“…Researchers have carried out decontamination of the environmental water contaminated by heavy metals using such methods as chemical precipitation, filtration, electrochemistry, coagulation-flocculation, oxidation, ion exchange, and adsorption [Cocheci et al, 2010;Ali et al, 2012;Mohamed et al, 2019;Castro-Castro et al, 2020;Normah et al, 2021] The adsorption method is preferred due to its simplicity, low cost, the ease of operation , the flexibility of the design and the choice of adsorbent, as well as environmental friendliness [Oktriyanti et al, 2019;Forghani et al, 2020;Silaen et al, 2020]. On the basis of various works of literature, different types of adsorbents have been applied to reduce the levels of heavy metals contained in wastewater, including the adsorbents that have porous or layered characteristics, such as bentonite, activated carbon, kaolin, and layered double hydroxides (LDHs) [Wahab et al, 2019;Chai et al, 2020;Zhang et al, 2020a].…”