Cd(II)与As(V)在一株土壤细菌Delftia sp.上的共吸附研究

This study used macroscopic batch adsorption experiments, potentiometric titration and spectroscopic methods to explore the co-adsorption characteristics and mechanisms of Cd(II) and As(V) on the surface of a soil bacterium (Delftia sp.). The results showed that: The surface of Delftia sp. bacteria is rich in functional groups such as carboxyl, phosphoryl, amino and hydroxyl, and the dissociation constants (pKa) are 4.57, 7.04, 8.22 and 10.45 respectively; when the pH is 5, there is little difference in the adsorption amount of Cd(II) in the composite and single systems; in the pH range of 2 - 9, the adsorption amount of As(V) in the composite system is less than that in the single system; the carboxyl and a small amount of amino groups on the bacterial surface participate in the complexation reactions of Cd and As on the bacterial surface, and Cd and As will compete at these sites. This study confirmed that soil pH is an important factor affecting the co-adsorption of Cd and As on the microbial surface.

本研究利用宏观批吸附试验、电位滴定及光谱学手段探讨Cd(II)与As(V)在一株土壤细菌(Delftia sp.)表面的共吸附特点和机制。结果表明:Delftia sp.细菌表面富含羧基、磷酰基、氨基和羟基等官能团,解离常数(pKa)分别为4.57、7.04、8.22和10.45;当pH5时,Cd(II)在复合和单一体系吸附量差异不大;在pH 2 ~ 9范围内, As(V)在复合体系的吸附量都小于单一体系;细菌表面的羧基和少量氨基参与了Cd、As在细菌表面的络合反应,且Cd、As会在这些位点发生竞争作用。本研究证实,土壤pH是影响Cd、As在微生物表面共吸附的重要因素。