Emulsion liquid membrane (ELM) is an emerging technology to remove the hydrocarbons from industrial wastewater and water. For the first time, the effects of the combination of magnetic nanoparticles and ionic liquid in ELM (water/organic/water) on the removal efficiency of 4-Nitrophenol as an example of hydrocarbons from synthetic wastewater was investigated. The 4-Nitrophenol removal efficiency of 99 % in 1 min was achieved and the emulsion stability was improved significantly to 81 % for 6 hours with the use of combination of surface-modified 0.05 % (W/W) magnetic Fe2O3 nanoparticles and 0.05 % (V/V) ionic liquid [BMIM]+[NTf2]- in ELM. Demulsifying emulsifier particles from the interfaces of the droplets can be enhanced by using a magnetic force without causing a change in the oil phase chemistry. The outcomes of this study can be extended to the removal of other hydrocarbons and polar pollutants from industrial wastewater and water.

Removal of hydrocarbons of 4-Nitrophenol by emulsion liquid membrane (ELM) using magnetic Fe2O3 nanoparticles and ionic liquid

Emulsion liquid membrane (ELM) is one of the processes widely used in industrial separation process. Extraction of benzoic acid from aqueous solutions by an emulsion type liquid membrane was investigated. The influence of two emulsion composition variables, namely the surfactant concentration, and organic phase to internal stripping phase ratio( V O / V I ), as well as three process parameters, emulsion to external feed phase ratio ( V E /V F ), mixing speed of feed solution, and extraction time on the rates of extraction of benzoic acid, was experimentally studied. The emulsion liquid membrane consists of kerosene as solvent, Span 80 as surfactant, and NaOH as internal stripping phase. The role of a hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIM] + [NTf 2 ] − in increasing the stability of the emulsion membrane was also studied. The stability of emulsion containing 0.2% (v/v) of [BMIM] + [NTf 2 ] − has significantly increased in comparison with that without ionic liquid. Approximately 99.7% of benzoic acid was extracted after only 5 min of contact with tested mixtures under the most favorable operating conditions.

Investigating the performance of ELM systems in separating organic pollutants from industrial wastewater

Established applications of emulsion liquid membranes (ELM) refer to refining in hydrocarbons and hydrometallurgical processing, rehabilitation of poisoned patients. In this work we investigated the separation of aromatic compounds of biological interest, more often encountered as intermediates in dyes and drugs industry: aniline, nitrobenzene, ortho and para-toluidine, using emulsion liquid membranes. The experimental results showed that in the case of basic substances separation the main physicochemical characteristics which have to be considered are alkalinity and water solubility. Thus, for the liquid emulsion membranes operation it is preferred to have a basicity as high as possible and a solubility as low as possible.

Separation of aromatic intermediates of biological interest using emulsion liquid membranes

A Comprehensive Review on Green Emulsion Liquid Membrane and Its Applicability Towards the Removal of Contaminants from the Aquatic Streams

The present study deals with the removal of phenol from aqueous solution using the emulsion liquid membrane technique. Kerosene was used as a diluent, sorbitan monooleate (Span 80) was used as a surfactant and sodium hydroxide as the stripping agent. The effect of various parameters such as surfactant concentration in the range 1 to 6 (v/v)%, stirring speed in the range 100 to 600 rpm, volume ratio of membrane phase to internal phase in the range 1:1 to 6:1, NaOH as the internal phase concentration 0.01 to 3 M, stirring time in the range 2 to 10 min, volume ratio of membrane phase to the external phase in the range 1:1 to 1:6 and emulsification time in the range 20 to 120 second was studied. The maximum percentage removal for phenol was found to be 98.95 at the best preparation conditions were surfactant concentration 2% (v/v), stirring speed 400 rpm, volume ratio of membrane phase to internal phase 5:1, NaOH concentration 2 M, stirring time 4 min, volume ratio of membrane phase to the external phase 1:2 and emulsification time 1 minute. The increase of surfactant concentration increases the removal efficiency to a certain extent of 2% (v/v), the higher stirring speed the higher percentage of phenol removal until 400 rpm, increasing of NaOH concentration increases the removal of phenol, the removal efficiency of phenol increases with increasing volume ratio of membrane phase to internal phase up to 5:1 and decreases thereafter, the removal percentage increases with the increase of stirring time until it reaches a maximum value then starts to decrease, the increasing in the external phase volume lead to the reduction of phenol removal and the increase in emulsification time increases the phenol removal, but for long emulsification time the removal dropped.

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Phenol Removal from Aqueous Solution Using Emulsion Liquid Membrane Process: Batch Experimental Studies

Wastewater is a potential source of pollutant causing serious problems to environments. Most of the techniques such as chemical precipitation, coagulation-flocculation, flotation, ion exchange, electro –oxidation and adsorption have their own limitations [1,2]. Hence alternative technique is required to remove and recovery of organic and inorganic matters. Emulsion Liquid Membrane (ELM) is one of the techniques to remove and recover contaminants in wastewaters [3]. It has been given considerable attention by researchers due to its outstanding characteristics such as simultaneous pollutants removal and materials recovery in a single unit, non-equilibrium mass transfer, high selectivity, high fluxes, reusability and low energy consumption [4]. The ELM technique has great potential for removal and recovery of different metal ions and hydrocarbons from wastewater, where conventional methods provide lower separation efficiency. The diffusivity of most molecules through liquids is much higher than through polymer membranes. Liquid membrane separation methods use conventional kerosene, organic solvents and carriers which are hazardous to the environment. Liquid membrane can be modified to “green liquid membrane” by using environmentally friendly materials. For example, supported liquid membrane using non-toxic vegetable oil (coconut or palm oil) as a carrier [5] can reduce toxic and hazardous chemicals level in wastewater.

Sathya M

Papers

Emulsion Liquid Membrane: Removal and Recovery of Organic and Inorganic Ions