Application of Electro kinetic technique to remediate fly ash for its sustainable use

Abstract

Fly ash is a by-product of coal combustion in thermal power plants which is classified as hazardous waste and a serious threat to environment. The study was conducted to determine the potential and examine the efficacy of electro kinetic technique (EKT) using variables like pH, total dissolved solids (TDS), e concentration of chlorides (Cl-), sodium (Na+),magnesium (Mg2+), potassium (K+), ammonia (NH3+) and calcium (Ca2+) on fly ash as a low-cost treatment for enhancing the use of fly ash in a more sustainable manner. The probability of removing heavy metals and chlorides from fly ash suspended in water using electro dialysis was studied as they are highly dependent on pH and conductivity of the fly ash. The voltage gradient and duration indicated significant effect in the change of pH values showing a range from 4.6 to 7.7 at cathode and anode respectively, while the Total dissolves solids (TDS) varying from 72.33±5.6 to 146±5.4 showed the enhanced availability of ions post electro dialysis. In terms of chlorides, Cl- the content was observed to be 265.06 mg/l which was high enough to cause corrosion problems in later stages of reuse of fly ash. The concentration of cations like Na+, K+, NH3+, Mg2+, Ca2+ were observed to be notably influenced by the duration of study and pH in electro dialysis. The experimental results of the study showed that the proposed technique based on the fundamentals of electro kinetics and dialysis could efficiently improve the remediation process which would remove metals by converting them to available form in fly ash.