Institute of Geotechnical Engineering, College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310014, China.
Institute of Geotechnical Engineering, College of Civil Engineering, Zhejiang University of Technology, Hangzhou, 310014, China.
Chemosphere. 2024 Sep;363:142873. doi: 10.1016/j.chemosphere.2024.142873. Epub 2024 Jul 15.
Electro-osmosis has been valued as a promising technology to enhance the dewatering of waste sludge, stabilization and environmental remediation of soils with low permeability. However, the coefficient of electro-osmotic permeability (k) is commonly taken as constant value which is particularly not the case in variable charge soil. As a result, the nonlinearity of the electro-osmotic flow (EOF) and the direction reverse could not be interpreted. Herein, the electro-chemical parameters were monitored in electro-osmotic experiment with natural variable charge soil. It was observed that the evolutions showed significant nonlinear behavior and were correlated. The comprehensive Zeta potential model proposed by the authors was applied to simulate the nonlinear k induced by the variable pH and electrolyte concentration. The agreement between tested and simulated flow rate variation and excess pore water pressure distribution demonstrated the reliability of the theory. The error rate of the simulations through coupling nonlinear k and voltage gradient E was reduced to 29.4% from 381.9% of calculations with constant parameters. The direction reverse of EOF was innovatively interpreted. Hence, the numerical model would act as a useful tool to connect these electro-chemical parameters and provide guidance to evaluate contributions of commonly used pH conditioning measurements.
电渗析作为一种很有前途的技术，已经被认为可以提高废泥的脱水效率，稳定低渗透性土壤，并进行环境修复。然而，电渗渗透率（k）通常被视为常数，这在可变电荷土壤中是不成立的。因此，电渗流（EOF）的非线性和方向反转无法得到解释。在此，作者在电渗实验中监测了天然可变电荷土壤的电化学参数。结果表明，这些演化表现出显著的非线性行为，并具有相关性。作者提出的综合 Zeta 电位模型被用于模拟由 pH 值和电解质浓度变化引起的非线性 k。通过测试和模拟流速变化和超孔隙水压力分布之间的一致性，证明了该理论的可靠性。通过将非线性 k 和电压梯度 E 进行耦合，将模拟误差率从 381.9%降低到 29.4%。EOF 方向的反转得到了创新性的解释。因此，该数值模型将成为连接这些电化学参数的有用工具，并为评估常用 pH 值调节测量的贡献提供指导。
