Octopus tentacle-like molecular chains in magnetic flocculant enhances the removal of Cu(II) and malachite green in water

Abstract

• A recyclable flocculant with strong adsorption configuration was prepared simply. • Flocculant can remove Cu(II) and malachite green efficiently and synchronously. • Adsorption by functional groups and sweep flocculation were the mechanism. • Flocculant was easily regenerated and separated. • Flocculant can remove multiple contaminants in single-stage water treatment. Conventional flocculants are difficult to effectively remove dissolved ions and organic matter from water. This work aims to develop an environmentally friendly and renewable core–shell type flocculant (MCHS-g-P(AM-IA)) with octopus tentacle-like strong adsorption structure. The organic shell hydrolyses into molecular chains like octopus tentacles and adsorb dissolved ions/organic macromolecules through suckers-like functional groups, while the magnetic core acts as the growth center of flocs. Configuration and physical/chemical properties of the flocculant were analyzed by a series of characterization methods. Set Cu(II) and malachite green (MG) as models of heavy metal and organic pollutants separately, the removal capacity of MCHS-g-P(AM-IA) for water contaminants was studied in single-contaminant system and binary-contaminant system. The flocculation behavior and mechanism of MCHS-g-P(AM-IA) were deeply investigated by analysis of pH-dependence, background cationic influence and flocculation kinetics and SEM-EDS/XPS analysis of flocs. Furthermore, the flocculation performance in actual water matrix and regeneration tests of MCHS-g-P(AM-IA) were carried out to evaluate the applicable feasibility of flocculants for purification of complex wastewater in single stage water treatment.