Reutilization of coal combustion ash as sorbent for arsenic removal from waters

Coal-fired power plants produce large quantities of solid combustion residues, including bottom ash, slag and fly ash. Coal combustion fly ash (CCA) accounts for approximately seventy percent of the solid waste produced from coal combustion and, due to its chemical properties, landfill disposal presents several environmental concerns mainly deriving from the potential leaching of toxic elements. An interesting alternative to CCA disposal is its reuse as low cost adsorbent material for heavy metal removal in wastewater and groundwater treatments. The presence of heavy metals in natural waters represents a serious human health threat; nowadays, arsenic is considered among the most dangerous compounds and, due to its world wide diffusion, it is subjected to severe environmental regulations. Hence, the development of new alternative technologies characterized by good efficiency, high simplicity and low-cost materials is of great importance, for the challenge of a wider diffusion of effective and accessible depuration technologies for arsenic removal. The objective of the present work is to investigate the effectiveness of CCA reutilization as low-cost arsenic adsorptive media, for polluted waters remediation. CCA is recovered from the combustion chamber of the ENEL power plant in Portoscuso, Cagliari, Italy.