Preparation Of CuO/Sepiolite Composite Three-Dimensional Electrode And Study On The Degradation Of BPA By Electro-Activated Sodium Persulfate

Bisphenol A?BPA?,as a typical environmental endocrine disruptor,widely exists in water environment,which has seriously threatened human health.BPA has strong hydrophobicity and poor biodegradability,which makes it difficult for traditional sewage treatment methods to effectively degrade it.Advanced oxidation technology based on persulfate has attracted wide attention because of its strong oxidation ability and high reaction temperature,which can degrade most refractory organic pollutants in water.In this paper,the material properties of CuO/sepiolite particle electrode were investigated,and BPA was used as the target pollutant.The degradation efficiency and main influencing factors of BPA on CuO/sepiolite particle electrode activated sodium persulfate?PS?were investigated.The mechanism of electro-activated sodium persulfate on CuO/sepiolite particle electrode was discussed.The paper draws the following conclusions:?1?The preparation conditions of CuO/sepiolite particle electrode were prepared and optimized by the same volume hydrothermal method.The optimum synthesis temperature was 130°C,and the optimal loading ratio was 20%.The results of TG,XRD,SEM,FT-IR and BET showed that CuO was dispersed on the sepiolite surface,and CuO has strong diffraction peaks on?-111?and?111?crystal planes.The characteristic absorption peak of CuO appeared at 617 cm^-1.After CuO loading,the specific surface area of sepiolite decreased from 154.290 m²/g to 91.994 m²/g,and the average pore diameter of sepiolite decreased from 18.545 nm to 18.459 nm.The above characterization results indicate that CuO is successfully loaded on the surface and pores of the sepiolite.?2?When the initial concentration of BPA is 25 mg/L,the dosage of PS is 500mg/L,the initial pH is 11,the dosage of CuO/sepiolite particle electrode is 2 g/L and the initial voltage is 9 V,the electro-activated PS system with CuO/sepiolite particle electrode has the best degradation efficiency for BPA.The BPA removal rate is 90.1%after 30 min reaction.The degradation efficiency of BPA by CuO/sepiolite particle electrode electro-activated PS system is obviously higher than that by CuO/sepiolite and electro-activated PS system,indicating that CuO/sepiolite composite electrode has synergistic effect on promoting electrolysis process and persulfate activation process;According to GC-MS analysis,BPA first undergoes·OH addition reaction under the oxidation of free radicals,then decomposed into cyclic lipids and transformed into chain esters,and finally mineralized into CO₂ and H₂O.?3?Compared with pure sepiolite,CuO/sepiolite composites have higher open voltage,surface exchange current density,corrosion potential and lower polarization overpotential,indicating that CuO/sepiolite has better antioxidant ability and electrochemical catalytic activity than sepiolite,and it is easier to achieve electrocatalytic oxidation reaction on the electrode surface.The oxygen evolution potential of CuO/sepiolite particle electrodes increased from 1.207 V to 1.239 V by adding PS,and the formation rate of dissolved oxygen decreased from 0.661 mg L^-1min^-11 to 0.493 mg L^-11 min^-1,indicating that the addition of PS increased the oxygen evolution potential and inhibited the oxygen evolution side reaction of CuO/sepiolite particle electrode in water electrolysis.The results of free radical scavenger showed that direct electron transfer reaction?DET?,non-radical oxidation,sulfate radical?SO₄·^-?oxidation and hydroxyl radical?·OH?oxidation contributed to the degradation of BPA by electro-activated PS system with CuO/sepiolite particle electrodes,and the·OH and SO₄·^-are the main active species,which contributed 58.2%and 12.4%to the degradation of BPA,respectively.The main role of CuO in the system is to catalyze the activation of S₂O₈^2-to promote its conversion to SO₄·^-,accelerating the activation process,and the CuO/Sepiolite particle electrodes still have good catalytic activation performance after four time reuse.