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One-pot synthesis of a novel magnetic activated carbon/clay composite for removal of heavy metals from aqueous solution

Authors: 

Van Thuan Le, Thi Kieu Ngan Tran, Dai Lam Tran, Hoang Sinh Le, Van Dat Doan, Quang Dung Bui and Hoai Thuong Nguyen*

Source title: 
Journal of Dispersion Science and Technology, 2018 (ISI)
Academic year of acceptance: 
2018-2019
Abstract: 

In the present work, a novel composite consisting of magnetite, activated carbon from spent coffee grounds and natural clay (MACCC) was prepared by a one-pot synthesis method via a simultaneous activation and magnetization processes. Various techniques (XRD, FTIR, SEM, TEM, EDX, BET) were utilized to characterize the synthesized composite before utilizing it as an adsorbent for removal of Cu(II), Ni(II) and Pb(II) ions from aqueous solutions. Conditions for removal of heavy metals were thoroughly optimized as 25°C, pH of 5.5, adsorbent dosage of 2g L−1, and a contact time of 60 min. Three models of pseudo first-, second-order and intraparticle diffusion as well as three models of Langmuir, Freundlich, and Temkin were used to analyze kinetics and isotherms of the adsorption process. Thermodynamics was discussed completely. Regeneration and recyclability of the adsorbent were also evaluated. Based on the analysis of experimental results, a possible adsorption mechanism of heavy metals onto the synthesized composite was proposed. The maximum capacities caculated from Langmuir model followed the order of Pb(II) > Cu(II) > Ni(II) as 143.56, 96.16 and 84.86 mg·g−1, respectively. The overall results indicated that MACCC is a potential adsorbent for removal of toxic Pb(II), Cu(II) and Ni(II) ions from wastewater due to simple preparation, high removal efficiency and good recyclability.