Regeneration of spent activated carbon by wet air oxidation

Abstract

The regeneration of activated carbon was studied using the wet air oxidation process in the temperature range of 150-240°C and oxygen partial pressure range of 0.2 to 1 .O MPa. Phenol was used as substrate. The overall mechanism of regeneration has been analysed and the different steps taking place during the regeneration process were individually investigated. Kinetics of oxidation of phenol and oxygen mass transfer coefficients have been estimated in the ranges of temperature and pressure studied. Oxidative degeneration characteristics of activated carbon were also studied. The conditions of temperature and pressure have been found at which the extent of regeneration is favourable.On a ktudi6 la rCgCnCration du charbon actif au moyen d'un procCdC d'oxydation a air humide a des temperatures comprises entre 150 et 240°C et des pressions partielles d'oxyghe variant de 0,2 5 1 ,O MPa. On a utilise du phknol comrne substrat. Le mCcanisrne global de rCgCnCration a ktk analysC et on a CtudiC s6parCment les diffkrentes etapes marquant le processus de rCgCnkration. La cinktique d'oxydation du phenol et les coefficients du transfert de matitre de I'oxygkne ont CtC estimis dans les gammes de tempkratures et depressions CtudiCes. On a kgalernent CtudiC les caractkristiques de dCgCnCrescence oxydante du charbon actif. Les conditions de tempCrature et de pression ont CtC deter-minCes 18 oh le degrC de dCgCnCrescence est favorable.

Catalytic wet air oxidation of phenol using active carbon: performance of discontinuous and continuous reactors

“…18 Simultaneously, WAO has been extensively studied for the regeneration of AC spent with organic compounds after its use in adsorption processes. 19,20 Also, AC and other carbonaceous materials have been successfully tested as supports for catalysts, 21 even for CWAO of low molecular weight acids. 21±24 Recently, a study carried out in a trickle bed reactor has demonstrated that activated carbon (AC) alone, without the help of any catalytic species, can effectively oxidise phenol solutions without the presence of any active metal.…”

Wet air oxidation of phenol using active carbon as catalyst

“…Thus, the success in renewing the active carbon lies in minimising the surface oxidation by selecting suitable regeneration conditions. For instance, regeneration of active carbon saturated with phenol was found to be attractive only at temperatures below 1508C [27]. Anyway, phenol removal by adsorption is a discontinuous two-step process.…”

CFD Simulation of Annular Centrifugal Extractors

“…Annular centrifugal extractors find wide applications in nuclear fuel processing where safety is the main concern [2,8,9], in biological operations where controlled shear field and/or facilitated settling is important [10,11] and polymerization [12,13], excellent mixing, heat, and mass transfer [14][15][16][17][18][19]. Annular centrifugal extractors can also be used for a variety of chemical reactions such as synthesis of monodisperse silica particles, regeneration of spent activated carbon [20,21], esterification, and hydrolysis [22,23], as cavitation reactor [24], and they have also been demonstrated for use with ionic liquids [25].…”