Advanced Treatment Of Low-concentration Heavy Metal Wastewater In The Electronics Industry With Thiobacillus Acidophilus And Nano-zero-valent Iron

The electronics industry is an important industry in the national economy.A large amount of industrial waste water will be produced during the production process,which contains a large amount of heavy metals,which may be discharged into water bodies without effective treatment,causing water body pollution.Appropriate methods need to be developed to deal with this.Class heavy metal wastewater.Traditional methods include chemical precipitation,thermal and hydrometallurgy,membrane filtration,solvent extraction,and ion exchange.There are disadvantages such as poor quality of wastewater after treatment,high cost of the treatment process,and difficulty in recovering precious metals.This subject takes the low-concentration platinum,palladium,lead,and copper wastewater from smelting and lead battery plants as the research object,and uses the principles of acidophilic Thiobacillus and nano-zero-valent iron precipitation and adsorption to remove platinum,palladium,and palladium from the wastewater.Lead,copper,and realize the recovery of precious metals.The main research contents and conclusions include:(1)Analysis and comparison of Acidithiobacillus ferrooxidans(Acidithiobacillus ferrooxidans,hereinafter referred to as A.f bacteria),Acidithiobacillus thiooxidans(hereinafter referred to as A.t bacteria),and Acidithiobacillus ferrooxidans(Acidithiobacillus ferrooxidans,hereinafter referred to as A.t bacteria)The removal rate of precious metal platinum and palladium by the mixed strain of A.f bacteria)and Acidithiobacillus thiooxidans(hereinafter referred to as A.t bacteria).The results showed that the A.f+A.t bacteria have an excellent treatment effect on precious metals platinum and palladium.A.t bacteria is better than A.f bacteria.(2)The effects of time,strain inoculation amount,initial p H,different medium composition,and other factors on the removal of low-concentration precious metals platinum and palladium by A.t bacteria,A.f bacteria,and A.t+A.f bacteria were explored.The results showed that when A.t bacteria,A.f bacteria,and A.t+A.f bacteria were treated with precious metal platinum,the highest removal rates reached 84.15%,62.85%,and 93.53% under different time conditions.Under the optimal inoculation amount,the highest removal rate was84.15%,62.85%,and 93.53%.The highest removal rates are: 81.26%,61.91%,and 90.94%;under different p H conditions,the highest removal rates are 84.31%,62.33%,and 95.22%;under different medium composition conditions,the removal rates are The highest are 80.71%,62.33% and 91.27% respectively.When A.t bacteria,A.f bacteria,and A.t+A.f bacteria were respectively treated with precious metal palladium,the highest removal rate reached 82.08%,62.98%,92.48% under different time conditions,and the highest removal rate was under different inoculation amounts.Respectively: 81.29%,63.18%,89.83%;Under different p H conditions,the highest removal rate reached 86.48%,63.88%,95.80%;Under different medium composition conditions,the highest removal rate was 79.45.%,67.03% and 94.32%.(3)The effects of time,strain inoculation amount,initial p H,different culture medium composition and other factors on the removal of lead and copper in low-concentration heavy metal wastewater from lead battery plants were investigated by A.t+A.f bacteria.The results showed that the highest removal rate of lead was 74.69% and the highest removal rate of copper was 38.48% in different time.Under different conditions of inoculation amount,the highest removal rate of lead is 73.82%,and the highest removal rate of copper is 38.67%.Under different p H conditions,the highest removal rate of lead was 73.36%,and the highest removal rate of copper was 37.28%.Under different medium composition conditions,the highest removal rate of lead reached 77.09%,and the highest removal rate of copper reached38.34%.(4)Explore the advanced treatment of low-concentration precious metals platinum and palladium in smelter wastewater by A.t+A.f bacteria in collaboration with nano-zero-valent iron,and heavy metals lead and copper in lead storage battery plants.It was found that adding nano-zero-valent iron based on the Thiobacillus acidophilus treatment system is beneficial to promote the complete removal of low-concentration precious metals platinum and palladium,and the highest removal rates of low-concentration heavy metals lead and copper reached97.29% and 59.59%,respectively.(5)Finally,combining the changes of p H and ORP under different conditions,as well as the changes of the substrate surface of the culture solution before and after the analysis by SEM-EDS,etc.,explore the effect of Thiobacillus acidophilus synergistically with nano-zero-valent iron-on low-concentration precious metals platinum,palladium,and low-concentration heavy metals.Removal mechanism of lead and copper.It was found that Thiobacillus acidophilus and nano-zero-valent iron remove platinum,palladium,lead,and copper from wastewater through the principle of precipitation and adsorption.