Sustainable use of contaminated soils amended with nano calcium silicate mixture for nickel encapsulation in an aqueous medium

Abstract Nickel and its compounds are naturally present in the Earth's crust, and releases to the atmosphere occur from natural discharges as well as from anthropogenic activities. Human exposure to these nickel polluted environments has the potential to produce a variety of pathological effects. In this study three different leaching methods viz. Toxicity characteristics leaching procedure (TCLP), extended TCLP, and caged TCLP have been used to study the leaching behaviour of Ni 2+ on a soil amended with nano calcium silicate (NCS) which was synthesised by a proprietary method of authors. Soil sampling was carried out from vicinity of Jindal South West (JSW) steel plant at Toranagallu, Bellary, and was amended with NCS. The studies revealed that as per TCLP, extended TCLP and caged TCLP tests the retention of Ni 2+ with amended soil was 85%, 91% and 93% better than soil respectively. Caged TCLP test quantified the leaching rate and was found to be 0.255cm/year for amended soil and 1.14cm/year for soil. It was found that over a period of time the retention levels were found to be satisfactory with NCS and confirming encapsulation of Ni 2+ in its matrix.