Influence of the stress of Na2S on component changes and sorption behavior on Cu (Ⅱ) and Zn (Ⅱ) of Bacillus vallismortis sp. EPS

作者：Li, Qiu-Hua; Song, Wei-Feng^*; Sun, Meng-Ge; Li, Jia-Yao; Yu, Ze-Feng

来源：China Environmental Science, 2019, 39(11): 4858-4864.

• Asorbent
• Chemical compositions
• Extracellular polymeric substances
• Heavy metal pollution
• Na2S
• Prevention and controls
• Pseudo-second order model
• Sulfhydryl

In order to study the mechanism of enhanced adsorption of heavy metals by extracellular polymeric substances (EPS), adsorption of typical heavy metals by the EPS from Bacillus vallismortis sp. induced by Na2S was investigated. The results showed that the maximum EPS production of 105.58mg/g VSS coupling with doubled increase in protein in which the contant of -SH increased by 48.2% from 104.15 to 154.36μmol/L were recorded in the presence of 20mg/L Na2S, As a coinstantaneous process, the maximum adsorption of Cu (Ⅱ) and Zn (Ⅱ) by the S-EPS was observed in the presence of 20mg/L Na2S. The kinetics of the adsorption process of Cu (Ⅱ) and Zn (Ⅱ) by the S-EPS can be well fitted by the Langmuir isotherm and the pseudo-second-order model mode and the theoretical maximum adsorption amount of 1428.57 and 979.09mg/g EPS could be obtained, respectively. The results of 3D-EEM and FTIR analyses indicated that the -SH, protein amide I and amide Ⅱplayed a major role in the adsorption of Cu (Ⅱ) and Zn (Ⅱ) by the S-EPS, especially for the adsorption of Zn (Ⅱ). The results obtained in this study demonstrated that the addition of sulfur source could increase the content of sulfhydryl protein, and effectively regulate the content of chemical composition, expecially for the sulfhydryl of EPS, and thereby greatly improving the removal efficiency of heavy metals, which showed a great application prospect in the prevention and control of heavy metal pollution.