Applying Fine Coal Ash for Removing Toxic Cations in Waters of Matola River, Maputo Province

This study is a proposal to apply fine ashes of coal tailings to eliminate toxic cations in waters in Matola River, Maputo Province coming from industrial activities in order to enhance the material discarded after processing and minimizing environmental impacts. To fulfill the objective, ashes from fine coal tailings were synthesized by calcination method, then physicochemical and chemical characterization of the ashes and physicochemical characterization of the effluent before and after interaction with the ashes were performed by X-ray fluorescence spectrometry (XRF) and inductively coupled spectroscopy (ICP-S). After characterizing, the effluent interacted with the ashes through the adsorption process, using 0.5 g, 1 g and 2 g of ash per 50 ml of effluent, respectively. Coal ashes act as a good agent in remediating toxic cations such as Zr, Cr, As, Th, Mn, Pb and Zn present in the effluent, which validates hypothesis H1, which states that it is possible to remove toxic metal cations present in polluted waters by using fine coal ashes as adsorbent. The efficient dose for treating and removing toxic cations present in the effluent from Mozal Company is 2 g per 50 ml of effluent, since the effluent has a pH of 7.38, conductivity of 21.64 μS/cm and TDS of 10.23 mg/l.