Hydrogen Peroxide Decay in Waters with Suspended Soils: Evidence for Biologically Mediated Processes

1990 ◽  
Vol 47 (5) ◽  
pp. 888-893 ◽  
Author(s):  
William J. Cooper ◽  
Richard G. Zepp
Keyword(s):  
Hydrogen Peroxide ◽  
Natural Water ◽  
Water Samples ◽  
First Order ◽  
Natural Water Samples ◽  
Major Reaction Product ◽  
Major Reaction ◽  
Chemical Sterilization ◽  
Pseudo First Order ◽  
Catalyzed Oxidation

Hydrogen peroxide decay studies have been conducted in suspensions of several well-characterized soils and in natural water samples. Kinetic and product studies indicated that the decay was biologically-mediated, and could be described by pseudo first-order rate expressions. At an initial H2O2 concentration of 0.5 μM, the hydrogen peroxide half-life varied from 1 to 8 h. The decay was inhibited by thermal and chemical sterilization of the soils. Peroxidase activity was inferred in several natural water samples, where the suspended particles catalyzed the oxidation of p-anisidine by hydrogen peroxide. The mass spectrum of the major reaction product indicated that it was the dimer, possibly benzoquinone-4-methoxyanil, a product that also was observed from the horseradish peroxidase-catalyzed oxidation of p-anisidine by hydrogen peroxide.

Multifactorial optimization of the decolorisation parameters of wastewaters resulting from dyeing flowers

2009 ◽  
Vol 59 (7) ◽  
pp. 1361-1369 ◽  
Author(s):  
Edison Gil Pavas ◽  
Miguel Ángel Gómez-García
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
Experimental Design ◽  
Order Reaction ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Effluent Standards ◽  
Degradation Of Dyes ◽  
Pseudo First Order ◽  
Dyes Mixture

This work deals with the treatment of the wastewaters resulting from the process of dyeing flowers. In some local cases for growing flowers near to Medellín (Colombia), wastewater color was found to be one of the main problems in meeting local effluent standards. Wastewaters were treated by photodegradation process (which includes photocatalysis) to achieve the degradation of dyes mixture and organic matter in the wastewater. A multifactorial experimental design was proposed, including as experimental factors the following variables: pH, and the concentration of both catalyst (TiO2) and hydrogen peroxide (H2O2). According to the obtained results, at the optimized variables values, it is possible to reach a 99% reduction of dyes, a 76.9% of mineralization (TOC) and a final biodegradability of 0.834. Kinetic analysis allows proposing a pseudo first order reaction for the reduction, the mineralization, and the biodegradation processes.

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