Wet oxidation

About: Wet oxidation is a(n) research topic. Over the lifetime, 3094 publication(s) have been published within this topic receiving 61536 citation(s).

A wet oxidation procedure suitable for the determination of nitrogen and mineral nutrients in biological material

Abstract: A digestion mixture suitable for the decomposition of soil and plant materials is described. This is based on sulphuric acid and hydrogen peroxide as oxidants with the addition of lithium sulphate to elevate the digestion temperature and selenium as catalyst. The subsequent solution is suitable for the determination of nitrogen, phosphorus and most mineral ions. A series of tests have been carried out to determine optimum conditions and check elemental recoveries and the procedure is compared with alternative systems.

Technologies for the removal of phenol from fluid streams: a short review of recent developments.

Abstract: The available technologies for the abatement of phenol from water and gaseous streams are briefly reviewed, and the recent advancements summarized. Separation technologies such as distillation, liquid-liquid extraction with different solvents, adsorption over activated carbons and polymeric and inorganic adsorbents, membrane pervaporation and membrane-solvent extraction, have been discussed. Destruction technologies such as non-catalytic, supercritical and catalytic wet air oxidation, ozonation, non-catalytic, catalytic and enzymatic peroxide wet oxidation, electrochemical and photocatalytic oxidation, supercritical wet gasification, destruction with electron discharges as well as biochemical treatments have been considered. As for the abatement of phenol from gases, condensation, absorption in liquids, adsorption on solids, membrane separation, thermal, catalytic, photocatalytic and biological oxidation have also been considered. The experimental conditions and the performances of the different techniques have been compared.

A review of imperative technologies for wastewater treatment II: hybrid methods

Abstract: In the first part of this two article series on the imperative technologies for wastewater treatment, a review of oxidation processes operating at ambient conditions was presented It has been observed that none of the methods can be used individually in wastewater treatment applications with good economics and high degree of energy efficiency Moreover, the knowledge required for the large-scale design and application is perhaps lacking In the present work, an overview of hybrid methods (the majority are a combination of advanced oxidation processes) has been presented Hybrid methods viz Ultrasound/H2O2 or ozone, UV/H2O2 or ozone, Ozone/H2O2, Sono-photochemical oxidation, Photo–Fenton processes, catalytic advanced oxidation processes, use of advanced oxidation processes in conjunction with biological oxidation, SONIWO (sonochemical degradation followed by wet air oxidation), and CAV-OX have been discussed with specific reference to the principles behind the expected synergism, different reactor configurations used and optimum considerations for the operating and geometric parameters An overview of different chemicals degraded has been presented Some of the important works evaluating the application of these processes to real effluents have been described in detail Some guidelines for the future work required to facilitate efficient large-scale operation have been given A model effluent treatment scheme based on the various techniques discussed in the present work has been presented

Changes in surface chemistry of activated carbons by wet oxidation

Abstract: A series of activated carbons with different degrees of activation were oxidized with H2O2, (NH4)2S2O8 and HNO3 in order to introduce different oxygen surface complexes Changes in the surface chemistry of the activated carbons after their oxidizing treatments were studied by different techniques including temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FTIR), titrations with HCl and NaOH, measurements of the pH of the point of zero charge and catalytic dehydration of methanol Results showed that treatment with (NH4)2S2O8 fixed the lowest amount of both total oxygen and surface acid groups However, this treatment yielded the acid groups with the highest acid strength This could be because it favors fixation of carboxyl groups close to other groups, such as carbonyl and hydroxyl, which enhances their acidity

Wet air oxidation

Abstract: Wet air oxidation (WAO), involving oxidation at high temperature (125--320 C) and pressure (0.5--20 MPa) conditions, is useful for the treatment of hazardous, toxic, and nonbiodegradable waste streams. The process becomes self-sustaining when the feed chemical oxygen demand (COD) is about 20,000 mg/l and can be a net energy producer at sufficient higher feed COD's. All the published information on WAO has been analyzed and presented in a coherent manner. Wet air oxidation studies on pure compounds have been critically reviewed. Mechanism, kinetics, and structure-oxidizability correlation for WAO of carboxylic acids, phenols, cyanides, and nitriles have been described. The industrial applications discussed include municipal sewage sludge treatment, distillery waste treatment, black liquor treatment, cyanide and nitrile wastewater treatment, spent carbon regeneration, and energy and resource regeneration. Waste streams from other sources and some miscellaneous applications of WAO have also been included. Special emphasis is given to WAO under supercritical conditions (above the critical temperature of water) and oxydesulfurization of coal. In addition to the industrial applications, some other aspects (like various catalysts and oxidizing agents) of WAO have also been discussed. Recommendations and suggestions for further investigations have been made. 560 refs.