Studies On The Electrochemical Oxidation Of4-chlorophenoxyacetic Acid And2,4,6-trinitrophenol Forwaste Water Treatment

In recent years, a large amount of waste water which contains toxic organiccompounds has been discharged with the economic social development. It is difficult forthe conventional biological process to treat these organic waste water for its complexcomponents, poor biodegradability, toxicity, high color, high salt, smell and so on. It hasbeen a problem in the field of water water treatment for meeting the discharge standards.The electrochemical oxidation process for organic waste water treatment has obtainedmore and more attention for its advantages of high efficiency, environment-friendly,simplely operation and no secondary pollution to the environment.The electrochemical oxidation of organic compounds bases on the two ways, that isdirect and indirect oxidation. The electrochemical oxidation efficiency is related closelywith the material of the anode, as well with the reaction conditions in the electrolysis. Ahigh oxygen evolution potential is essential for the anode, and the reaction conditions needto be optimized systemly.The main research and results as follows:1. The electrochemical oxidation of4-chlorophenoxyacetic acid and2,4,6-trinitrophe-nol on Ti/SnO2-Sb2O5/PbO2electrode, a platinum electrode and a glassy carbon electrodewas studied by cyclic voltammetry. The Ti/SnO2-Sb2O5/PbO2electrode was used as theanode of4-chlorophenoxyacetic acid and2,4,6-trinitrophenol on cyclic voltammetry.2. The optimized conditions of4-chlorophenoxyacetic acid conditions: the initialconcentration of4-chlorophenoxyacetic acid was1.0×10-4mol/L, the pH was6, theconcentration of the support electrolyte, Na2SO4, was3.5g/L, a flow rate was600mL/min,the current density was40mA/cm2, the space between the anode and cathode was5mm.The optimized conditions of2,4,6-trinitrophenol conditions: an initial concentration of2,4,6-trinitrophenol was8.0×10-5mol/L, the current density was50mA/cm2, theconcentration of the support electrolyte2.0g/L, Na2SO4, was, the pH was4, the spacebetween the anode and cathode was10mm, a flow rate was600mL/min, the optimizedconditions of4-chlorophenoxyacetic acid and2,4,6-trinitrophenol was used as degradatedin the waste water speed and high performance, the electrolysis process was monitored by UV-visible spectrometry and high performance liquid chromatography (HPLC) and pHvalue and cyclic voltammetry.3. The chemical oxygen demand (COD) was monitored with potassium dichromatemethod in the process of being degraded at different times under the optimized conditions,the removal rate was calculated, the rate of COD removal of4-chlorophenoxyacetic acid wasreached61.2%, the rate of COD removal of2,4,6–trinitrophenol at the degradation time260min was reached80.99%. The electrochemical oxidation degradation was feasibly andeffectively demonstrated by HPLC and UV-Visible spectra, the degradation of organiccompounds can be achieved, the COD decreased nearly directly with the electrolysis time,the rate of COD being removed was closed to100%.4. The experimental method was simplely operation and feasible and stable conditions,the organic pollutants could be degradated to CO2and H2O finally, the method could alsobe used in the pretreatment of waste water on plant, then further biodegradable of wastewater could be directly into the waste water treatment plant.