Highly reusable bentonite clay@biochar@Fe3O4 nanocomposite for Hg(II) removal from synthetic and real wastewater

Abstract

The present research investigates the performance of bentonite clay@biochar@magnetic nanocomposite in removing mercury (Hg 2+ ) ions from aqueous media. Bentonite clay@biochar@magnetic nanocomposite was characterized by BET, VSM, TEM, Mapping, EDX, SEM, FT-IR, XRD and Raman analyses. According to the results, the highest uptake e ciency of Hg 2+ was attained at pH 6, Hg 2+ concentration of 10 ppm, 80 min, and composite dose of 1.5 g/L. In these conditions, the uptake e ciency of bentonite@activated carbon@Fe 3 O 4 nanocomposite and bentonite were 98.78% and 97.67%, respectively, which are remarkable values. Also, the W max value for Hg 2+ removal using bentonite@biochar@magnetic nanocomposite and bentonite were 66.66 and 60.98 mg/g, respectively.Moreover, the uptake process of Hg 2+ ions using bentonite@biochar@magnetic nanocomposite and bentonite was spontaneous, physical, favorable and exothermic. Besides, the impact of various divalent ions such as Co 2+ , Cu 2+ , Pb 2+ , Ni 2+ , and Zn 2+ was studied on the elimination e ciency of Hg 2+ using bentonite and bentonite clay@biochar@magnetic sorbents. The results showed that Co 2+ and Zn 2+ ions have the highest and lowest interfering effects in the removal of Hg 2+ . Also, the reusability of adsorbents showed that they have high stability and can be used in at least 5 reuse cycles with high uptake e ciency. Additionally,