A Novel Approach for Sand Stabilization Using Mg-rich Alkaline Brine

The vast amount of Mg-rich alkaline brine in the desert areas of northwestern China makes it a promising approach to control desertification by microbially induced magnesium carbonate precipitation (MIMP). We propose here a novel sand stabilization approach using magnesium carbonate and a bacteria urea hydrolysis (Sporosarcina pasteurii, ATCC 11859). We investigate the feasibility of this method by examining the bacterial growth rate, mineralogy of the precipitates, relative chemical conversion efficiencies, and the sources of materials for applicable potentials. The differences between previously-proposed MICP (microbially induced calcium carbonate precipitation) and MIMP are also compared. Our results suggest that excess Mg²⁺ motivates the growth of the bacteria. The magnesium carbonate precipitates appear as nesquehonite, Mg-ACC and Mg-rich calcite, suitable for engineering purposes. The relative chemical conversion efficiency of Mg medium is higher than Ca medium. We further present an estimate of the potential desert area that can be controlled by MIMP, considering the PRC national standard GB/T 21141-2007. This novel MIMP approach is a green technique, with the main products as organic nutrient and ammonium. It will not bring pollution to the sand-fixation area and instead will be beneficial to the revegetation in the future.