Performance Of Monolithic Microchannel Carbon-based Electrochemical Filter In Degradation Of Chlorinated Organics In Water

In recent years,electrochemical hydrodechlorinated technology has received increasing attention in the treatment of chlorinated organics.It is one of the most promising technologies that has the advantages of high efficiency,low equipment cost,mild reaction conditions,simple operation and no secondary pollution.Electrode is very important in the electrochemical catalytic hydrogenation process.At present,the electrode of the electrochemical filter is carbon-based membrane.The electrode is thin and easy to fall off,and the preparation method is complicated,which is not easy to expand the application.Then,the electrode prepared by carbonizing wood with natural vertical channels is widely concerned due to its rich material,simple preparation and easy access to bulk electrodes.Pd is a great electrocatalytic dechlorination catalyst that has a strong ability to adsorb and maintain H^*.Therefore,monolithic microchannel carbon electrode was prepared by carbonizing natural wood and Pd was deposited into the channel.A flow dynamic reactor was constructed to improve the efficiency of electrochemical hydrodechlorination.The electrosorption and hydrodchlorination performance of the electrode for chlorinated organic compounds were analyzed in the following:First,monolithic microchannel carbon was obtained by carbonized wood and treatmented by using the KOH soaking and calcination.The characterization results show that treatment of KOH increases the specific surface area of the material and increases the number of mesopore and micropore in the channel.With p-chlorophenol as the detected pollutant,the effect of different treatment conditions on the adsorption performance of monolithic microchannel carbon electrode was investigated.As a result,it was found that the unit adsorption capacity of activated charcoal for pollutants was 20 times higher than that of carbonized materials(carbonization 7.43 mg·g^-1,activation 163.79 mg·g^-1),and the best effect was obtained by impregnate in 1 mol·L^-1 KOH solution for 3 h.The adsorption capacity of monolithic microchannel carbon electrode was investigated,and its unit adsorption capacity is170.98 mg·g^-1 in 1.0 V voltage.The electrodeposition method was used to load Pd into the monolithic microchannel carbon.Then its hydrodechlorinated performance for chlorinated organic pollutions was investigated.First,it is found that the best deposition current and time were 25 mA and 15min,respectively.Under this condition,monolithic microchannel carbon electrode loaded with Pd was prepared,and the adsorption and reduction properties of 4-CP on the electrode were investigated in a continuous flow state.Then the mechanism of hydrodechlorination was analyzed through the determination of the intermediate product phenol and chloride ion.Finally,through the determination of H^*and intermediate products,the mechanism of hydrodechlorination was inferred.Ca²⁺and Mg²⁺in water was removed by monolithic microchannel electrochemical filter.The presence of Ca²⁺and Mg²⁺will affect the efficiency of hydrodechlorination,and the resulting precipitate will block the electrode channel and affect the reaction.The influence of residence time,operating voltage and aqueous solution alkalinity on the removal effect of Ca²⁺and Mg²⁺was investigated during the experiment.According to test of the service life of the electrode,it was found that the electrode has great stability because it can run 11 h continuously.In summary,monolithic microchannel carbon electrode loaded with Pd has a great adsorption and hydrodechlorination performance for chlorinated organic compounds.In addition,it also can effectively reduce the water hardness.So,it can provide ideas for rapid dechlorination of chlorinated organic compounds.