It is easy to volatilize, spread, and stay in the atmosphere in the form of a gas, and redeposit in water or soil in the form of rain or dry gas. Mercury (Hg) is a common, naturally occurring, toxic heavy metal. This study provides an efficient and unused bacterium for the biological treatment of Hg pollution. When all three mechanisms coexisted, the reduction of Hg(II) occurred within 8 h, the adsorption of Hg(II) by EPSs and DBB occurred within 8–20 h and after 20 h, respectively. At moderate concentrations, the bacteria primary employed EPS and DBB adsorption to remove Hg(II), where the percentages were 19.09 ± 0.04% and 80.91 ± 2.41% of the total removal rate, respectively. At low concentrations, RTS-4 bacteria employed Hg(II) reduction and DBB adsorption to remove Hg(II), and the removal percentages were 54.57 ± 0.36% and 45.43 ± 0.19% of the total removal efficiency, respectively. The Hg(II) bioremediation mechanisms of RTS-4 bacteria are as follows: (1) the reduction of Hg(II) through Hg reductase encoded by the mer operon (2) the adsorption of Hg(II) through the production of extracellular polymeric substances (EPSs) and (3) the adsorption of Hg(II) using dead bacterial biomass (DBB). To explore the strong tolerance of bacteria to Hg pollution, aquatic Rheinheimera tangshanensis (RTS-4) was separated from industrial sewage, with a maximum Hg(II) tolerant concentration of 120 mg/L and a maximum Hg(II) removal rate of 86.72 ± 2.11%, in 48 h under optimum culture conditions.
0 Comments
Leave a Reply. |