Research On Electrolytic Product Of Different Electrodes And Their Continuous Removal Of Algae

Ballast water discharging may lead to biological invasion,which may be a threat to the native species and the residents’ normal life.Electric catalytic processing is widely used in ballast water for its in situ generated active species and well sterilizing algae removal effect.But apart of electrocatalysis product are rarely reported.What’s more,separate electric catalytic product can help determine the main composition,and have a good advantage of understanding the mechanism of electrocatalysis’ s algae continuous removal performance clearly.This experiment explored the electric catalytic products and the algae removal performance with the seclected electrode——Ti/RuO₂-Sb₂O₅-SnO₂ and Ti/Sb-SnO₂.Also,the relationship between them were studied for providing data support for the continuous alga removal mechanism.Experiments also determined attenuation of electric products and the amounts of the bromate after letting stand 120 hours,which can provide data support for the pretreatment of the ballast water discharging.Spectrophotometric method was used to determine the total residual oxidants and its attenuation.Hydrogen peroxide was ddetected by spectrophotometry method using titanium salt.The amounts of the ozone was counted on the specific absorptions at 254 nm.Using 2,6-dimethyl phenol as derivative agent,liquid chromatography was used for detection of the content of the hypochlorous acid.Results showed that the Ti/RuO₂-Sb₂O₅-SnO₂ catalytic electrode had an significant anvantage over Ti/Sb-SnO₂ in oxidants production.Under the condition of 30‰ salinity,HRT 4.0 s,200 mA·cm-2,the oxidants generated by Ti/RuO₂-Sb₂O₅-SnO₂ electrode can reach 180.95 mg·L-1.And the total residual oxidants produced by electrocatalysis increases with current density,water retention time,and salinity.The production of hydrogen peroxide was detected under low current density,and there was no significant difference between hydrogen peroxide content about the two anodes and the hydrogen peroxide production wasn’t high with a maximum of 2.5 mg·L-1.The result showed that NaClO generated by electrocatalysis is the main component of the total residual oxides which accounted for about 70%.While there was not obvious content of ozone be detected.Chlorpromazine was used as chromogenic agent to determine the content of bromate.The result showed the amounts of the bromated produced by both anodes were over the standard after 120 hours.The instant emissions has potential threats to the aquatic organisms.The attenuation experiments showed the total residual oxidants stabilized to about 25 mg·L-1 after 120 hours,which was a failure to meet the standards of the International Maritime Organization.It needs to be pre-neutralized.Fluorescence double staining method were used for the count of electrocatalysis alga remaining number.Determination results was consistent with the total residual oxide attenuation results.The algae reduced faster during the first 10 hours,and then it reduced slowly.And electrocatalysis algae removal effect are greatly influenced by instant amount of total residual oxidants.It is concluded that when instant total residual oxidants can reach 40 mg·L-1,discharging standard can be achieved 120 hours later.Combined with single oxidants generated by anodes and its attenuation,it is thought that electrocatalysis has a good performance of algae removing was due to the synergistic effects of different oxides produced by electro catalysis.But it is thought that NaClO plays a major role in continuous inactivation of algae.