The combination of microbial electrolytic cells and anaerobic digestion (MEC-AD) became an efficient method to improve CO capture for waste sludge treatment. By adding CaCl and wollastonite, the CO sequestration effect with mineral carbonation under 0 V and 0.8 V was studied. The results showed that applied voltage could increase dissolved chemical oxygen demand (SCOD) degradation efficiency and biogas yield effectively. In addition, wollastonite and CaCl exhibited different CO sequestration performances due to different Ca release characteristics. Wollastonite appeared to have a better CO sequestration effect and provided a wide margin of pH change, but CaCl released Ca directly and decreased the pH of the MEC-AD system. The results showed methane yield reached 137.31 and 163.50 mL/g SCOD degraded and CO content of biogas is only 12.40 % and 2.22 % under 0.8 V with CaCl and wollastonite addition, respectively. Finally, the contribution of chemical CO sequestration by mineral carbonation and biological CO sequestration by hydrogenotrophic methanogenesis was clarified with CaCl addition. The chemical and biological CO sequestration percentages were 46.79 % and 53.21 % under 0.8 V, respectively. With the increased applied voltage, the contribution of chemical CO sequestration rose accordingly. The findings in this study are of great significance for further comprehending the mechanism of calcium addition on CO sequestration in the MEC-AD system and providing guidance for the later engineering application.

中文翻译：

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微生物电解池CO2封存-厌氧消化系统结合矿物碳酸化处理污泥水解液

微生物电解池和厌氧消化（MEC-AD）的结合成为提高废污泥处理二氧化碳捕获的有效方法。通过添加CaCl和硅灰石，研究了0 V和0.8 V下矿物碳酸化的CO封存效果。结果表明，施加电压可以有效提高溶解化学需氧量（SCOD）降解效率和沼气产量。此外，硅灰石和CaCl由于不同的Ca释放特性而表现出不同的CO封存性能。硅灰石似乎具有更好的CO2封存效果并提供了较宽的pH变化范围，但CaCl直接释放Ca并降低了MEC-AD系统的pH。结果表明，在0.8 V条件下，添加CaCl和硅灰石，甲烷产率分别达到137.31和163.50 mL/g SCOD降解，沼气中CO含量分别仅为12.40 %和2.22 %。最后，通过添加 CaCl2 阐明了矿物碳酸化化学 CO 封存和氢营养产甲烷作用生物 CO 封存的贡献。0.8V下化学和生物CO封存率分别为46.79%和53.21%。随着施加电压的增加，化学CO封存的贡献相应增加。本研究结果对于进一步理解MEC-AD系统中钙的添加对CO封存的作用机制，并为后期的工程应用提供指导具有重要意义。