Solubilization of polycyclic aromatic hydrocarbons by novel biodegradable cationic gemini surfactant ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride and its binary mixtures with conventional surfactants

Abstract

The aqueous solubility enhancement of the polycyclic aromatic hydrocarbons (PAHs) anthracene and pyrene was investigated by means of micellar solubilization. The solubilization capacity of equimolar binary mixed surfactant solutions of a biodegradable ester-bonded cationic gemini surfactant ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)dichloride (C16H33(CH3)2N+(CH2COOCH2)2N+(CH3)2C16H33·2Cl−, 16-E2-16) with cationic cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium chloride (CTAC); anionic sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS); nonionic polyoxyethylene (20) cetyl ether (Brij 58) and Triton X-100 (TX-100) towards the PAHs were studied spectrophotometrically. The solubilization capabilities have been discussed in terms of molar solubilization ratio (MSR), micelle–water partition coefficient (Km) and free energy of solubilization (ΔG0S) of the PAHs. While studying the surface and micellar properties of the single/mixed equimolar gemini–conventional surfactant systems by conductometric, tensiometric and fluorescence quenching methods, synergism between the component surfactants in the mixed micellar solutions was observed. The gemini–anionic surfactant mixtures show better solubilization capacity than the gemini–cationic and gemini–nonionic surfactant mixtures.