Investigation on applying sapropel for removal of heavy metals (cadmium, chromium, copper, and zinc) from aqueous solutions

Sapropel is a layer of sediment composed of organic and inorganic substances that accumulates at the bottom of lakes. The water of such lakes often have elevated levels of heavy metals such as Cd, Cr, Cu, and Zn, which can pose risks to human health. Sapropel may be used as a biosorbent in removing these heavy metals from aqueous solutions. Various doses of sapropel ranging from 1 to 50 g/L and different mixing times from15 to150 minutes have been tested. The maximum removal efficiencies for Cd (93%), Cr (31%), Cu (84%), and Zn (84%) from aqueous solutions were achieved using the minimum doses of sapropel (50 g/L). The study has shown that mixing sapropel for 15 minutes is sufficient for the removal of Cr, 30 minutes for Cd and Cu, and 60 minutes for Zn.