The Treatment Of Residual Organic Agents In Beneficiation Wastewater By Microwave Activated Persulfate

In the processed of rapid development of national economy,mineral resources must occupy a strategic position,which is the pillar industry of social and economic development.With the development of national economy,the demand for mineral resources has been increasing.And the resulting mineral processing wastewater has attracted extensive attention due to the threat to the natural environment and human health caused by the presence of a large number of mineral processing agents.In recent years,it has been found that SO₄^-·has a high redox potential,which can quickly oxidize and degrade the refractory pollutants contained in wastewater without secondary pollution,with high efficiency and easy control.Therefore,the advanced oxidation technology based on sulfate radical(SO₄^-·)has been continuously developed.In this paper,butyl xanthate,salicylhydroxamic acid and aniline aerofloat agent were selected as the target pollutants to study the feasibility of microwave activated persulfate degradation of mineral processing agents,change the single factor conditions,simulate the actual mineral processing wastewater added metal ions,simulate the natural water added inorganic anions and humic acid.1.With the increased of microwave radiation power and persulfate dosage,the degradation rate of each reagent increased,but decreased with the increased of initial concentration of pollutants and initial p H of reaction solution.The mineralization rate of butyl xanthate was47.74%after 90 min in the reaction system.The mineralization rates of salicylhydroxamic acid and aniline aerofloat were 45.22%and 45.27%after 180 min degradation,respectively.By compared the degradation rates of mineral processing reagents under microwave heating and water bath heating,it was concluded that microwave activation of persulfate has both thermal and non thermal effects.The free radical scavenger experiments with ethanol and tert butyl alcohol showed that SO₄^-·and·OH participate in the oxidation and SO₄^-·was the main actived free radical.2.The effect of coexisted metal ions on the degradation of mineral processing reagents by microwave activated persulfate was investigated.It was found that the degradation of mineral processing reagents was inhibited when the concentration of Fe²⁺in the reaction solution exceeded 0.25 mmol/L,while the degradation of mineral processing reagents was promoted when the concentration of Fe²⁺increased from 0 to 0.25 mmol/L,and with the increased of Cu²⁺concentration,butyl xanthate decreased The results showed that the degradation rate of aniline aerofloat was increased with the increased of the concentration of 0.25 and 0.50 mmol/L,and salicylhydroxamic acid was inhibited at the later stage of the reaction at the concentration of0.50 mmol/L.The addition of metal ion Mn²⁺promoted the reaction of butyl xanthate and inhibited the degradation of salicylhydroxamic acid and aniline aerofloat.The addition of Ca²⁺and Mg²⁺promoted the reaction of butyl xanthate and inhibited the degradation of salicylhydroxamic acid and aniline aerofloat can promote the degradation of mineral processing reagents in varyed degrees.3.In the exploration experiments of reaction in simulated natural water,it was found that the addition of Cl^-inhibited the degradation of various mineral dressing agents in the reaction process.With the increased of HCO^3-concentration,the degradation rate of mineral processing agents gradually decreased.After the addition of NO₃^-the degradation rate of butyl xanthate and salicylhydroxamic acid decreased.In the process of reaction,it also has a certain role in promoting,but it was a kind of inhibition to the degradation of mineral processing agents.With the increased of Si O₃^2-concentration and humic acid concentration,the degradation rate of mineral processing agents also decreased.When salicylhydroxamic acid and aniline aerofloat were mixed,the degradation rate of each reagent decreased due to the competitive reaction between them.It was speculated that the degradation pathway of salicylhydroxamic acid in microwave activated persulfate reaction system was salicylhydroxamic acid?salicylic acid?catechol?carbon dioxide+water+NO₃^-+other small molecules;the degradation pathway of aniline aerofloat was aniline aerofloat?catechol?carbon dioxide+water+PO₄^3-,NO₃^-+other small molecules.