Modified Iridium Electrode For Electrocatalytic Degradation Of Carbamazepine

The widespread use of drugs has posed a great threat to the natural environment and biological health.Electrochemical advanced oxidation technology,which has the advantages of green environmental protection,mild reaction conditions,and strong controllability,has been applied to the treatment of refractory organic wastewater.In this paper,two modified Ir-based electrode methods were used to prepare(Ir,W)Ox(Na2WO4)electrodes,(Ir,W)Ox(H28N6O41W12)electrodes,(Sn,Sb,Ir)Ox electrodes and(Sn,Sb,Ir,Ti)Ox electrodes.The electrochemical performance and stability of different electrodes are compared through a series of physical and chemical characterizations.Finally,two electrodes with excellent performance are screened out for carbamazepine(CBZ)simulated wastewater degradation.The specific conclusions are as follows:(1)Although doping W with Na2WO4 as the precursor of W can improve the electric double-layer capacitance and electrochemical active area of the IrO2 electrode,it will cause a large number of cracks on the electrode surface and affect the stability of the electrode.Using H28N6O41W12 as the W precursor,the electrode not only has a larger active area(245.286 cm2),but also improves the activity of per unit iridium mass(13.898 A·gIr-1).In addition,the amount of precious metal Ir is reduced by 30%,and the stability of electrode is greatly improved.The life of the(Ir0.7W0.3)Ox(H28N6O41W12)electrode can reach 3.77 times that of the IrO2 electrode.(2)The doping of Ir and Sb can not only improve the conductivity and electrocatalytic activity of the SnO2 electrode,but also reduce the surface crack of the electrode.The modified electrode surface is dense and compact,the porosity is reduced,and its service life is increased by 3242 times that of the SnO2 electrode.The charge transfer resistance of the electrode decreased from 1128 Ω to 20.25 Ω with 0.4%Ir doping,and the electrochemical active area increase per unit mass of Ir is the most significant,which can reach 3.198 Δcm2·μgIr-1.Although Ti doping significantly increases the oxygen evolution potential of the electrode,it also causes a large number of cracks on the electrode surface,and the life of the electrode gradually decreases with the increase of Ti doping.(3)The(Ir0.7W0.3)Ox(H28N6O41W12)electrode and(Sn0.896Sb0.100Ir0.004)Ox electrode with better performance are used as anodes for electrocatalytic degradation of CBZ simulated wastewater.Under the optimal conditions of voltage of 3 V,pH of 1.5 and Na2SO4 concentration of 0.10 mol·L-1,the conversion rate of CBZ was 87.21%after 90min of reaction,and the energy consumption was 6.70 kWh·m-3.Under the optimal conditions of voltage of 3 V,pH of 1.5 and Na2SO4 concentration of 0.15 mol·L-1,the conversion rate of CBZ was 93.82%after 90 min of reaction,and the energy consumption was 2.80 kWh·m-3.The research proves that both electrodes are degraded by indirect oxidation of CBZ by releasing active radicals,and CBZ has a similar degradation path on the two electrodes.