Adsorption Behaviour of EDTA Modified Magnetic Fe3O4 Coated Brewed Tea Waste on Cr(VI) Removal

The study focused on fabricating a novel magnetic Fe3O4 loaded and EDTA modified brewed tea waste (TW-Fe3O4-EDTA) as a cheap, environmentally friendly, and efficient adsorbent for the removal of Cr(VI) ions from aqueous medium in a batch system. Characterization of the prepared adsorbent was performed with different techniques. Adsorption experiments were implemented at different conditions including initial solution pH (1.0-7.0), equilibrium time (1-480 min), adsorbent dosage (1.0-20.0 g L-1), and initial Cr(VI) concentration (50-1000 mg L-1). The optimum adsorption performance was observed at pH 2.0 with 120 min of contact time. Maximum adsorption capacity of 114.9 mg g(-1) was acquired for TW-Fe3O4-EDTA which is much higher than the recently developed adsorbents for Cr(VI) removal. Adsorption process was well explicated by Freundlich isotherm model and the adsorption rate is described in accordance with pseudo-second order kinetic model. It was observed that common salts did not have a notable influence on Cr(VI) adsorption. The results of the study indicated that TW-Fe3O4-EDTA can be applied as an effective adsorbent in heavy metal removal as an alternative to many expensive adsorbents available in the literature.