Adsolubilization of organic compounds by silica modified with mixed conventional surfactant and EO/PO-based block copolymer

Abstract

The concern over wastewater problems has led to the development of various treatment modalities. Adsorption and adsolubilization have been found to be useful in application for the removal of organic compounds from wastewater. In this study, a silica adsorbent was modified by using mixed systems of conventional surfactants cationic surfactant (CTAB), anionic surfactant (SDS), nonionic surfactant (Triton X-100) with EO/PO-based block copolymer (Pluronic L 64) in order to enhance the adsolubilization efficiency. Phenol, 2-naphthol, and naphthalene with different polarities were then used as the model toxic organic contaminants in the adsolubilization study. Pluronics are known to be environmentally friendly materials with low toxicity. The addition of ethylene oxide (EO), which is hydrophilic, and propylene oxide (PO), which is hydrophobic arranged in a tri-block structure with a pluronic block copolymer, provides greater efficiency in adsorbing insoluble undesired aromatic organic compounds. The mixed surfactant can be used to enhance the adsolubilization capacity of the organic compound. However, it depends on the type of surfactant which is used for mixing with Pluronic L64. Based on this study, the results suggest that suing the mix of block copolymers with CTAB in adsolubilzation can use to adsorb the organic solute better than a single Pluronic L64 surfactant system. A possible cause may be the stronger synergistic interaction between the block copclymer and the cationic surfactant ; the mixture of Pluronic L64 and CTAB was shown to enhance the sorption of organic compounds more than the mixed surfactant systems of Pluronic L64-SDS, and Pluronic L64-Triton X-100 because of the stronger bonding between the PEO chains and the hydrophilic silica surface sites.