Evaluation of the Performance of Flow-through Anodic Fenton Treatment in Amide Compound Degradation

ArticleinJournal of Agricultural and Food Chemistry 55(10):4073-9 · June 2007with4 Reads
Impact Factor: 2.91 · DOI: 10.1021/jf070104u · Source: PubMed

A flow-through anodic Fenton treatment (FAFT) system based on the batch AFT technology was previously developed to degrade pesticides in aqueous solution. As one of a series of benchtop and pilot-scale studies in process optimization, the goal of the reported work is to evaluate the performance of the FAFT system under various operating conditions, which is critical to bringing this technology into practical general use in the field. For this purpose, the removal efficiency of the parent pesticide and the concentration of the hydroxyl radical in FAFT were calculated on the basis of a previously developed FAFT kinetic model and used for the evaluation. N,N-Diethyl-3-methylbenzamide (DEET), an insect repellent, was used as a chemical probe. Experimental data showed that the key to a high treatment efficiency is to operate the FAFT system to achieve a maximum *OH production with a minimum input of energy and chemicals. For the anodic half-cell, the system should be operated under flow-through conditions with a self-developed optimum pH of 3.0, a relatively high flow rate, and the initial effluent recycled within 6-10 min to the FAFT system for further treatment; for the cathodic half-cell, it should have a fixed volume and be entirely replaced by another batch of cathodic solution only when the pH reaches a very high value. The delivery rate of the ferrous iron should be maintained at an electrolytic current between 0.01 and 0.02 A; the ratio of H2O2/Fe2+ should be between 5:1 and 10:1. NaCl was found to be the best electrolyte, with concentrations of 0.01-0.02 and 0.08 M in the anodic and cathodic half-cells, respectively. The FAFT system was successfully applied to degrade various model amide compounds and DEET formulations, which suggests the likelihood of extending this approach to other pesticide-containing wastewaters.

  • [Show abstract] [Hide abstract] ABSTRACT: Starting from (substituted-)benzaldehydes, the title compounds 6 were synthesized through five step reactions. Benzaldehydes were treated with ammonium hydroxide, followed by dialkyl phosphite, to give dialkyl N-(arylmethylene)-1-amino-1-aryl methylphosphonates ( 3). Phosphonates 3 were then easily hydrolyzed to give dialkyl 1-amino-1-aryl-methylphosphonates 5. Target compounds 6 were then obtained by the reaction of 5 and substituted benzoic or cinnamic acid. Their structures were clearly verified by spectroscopic data (IR, 1H, 13C, and 31P NMR, and elemental analysis). These compounds were shown to be antivirally active in the bioassay. It was found that title compounds 6g, 6l, and 6n had the same inactivation effect of TMV (EC 50 = 54.8, 60.0, and 65.2 microg/mL, respectively) as commercial product Ningnanmycin (EC50 = 55.6 microg/mL). To the best of our knowledge, this is the first report on the synthesis and antiviral activity of amide derivatives containing an alpha-aminophosphonate moiety.
    No preview · Article · Mar 2008 · Journal of Agricultural and Food Chemistry
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  • [Show abstract] [Hide abstract] ABSTRACT: A study was conducted to demonstrate the advantages of electro-Fenton process and related electrochemical technologies based on Fenton's reaction chemistry. The electrochemical technology had gained significance due to its ability to prevent pollution problems. Its main advantage was its environmental compatibility, as the electron was the clean reagent. The technology also offered advantages, such as versatility, high energy efficiency, amenability of automation, and safety. It was revealed that the electrochemical technologies had the ability to decontaminate wastewaters containing a large variety of organic pollutants in a wide range of experimental conditions. All these technologies were suitable for destroying the initial pollutant and mineralize the solutions treated.
    No preview · Article · Oct 2009 · Chemical Reviews
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  • [Show abstract] [Hide abstract] ABSTRACT: As a kind of natural amino acid analogue, α-aminophosphonates constitute an important class of compounds with diverse biological activities and potential to be employed as enzyme inhibitors, antibiotics, and anticancer agents. They also have a wide range of antiviral and antifungal properties and are extensively used as insecticides and herbicides.1–6 The importance of chiral α-aminophosphonates emanates from their increased industrial applications and evident from overwhelming rise in the number of reports on enantioenriched α-aminophosphonic acid derivatives.7–9 Some racemic a-aminiophosphonates containing fluorine or heterocycle moieties such as thiophene, pyrrole, 1,3,4-thiadiazole and benzothiazole are reported to have potential anticancer properties, with the later one displaying excellent fungicidal activity in addition to antitumour activity.10–13 However, further studies are necessary to identify chiral α-aminiophosphonates containing fluorine or heterocycle moieties with potent antitumour activities. Although, diasteroselective addition of phosphite derivatives to chiral imines, enantioselective addition of phosphites to imines in the presence of chiral metal complexes and other methods have been reported for the preparation of optically active α-aminiophosphonates,14–25 the need to develop a general practical asymmetric route for their synthesis from achiral acyclic imine and simple dialkyl phosphites still remains.
    No preview · Chapter · Jan 2010
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