Study On New Technology Of Disposal Of Nonbiodegradable Organic Wastewater Using Modified Nanometer Titanium Dioxide

Aiming to advance the practicability of photocatalytic technology, titanium and active carbon were used as carrier to prepare TiO₂/Ti and TiO₂/AC system. The loading and modification conditions were investigated in the process of photocatalytic degradation of PEG simulated wastewater. The dynamics of photocatalytic reaction and degradation mechanism of PEG were discussed. The feasibility of using TiO₂/Ti system for acrylon wastewater treatment was also investigated.TiO₂/Ti system was prepared by active TiO₂ powder loading method and sol-gel method respectively. Fe³⁺,Ag⁺,Pt4+,Ce³⁺,La³⁺ and Y³⁺ were used to modify the performance of the system. It was indicated that system prepared by active TiO₂ powder loading method exhibited better performance. The optimum conditions for this system were: filming times was 3, concn of TiO₂ was10g L-1, pH was 7, concn of CMC was 3g L-1, calcinating temperature was 600℃, Ag⁺ behaved the best modification effect in the 6 kinds of metal ions and the optimal molar rate of Ag/Ti was 0.07%. 84.8% of COD removal was achieved in 2.5 hours of reaction for PEG wastewater using this system. The optimum conditions of sol-gel method were: filming times was 8, pH was 3, calcinating temperature was 700℃, calcinating time was 2h, Ag⁺ also behaved the best modification effect in the 6 kinds of metal ions and the optimal molar rate of Ag/Ti was 0.3%. 79.5% of COD removal was achieved in 2.5 hours of reaction for PEG wastewater using this system. The XRD analysis indicated that both the loading process and the adulteration of metal ions inhibited the transformation from anatase to rutile of TiO₂. The ratio of anatase and rutile was about to 7:3 under the optimum conditions. The optimum conditions for the preparation of TiO₂/AC system using active TiO₂ powder loading method were: loading time was 3min,the concn of TiO₂ was 10g L-1, pH was 7, calcinating temperature was 400℃, Ag⁺ behaved the best modification effect in the 6 kinds of metal ions and the optimal molar rate of Ag/Ti was 0.07%. 88.2% of COD removal was achieved in 2.5 hours of reaction for PEG wastewater using this system. The prepared systems behaved good stability with no descend after 30 times'reaction.The GC-MS analysis indicated that in the photocatalytic reaction PEG was first decomposed to little molecules and then been oxidized. The photocatalytic of PEG was zero order reaction using TiO₂/Ti system, and was first order reaction using TiO₂/AC system.The prepared TiO₂/Ti system showed good treatment effect to acrylon wastewater. The removel of COD for pre-biological treatment water achieved 79.0% in 6 hours'reaction, and the value of B/C increased form 0.22 to 0.89. The removel of COD for after-biological treatment water achieved 54.8% in 6 hours'reaction, and the value of B/C increased form 0.11 to 0.34.