TY - EJOU AU - Guo, Xuying AU - Jiang, Guoliang AU - Fu, Saiou AU - Hu, Zhiyong AU - Di, Junzhen AU - Dong, Yanrong AU - Li, Ying TI - Treatment of Agate Dyeing Wastewater Using an Immobilized Gel Mixture with Nano-Fe3O4 Sulfate-Reducing Bacteria T2 - Journal of Renewable Materials PY - 2021 VL - 9 IS - 11 SN - 2164-6341 AB - To solve the problems of high Cr6+, Cr3+, SO42– and H+ concentrations, pollution and processing costs associated with agate dyeing industrial drainage, we prepared an immobilized gel mixture for the treatment of such drainage on the basis of microbial immobilization technology. The immobilized gel mixture was composed of sulfate-reducing bacteria (SRB), corn cob, and nano-Fe3O4 (nFe3O4). We used a single-factor experiment to determine the optimal dose of each matrix component. We analyzed the mechanism underlying the treatment of agate dyeing wastewater with an immobilized gel mixture by X-ray diffraction and scanning electron microscopy detection. The results of the single-factor test showed that the best treatment was obtained under the following conditions for each matrix component: SRB mass percentage of 30%, nFe3O4 dose of 3%, and corn cob mesh size of 100 and dose of 3%. On this basis, we conducted an L9(34 ) orthogonal experiment to determine the optimal proportion of each matrix component. The results showed that the best treatment was obtained when the gel mixture met the following conditions: SRB mass percentage of 40%, nFe3O4 dose of 4%, and corn cob dose of 1% and mesh size of 100. Accordingly, the SO42– , Cr6+ and Cr3+ removal rates from the agate dyeing drainage were 70.54%, 84.75%, and 73.80%, respectively; the total Fe and chemical oxygen demand releases were 1.086 mg·L–1 and 1104 mg·L–1 , respectively; and the pH was 6.27. The gel mixture had the best treatment effect on agate dyeing wastewater under this composition ratio. KW - Agate dyeing drainage; corn cob; immobilized gel mixture; nano-Fe3O4; orthogonal test; sulfate-reducing bacteria DO - 10.32604/jrm.2021.015878