“…Some heavy metal ions, such as lead, cadmium, and mercury, are highly toxic even at low ion concentrations and are not biodegradable, which is very harmful when returned to humans by ecosystem circulation [ 3 , 4 ]. Therefore, it is urgent to remove the harmful substances from wastewater to minimize the negative effect on the environment [ 6 ]. Several methods have been used to resolve this problem, including membrane filtration, photodegradation, ion exchange, adsorption, and chemical precipitation [ 7 , 8 ].…”