The application of emulsion liquid membrane process and heat-induced demulsification for removal of pyridine from aqueous solutions

In the current work the removal of pyridine from aqueous solutions by emulsion liquid membrane (ELM) which can be demulsified by heating has been investigated. The ELM consists of commercial kerosene as organic solvent, OP-4 as surfactant agent, hydrochloric acid as the stripping phase. Effect of different operating parameters such as internal phase type, internal phase concentration, surfactant concentration, emulsification speed, pH value in external phase, volume ratio of membrane phase to internal phase, volume ratio of membrane phase to external phase, stirring speed and salt concentration were investigated on the removal efficiency of pyridine from aqueous solutions. Optimum operating parameters were obtained and about 96.5% pyridine was removed in less than 20 min of contact time. The demulsification of the emulsion membrane was also investigated. The membrane phase was successfully demulsified by heating at 70 °C. The emulsion membrane containing recycled solvent and surfactant can achieve high removal efficiency. This study suggests that the ELM process using OP-4 as the surfactant provides a promising alternative technology to treat wastewater containing pyridine which is toxic and refractory to biodegradation.

► Removal efficiency of pyridine through emulsion liquid membrane can reach 96.5%.
► Membrane leakage analyzed by an ion concentration detecting method was low.
► Heat-induced demulsification was investigated and proved to be highly efficient.