Synthesis of dithiocarbamate-modified crosslinked poly(β−cyclodextrin-co-triethylenetetramine) microspheres for simultaneous and highly efficient removal of Cu2+ and methyl orange/thymol blue from wastewater

Abstract

Novel dithiocarbamate (DTC)-modified crosslinked poly(β−cyclodextrin-co-triethylenetetramine) microspheres (DTC-PCDTTM) possessing a particle size distribution of 141 μm with a span value of 0.65 were fabricated and evaluated by Cu2+−MO/TB binary-component systems. DTC-PCDTTM shows excellent simultaneous adsorption performance for Cu2+ and methyl orange (MO) or thymol blue (TB) at a DTC graft ratio of 0.21; it also exhibits eminent regeneration and recyclability. The adsorption isotherm data of DTC-PCDTTM for Cu2+ and MO or TB in Cu2+−MO/TB binary-component systems can be described by the Freundlich and Langmuir models, respectively. The adsorption kinetic data of Cu2+, MO, and TB by DTC-PCDTTM are related to the pseudo-second-order kinetic model. The adsorption is a process of spontaneous endothermic entropy increment. The coordination, electrostatic attraction, and the host−guest interaction of β−cD moieties with contaminants are the primary mechanisms for Cu2+, MO, and TB adsorption. In the Cu2+−MO/TB binary-component systems, competitive adsorption is effectively avoided, and Cu2+ shows good synergistic effects with MO and TB.