Potential Use of Waste as a Source of Calcium for Microbial Induced Carbonate Precipitation (MICP)

Abstract

Microbial induced Calcium carbonate precipitation (MICP) is a promising new technology in the pursuit of sustainable concrete improvement. For MICP to occur, a medium with alkaline pH, dissolved inorganic carbon and a source of calcium must be used, associated with bacteria that serve as nucleation sites through their cell walls. The use of this technology on a large scale is linked to a high financial and environmental cost, so replacing traditional sources of carbon and calcium with waste is a way to mitigate these expenses and possible environmental liabilities using circular economy. The objective of this work is to evaluate the potential use of alternative sources of calcium in the MICP process from eggshells and mussel shells. For this, these materials were collected, washed and ground to carry out a chemical characterization using X-ray Fluorescence spectrometry (XRF), thermogravimetry (TGA) and X-ray diffraction (XRD). The source of calcium was produced from the mixture of waste processed with acids (hydrochloric, lactic and nitric) and vinegar. The solubilized mass was confirmed from the filtration of the remaining solid material. The chemical characteristics of the materials and its solubilization in various acids show that residues have the potential to be used for Microbial induced carbonate precipitation.