Preparation Of Titanium Based SnO₂Electrode And Modified Graphite Electrode And Research On Treatment Of Phenol In Coking Waste Water

The characteristics of water resources in China are getting worse. The utilizationand per capita of water resource are low. Also, distribution of water resource is notbalanced.At the same time, water pollution is grievous because of the industrialpollutants, which is the main cause of water pollution. Coking wastewater is a kind ofindustrial waste water, which is very common now. There are so many complex andpoisonous pollutants in coking wastewater. Thus, in recent years, dealing with cokingwastewater is not only difficult but also significant.In recent years, treatment of coking wastewater includes adsorption, microbialdegradation and electrochemical oxidation. Adsorption is not the best treatment ofcoking wastewater because of the high cost and the low recovery rate. But coke isavailable for absorbing extra COD of the high-COD coking wastewater to reduce COD.Microbial degradation is also not the best treatment. It is very hard to controlreaction conditions and the reaction will be unstable. In reaction of electrochemicaloxidation, there are hydroxyl free radicals on the surface of the electrode. Inorganiccontaminants and organic contaminants are transformed into non-toxic material byreaction of electrochemical oxidation. The efficiency of electrochemical oxidation isvery high.In the experiment, the titanium substrate is used for an anode. Hightemperature thermal oxidation is used for metal oxide anode SnO2, also Metal ionsZn is doped to strengthen the efficiency of electrode. Graphite is used for thecathode. Carbon electrodes are used to modify the cathode by chemical deposition.The specification of electrode is40mm×60mm×20mm. Scanning electrodes withelectron microscope to analysis surface features of electrodes.The modified electrodes are used to remove phenol of simulate wastewater bycatalytic oxidation reaction. Coke is used to adsorb phenol and other pollutants of coking wastewater as a pretreatment.Thus, COD can be reduced after pretreatment.In the experiment, five reaction conditions, distance of the electrodes, currentintensity, initial PH, concentration of electrolyte, time of reaction are changed.Methods of potassium dichromate and spectro photometer are used to detect CODand concentration of Phenol before and after reaction.Comparing efficiency of titanium based SnO2electrode with modified graphiteelectrode. Calculate Removal rate of COD and concentration of Phenol in both cokingwastewater and simulate phenol wastewater.With the treatment of modified electrode for coking wastewater, removal rateof concentration of phenol and COD is slightly lower than simulate phenolwastewater. effect of electrolyte concentration on the efficiency of degradation isnot obvious. Other reaction conditions, such as PH, distance of electrode, time ofreaction, current intensity, obviously effect on efficiency of reaction, which is thesame as simulate phenol wastewater.With reaction conditions of pH=7, distance of electrodes D=1cm, currentintensity I=1A, reaction time t=10h, removal rate of phenol reached94%,removalrate of COD reached95.32%in the coking wastewater, the efficiency of removal rateis obvious.Comparing treatment efficiency of pretreatment graphite electrode with carbonnano-tubes modified graphite electrodes for coking wastewater, at the sameconditions, COD both the removal efficiency of COD and the removal efficiency ofphenol is higher than the pretreatment of electrode.