Cationic surfactant hemimicelle on alginate gel for removing bisphenol A from aqueous solution

Abstract

In this paper, alginate gel (AG) was prepared by cross-linking sodium alginate with calcium ion. By adding cationic surfactant cetyl trimethyl ammonium bromide (CTAB) as sorption medium, the bisphenol A (BPA) sorption from aqueous solution onto AG was investigated. The BPA removal was found to be dependent on initial pH, AG dose, CTAB concentration, BPA concentration, contact time, and temperature. The isothermal data of BPA sorption on AG conformed well to the Langmuir model, and the maximum sorption capacity (Q_m) of AG for BPA was 30.96 mg/g. The BPA sorption process could be described by the pseudo-second-order rate kinetic model. The thermodynamic study indicated that the BPA sorption process was spontaneous and exothermic. The results in this research confirmed that the AG could effectively remove BPA from aqueous solution in presence of the CTAB. The following sorption mechanism was proposed. Firstly, the negatively charged AG sorbed CTAB to form hemimicelle, then BPA was sorbed on hemimicelle by hydrophobic interaction.

Keywords:

• Cationic surfactant
• Hemimicelle
• Alginate gel
• Bisphenol A
• Sorption

Acknowledgments

The authors wish to express their thanks to the Key Laboratory of Bioresource Protection and Utilization of Anhui Province, the Key Laboratory of Biotic Environment and Ecological Safety of Anhui Province, and the Key Science Research Item of Anhui Normal University for the financial supports.