Study The Influence Of Copper And Iron Ions On The Biological Purification System And Properties

Phosphine is widely comes from human activities and natural processes such as yellow phosphorus production,calcium carbide preparation,anaerobic treatment of sludge,wetlands and swamps.The high-concentration phosphine was produced by the yellow phosphorus process,and it was mostly treated by physical and chemical methods,but the purification process technology requires frequent replacement of the absorption liquid or adsorbent,the process was complicated and the exhaust gas purification cost is relatively high.In recent years,the biological purification had been used in low-concentration phosphine of sewage treatment plants and landfills got attention.Restricted by factors such as phosphine insoluble in water and biological toxicity,the increase of microorganisms was very slow in the biological purification system,the removal rate of phosphine was sometimes not well.How to keep microorganisms in a better growth condition and improve the efficiency of phosphine biological purification requires in-depth application of basic research.This study focused on the process of enhanced biological purification of phosphine,and selected Mn²⁺、Fe²⁺、Cu²⁺and Co²⁺,according to the phosphorus removal rate and the change of microbial biomass in each system,compared the four metals added to a biological system,the effect of adding four kinds of metals in biological system on improving the removal rate of phosphine was compared.It was found that Co²⁺can better improve the efficiency of microbial method to remove phosphine,the removal rate of Cu²⁺and Fe²⁺was lower than Co²⁺,and Mn²⁺removal rate was the lowest.By comparing the advantages and disadvantages of the four metal ions,Cu²⁺and Fe²⁺were more economical and effective.The optimum dosage of Cu²⁺and Fe²⁺was studied under batch conditions.When the concentration of Cu²⁺was 1.5mmol/L,the removal rate was the best,the maximum removal rate was 81.3%,and the average removal rate was 76.7%.At this time,the corresponding average values of SOD and CAT enzymes were 97.6 U/g and 7.5 U/g,When the concentration of Cu²⁺was 1 mmol/L,the removal rate was lower than that when the concentration was 1.5 mmol/L,the highest and average removal rate were78.0%and 74.3%.And at these two concentrations,the enzyme activity in the system was high,the corresponding oxidative stress was weak,it showed that the system can effectively alleviate the negative effects of free radicals on microorganisms.When the amount of Fe²⁺was 1mmol/L,the removal rate of microbial system was higher than other system,the highest removal rate was 77.0%,the average removal rate was 71.9%.The average SOD and CAT enzyme activity was 86.4 U/g and 7.7 U/g.Compared with the blank group,adding a certain concentration of metal ions was helpful to improve the purification effect of phosphine in the biochemical system.In the process of exploring how adding metal ions can improve the purification effect of phosphine,Cu²⁺and Fe²⁺were added into the reactor in a semi-continuous manner at the same concentration.In a system with added Cu²⁺,the average of OD₆₀₀was 1.12.The activities of SOD and CAT enzyme were 74.1 U/g and 6.7 U/g,respectively,compared to the reactor with added Fe²⁺,The concentration of O₂^-·and MDA decreased to 260 and 0.32umol/g.Comparing the metal ion composite system,it was found that the comparison of the metal ion composite system found that the more copper ions added to the system,the more beneficial the purification of phosphine.The copper ions were complexed with EDTA and entered the cell in the system,which promotes the activity of SOD enzyme and CAT enzyme,so that the content of O₂-·and MDA in the system is reduced,that is,the effect of oxidative stress is reduced;After iron ions were complexed with EDTA,the stability of the complex is weaker than the copper complex,and the content of ions that can be complexed with EDTA is not high,so the content of iron complex entering the cell is not high.And only a small amount of ions can complex with EDTA,so the iron complex content in the cell is not high.After the complex entered the cell,although it can increase the enzyme activity,it also produced hydroxyl free radicals,which is not conducive to cell growth.Therefore,the overall promotion of microorganisms was lower than the copper ions.In addition,during stable operation,The analysis of the microbial population structure showed that the microbial species of the system with metal ions were similar at the level of phylum,family,genus,and species,and compared with the system without metal ions,the level of microbial richness and diversity was significantly improved.