Study On Cu²⁺ Enhanced Fe²⁺ Activated Persulfate Degradation Of Organic Pollutants

In recent years,the discharge of industrial dye wastewater and pharmaceutical wastewater has caused serious water pollution.Among them,azo dyes（such as rhodamine B（RhB））have the problems of high proportion,mutagenicity and carcinogenicity;As a new pollutant,minocycline（MNC）has a variety of potential toxicity to organisms in the environment,such as liver and kidney damage,dysbacteriosis and allergic reactions;As a kind of tetracycline antibiotics with broad-spectrum antibacterial effect,it is often detected in water in recent years,and the concentration is increasing.The environmental health risks caused by both of them have received considerable attention.In recent years,advanced oxidation technology based on persulfate（PS）and H2O2 has been proved to be one of the most promising methods to remove refractory pollutants in water.The content of this experimental study is that Cu²⁺strengthens Fe²⁺activated persulfate to degrade organic pollutants.The main conclusions obtained are as follows:（1）The Fe²⁺/PS basic system was adopted,and the Fe²⁺/Fe³⁺cycle was established by introducing Cu²⁺with reducing function and CA with complexing function into the system.Meanwhile,the introduction of CA avoided the precipitation of Fe²⁺and enhanced the degradation effect under different pH conditions.（2）When the temperature is 20±2℃,the concentration of Fe²⁺is 0.5 m M,the concentration of PS is 1 m M,the concentration of Cu²⁺is 50μM,and the concentration of CA is 25μM,RhB has the best decolorization effect,and the decolorization rate of RhB is as high as 98.4%after 30 min reaction in neutral condition（pH=7）.Because of the existence of complexing agent CA,pH has little effect on the degradation rate of RhB,and only when pH is too low（pH=1）can the reaction system be inhibited to some extent.（3）The natural bornite（NBo）rich in iron and copper is taken as the target activator,which has good catalytic effect on PS and H2O2,and can effectively degrade minocycline（a new antibiotic）in water.Under the conditions of pH=4.5±0.1,CNBo=0.15 g/L,CPS=CH2O2 and its concentration of 0.5 m M,the degradation rates of MNC in NBo/PS system and NBo/H2O2 system were 86.4%and 87.5%,respectively.（4）pH has great influence on the catalytic reaction of NBo,and low pH is beneficial to increase the degradation efficiency of MNC.Oxidant and catalyst also have their best dosage.The degradation process is accompanied by the decrease of biological toxicity and the increase of salinity.（5）Typical inorganic anions in water,such as Cl^-,NO3^-and CO3^2-can inhibit the reaction to some extent,and the inhibition intensity is proportional to the concentration of these anions.However,the inhibitory effect of HCO3^-on the reaction is inversely proportional to its concentration,and high HCO3^-concentration can promote the reaction to some extent.Through the analysis of the degradation path of pollutants,it can be seen that the advanced oxidation system based on sulfate radical mainly destroys the structure of pollutants by electron transfer,such as destroying the C-C bond of pollutants and deamidating to produce pollutants with ring structure;Advanced oxidation system based on hydroxyl radical mainly completes the degradation process of pollutants by free radical addition.