Chunde Wu

Photosonochemical degradation of Phenol in water

The combination of ultrasound (US) and photochemistry has been used to degrade an aqueous solution of phenol. It was considerably more effective than ultrasound or ultraviolet (UV) light alone. Based on the results of total organic carbon (TOC) removal, it was shown that the synergistic action of ultrasound and ultraviolet light existed. Identification of the first intermediates of the reaction (hydroquinone, catechol, benzoquinone and resorcin) indicates that OH radicals are involved in the photosonochemical degradation mechanisms. The effects of parameters such as pH, saturating gases, and Fe2+ on the photosonochemical degradation have been studied. The experimental results have shown that lower pH and higher concentration of dissolved oxygen favor the phenol degradation and that the presence of Fe2+ enhanced TOC removal of phenol solutions.

Progressive study and robustness test of QSAR model based on quantum chemical parameters for predicting BCF of selected polychlorinated organic compounds (PCOCs).

Systematic analyses on the effects of chemical structures of 31 polychlorinated organic compounds (PCOCs) on their bioconcentration behavior in rainbow trout (Oncorhynchus mykiss) were conducted using quantitative structure-activity relationship (QSAR) techniques. The cluster analyses of individual variables as well as the quality control chart of QSAR model implies the existence of outliers, while the simulation model excluding such samples showed an extreme robustness even if it was tested with different methods. Furthermore, the quantum chemical parameters entering into QSAR model were used to describe the bioconcentration pathways, and the results indicated that bioconcentration behaviors of selected compounds were complicated processes involving permeation stages as well as bio-chemical reaction stages.

Photosonochemical degradation of trichloroacetic acid in aqueous solution

The degradation of trichloroacetic acid (TCA) was studied with ultraviolet (UV) photolysis, ultrasound (US) sonolysis and their combination. It was found that the degradation in the combined processes was more significant than in the UV photolysis or sonolysis alone. The effects of pH and dissolved gases on the rate of photosonochemical degradation of TCA were investigated and the degradation kinetics, mechanism and possible degradation products were discussed in detail.

Ultrasonic destruction of chloroform and carbon tetrachloride in aqueous solution

The sonochemical destruction of binary mixtures of chloroform and carbon tetrachloride in aqueous solution at 30 kHz has been studied. The influences of initial concentration, bicarbonate/chloride, and acoustical intensity on the destruction rates have been observed. It was found that the destruction of the two compounds appeared to follow pseudo-first-order reaction kinetics with the current experimental concentration range. The rate constant of chloroform for initial concentration as high as 100.4 mg/L decreased compared to initial concentration 36.13 μg/L, when the rate constants of carbon tetrachloride hardly changed. However, their destruction rates increased with increasing acoustical intensity and were independent of addition of bicarbonate or chloride. The resulting yield of ionic product (Cl−) for chloroform was determined.

Predicting physicochemical properties of α‐branched phenylsulfonyl acetates using quantum chemical descriptors

Water solubility (Sw) and octanol/water partition coefficients (Kow) of 20 new α‐substituted phenylsulfonyl acetates were determined. The TLSER and atomic charge methods were applied to model the properties. For TLSER, the introduction of structural indicator variable I into the model largely improves the predictive power. For the atomic charge method, the utilized molecular descriptors are molecular surface (S), weight (Mw), ovality (O), charge densities on carboxyl, nitro group, nitrogen and sulfur atoms of the molecule. The correction coefficients r2 adj (adjusted for degrees of freedom) of 0.971 and 0.984, and the standard errors of 0.159 and 0.132 for log Sw and log Kow, reveal that the models are successful.