Brief Introduction to Microbial Induced Calcium Carbonate Precipitation (MICP)
Keywords
Microbial Induced Calcium Carbonate Precipitation, MICP
Overview
The essence of MICP is to use certain types of bacteria in nature. Their metabolism can produce urease that decomposes urea. The carbonate ions produced after urea decomposition combine with free metal cations in nature to form gelled crystals.
The application of MICP technology requires low production energy consumption and production cost, and can reduce greenhouse gas emissions. MICP technology can improve the geological characteristics of soil.
Principle of MICP technology
At present, there are two main mechanisms for microbial-induced calcium carbonate precipitation: microbial-controlled precipitation and microbial-induced precipitation.
MICP is currently the most widely studied microbial mineralization reaction. Its principle is to add urea, calcium source and nutrients to the microbial liquid, and rely on the metabolism of the microorganism itself. Urease catalyzes the hydrolysis of urea to produce carbonate ions and ammonium ions. In an alkaline environment, calcium carbonate ions can combine with surrounding calcium ions to precipitate CaCO3 crystals.
Materials needed for MICP
The cementing fluid is generally composed of urea, calcium source, nutrients, etc., not only has an important impact on the activity of microorganisms and urease activity, but also has a great impact on the morphology of calcium carbonate crystals.
MICP application
Slope reinforcement, windbreak and sand fixation in desert areas, concrete crack repair, self-healing concrete, anti-seepage and plugging, etc.
