Study Of Fenton Oxidation Method-Adsorption-Ion Exchange Combination Process To Degradate The Photocatalytic Degradation Of Organic Pollutants In Purified Terephthalic Acid Wastewater

The process of producing PTA produces large amount of organic waste water, which contain high concentration of various organic pollutants (acidic aromatic organic compounds) with wide range of pH values. The organic pollutants with benzene ring structure in waste water are stable, so they are difficult to biodegradate. Photocatalytic degradation has been developed for degradation of molecule-structure complex contaminants recently. Meanwhile, photocatalytic reaction sensitized by TiO2 has attracted extensive interests as a potential way to treat wastewater due to its high photocatalytic stability and efficiency, and non-toxic to the health of human livings:The treatment of PTA wastewater one by Fenton oxidation has been investigated. The influence of pH, the dosage of FeSO4·7H2O and H2O2, the dosing method of H2O2 and reaction time on treatment efficiency have been studied. With orthogonal experiments and considering of the actual production, the optimized operating conditions had been obtained: pH 3.0, one-time dosage of H2O2 20mL/L, dosage of FeSO4·7H2O 1.5g/L, reaction time 3h, 55℃, COD removal efficiency of the PTA wastewater was 65.5%.The HPD-950 macroporous resin was ultimately chosen to reduce COD of PTA wastewater two further. The influences of the usage of HPD-950, temperature of adsorption, pH value, and oscillation intensity had been investigated. The results showed that with the decrease of temperature and pH, and increase of oscillation intension, adsorption efficiency increased. The obtained optimum adsorption conditions were:pH value 4, temperature 25℃, usage of macroporous resin 8g, and the oscillation intention 200rpm. The effects of residence time, running time and regeneration time on resin adsorption efficiency had been investigated through dynamic experiments. The optimum operating conditions:residence time was 30min, running time was 50h, regeneration time was 30min, COD removal efficiency of the PTA wastewater was above 90%.Handle the wastewater with ion exchange method to make the metal ion reach the standard. Through screening experiment, the resin LS101 was suitable for PTA wastewater three treatment relatively. When the resin addition amount was 5mL/L wastewater, the metal ions removal reached 89.7%. As the temperature increases, ion exchange reaction speed-up, the exchange capacity change also accelerates, the time needed for balance decreases. Resin structure will happen small changes at high temperature, which affects the exchange capacity, so when the temperature system over 45℃, resin efficiency decreased obviously. we choose 45℃for the best temperture.The hydrochloric acid regeneration can restore the activity of saturated resin. Using a static immersion method, the rate of regeneration agent and the resin LS101 is only 90mL:60mL.