Biosorption Of Arsenic In Different Environmental Conditions Using Acidithiobacillus Ferrooxidans And Its Application

Arsenic is a kind of metal element commonly found on the earth.It ranks twentieth in nature,and arsenic in rock minerals is also more distributed.Arsenic is toxic to humans and the environment.Arsenic pollution in drinking water has become a global problem that represents an enormous challenge for scientists and policy makers.To date,there are many traditional technologies that remove arsenic from water solutions,including flotation,coagulation–precipitation,adsorption,ion exchange,membrane filtration and electrochemical treatment.However,although these methods have been put into practice,several shortcomings,such as high cost,low selectivity and high energy consumption,have limited their further application.Compared to the traditional methods mentioned above,bioadsorption produces extraordinary increases in solubility and bioavailability and is efficient,ecologically safe,low cost and harmlessness without secondary pollution.Acidithiobacillus ferrooxidans type strain DLC-5,isolated from Wudalianchi in Heihe of Heilongjiang Province,China.This study investigated the equilibrium,thermodynamics and bioadsorption characteristics of arsenite [As(III)] and dimethylarsinate [DMA(?)] by Acidithiobacillus ferrooxidans(A.ferrooxidans)DLC-5 in aqueous solution.Optimum bioadsorption conditions were determined by identifying the optimum temperature,pH,biomass dosage,initial arsenic concentration and contact time.The equilibrium data were then applied to Langmuir and Freundlich isotherm models.The results indicated that the bioadsorption processes for both As(III)and DMA(?)involved pseudo-second-order kinetics.Additionally,the bioadsorption of As(III)and DMA(?)by A.ferrooxidans DLC-5 was feasible,spontaneous and endothermic under the tested conditions.Fourier transform infrared spectroscopy(FT-IR)showed that-OH and-NH groups were involved in the bioadsorption process.A.ferrooxidans DLC-5 demonstrates potential for use in removing arsenic from aqueous solutions,especially those with very low arsenic concentrations.The schwertmannite,a new kind of arsenic adsorption materials,was preparated by biological methods.Using the mechanism of biosorption of A.ferrooxidans to regenerate the material so that it can be used reproducible.We have established a novel method for biosorption and desorption.After using schwertmannite to adsorb arsenic,it was eluted and regenerated with A.ferrooxidans DLC-5.The arsenic containing bacteria were collected and treated regularly to remove arsenic in water body.This is an arsenic containing water treatment technology with potential application.Finally,the triangles of Ag@Au core shell nanoparticles were successfully prepared,and the stability and sensitivity of the nanoparticles were tested.The experiment proved that the material was stable and sensitive.On this basis,a LSPR detection chip is made by using the Localized surface plasmon resonance effect of the triangular Ag@Au core shell nanoparticles.The glutathione is added to the chip as a recognition unit.This biometric unit can react with the arsenic ion in the solution to induce the folding of the external medium of the metal nanoparticles.The emissivity is changed into an intuitive and measurable peak absorption wavelength of LSPR,and the detection of arsenic in the solution is realized according to the regular variation of the peak wavelength.