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Efficiency and Morphology of Calcium Carbonate Precipitate Induced by Urease Enzymes
Ist Teil von
Geotechnical and geological engineering, 2024-03, Vol.42 (2), p.1153-1171
Ort / Verlag
Cham: Springer International Publishing
Erscheinungsjahr
2024
Link zum Volltext
Quelle
SpringerNature Journals
Beschreibungen/Notizen
Economic and efficient application of enzyme induced calcium carbonate precipitation (EICP) requires optimisation of the process and understanding of the precipitate microstructure. The objective of this study was to compare the precipitate efficiency and the interface shearing resistance of the precipitate, using Taguchi method. The factors which controlled the precipitate were urea-calcium chloride concentration, urease activity and reaction duration. Precipitation tests and torsional shear tests were performed using orthogonal L25 with 25 array runs. Taguchi method suggests two different optima for precipitate efficiency and interface shearing resistance. However, to obtain a single optimum through simultaneous optimisation of both the responses, Taguchi method was integrated to grey relational analysis. The obtained optimum, henceforth, was set at 0.5 mol/L of urea and calcium chloride concentration, 45 kU/L of urease activity and reaction duration of 48 h. The results show that the interface shearing resistance was controlled by the morphology of the precipitate, especially since the chemical concentration and kinetics of ureolysis resulted in different precipitate morphology. All the control factors were significant, including the contribution of the urease activity. Urease activity enhanced the precipitate efficiency and the interface shearing resistance. Aggregation of particles at higher urease activity resulted in improved shearing resistance.