Performance Evaluation and Driving Mechanisms of Synergistic Solidification with Nano-Sio2 and-MICP for Sludge
The development of green and low-carbon chemical solidification technology is crucial for rapid solidifica-tion of soft ground under the"Dual Carbon"context.This study introduces an innovative synergistic technology that combines active nano-SiO2with microbial induced carbonate precipitation(MICP)for sludge solidification.Through unconfined compressive strength tests,pH monitoring,Ca2+utilization rate analysis,and scanning electron micros-copy,the reinforcement efficiency and micromechanisms of this technology are examined.Key findings include:1)An increase in compressive strength of nano-SiO2-MICP solidified sludge is observed with increasing nano-SiO2 con-tent up to 0.1％.2)Samples treated with 0.1％nano-SiO2at Ca2+concentrations of 0.5,1,and 2 mol/L exhibit compressive strength enhancements of 64.21％,10.28％,and 75.98％,respectively,compared to those without nano-SiO2.3)Nano-SiO2 provides new nucleation sites for MICP,fills pores,induces aragonite-to-calcite transfor-mation,and forms cementitious gels,thereby boosting sample strength.4)The presence of nano-SiO2enhances Ca2+utilization and pH regulation within the pore solution.Together,microbial-induced bio-CaCO3 processes(cementa-tion,filling,bridging)and nano-SiO2-induced physicochemical effects(new nucleation sites,micro aggregate fill-ing,and gelling products)synergistically improve the mechanical properties of solidified sludge and optimize the microscopic structural construction.
Nano-SiO2microbial induced carbonate precipitationunconfined compressive strengthCa2+utiliza-tionscanning electron microscopysolidified sludge
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