the adsorption performance of pure chitosan beads and CS/CuO nanocomposite beads. The combination of chitosan with CuO nanoparticles enhanced the efficiency of chitosan beads to remove these dyes from their aqueous solution. More than 97% of dyes were removed within a time span of 2 h. The maximum adsorption capacity of congo red and eriochrome black T dyes over polymer nanocomposite beads was found to be 119.70 and 235.70 mg g−1 respectively. The study of kinetics revealed that the adsorption process followed pseudo first order kinetics while the adsorption isotherm of the dyes demonstrated that the adsorption equilibrium can be related to Freundlich model. The recovery rate of nanocomposite beads was 100% after each cycle and these beads were reusable even up till 5 cycles.