Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil. (March 2017)

• Record Type: Journal Article
• Authors: Wang, Xiaonan; Zhang, Daoyong; Pan, Xiangliang; Lee, Duu-Jong; Al-Misned, Fahad A.; Mortuza, M. Golam; Gadd, Geoffrey Michael
• Is Part Of: Chemosphere. Volume 170(2017)
• Page Start: 266
• Page End: 273
• Publication Date: 2017-03
• Subjects: Bioremediation -- Selenium -- Mercury -- Metal immobilization -- Selenium nanoparticles; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2016.12.020
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se 0 ) under both aerobic and anaerobic conditions. The biogenic nano-Se 0 converted 45.8–57.1% and 39.1–48.6% of elemental mercury (Hg 0 ) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg 0 remediation, probably owing to the release of intracellular nano-Se 0 from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se 0 and Hg 0 . Biosynthesis of nano-Se 0 both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg 0 -contaminated surface and subsurface soils, where the redox potential often changes dramatically. Highlights: A new promising bioremediation technology for soil Hg was reported. Hg was stably immobilized as HgSe by bacteriogenic nano-Se 0 . Aerobically and anaerobically produced nano-Se 0 can be applied to surface and subsurface soils. Biogenic nano-Se 0 is better than chemically synthesized nano-Se 0 for Hg remediation. Sodium dodecyl sulfonate can increase Hg remediation using biogenic nano-Se 0 .