Evaluation of The Performance of Enzyme-Induced Calcite Precipitations (EICP) Solutions Based on pH and Electrical Conductivity

Abstract EICP is an innovative, sustainable technology that utilizes specific chemicals, particularly urea and calcium chloride, in conjunction with the urease enzyme to induce the precipitation of calcium carbonate. The abovementioned technology is widely acknowledged as contemporary and environmentally responsible, aligning with established sustainability principles and green construction criteria. The quantity of precipitated calcium carbonate is contingent upon the composition of the materials employed in the precipitation process and their respective proportions. The investigation focused on determining the best percentage of calcium carbonate precipitation by conducting experiments on different concentrations of urea, calcium chloride, and the urease enzyme and examining the specific characteristics of the chemical solution that facilitate the precipitation process. The augmentation of urea and calcium chloride to a certain proportion resulted in a corresponding augmentation in the quantity of precipitated substances such as calcium carbonate. In the course of furthering the increase process, it was observed that the value of the precipitated materials remained constant and did not exhibit any further augmentation for some mixing ratios. According to the results of current study, the best ratio to precipitated calcium carbonate can be attributed to using an optimal ratio of 1 mol/L of urea and 0.5 mol/L of calcium chloride. Due to the notable efficacy of urease, the concentration increment of urease did not exhibit significant variation beyond 1 g/l. However, the alteration in the rate of reaction velocity will influence the outcome of EICP process. The experimental results and integration of several methodologies demonstrated a positive correlation between temperature elevation and reaction rate augmentation, resulting in a rapid reaction termination.