Entrapment of Nickel in Ferrochrome Ash by Native Lysinibacilus sp Bacteria

Abstract

Nickel contamination in water is a significant environmental concern and causes several health effects such as allergies, cardiovascular diseases, and cancers in human beings. Ferrochrome ash is a fine dust generated as the waste from steel industry and pollutes the flow-through water by leaching nickel present in it. By providing a pre-disposal treatment of microbial induced calcite precipitation (MICP) to ferrochrome ash, the nickel leaching can be substantially reduced. Bacteria secrete the urease enzyme that decides the rate of urea hydrolysis reaction and they are the nucleation sites for the precipitation of calcium carbonate in calcium rich environment. During MICP, calcium carbonate entraps the nickel present in the ash. As a result, the nickel cannot escape the ash matrix and hence do not pollute the contacting water. This was confirmed by the atomic absorption spectrophotometric analysis (AAS) on leachates from treated and untreated ash. The analysis resulted in less nickel content from treated ash with highest treatment efficiency of 98% at LS 100. Results from SEM, FTIR, XRD, and TG implied that calcium carbonate developed in the ash due to MICP. © 2023, Avestia Publishing. All rights reserved.