화학공학소재연구정보센터
Transport in Porous Media, Vol.132, No.2, 283-297, 2020
Using Microfluidic Set-Up to Determine the Adsorption Rate of Sporosarcina pasteurii Bacteria on Sandstone
Microbial-induced carbonate precipitation (MICP) in porous media is a two-step procedure: First, the suspension of bacteria is injected and some of the bacteria get stuck on the grains. The second stage consists in the injection of a calcifying solution that triggers the calcite precipitation and creates a calcite shell around the bacteria. In the present article, we describe a novel method to measure the adhesion rate of Sporosarcina pasteurii bacteria on sandstone and that, additionally, allows to obtain information about local position of the calcite crystals on the sandstone grains. The method is based on the detection of the crystals developed on grains placed inside a microfluidic cell. The potential of the technique was evaluated and demonstrated by studying the influence of the injection time and ionic strength on the adhesion rate and on the spatial distribution of the crystals. The values of the adhesion rates are in good agreement with values determined using column experiments. We find, for example, an increase in the adhesion rate with the NaCl in solution, with a rate of the order of 0.005 min-1\ for a concentration of 3 g/L. with a maximum of 0.03 min-1 for experiments realized with a salt concentration of 20 g/L. Our work shows it is possible to use small volumes of fluid to determine quantities accurately, such as adhesion rate or crystals spatial repartition, avoiding the waste of a large quantity of fluids. The method also opens the possibility to screen different fluid compositions and flow conditions to optimize the MICP process.