School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China.
School of Environment, Jinan University, Guangzhou, 510632, China.
J Environ Manage. 2022 Jan 1;301:113894. doi: 10.1016/j.jenvman.2021.113894. Epub 2021 Oct 9.
A biotic iron (Fe) treatment system combined with mixed microorganisms was applied to remediate cadmium (Cd)-contaminated groundwater under the intervention of sulfate. Due to hydrogenotrophic desulfuration effect, severe iron corrosion was observed in this microbe-collaborative Fe system according to surface morphology analysis as lots of secondary minerals (e.g. magnetite, green rust and lepidocrocite) were generated, which was essential for Cd(II) adsorption and immobilization. The sulfate-mediated biotic Fe system thereafter achieved a significantly enhanced Cd(II) removal efficiency of 86.1%, over 3.3 times than that in the abiotic Fe system. Increasing initial sulfate concentration could improve the removal of cadmium, which further proved that hydrogenotrophic desulfuration played a key role for enhanced Cd removal. According to the experimental results and current reports, the mechanism of Cd(II) removal was revealed into three pathways including adsorption to secondary iron minerals, co-precipitation with iron (hydr)oxides and formation of cadmium sulfide precipitation. Increasing Fe dosages showed positive correlation to Cd(II) removal and neutral pH was preferred to sulfate-mediated biotic Fe corrosion. These results indicated that sulfate-mediated biotic Fe corrosion could greatly relieve the limitation of Fe in Cd(II) immobilization, which could be a promising method to eliminate Cd(II) pollution from groundwater.
采用一种生物铁（Fe）处理系统与混合微生物相结合的方法，在硫酸盐的干预下修复受镉（Cd）污染的地下水。由于氢营养型脱硫作用，根据表面形貌分析，在这种微生物协同 Fe 系统中观察到严重的铁腐蚀，生成了大量的次生矿物（如磁铁矿、绿锈和纤铁矿），这对于 Cd（II）的吸附和固定是必要的。此后，硫酸盐介导的生物 Fe 系统实现了显著增强的 Cd（II）去除效率，达到 86.1%，比非生物 Fe 系统高 3.3 倍。增加初始硫酸盐浓度可以提高镉的去除率，这进一步证明了氢营养型脱硫对增强 Cd 去除的关键作用。根据实验结果和现有报道，揭示了 Cd（II）去除的三种途径，包括对次生铁矿物的吸附、与铁（氢）氧化物的共沉淀以及形成硫化镉沉淀。增加 Fe 剂量与 Cd（II）去除呈正相关，中性 pH 值有利于硫酸盐介导的生物 Fe 腐蚀。这些结果表明，硫酸盐介导的生物 Fe 腐蚀可以大大缓解 Fe 在 Cd（II）固定中的限制，这可能是一种从地下水中消除 Cd（II）污染的有前途的方法。
