Study On The Removal Law Of Statins In Sewage Plant And Persulfate System

With the development of society,all kinds of pharmaceuticals and personal care products（PPCPs）have been widely used and entered the environment through various ways.Hypolipidemic drugs,anti-inflammatory and analgesic drugs and estrogen are common in the survey reports of scholars around the world.The source,distribution and treatment technology of pharmaceuticals in environmental water has become a research hotspot.The distribution status and removal law of three typical drugs in four sewage treatment plants in Hefei city were investigated in the study.And the degradation effect and influencing factors of statins in UV/PMS/H₂O₂ advanced oxidation system and ultrasonic combined modified activated carbon activated potassium persulfate system was studied.The analysis method for typical pharmaceuticals based on gas chromatography-mass spectrometry（GC-MS）was established,and the distribution status and removal law of three kinds of drugs:hypolipidemic,antibacterial and anti-inflammatory and estrogen in urban sewage were investigated.The results showed that 14 drugs were detected in urban sewage,including lipid-lowering drugs:clofibrate（Clb）,clofibric acid（CA）,gefibezil（GEM）,atorvastatin（ATV）,simvastatin（SIM）and lovastatin（LOV）;Anti-inflammatory antibiotics:ibuprofen（Brf）,naproxen（Npr）and triclosan（Tri）;Estrogen:17α-Estradiol（17α-E2）、17β-Estradiol（17β-E2）,acetylene estradiol（17α-Et）,estrone（E1）and estriol（E3）.The three kinds of drugs were introduced into the wastewater treatment plant in two forms of dissolved and adsorbed states,and the difference of different drug concentrations in the influent was large between 7.2 ng/L and 1416.8 ng/L.The removal rates of different drugs in municipal wastewater treatment plants were-65.9%–99.1%,and the drug concentrations in effluent after treatment in municipal wastewater treatment plants varied greatly from 2.5 ng/L to 819.9 ng/L.It indicated that some PPCPs could not be removed effectively by wastewater treatment plant.The removal efficiency and influencing factors of UV/PMS/H₂O₂（UV-Catalyzed Potassium Persulfate Combined with Hydrogen Peroxide）system for atorvastatin（ATV）and rosuvastatin calcium（ROSC）were studied.The results showed that in the UV/PMS/H₂O₂ system,the degradation processes of the two statins conformed to pseudo-first-order kinetics.The removal rate of ATV reached 48.74%after 180 min of reaction,and that of ROSC reached 88.66%within 8 min.In the degradation process of statins,p H was the main influencing factor.The change of p H not only changes the formation of free radicals,but also affects the morphological structure of statins.Humic acid inhibited the degradation of two statins.After the degradation of statins,carboxyl,carbonyl and amide groups will be generated,which will become the reaction substrate of disinfection by-products.The degradation effect of ultrasound combined with modified activated carbon activated potassium persulfate system for ATV was discussed.After 6 mol/L sulfuric acid modification,more carboxyl and lactone functional groups were formed on the surface of activated carbon.Activated carbon tends to be more disordered,and active carbon C=C will increase significantly.This contributes to the adsorption of ATV on activated carbon.The experimental results showed that the removal rates of ATV by activated carbon（PAC）system,acid modified activated carbon（PAC（H⁺））system,alkaline modified activated carbon（PAC（OH^-））system were 91.87%,93.93%and 38.09%,respectively,in the 15 min adsorption and 30 min oxidation stage.The mineralization rates were 23.36%,31.27%and 8.99%,respectively.Under this oxidation system,the degradation efficiency and mineralization rate of ATV were improved.Further experiments showed that low concentration of humic acid could promote the activation of PMS on activated carbon surface.However,higher concentrations of humic acid competed with the active sites of PMS,resulting in a decrease in the ability of the system to produce free radicals.Fe³⁺ions promoted the PAC（H⁺）system,while Al³⁺promoted the PAC（OH^-）system.Weak acid conditions can promote the ultrasonic activation of potassium persulfate combined with activated carbon system.