ascorbic-acid and potassium-persulfate

The inhibitory effect of commonly known oxidants and their quenching agents was investigated by employing a battery of toxicity tests. Hydrogen peroxide toxicity could be effectively eliminated by the enzyme catalase, whereas sodium thiosulfate and ascorbic acid were recommended as suitable quenching agents for the removal of the oxidants persulfate and peroxymonosulfate in the Vibrio fischeri bioassays. None of the studied quenching agents was found to be suitable for persulfate and peroxymonosulfate in the Daphnia magna bioassays since high inhibitory effects were obtained for both oxidants. In the case of Pseudokirchneriella subcapitata, manganese dioxide powder should be used as an alternative quenching agent to catalase, since this enzyme exhibited a highly toxic effect towards these microalgae. Sodium sulfite, which is extensively used as a quenching agent, was not appropriate for quenching peroxymonosulfate in all studied bioassays.

Topics: Aliivibrio fischeri; Animals; Antioxidants; Ascorbic Acid; Biological Assay; Catalase; Chlorophyta; Daphnia; Hydrogen Peroxide; Luminescence; Manganese Compounds; Oxidants; Oxidation-Reduction; Oxides; Peroxides; Potassium Compounds; Sulfates; Sulfites; Thiosulfates; Waste Disposal, Fluid; Water Purification

Biodegradable flocculants of Gum ghatti (Gg) with acrylamide (AAm) were prepared through graft co-polymerization technique using potassium persulphate (KPS)-ascorbic acid (ABC) redox pair as initiator and N,N'-methylene-bis-acrylamide (MBA) as a crosslinker. Gg-cl-poly(AAm) was found to exhibit pH and temperature responsive swelling behavior. Maximum flocculation efficiency of Gg-cl-poly(AAm) was observed with 15 mg L(-1) polymer dose in acidic medium at 50°C. Biodegradation studies of Gg and Gg-cl-poly(AAm) were done using composting method. Gg was found to degrade within 20 days, whereas, Gg-cl-poly(AAm) was found to degrade 88.18% within 60 days. Different stages of bio-degradation were characterized through FT-IR and SEM techniques.

Topics: Acrylamide; Ascorbic Acid; Biodegradation, Environmental; Flocculation; Hydrogels; Hydrogen-Ion Concentration; Microscopy, Electron, Scanning; Osmolar Concentration; Plant Gums; Polymerization; Potassium Compounds; Spectroscopy, Fourier Transform Infrared; Sulfates; Surface Properties; Thermogravimetry

A novel and high-sensitive stopped-flow kinetic spectrophotometic method for the determination of perphenazine based on monitoring the variation of absorbance of the intermediate within a few seconds has been developed. The optimum conditions for various parameters on which the forming of the intermediate depends, were investigated. It was found that the initial reaction rate increased linearly with an increase in the perphenazine concentration in the range from 1.0 x 10(-5) to 1.6 x 10(-4)M. The detection limit was calculated to be 5.3 x 10(-6)M. The kinetics of the reaction was established by the aid of single-mixing or double-mixing stopped-flow techniques, a successive reaction model was proposed to analyze and simulate the reaction. The influence of both ascorbic acid and NADH on the time courses was also investigated.

Topics: Ascorbic Acid; Kinetics; Oxidation-Reduction; Perphenazine; Potassium Compounds; Spectrophotometry; Sulfates; Time Factors