Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
Innovation Academy for Green Manufacture, National Engineering Research Center of Green Recycling for Strategic Metal Resources, Key Laboratory of Green Process and Engineering, Beijing 100190, China; Engineering Research Centre of Process Pollution Control, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
J Hazard Mater. 2023 Mar 15;446:130702. doi: 10.1016/j.jhazmat.2022.130702. Epub 2022 Dec 29.
Secondary mineralization is a promising method for remediating cadmium (Cd) pollution in sediments, but the poor stability of Cd-containing secondary minerals is a bottleneck that limits the development of this approach. The existence of phosphate can enhance the formation of stable secondary minerals and points a new direction for Cd immobilization. In this research, a novel syntrophic system composed of phosphate solubilizing bacteria (PSB) and dissimilatory iron reducing bacteria (DIRB) was established and the effect and mechanism of Cd immobilization in the system were also explored. The results showed that under the conditions of DIRB:PSB (V:V)= 3:1, syntrophic bacteria dosage of 5% and glucose dosage of 5 g/L, Cd incorporated in the secondary minerals could account for about 60% of the total Cd. In the pH range of 5-9, alkaline environment was conducive to the immobilization of Cd and the percentage of combined Cd was up to 58%, while the combined Cd in secondary minerals decreased from 62% to 56% with the increase of initial Cd concentration from 0.1 to 0.3 mmol/L. In addition, XRD, XPS, Mössbauer and other characterization results showed that secondary minerals, such as Cd exchange hydroxyapatite (Cd-HAP) and kryzhanovskite (Fe(PO)(OH)) were formed in this new system. The established syntrophic system of PSB and DIRB is thus a prospective bioremediation technology for Cd immobilization in sediments and can avoid the potential risk might be caused by the addition of phosphorus-containing materials.
次生矿物固定化是一种很有前景的修复沉积物中镉（Cd）污染的方法，但含镉次生矿物的稳定性差是限制该方法发展的瓶颈。磷酸盐的存在可以促进稳定的次生矿物的形成，为 Cd 固定化开辟了新的方向。在这项研究中，构建了一种由解磷菌（PSB）和异化铁还原菌（DIRB）组成的新型共生体系，并探索了该体系中 Cd 固定化的效果和机制。结果表明，在 DIRB:PSB（V:V）=3:1、共生细菌用量为 5%、葡萄糖用量为 5 g/L 的条件下，Cd 可与次生矿物结合，占总 Cd 的 60%左右。在 pH 值为 5-9 的范围内，碱性环境有利于 Cd 的固定，结合态 Cd 的比例高达 58%，而随着初始 Cd 浓度从 0.1 到 0.3 mmol/L 增加，次生矿物中结合态 Cd 从 62%减少到 56%。此外，XRD、XPS、穆斯堡尔等表征结果表明，在这个新体系中形成了次生矿物，如 Cd 交换羟磷灰石（Cd-HAP）和 kryzhanovskite（Fe(PO)(OH)）。因此，PSB 和 DIRB 的共生体系是一种很有前景的沉积物中 Cd 固定化的生物修复技术，可以避免添加含磷材料可能带来的潜在风险。
