Simultaneous leaching of multiple heavy metals from a soil column by extracellular polymeric substances of Aspergillus tubingensis F12. (January 2021)

• Record Type: Journal Article
• Authors: Tang, Aixing; Lu, Yuhao; Li, Qingyun; Zhang, Xianglu; Cheng, Ning; Liu, Haibo; Liu, Youyan
• Is Part Of: Chemosphere. Volume 263(2021)
• Publication Date: 2021-01
• Subjects: Extracellular polymeric substances -- Leaching -- Heavy metals -- Aspergillus tubingensis -- Microbial community structure; Extracellular polymeric substances (EPS) -- China General Microbiological Culture Collection (CGMCC) -- energy dispersive X-ray spectroscopy (EDS) -- inductively coupled plasma optical emission spectrometry (ICP-OES) -- response surface methodology (RSM) -- X-ray photoelectron spectroscopy (XPS); Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127883
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The use of the biological agents for leaching heavy metals from contaminated soils is a very promising method that is both efficient and eco-friendly. In this study, a fungus Aspergillus tubingensis F12 was reported to possess a strong adsorption capacity for various heavy metal ions and shown to adsorb 90.8% Pb, 68.4% Zn, 64.5% Cr, 13.1% Cu, 12.9% Ni, and 6.9% Cd in aqueous solution. As extracellular polymeric substance (EPS) was found to play a leading role in the adsorption of metal ions, we applied EPS as a leaching agent to simultaneously remove six metals from soil in a column leaching experiment. The flow rate, initial solution pH, initial EPS concentration, and ionic strength were investigated using response surface methodology. The minimum and maximum metal leaching capacities were determined to be 0.089 mg/g and 3.703 mg/g, respectively. Verified by Fourier transform infrared spectroscopy, scanning electron microscope energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy, we made the preliminary deductions that ion exchange determines the leaching capacity limit and that biosorption plays a large role in reaching that limit. Additionally, the redox behaviour of Cu produced more carboxyl groups, which increased the adsorption of heavy metals. The ecological impact of this method was also examined; we found that the influences of leaching with EPS on soil properties and microbial community structure were slight. Therefore, the reported leaching process might have application prospects for metal removal from soil. Graphical abstract: Image 1 Highlights: Fungus F12 shows strong adsorption capacity for Pb(II), Cr(III), and Zn(II). Extracellular polymeric substances play a leading role in adsorbing metal ions. EPS as a leaching agent can effectively leach heavy metals from soil column. Ion exchange, biosorption and redox are critical in metal leaching. EPS treatment has little influence on soil characteristics and biological community.