海藻酸钠固定硫酸盐还原菌、镍-铁纳米粒子生物微球对污水中Cd2+的去除

为寻求一种高效去除高浓度含Cd²⁺废水的方法，本研究以海藻酸钠为载体固定硫酸盐还原菌(SRB)和镍铁双金属纳米粒子,制备了高效去除Cd²⁺的活性生物微球(SSNF)，并通过对比不同的固定化材料来探讨其对废水中高浓度Cd²⁺的去除效果。通过改变镍-铁添加量，pH，反应时间,初始Cd²⁺浓度探讨了SSNF去除Cd²⁺的能力，并结合吸附动力学探究了SSNF对Cd²⁺的去除过程及相关机制。结果表明，当镍-铁添加量为0.3 g、pH为7、反应时间5 d、Cd²⁺初始浓度为400 mg·L⁻¹时，SSNF去除率可达到100 %，吸附量为103.86 mg·g⁻¹。镍-铁对 SRB去除Cd²⁺具有明显的协同促进作用，且符合准二级动力学模型，以化学吸附作用为主，物理吸附为辅。离子交换或共价电子作用可能是SSNF吸附Cd²⁺的主要机制。利用无菌生理盐水对活性生物微球进行洗涤，重复使用3次后，微球仍能保持较高的去除能力。该研究结果可为解决含有高浓度Cd²⁺污染的废水问题提供技术参考。

Removal of Cd2+ in sewage by sodium alginate immobilized sulfate-reducing bacteria and nickel-iron nanoparticle biological microspheres

In order to find an efficient method to remove high-concentration Cd2+ contained in wastewater, sodium alginate was used as a carrier to immobilize sulfate-reducing bacteria (SRB) and nickel-iron bimetallic nanoparticles, and a type of active biological microspheres(SSNF) that can efficiently remove Cd2+ was prepared. Through the comparison of different immobilized materials, its effect on high-concentration Cd2+ removal from wastewater was explored. The Cd2+ removal ability by SSNF was discussed with the variations of the amount of ferronickel, pH, reaction time, and initial Cd2+ concentration, and the adsorption kinetics was combined to study the Cd2+ removal process and related mechanisms by SSNF. The results showed that when ferronickel addition was 0.3 g, pH=7, reaction time was 5 d, and Cd2+ initial concentration was 400 mg·L−1, Cd2+ removal rate by SSNF reached 100 % with the adsorption capacity of 103.86 mg·g−1. Ferronickel has an obvious synergistic promotion effect on Cd2+ removal by SRB, and it conforms to the quasi-second-order kinetic model, and was dominated by chemical adsorption with physical adsorption as supplement. Ion exchange or covalent electron interaction may be the main mechanism for Cd2+ adsorption onto SSNF. The research results can provide a technical reference for solving the problem of high concentration-Cd2+ wastewater treatment.