Application Research On Manganese Oxides Activated Peroxymonosulfate Process

Manganese oxides were widely used in our daily life due to the rich content,moderate price and low toxicity.Furthermore,manganese oxides can also efficiently activate PMS to generate sulfate radical(SO4·-).This paper comprehensively investigated manganese oxides activated PMS process in environmental application,including the degradation of ciprofloxacin(CIP)and the conditioning of waste activated sludge:(1)Acidic condition was more beneficial to CIP removal than neutral condition,and the degradation would be greatly accelerated in alkaline circumstance.The introduction of chloride and bicarbonate displayed concentration-dependent dual effect.The presence of natural organic matter(NOM)extered the detrimental effect on CIP degradation.Eleven oxidation products were identified by UPLC-MS/MS,five products showed monotonous uptrend while four intermediates presented monotonous downtrend once they were generated.Piperazine ring cleavage,hydroxylation and F/OH substitution were found to be the important oxidation pathways.The acute toxicity of resulted solution gradually decreased with the lapse of time,and higher PMS concentration favored the detoxification.The CIP removal in ?-MnO2/PMS process was also efficient under the actual water background,which was testified by the results of fluorescence excitation-emission matrix.(2)After addition of 4 mmol/g VSS KMnO4 and 3 mmol/g VSS PMS,the dewaterability of waste activated sludge significantly enhanced,capillary suction time(CST)was decreased from 73.65 s to 24.65 s,and the water content of dewatered sludge cake was also decreased from 78.96%to 70.47%.The combined use of PMS and KMnO4 process can reduce negative zeta potential,floc size and the concentrations of protein and polysaccharide in extracellular polymeric substances(EPS).Through the observation of TEM and EDX,the synergistic effect of KMnO4 and PMS could be ascribed to the production of manganese oxides,and the generation of SO4·-could effectively disintegrate EPS,thus improve sludge dewaterability.