Study On The Decontamination Efficiency Of Copper-based Oxides Activated Peroxymonosulfate And The Formation Of By-products

With the improvement of environmental analysis level,some emerging pollutants（endocrine disruptors,drugs and personal care products,carcinogenic polycyclic aromatic hydrocarbons,brominated flame retardants,etc.）are detected in drinking water,surface water,groundwater and sewage at home and abroad.Traditional water treatment processes（coagulation/flocculation,precipitation,filtration,chlorination,etc.）have poor treatment effects.Advanced oxidation technology based on sulfate radical(SO₄^·-)has a broad scope for the removal of refractory organic pollutants.Copper pipes used in some water distribution systems will produce corrosion products such as copper oxide（CuO）,cuprous oxide（Cu₂O）,and copper hydroxide（Cu（OH）₂）.However,perisulfate（PMS）is easily activated by metal oxides to produce SO₄^·-,which degrades organic pollutants and produces corresponding by-products.In the first part of this paper,CuO,Cu₂O and Cu（OH）₂ are taken as the research object to construct the oxidation system based on PMS and experiment with2,2-Bis（bromomethyl）propane-1,3-diol as the target pollutant.We found that CuO,Cu₂O,and Cu（OH）₂ can activate PMS and degrade BBMP to varying degrees.The effect is CuO>Cu（OH）₂>Cu₂O.Free radical inhibition and electron paramagnetic resonance（EPR）detection showed that the degradation of BBMP was dominated by SO₄^·-produced by PMS.Debromination is one of the degradation pathways of BBMP.Most of the removed bromine exists in the form of bromide,and part of it is converted from bromide to bromate.Changing the PMS concentration and copper dosage will affect the degradation of BBMP and the final proportion of inorganic bromine to varying degrees.With the increase of the concentration of bicarbonate（HCO₃^-）,the degradation rate of BBMP in the copper oxides/PMS system first increased and then decreased.With the increase of natural organic matter（NOM）concentration,the degradation rate of BBMP gradually decreased in the copper oxides/PMS system.Copper oxides can activate PMS and effectively degrade BBMP in actual water.The first part of the research results showed that CuO/PMS has the best degradation effect on BBMP,but it caused the formation of bromate.The second part chooses CuO/PMS system to explore the law of bromate formation.Experiments showed that CuO significantly promoted the oxidation of bromide ions,and 87.2%of bromide ions were converted to bromate after 30 minutes of reaction.The formation of bromate in CuO/PMS system is divided into two steps:firstly,the bromide ion is oxidized to free bromine,which is further oxidized to bromate.CuO plays a dual role in the formation of bromate.It can not only catalyze PMS to generate SO₄^·-,oxidize bromine ions to free bromine and further oxidize to bromate,but also catalyzes the disproportionation reaction of free bromine to produce bromate.With the increase of PMS concentration,CuO dosage and initial bromide ion concentration,the amount of bromate produced increased;but with the increase of HCO₃^-concentration and NOM concentration,the amount of bromate produced decreased.CuO can still convert more than 70%of the initial bromide ions to bromate after 6 cycles.CuO can also catalyze the oxidation of bromide to bromate by PMS in real water.The third part of research found that CuO can activate PMS to degrade sulfamethoxazole（SMX）,carbamazepine（CBZ）and atrazine（ATZ）.Active substance inhibition experiments and EPR test results showed that the degradation of SMX is the dominant role of ¹O₂produced in the system,and the degradation of CBZ and ATZ is the major role of SO₄^·-produced in the system.In the CuO/PMS system,the degradation rate and reaction rate of organic matter are closely related to the PMS concentration,CuO dosage,HCO₃^-concentration,and NOM concentration.Experiments have proved that CuO can also activate PMS to degrade various organic substances in actual water.