Characteristics Of Mn(?) Oxidation By A Manganese Oxidizing Bacterium And Adsorption Of Sb(?) During Mn(?) Mineralization

Manganese is an important mineral resource in China.Recently,the health and environmental problems caused by manganese pollution in manganese mining areas have attracted people's attention.Manganese resources in China have the characteristics of complex composition.In addition to manganese,the ore will also be associated with other heavy metals,such as antimony magnesium manganese ore,high lead manganese ore and other heavy metals associated with antimony and lead.Some mining areas will also have different distribution of heavy metal deposits,associated with a variety of heavy metals.Some harmful heavy metals will also be associated with waste water from mining and smelting,which should also be considered in heavy metal mining It is within the scope of pollution control.Compared with other methods,such as chemical method,the cost of manganese removal is high and the treatment capacity is limited.Microbial biological manganese removal process has many advantages,such as high speed,strong impact resistance,good effluent conditions and stable effect,which is one of the hot research topics.However,there are few studies on the removal of mine wastewater by manganese oxidizing bacteria,especially the wastewater with high manganese concentration,acidity and other heavy metals.In this paper,the characteristics of Mn(?)removal by Manganese Oxidizing Bacteria and the adsorption of sb(?)during mineralization were studied.The main research contents and conclusions are as follows(1)Manganese oxidizing bacteria were screened from activated sludge of sewage treatment plant by gradient dilution method and plate marking method;then,the main manganese oxidizing bacteria were identified by colony morphology,and the Manganese Oxidizing Bacteria with relatively strong oxidation performance were selected to study their Mn(?)removal ability and tolerance.The Mn(?)oxidation ability of the selected Mn oxidizing bacteria is very good.When 2%inoculation amount of Mn oxidizing bacteria is inoculated into 500 ml Mn(?)solution with initial concentration of 10 mg/L,the removal rate can reach 98.26%after about 5 days of reaction.0?20h is the slow growth period,and20?40H is the logarithmic growth period.During this period,the growth of the strain is vigorous,and the subsequent stable period can last about 20h.DNA extraction and PCR amplification were used to sequence the gene of Manganese Oxidizing Bacteria.The species identification showed that the manganese oxidizing bacteria was Klebsiella sp.strain m3.The strain grew well in the range of p H 5.0?10.0,and the optimum p H was 7.0.Under the condition of 30?,the liquid medium had the most bacteria content and the best growth condition.The dry weight of manganese oxidizing bacteria cultured in liquid medium reached the highest when the rotation speed was 150 R/min,too fast rotation speed would inhibit its growth and reproduction.(2)The removal ability of Mn(?)by manganese oxidizing bacteria was studied.The effects of nutrient and environmental factors on the activity and removal ability of manganese oxidizing bacteria were investigated by single factor experiment.Generally speaking,for the simulated water containing Mn(?)with initial concentration of 10mg/L,when the dosage of manganese oxidizing bacteria is 10ml,temperature is 30?,p H 7.0,rotation speed of incubator is 150r/min,and aerobic light conditions,manganese oxidizing bacteria can give full play to its manganese removal performance.K⁺,NO₃^-,Na⁺,Mg²⁺and other coexisting ions have little effect on the growth of Manganese Oxidizing Bacteria and the removal of Mn(?).Only Ca²⁺can promote the removal of Mn(?).The biomaterial shows good anti-interference ability,which has great potential for its application in practical engineering.The results showed that the products were formed by massive bacteria,and there were nanoscale spherical manganese oxides on the surface.The content of Mn was 17.03%(mass fraction).FTIR results show that the product contains oxygen-containing functional groups,which is conducive to the ion exchange with Mn and the formation of oxides.XPS peak fitting showed that there was more than one chemical valence and state of Mn in the product,including Mn(IV)and Mn(III).Nitrogen adsorption desorption isotherm test showed that the specific surface area and pore volume of the product were 329.335m2/g and 0.162cm3/g,which could provide and expose more adsorption sites.It was speculated that the product should have excellent adsorption performance for heavy metals.(3)The adsorption and removal ability of sb(?)in the process of Mn(?)bio-mineralization was studied.Compared with the addition of single bacteria and manganese dioxide,the removal efficiency of antimony by adding manganese oxidizing bacteria and manganese ion at the same time is obviously better.The removal rate of sb(?)increased gradually with the increase of the amount of bacterial solution,and the final removal rate reached 80.95%;the removal rate of sb(?)increased with the increase of Mn(?)concentration,but it decreased when the concentration of Mn(?)was too high;the optimal growth p H of the strain was 7.0,and the removal rate of sb(?)decreased with the increase or decrease of p H.After the bacteria oxidize Mn(II)to form manganese oxide,it is covered on the surface to enhance the resistance to harsh environment.Meanwhile,the biogenic manganese oxide has smaller particle size,larger specific surface area and better adsorption effect on antimony.Characterization analysis showed that mineralized substances were formed in the product.The fine spectra of Fe,Sb and Mn were fitted and combined with FTIR results.It was found that there were iron and manganese oxides,and there might be mnooh and Fe OOH.Mn-o and Fe-O bonds coordinated with sb(?)in the solution to achieve adsorption removal effect.