Application of technical grade reagent in soybean-crude urease calcite precipitation (SCU-CP) method for soil improvement technique

Abstract

Soybean crude urease-calcite precipitation (SCU-CP) is a potential method as a sustainable and economical soil improvement technique. This method begins with developing the bio-cementation method that has successfully increased soil strength. The use of laboratory-grade material is high-cost for large-scale. The applicability of original soybean material combined with technical grade reagent in SCU-CP was discussed, considering its relevance for a larger scale treatment. The hydrolysis rate, test-tube experiment, and X-Ray Diffraction (XRD) test were conducted to evaluate the entire material's potential for the calcite precipitation method considered for precipitation materials. This study shows that low-cost soybean material and technical-grade reagents have a good level of effectiveness for calcite production. The low-cost material of soybean 20 g/L produced the highest hydrolysis rate of 331.701 u/g. Technical-grade reagent with a concentration of 1 mol/L was proven effective compared to laboratory-grade with a precipitation ratio of 114.44%. XRD results showed that the highest calcite formation was in technical-grade samples using soybean Gasol with a crystallinity of 40.25%. Unconfined compressive strength (UCS) results showed that the original soybean has a higher value than other solutions, which is 66.18 kPa in 14 days. Therefore, technical-grade materials are more economical with 100% cheaper than laboratory-grade. The result of this study elucidated that SCU-CP has a high potential to be an economical, sustainable and effective soil improvement technique.