Removal of haloacetonitriles in aqueous solution through adsolubilization process by polymerizable surfactant-modified mesoporous silica

• Published in: Journal of hazardous materials 2013-01, Vol.244-245, p.151-159
• Main Authors: Prarat, Panida, Ngamcharussrivichai, Chawalit, Khaodhiar, Sutha, Punyapalakul, Patiparn
• Format: Article
• Language: English
• Subjects: Acetonitriles - chemistry; Adsolubilization; Adsorption; Haloacetonitrile; Hydrogen-Ion Concentration; Mesoporous silica; Polymerizable gemini surfactant; Polymers - chemistry; Silicon Dioxide - chemistry; Solubility; Solutions; Surface-Active Agents - chemistry; Time Factors; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2012.11.012

[Display omitted] ► Selective organic partition of HAN5 is strongly affected by halogen substitution in molecule. ► Hydrophilic HANs can be adsorbed by surface adsorption via ion–dipole electrostatic interactions. ► Organic partition plays an important role for hydrophobic HANs adsorption. ► Enlarged pore size of SBA-15 can increase the internal surface coverage of surfactant. ► Polymerization of cationic gemini surfactant can be confirmed by FT-IR spectra. To investigate the adsorption properties and mechanisms of haloacetonitriles (HANs), large-pore SBA-15 mesoporous silica (SBA-CHX) was synthesized using cyclohexane as a swelling agent, and the surface was modified with polymerizable gemini surfactant (PG). The structure and textural properties of the synthesized adsorbents were characterized. PG surfactant coverage on the surface and the degree of polymerization were confirmed with FT-IR analysis. Adsorption experiments were performed under batch conditions to evaluate the influence of the contact time, adsorption isotherms, the effect of the pH solution, and the selective adsorption of five haloacetonitriles (HAN5) in individual-solute and mixed-solute solutions and surfactant leaching studies. The results indicated that the hydrophobic HANs were efficiently adsorbed onto PG surfactant-modified SBA-CHX. The selective adsorption mechanisms involved a more complex interplay between the organic partition, surface adsorption (i.e., ion–dipole electrostatic interactions) and hydrophobic interaction that depended upon the adsorbent and adsorbate characteristics. An increased degree of halogen substitution in the HAN molecule significantly affected the adsorption capacity and selectivity by the organic partition. Polymerization of the polymerizable surfactant increased the stability of the adsorbed surfactant on the adsorbent surface.