The Effect Of Precipitable Calcium Salts On Electrochemical Degradation Of Organic Pollutants

Phenols was considered as one of the most important organic pollutants in wastewater treatment due to their widely sources,largely emission,highly toxicity,non-biodegradable,and high standard of emission.The traditional physic-chemical,biological treatments meet with many difficulties because of the highly toxicity and stability of phenol.Salts,universally along with phenolic wastewaters are from variety of industries,which enhance the difficulties of being treated.The electrochemical oxidation has some incomparable advantages,it has simple equipment,no extra need of adding chemical regent,what's the most,the presence of salts provides a good electric conductivity,which promote the degradation of organic pollutants.In this paper,phenol,was studied as a model pollutant,the flow-by Ti-based anode,as the working electrode in the both dynamic and static electrolysis.The effects of the type,concentration,composition of electrolyte and phenol initial concentration on the degradation of phenol were investigated in static test.The results showed that,the phenol removal rate increased with the concentration of CaCl2,and reached 90.96%in 6 hours with the 2%CaCl2as supporting electrolyte under the voltage of 12V,when the voltage raised to 15V,CaCl₂were the most efficient among the three electrolyte of NaCl,CaCl2 and Na2SO4.What's more,the result of active chlorine concentration,pH and the Ca²⁺deposition showed that,there was more active chlorine and pH range in CaCl2 solution compared to NaCl,which indicated that,the active chlorine has a indirect oxidation effect,and the the process of phenol degradation also did good to the desalination of CaCl₂.In the dynamic experiment,the effect of the type,flow rate,water discharge and the addition of NaHCO₃ on the degradation efficiency of phenol were investigated.The results showed that,it is best to degrade the electrolyte with calcium chloride.when the velocity ratio is 1:1,the phenol removal rate was best.It is also best in the situation when the flow rate of anode and cathodic were 1:1.The phenol removal rate was reduced when using single electrode zone discharged and adding NaHCO₃.And added to 400mg/L,the removal efficient is the best.