Bioleaching of available silicon from coal tailings using Bacillus mucilaginosus: a sustainable solution for soil improvement

• Published in: Environmental science and pollution research international 2023-08, Vol.30 (40), p.93142-93154
• Main Authors: Zhang, Qingshan, Liang, Long, Jing, Mengjuan, Yan, Xinxin, Peng, Yaoli
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bacillus mucilaginosus; Bacterial leaching; Chemical reactions; Coal; Crop growth; Crop yield; Crops; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Environmental utilization; Fourier transforms; FTIR spectrometers; High performance liquid chromatography; Infrared spectrometers; Kinetics; Leaching; Liquid chromatography; Mine tailings; Nutrients; Research Article; Scanning electron microscopy; Shaking; Silicon; Soil improvement; Soils; Solid wastes; Spectroscopy, Fourier Transform Infrared; Tailings; Waste Water Technology; Water Management; Water Pollution Control; X-ray diffraction
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-023-28921-y

In China, a large amount of soil lack available silicon, which leads to a decrease in crop yield. Furthermore, the solid waste coal tailings contain abundant minerals that are rich in silicon, which have not been fully utilized. In this work, we used Bacillus mucilaginosus as the leaching agent to convert insoluble silicon in coal tailings into available silicon for crop. After single-factor experiments, the optimal leaching conditions with bacterial dosage, coal tailings weight, initial pH, leaching temperature, and shaking speed were obtained. Kinetic analysis showed that the controlling process of the leaching was a chemical reaction. The leaching process was characterized by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectrometer (FT-IR), and high-performance liquid chromatography (HPLC). The results showed that bioleaching is a feasible and efficient method to extract silicon from coal tailings, with a maximum leaching amount of 260 mg L −1 after 16 days, which occupied 93% of the total effective silicon. In conclusion, this work demonstrates that bioleaching technology can effectively solve the problem of the environmental utilization of coal tailings by converting them into a soil improver that can provide beneficial nutrients for crop growth.