The Synergistic Effect Of Cathode And Metal/Peroxymonosulfate On Phenol Degradation

In recent years, advanced oxidation technology based on the sulfate radicals has been widely researched. The phenolic wastewater has been widely concerned for its toxicity and recalcitrance. This thesis aimed to explore the feasibilty and the influence factors of the degradation of phenol in Cathode/PMS/Cu²⁺ system and Cathode/PMS/Fe³⁺ system, which combines divided electroche mistry system and metal/peroxymonosulfate system(Mⁿ⁺/PMS).In Cathode/ PMS/Mⁿ⁺ system, the ability of degrading phenol is N i2+ ?Zn2+ ?Mn2+ ?Cu²⁺ ?Fe³⁺. Compared with undivided electrochemistry system, divided Cathode/ PMS/Mⁿ⁺ system is more enery-saving.In Cathode/PMS/C u2+ system, the removal rate of phenol increased first and then decreased with the increasing of current density as the excessive current density would lead to the reduction of effective Cu+. The removal rate of phenol increased first and then decreased with the increasing of PMS concentration. The removal rate of phenol increased with the increasing of C u2+ concentration. When the mole ratio of [phenol], [PMS], [C u2+] is 1:20:1 with current density of 1.5 m A/cm2, the removal rate of phenol reaches 72% after two hours reaction, and ?OH plays the leading role.In Cathode/PMS/Fe³⁺ system, increasing of current density, PMS concentration, Fe³⁺ concentration would promote the degration of phenol while the increasing of supporting electrolyte concentration and initial phenol concentration have an inhibitory effect. C lconcentration has a promoting effect on the degration of phenol, and the higer the C lconcentration, the stronger the promoting effect. Low concentration of HCO3- has no effect on phenol degradation while high concentration has inhibit effect. NO3- has little effect on phenol degradation. When the mole ratio of [phenol], [PMS], [Fe³⁺] is 1:20:1 with current density of 1.5 m A/cm2, the removal rate of phenol reaches 99% after two hours reaction, both ?OH and SO4?- were responsible for phenol degradation. The study on Fe²⁺ concentration indicates that the increase of current density, PMS concentration and Fe³⁺ concentration would promote the transformation of Fe³⁺ to Fe²⁺ on the cathode surface so as to promote the degradation rate of phenol. The increase of initial phenol concentration also would promote the transformation of Fe³⁺ to Fe²⁺. But the increase of phenol concentration would lead to the reduction of unit pollutant getting radicals. The combination of two kinds of effects led to the decrease of the phenol degradation rate. C lalmost has no effect on Fe²⁺ concentration, the promoting effect on phenol degradation is due to the generation of other active species.