Remediation of Soils Contaminated with Cadmium by In-Situ Immobilization Process Using Animal Bones

To immobilize lead, chromium, and cadmium in clay, sandy, and laterite soils, researchers looked at using animal bones (cow, pig, and horse) as a material. After being heated to 700 °C for four hours, the bone byproducts were carbonized. Three types of animal bone ash were used for analysis: cow bone ash (CBA), pig bone ash (PBA), and horse bone ash (HBA). SEM was the tool used for this process. Additionally, physicochemical analyses were carried out on the soil samples, which included clay, sandy, and lateritic soil types. The physicochemical analysis of the additives revealed that calcium phosphate is their primary component. The scanning electron microscopy (SEM) analysis of the amendments showed their high pore density and the specific atomic weights of the carbon, phosphorus, and calcium ions. The order of increasing calcium and phosphorus concentration is CBA>PBA>HBA. The XRF analysis showed that the percentage of CaO and P2O5 in CBA, PBA, and HBA, respectively, is 49.25%, 46.64%, and 33.857 percent. The presence of several functional groups, such as aromatic phosphates and ethylene, which immobilize and stabilize metals in soil, was indicated by the FTIR analysis. Results from a batch immobilization experiment showed that CBA was the most effective sorbent for removing Pb, Cr, and Cd from lateritic, clay, and sandy soils. Lateritic soil removed 74.55% of Pb from 100 g of soil, followed by clay soil at 71.2 % and sandy soil at 63.3 %.