Removal of chromium (VI) from aqueous solutions using Lewatit FO36 nano ion exchange resin

The adsorption of hexamine onto powdered activated carbon from aqueous solutions was studied in a fixed bed system. Langmuir, Freundlich, Redlich-Peterson and Toth isotherm models were used to fit the experimental data and isotherm parameters were determined. The results revealed that the adsorption isotherm models fitted the data in the order of Langmuir [ Toth [ Redlich-Peterson [ Freundlich. Lagergren pseudo-first order kinetic model was found to correlate well with the experimental data. The effects of solution pH, temperature, initial hexamine concentration and added salts concentration on the adsorption capacity and the rate of adsorption were studied. The results indicate that the rate of adsorption increases and then decreases as temperature of the hexamine solution increases, however, the adsorption capacity decreases. The addition of low concentration of salt significantly increases the adsorption capacity of activated carbon. The results showed that the activated carbon has potential for the adsorption of hexamine from industrial hexamine wastewater.

Section: Introductionmentioning

confidence: 99%

Hexamine adsorption study on activated carbon from aqueous solutions for application in treatment of hexamine industrial wastewater

Taghdiri

Zamani

2012

“…It needs post treatment separation in a slurry system after photocatalyst reaction. Though this can be overcome by converting TiO 2 into nanotubes which resulted in increase surface area and catalytic activity (Fujishima et al, 2006;Khanfekr et al, 2009;Zhu et al, 2009;Rafati et al,2010). Interest in TiO 2 nanotubes photocatalysis increased after the pioneering study of Fujishma and Honda in 1972.…”

Section: Introductionmentioning

confidence: 99%

Iron and chromium doped titanium dioxide nanotubes for the degradation of environmental and industrial pollutants

Hussain

Siddiqa

2011

Pure titanate nanotubes and titanate nanotubes doped with iron (III) and chromium (III) were fabricated by the hydrothermal treatment in methanol and sodium hydroxide mixture. The fabricated nano tubes have high surface area, high aspect ratio, consisted of very good surface morphology and high metals dispersion. The morphology, crysralline phase, composition were characterized by powdered X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Barrett-Joyner-Halenda methods and X-ray photoelectron spectroscopy. The results showed that nanotubes possess anatase phase and are composed up of 8-12 nm in diameter and 360-400 nm in length. The band gap of the titanium dioxide nanotubes was determined using transformed diffuse reflectance spectroscopy according to the Kubelka-Munk theory, showed pronounced band gap decrease on doped titanium dioxide nanotubes. The photocatalytic activity of doped nanotubes were evaluated in terms of degradation of phenol and photoreduction of carbon dioxide into methanol and ethanol under Ultra violet and Infra red irradiation. It was found that with iron (III) and chromium (III) doped titanium dioxide nanotubes exhibited much higher photocatalytic activity than undoped titanate nanotubes.

“…Insoluble anion exchange resins contain anions capable of exchanging with chromium ions in solutions passed over them (Petruzelli et al 1995;Rengaraj et al 2006). Several studies have been reported in the literature to remove chromium from aqueous solutions using ion exchange resins (Cavaco et al 2007;Ibrahim and Jimoh 2008;Rafati et al 2010). Gode and Pehlivan (2003) removed Cr(III) from aqueous streams using Chelax 100 and Lewatit TP 207 cationic exchange resins.…”

Section: Introductionmentioning

confidence: 99%

Removal of hazardous hexavalent chromium from aqueous solution using divinylbenzene copolymer resin

Bajpai

Dey

Jha

et al. 2012

This paper presents the removal of hazardous hexavalent chromium from liquid waste streams using divinylbenzene copolymer resin Amberlite IRA 96. Important sorption parameters such as contact time, pH, resin dosage and initial metal concentration were studied at 30°C. The kinetic study was conducted using pseudo-first and pseudo-second-order kinetics at 30°C. The sorption process was found to be pH dependent. Maximum removal was obtained at pH 2 under optimized conditions. The sorption process was rapid and 99 % of the removal was achieved in first 30 min. The equilibrium data were fitted to both Langmuir and Freundlich models. The better regression coefficient (R 2 ) in Freundlich model suggests the multilayer sorption process. The value of Gibbs free energy for sorption process was found to be -12.394 kJmol -1 . The negative value indicated the spontaneity of the sorption process. Scanning electron microscope and energy dispersive X-ray spectroscopy studies were conducted to find the role of surface morphology during sorption process. The Fourier transform infrared study was conducted to identify the functional groups responsible for interaction between the resin and chromium. Desorption and regeneration studies were also carried out.