| Eutrophication has been a serious water environment problem and the treatment of phosphorus-containing wastewater is an effective way to control eutrophication of water bodies.Electrocoagulation(EC),as an effective method for phosphorus removal,has been widely studied.However,most of the anodes in the conventional EC device are plate-like electrodes with low current efficiency and high water treatment cost,which limit the further application of EC.In this study,a magnetized particle iron anode EC device(MPIA-EC)was constructed to remove phosphorus from wastewater.The main research contents and results are as follows.(1)The electrochemical characteristics of different anode configurations and their influence on phosphorus removal efficiencies of EC were studied.The cyclic voltammetry curves of five configurative anodes showed that the anodes current response with voltage changes was anode C,anode B,anode E,anode A,anode D in turn.The order of increasing rate in voltage was anode D,anode E,anode A,anode C.and the order of phosphorus removal efficiency in magnetized anode configurations was anode C,anode B,anode A.The results indicated that the magnetized particle iron anode can enhance the phosphorus removal efficiency by enlarging the electrode surface area,enhancing the electrochemical reaction and mass transfer,and stabilizing the electrode current.It is valuable for application research.(2)The effects and influence factors of MPIA-EC treating inorganic phosphorus wastewater were studied.The results showed that the current density,the quality of the anode iron particles,p H,magnetic field had certain effects on phosphorus removal.The current density and the quality of the iron particle anode were positively correlated with phosphorus removal.The suitable parameters were the current density of 8 m A·cm-2,the quality of particle iron anode of 3 g,p H of 7.Under this conditions,the phosphorus removal rate can reach more than 97%when the electrolysis time was 15 min,which showed that MPIA-EC had a significant effect on the removal of inorganic phosphorus.The magnetic field can improve the efficiency of phosphorus removal,promote the solid-liquid separation of sediments and slow down the decrease of the current density.(3)Amino trimethylene phosphonic acid(ATMP)was used to prepare simulated organophosphorus-containing wastewater,and the influencing factors,the characteristics of the sediments in EC cell and the ATMP removal mechanism by MPIA-EC were studied.The results showed that MPIA-EC also had a good effect on organophosphorus removal.The current density was positively correlated with the removal of organophosphorus,while the ratio of organophosphorus and inorganic phosphorus was negatively correlated.Neutral p H was better for phosphorus removal.In addition,organphosphorus removal was more difficult than inorganic phosphorus.The sediments in EC cell was characterized by Fourier Transform Infrared Spectroscopy(FT-IR),Energy Dispersive Spectrometer(EDS),Scanning Electron Microscope(SEM)and X-ray Diffraction(XRD),respectively.The results showed that the removal of organophosphorus was mainly by direct adsorption of the flocs formed by iron ions hydrolysis or the adsorption of the flocs on the chelate formed by iron ions and ATMP.(4)The effect and cost were compared between MIPA-EC and conventional EC(anode D),when treating phosphorous-containing cleaning wastewater from enterprises.The results showed that the removal efficiencies of chemical oxygen demand(COD),total phosphorus(TP)and ammonia nitrogen(NH4+-N)by MPIA-EC were significantly higher than that by conventional EC.When the treated water quality meets the pipe standard of COD?300 mg·L-1,NH4+-N?30 mg·L-1,TP?3 mg·L-1and p H=6-9,the former energy consumption and the operation cost can be reduced by 38.5%and 41.5%,respectively,which indicated the economic advantages of MIPA-EC.In addition,the recovery of hydrogen gas(H2)may further improve the economy of EC. |
PDF Full Text Request