Removal of Toxic Pollutants from Aqueous Solutions by Adsorption onto Organo-kaolin

Abstract

In this study, the adsorption of toxic pollutants onto cetyltrimethylammonium kaolin (CTAB-Kaolin) is investigated. The organo-kaolin is synthesized by exchanging cetyltrimethylammonium cations (CTAB) with inorganic ions on the surface of kaolin. The chemical analysis, the structural and textural properties of kaolin and CTAB-kaolin were investigated using elemental analysis, FTIR, SEM and adsorption of nitrogen at −196 o C. The kinetic adsorption and adsorption capacity of the organo-kaolin towards o-xylene, phenol and Cu(II) ion from aqueous solution was investigated. The kinetic adsorption data of o-xylene, phenol and Cu(II) are in agreement with a second order model. The equilibrium adsorption data were found to fit Langmuir equation. The uptake of o-xylene and phenol from their aqueous solution by kaolin, CTAB-kaolin and activated carbon proceed via physisorption. The removal of Cu(II) ion from water depends on the surface properties of the adsorbent. Onto kaolin, the Cu(II) ions are adsorbed through cation exchange with Na + . For CTAB-kaolin, Cu(II) ions are mainly adsorbed via electrostatic attraction with the counter ions in the electric double layer (Br − ), via ion pairing, Cu(II) ions removal by the activated carbon is probably related to the carbon-oxygen groups particularly those of acid type. The adsorption capacities of CTAB-kaolin for the investigated adsorbates are considerably higher compared with those of unmodified kaolin. However, the adsorption capacities of the activated carbons are by far higher than those determined for CTAB-kaolin.

Simultaneous Adsorption and Antibacterial Activities of Surfactant-Modified Kaolinite

“…KaoH4.0 had the lowest number of bacteria colonies, proving to be an effective antibacterial agent capable of inhibiting bacterial growth. The HDTMA-Br possesses positively charged quaternary ammonium compound and hence, the presence of cationic surfactant on kaolinite changes the surface properties from hydrophilic to hydrophobic and increases the adsorption capacity towards anionic compounds [21]. Therefore, the positively charged ammonium will attract anions and the negatively charged bacterial cell wall or membrane, eventually killing the bacteria and inhibiting bacterial growth through electrostatic forces [22].…”