Optimization of Urease Amount for Calcite Precipitation in Indian Desert Sand Using Biologically Inspired Method

Abstract

A sustainable technology that supports the binding of sand grains is required to mitigate wind generated sand erosion. The biologically inspired method, i.e., enzyme-induced carbonate precipitation (EICP) has recently become popular and a practical substitute to improve the cohesion among sand grains (especially to control wind erosion). The formation of calcium carbonate (CaCO3) using the EICP method mainly depends on the amount of urease (Jack bean). The current study explores the effect of 1 pore volume (PV) solution on calcite formation using different amounts of urease 2 g, 4 g, and 6 g, with 0.5 M (molar) and 1 M cementation solution using tap and distilled water for 1, 2 and 4 treatment cycles. The pH and EC (electrical conductivity) were measured during treatment at every 1 h interval, for 12 h duration. The calcite precipitation was confirmed using SEM (scanning electron microscopy analysis), EDX (Energy Dispersive X-ray analysis), XRD (X-ray diffraction analysis), and calcite test. TGA (Thermogravimetric analysis) tests have been performed to know insight into the thermal behavior. The minimum calcite percentage formation was 2% with T/1M/6/1D and the maximum calcite percentage formation was 3.75% with D/0.5M/4/4D. It was observed that 6 g of urease generates lower calcite precipitation than 2 g and 4 g urease. Overall, it was suggested that 4 g urease with 0.5 M cementation solution gives optimum results. The outcome of this study offers valuable insights and support for geotechnical engineers trying to improve the cohesion and binding of sand particles. © 2024, The Author(s), under exclusive licence to Indian Geotechnical Society.