Box–Behnken Statistical Design for Removal of Methylene Blue from Aqueous Solution Using Sodium Dodecyl Sulfate Self-microemulsifying Systems

Abstract

In the present study, attempts were made to develop sodium dodecyl sulfate self-micromemulsifying systems (SDS-SMES) for removal of methylene blue (MB) from its aqueous solution. Box–Behnken design was applied for optimization of SMES composition for maximum removal of MB. Various SDS-SMES were prepared by spontaneous emulsification method. Adsorption studies were carried out for 8, 16, and 24 h by mixing small amounts of concentrated SMES with relatively large amounts of bulk aqueous solution of MB. Droplet size and viscosity of SDS-SMES were significantly influenced by Triacetin and surfactant concentration. However, the percent removal of MB from its aqueous solution was significantly influenced by Triacetin concentration, surfactant concentration, and adsorption time. On the basis of lowest droplet size (51.37 nm), lowest viscosity (16.97 cP), and highest percent removal efficiency (91.44%), the formulation S14 containing 5% w/w of Triacetin, and 30% w/w of surfactant mixture (15% w/w of SDS and 15% w/w of polyethylene glycol-400) was optimized as the best formulation for removal of MB from its bulk aqueous solution after 24 h. These results indicated that SDS-SMES could be successfully applied for the removal of toxic dyes such as MB from its aqueous solution through liquid–liquid extraction.