Diethylenetriaminepentaacetic acid-thiourea-modified magnetic chitosan for adsorption of hexavalent chromium from aqueous solutions

Chromium pollution is a serious environmental problem given that like most heavy metals, Cr tends to persist and accumulate in the environment. In this study, diethylenetriaminepentaacetic acid-thiourea-modified magnetic chitosan (DTCS-Fe3O4) was synthesized for use as an adsorbent for Cr(VI) removal from aqueous solutions. The effects of various treatment conditions on the Cr(VI) adsorption performance of DTCS-Fe3O4 composite as well as the kinetics were elucidated. Moreover, by observing the structure and morphology of DTCS-Fe3O4, the possible Cr(VI) adsorption mechanism was proposed. DTCS-Fe3O4 exhibited a maximum adsorption capacity of 321.3 +/- 6.0 mg g-1. Further, the adsorption process, which followed the Langmuir model for monolayer adsorption, was predominantly governed by chemical adsorption, and could be fitted using the pseudo-secondorder kinetics model. Furthermore, given its ease of preparation, low cost, and remarkable performance, it is expected that the DTCS-Fe3O4 composite would find wide practical application in the removal of toxic Cr(VI) from wastewater.