Experimental study of the remediation of acid mine drainage by Maifan stones combined with SRB.

Xuying Guo,Zhiyong Hu,Yanrong Dong,Guoliang Jiang,Saiou Fu,Ying Li,J Paul Chen

doi:10.1371/journal.pone.0261823

Xuying Guo, Zhiyong Hu + Show 5 more

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https://doi.org/10.1371/journal.pone.0261823

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Journal: PloS one	Publication Date: Jan 19, 2022
Citations: 6	License type: CC BY 4.0

Affiliation: Liaoning Technical University

Abstract

The problems of acid mine drainage (AMD) in coal mine acidic wastewaters arise from a range of sources, including severe pollution with heavy metals and SO42- and difficulties during treatment. Based on the ability of Maifan stone to adsorb heavy metals and the dissimilatory reduction of SO42- by sulfate-reducing bacteria (SRB), Maifan stone-sulfate-reducing bacterium-immobilized particles were prepared via immobilization techniques using Shandong Maifan stone as the experimental material. The effects of Maifan stones containing SRB on mitigating AMD were investigated by constructing Dynamic Column 1 with Maifan stone-sulfate-reducing bacterium-immobilized particles and by constructing Dynamic Column 2 with SRB mixed with Maifan stones. By the use of adsorption isotherms, adsorption kinetics, a reduction kinetics model and X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies, the mechanism by which Maifan stone-sulfate-reducing bacterium-immobilized particles mitigate AMD was revealed. The results showed that the total effect of Maifan stone-sulfate-reducing bacterium-immobilized particles on AMD was better than that of biological Maifan stone carriers. The highest rates for the removal of Fe2+, Mn2+, and SO42- in AMD were 90.51%, 85.75% and 93.61%, respectively, and the pH value of the wastewater increased from 4.08 to 7.64. The isotherms for the adsorption of Fe2+ and Mn2+ on Maifan stone-sulfate-reducing bacterium-immobilized particles conformed to the output of the Langmuir model. The adsorption kinetics were in accordance with Lagergren first-order kinetics, and the kinetics for the reduction of SO42- conformed to those of a first-order reaction model.

Highlights

Acid mine drainage (AMD) is polluted water produced by coal mining [1]
Zheng et al used iron slag (FS) and carbon steel slag (CSS) from steel mills as adsorbents to remove sulfate from AMD; the results showed that the adsorption capacities of FS and CSS were 225.07 mg.g-1 and 320.57 mg.g-1, respectively [11]
3.1 Dynamic test of Maifan stones combined with sulfate-reducing bacteria (SRB) for mitigation of AMD

Summary

Introduction

Acid mine drainage (AMD) is polluted water produced by coal mining [1]. Zheng et al used iron slag (FS) and carbon steel slag (CSS) from steel mills as adsorbents to remove sulfate from AMD; the results showed that the adsorption capacities of FS and CSS were 225.07 mg.g-1 and 320.57 mg.g-1, respectively [11]. The adsorption method has the advantages of simple operation, low cost and availability, but if the adsorption of heavy metal ions is not properly treated, secondary pollution is likely [12]. The microbial method mainly uses SRB to treat AMD [13,14], which can remove SO42- and produce alkalinity to improve the pH of waste, which has the advantages of easy access and low treatment cost. Jennyfer used SRB to remove heavy metals such as As and Fe in AMD; the results showed that the removal rates of As and Fe were 73% and 78%, respectively, [16]. SRB had limited tolerance to high metal concentrations and low pH, and high acidity and high concentrations of heavy metal ions inhibit biological activity and harm biological organisms [17]

Methods

Results

Conclusion