Chromium(VI) adsorption from aqueous solution onto Moroccan Al-pillared and cationic surfactant stevensite

J Hazard Mater. 2007 Feb 9;140(1-2):104-9. doi: 10.1016/j.jhazmat.2006.06.077. Epub 2006 Jun 27.

Abstract

Batch adsorption of the chromium(VI) onto Moroccan stevensite pillared by Keggin aluminium hydroxypolycation (Al-stevensite) and cationic surfactant cetyltrimethylammoniumbromide (CTA-stevensite) was investigated. The results showed that the CTA-stevensite has a higher affinity than that of Al-stevensite for chromium(VI) adsorption. The adsorption capacities for natural stevensite, Al-stevensite and CTA-stevensite calculated according to the Dubinin-Kaganer-Radushkevich isotherm (DKR) are 13.7, 75.4 and 195.6mmolkg(-1), respectively. The study of the pH effect showed that the optimal range corresponding to the Cr(VI) maximum adsorption on Al-stevensite is pH 3.5-6 and that on CTA-stevensite is pH 2-6. The adsorption rates evaluated according to the pseudo-second-order model are 7.2, 207.2 and 178.5mmolkg(-1)min(-1) for the natural stevensite, Al-stevensite and CTA-stevensite, respectively. The low values of the adsorption energy calculated by (DKR) suggest that anion exchange is the main mechanism that governs the chromate adsorption.

MeSH terms

  • Adsorption
  • Aluminum
  • Cations
  • Chromium / isolation & purification*
  • Hydrogen-Ion Concentration
  • Kinetics
  • Solutions
  • Surface-Active Agents / chemistry*
  • Water
  • Water Pollutants, Chemical / isolation & purification*

Substances

  • Cations
  • Solutions
  • Surface-Active Agents
  • Water Pollutants, Chemical
  • Water
  • Chromium
  • Aluminum