Arsenic ; Adsorption and desorption; Microbial reduction Kinetics; Fe and Al hydroxide; Arsenate ; Arsenite
Huang Jen-How, Voegelin Andreas, Pombo Silvina Andrea, Lazzaro Anna, Zeyer Josef, Kretzschmar R (2011), Influence of arsenate adsorption to ferrihydrite, goethite, or boehmite on the kinetics of arsenate reduction by Shewanella putrefaciens strain CN-32, in Environmental Science & Technology
, 45, 7701-7709.
Huang Jen-How, Elzinga Evert Jan, Brechbuehl Yves, Voegelin Andreas, Kretzschmar Ruben (2011), Impacts of Shewanella putrefaciens cells and extracellular polymeric substances on the sorption of As(V) and As(III) on Fe(III)-(hydr)oxides., in Environmental Science & Technology
, 45, 2804-2810.
Huang Jen-How, Hu Kan-Nian, Decker Berryinne (2010), Organic arsenic in the soil environment: speciation, occurrence, transformation and adsorption behaviour, in Water, Air, & Soil Pollution
, 219, 401-415.
Huang Jen-How, Kretzschmar Ruben (2010), New sequential extraction method for arsenic speciation in oxic and anoxic, in Analytical Chemistry
, 82, 5534-5540.
Arsenic in drinking water and soils poses a serious threat to millions of people worldwide due to its chronic toxicity. The oxidized arsenate (As(V)) is less mobile and toxic than the reduced arsenite (As(III)). The reduction of As(V) to As(III) in most environmental systems is driven by microorganisms, but arsenic sorption at the mineral-water interface may strongly influence the rates of this transformation. Understanding the influence of mineral surfaces on the kinetics of microbial As(V) reduction is thus essential to better assess the arsenic mobility and toxicity in soils, sediments, and natural waters. In this project, incubation experiments will be performed to study the influence of As(V) sorption on iron and aluminium hydroxide surfaces on the kinetics of the microbial As(V) reduction. The effects of As(V) surface loading and of competitive sorption with phosphate and sulphate will be studied in detail. The experiments are carried out with arsenic reducing bacteria to focus on the effect of arsenic sorption on As(V) reduction and with mixtures of iron and arsenic reducing bacteria to study the combined effects arising from oxide dissolution and As(V) reduction. The biogeochemical fate of arsenic at the water-solid interface is considered parallel from the aspects of microbial activities, chemical speciation and physiochemical processes. The knowledge generated in this study provides new insight into an important environmental process and is needed for the implementation of powerful strategies to cope with the problem of large-scale arsenic release from sediments into water worldwide.The applicant has excellent skills in field studies on trace element fluxes and transformation in forest ecosystems as well as in speciation techniques for trace elements in environmental samples. In the proposed study, the applicant extends his scientific skills in various fields, including surface, soil, and colloid chemistry, mineralogy, microbiology, and various experimental and analytical techniques. It offers the applicant a new and stimulating research environment. The opportunity to work at ETH Zurich through an Ambizione fellowship will raise his international profile. The applicant will personally benefit from stimulating contacts with some of the best researchers in the field worldwide. The Ambizione fellowship at ETH Zurich would allow the applicant to develop complementary skills in teaching, communication, scientific writing, and project management and provides the ideal basis for his further research career in environmental sciences.