[Aspartic Acid Generated in the Process of Chlorination Disinfection By-product Dichloroacetonitrile].

In this study, a method was developed for the determination of dichloroacetonitrile (DCAN) in drinking water by liquid- liquid micro-extraction and gas chromatography/mass spectrometry ( LLE-GC/MS), which used 1,2-dibromopropane as the internal standard and methyl tertiary butyl ether (MTBE) as the extractant for high accuracy. The aspartic acid was used as the precursor of the DCAN formation during chlorination and the influencing factors were evaluated. The formation mechanism of DCAN was also discussed.

[Performance Study of Bromochloracetonitrile Degradation in Drinking Water by Fe/Cu Catalytic Reduction].

The paper used the method of iron copper catalyst reduction to degrade low concentrations of bromochloracetonitrile (BCAN) to lighten the damage to human being, which is a kind of disinfection by-products (DBPs) produced during the chlorination process of drinking water. The removal efficiency of BCAN and its influencing factors were investigated. The mechanism of degradation and kinetics were also explored.

[Formation Mechanism of the Disinfection By-product 1, 1-Dichloroacetone in Drinking Water].

A novel method using methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of the disinfection by-producs 1,1-dichloroacetone (DCAce) by gas chromatography mass spectrometry (GC-MS) was described. The formation process of DCAce and its influencing factors were discussed with L-leucine as the precursor during the chloramination process. The results indicated that the DCAce production increased with the increase of chloramine dosage when the chloramine addition was in the range of 5-30 mg · L(-1).

[Formation process of nitrogenous disinfection byproduct trichloronitromethane in drinking water and its influencing factors].

A novel method is described in this paper, which uses methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of nitrogenous disinfection byproduct trichloronitromethane (TCNM) by gas chromatography mass spectrometry (GC-MS). The formation process of TCNM and its influencing factors were evaluated with methylamine as the precursor during chlorination. The results indicated that the TCNM amount produced under alkaline condition was higher than those produced under the neutral and acidic conditions, and the TCNM amount increased with the increase of pH value.

[Influencing factors on the paranitrobenzoic acid wastewater treatment by chlorine dioxide and activated carbon catalysis-oxidation technology].

The effect of activated carbon dosage, chlorine dioxide dosage, pH value and reaction time on the paranitrobenzoic acid wastewater treatment on chlorine dioxide (ClO2 ) and activated carbon (AC) catalysis-oxidation technology were analyzed, and the efficiencies of the process to remove COD and increase biodegradation capacity (BOD5/COD ratio) were also examined under the optimum conditions as the pretreatment method for paranitrobenzoic acid wastewater with high-concentration. The result showed that the COD removal efficiency of the ClO2/AC catalysis-oxidation system was 10% higher than that of the system with only ClO2 when the COD concentration of paranitrobenzoic acid wastewater was 10 960 mg/L. It was also found that the COD removal was decreased by 35% with the concentration of 7 100 mg/L under the conditions of pH value 4.

[The affect of the skin stretch on the biomechanical changes of skin].

Objective: To investigate the biomechanical changes in skin after employing the skin stretch.

Methods: Skin samples were took from the test group which was stretched for 7 days and control group without stretch respectively in the end of 1, 2, 3, 4, 6, 8 week. The biomechanical index were measured by tensiometer.