[Catalytic hydrodechlorination of 2,4-dichlorophenol over Pd/TiO2].

Pd/TiO2 catalysts were prepared by the deposition-precipitation and impregnation methods, and were further characterized by TEM, XRD and ICP-AES. The liquid catalytic hydrodechlorination of 2,4-dichlorophenol over the catalysts was investigated. It is demonstrated that despite catalyst prepared by deposition-precipitation method exhibits higher activity than that synthesized from impregnation method, both catalysts show good performance in hydrodechlorination process. When initial concentration of the reactant was 3.11 mmol x L(-1), pH was 12 and amount of catalyst used was 50 mg, hydrodechlorination of 2,4-dichlorophenol was completed within 45 min. Acidic condition facilitates hydrodechlorination process. The initial activity was not significantly influenced when the amount of catalyst used varied between 15-80 mg, which proves that mass transport limitation exerts little impact on hydrodechlorination reaction. Finally, the initial activity sharply enhanced with the increase of initial concentration of 2,4-dichlorophenol when the concentration was in the range of 0.62-3.11 mmo x L(-1) while it almost remained constant with further increasing the initial concentration. Therefore, the catalytic hydrodechlorination of 2,4-dichlorophenol over Pd/TiO2-DP follows the Langumuir-Hinshelwood model, indicating that the catalytic hydrodechlorination is controlled by 2,4-dichlorophenol adsorption.

Purified terephthalic acid wastewater biodegradation and toxicity.

The biodegradation and toxicity of the purified terephthalic acid (PTA) processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process (CASP). Sludge loading rate (SLR) for Fhhh to COD of the wastewater was 1.09 d(-1) and to PTA in the wastewater was 0.29 d(-1). The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 (median lethal concentration) to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were 5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

Pilot regulation of MnP-SA for treating PTA wastewater.

In the pilot study of treating the purified terephthalic acid (PTA) wastewater with the functional Strain Fhhh in the carrier activated sludge process (CASP), the ratio of COD: TN: TP and the concentrations of Cu, Mn, Se and Zn were controlled to improve the manganese peroxidase (MnP) levels for increasing the treatment efficiency. When the ratio of COD: TN: TP was 100: 0.36: 0.15 and the concentrations of Cu, Mn, Se and Zn were 0.54, 5.07, 0.00 and 0.08 mg/L, the MnP specific activity (MnP-SA) reached 689 U/L, and the sludge loading rate to COD(SLRC) was 1.09 d(-l), which was 4--7 fold of that in other processes reported. The data indicated that improving MnP level could enhance the degradability of Fhhh. And the potentials of Fhhh and CASP will be also discussed in this paper.

[Effects of phosphorus sources of different forms on phosphorus metabolism of Microcystis aeruginosa and adhesive Pseudomonas sp].

The effects of different forms of phosphorus sources on the phosphorus metabolism of Microcystis aeruginosa and attached Pseudomonas sp. were investigated after four substance of different phosphrus forms: NaH2PO4, Natrium-beta-glycerophosphate (NaGly), Ca3(PO4)2 and lecithin were added in the non-phosphorus MA culture. The growth of Microcystis aeruginosa, total phosphorus, alkaline phosphatase activity in water and total phosphorus in Microcystis aeruginosa were measured every day or every two days. Results show that attached Pseudomonas sp. could accelerate the growth of Microcystis aeruginosa, and transform some phosphrus forms which could not be assimilated very easily by Microcystis aeruginosa to some forms as phosphate to utilize for Microcystis aeruginosa. Alkaline phosphatase plays an important role in the utilization of large molecular organic phosphorus by Microcystis aeruginosa and attached Pseudomonas sp.