Study On The Degrading Anion Surfactants Wastewater By Biopolar Three-dimentional Electrode Cell

Based on the introduction of the characteristics and harmfulness of surfactants wastewater, the paper compared the advantages, disadvantages and mechanics with all different technology for the Anion Surfactants Wastewater treatment. A new technology —Biopolar three dimentional electrode cell (BTDEC) was introduced for many advantages. Considering the LAS wastewater as the object, the experiments were carried out in electrode cell by graphite and DSA electodes, with activated carbon and glass ball as the filling material. Comparison of degradation efficiency and energy consumption of two-dimentional electode cell and BTDEC, the LAS removal efficiency of BTDEC was higher than traditional two-dimentional electode cell. The energy consumption comparison experiment showed that with the higher removal efficiency, the energy consumption was lower. It also discussed the relation between the operation conditions and the removing efficiency. The mechanic was studied on with the effect factors. The most effective factors and the optimization levels were given. The reaction kinetic and process of BTDEC were also discussed. The results were shown as following:(1) The single parameter experiments showed that the best removal efficiency was achieved under the condition that the electodes were graphite , and the best distance of anodic electrode and cathodic electrode was 4cm.Improving conductivity by changing pH value and adding electrolyte can improve LAS removal efficiency from 36.6% to 80.2%.(2) The orthogonal experiment showed that the most effective factors were voltage and pH value.LAS wastewater achieved best treatment efficiency under the condition that the filling material was blended by activated carbon and glass ball by the ratio of 2:1, inlet concentration of wastewater was 250mg/L, pH value was 2, voltage was 30V, electrolyses time was 60-90 minutes.(3) Dynamic experiments showed that at the beginning of 2³ hours of process, removal efficiency improved gradually,and it was stable at about 19%. After 4 hours, BTDEC was very stable in treating LAS wastewater.The outlet of LAS removal efficiency was lower than that achieved in the static experiment with the same conductivity.The reason was possibly that the HRT was too short and the the conductivity was too low. In practice, extending the HRT and adding more electrolyte can improve removal efficiency.(4) Under the condition that removal rate was above 30%, the consumption of BTDEC was lower than traditional two-dimentional electode cell. Especially when the removal efficiency was around 42% ,the energy consumpution of BTDEC was about 20% lower than the consumpution of traditional two-dimentional electode cell.so the advantage of low energy consumption of BTDEC was overwhelming.(5) Kinetic experiment showed that treating LAS wastewater by BTDEC wassecond-order kinetic reation. k is reaction rateConstance, k=7. 0×10^-5 L·mol^-1·min^-1.(6) The process and medium product of degradation of LAS by BDTEC,LAS was oxidative degraded step by step. It was degraded into medium products namely smaller molecular substances. At the end of reaction, 67.6% of LAS was degraded, 60.1% of LAS was degraded into inorganic substances and the amount of medium substances was very little.It was concluded that the control step of degradation of LAS was the step that degrading LAS into medium substances.UV spectrum analysis showed that both graphite and DSA electrodes system can destroy phenyl in LAS molecular, and DSA electrode system was more effective than graphite electrode system in destroying phenyl.