Remediation of industrial brine using coal-combustion fly ash and Co2

A protocol is proposed whereby waste fly ash and CO2 emissions from coal fired power plants are utilized in remediating brine waste. The solid residues generated may be used as mine backfill since they consist mainly of benign calcium carbonate. Following treatment with fly ash and CO2, over 99% removal of NO− was achieved 3 while B3+, V2+, MO2+ and Cl− concentrations increased. Major element removal from brine upon carbonation was as follows: Na+ (15–29%), Mg2+ (53–87%), K+ (70–88%), Ca2+ (40–73%) and SO2− (12–36%). Speciation 4 modeling of the major elements present in brine showed that Na+, K+ and Cl− exist mainly as free ions while Mg2+ and Ca2+ are associated with SO2− as well as being in their free forms. SO2− ions were present in its 4 4 free form to a great extent as well as associated with Na+, Ca2+, Mg2+ and K+ respectively, in a decreasing order. Co-treatment of brine using FA and CO2 may therefore be a potent brine remediation protocol which can be optimized for maximum removal of various elements. © 2014 Elsevier B.V. All rights reserved.

The major and trace element load of the untreated brine was reduced upon contacting it with FA and CO2. Modeling showed that mineral carbonates are the main products of treating brine with FA and CO2. An optimized brine treatment protocol may be potent in remediating waste brine. The treatment further leads to recycling of waste FA and CO2 capture. Acknowledgments This research was financially supported by the NRF and the Water Research Commission (WRC) project number: K5/2128.