Effect of pH, salt concentration and chain length of surfactants on the MO removal from water by pyridinium-based gemini surfactant

Abstract

Dye stuffs are an environmental problem, and their presence in drinking water and bio ecosystems such as rivers and water ways have long been recognized as deleterious. Current methods for their removal largely rely on adsorption techniques which are costly and produce another waste to be disposed off, whereas the concept of reverse micelles acting to encapsulate the dye in aqueous micro pool in solvent environment provides a useful chemistry. The removal of methyl orange from aqueous phase in amyl alcohol solvent using cationic surfactants was studied. Experiments were conducted by mixing a known quantity of dye in aqueous phase and solvent-containing surfactants in a simple mixer. The separation of solvent phase, containing encapsulated dye in reverse micelles, from aqueous phase due to gravity results in the separation of dye from water. The effects of dye and surfactant concentration, pH, salts like KCl and MgCl2 were studied. The percentage removal of the dye depends upon the size of the reverse micelle of the surfactant. The solvent used for the dye removal can be recovered by distillation method and can be reused.