Extraction of phenol from aqueous effluent using triglycerides in supported liquid membrane

Abstract

A B S T R A C TThis research work focuses on the removal of phenol using a flat sheet supported liquid membrane impregnated with triglycerides (vegetable oils). The mass transfer of phenol was found to be dependent on various factors such as type of vegetable oil, support material, feed phase pH and concentration, stripping phase concentration and stirring speed. The phenol transport was found to be higher when PTFE membrane (pore size 0.45 mm) impregnated with coconut oil was used and mass transfer coefficient was found to be 3.50 Â 10 À6 m/s. The corresponding stirring speed, pH of feed solution, concentration of stripping (NaOH) solution were 350 rpm, 4.0 and 0.2 M, respectively. The 92.5% of phenol was extracted from feed phase to stripping phase in 20 h. The aqueous boundary layer thickness reduced with an increase in stirring speed up to a certain extent (350 rpm), beyond which, it resulted in turbulence leading to displacement of impregnated oil from membrane pores. Phenol can be transported through the membrane, when it is present in molecular or undissociated state in aqueous solution. Since the pKa value of phenol is 10, the phenol will be present in undissociated form when the pH of the feed solution was 4.0, which resulted in the highest membrane mass transfer coefficient. The extraction of phenol was found to be dependent on the composition of fatty acids (chain length and position of double bond) in triglyceride. It may be concluded that PTFE membrane impregnated with triglyceride from coconut can be successfully used for the extraction of phenol from aqueous feed.

Easy removing of phenol from wastewater using vegetable oil-based organic solvent in emulsion liquid membrane process

“…The phenol-triglyceride complex reacted with the aqueous sodium hydroxide solution leading to the formation of sodium phenolate, and the triglyceride molecules returned back to the liquid membrane to form complex with incoming phenol [9]. Therefore, both of the liquid membrane played important roles in the transportation of phenol and provided an excellent mass transfer.…”

“…Separation is based on the diffusion of solutes pass through the supported liquid membrane whereby liquid is immobilize in the pores of thin microporous solid support 67%~ 92.5% -Simple operation and easy to scale up -low capital investment and operating cost -low energy consumption -Minimal loss of extractant -Low liquid membrane (LM) requirement 9 [8,9,10] …”

Green Emulsified Liquid Membrane for Hexavalent Chromium Extraction: Formulation and Process Optimization

“…The innovative applications of green solvents will be helpful in making this process more cost-effective and environmentally friendly [14,15], since till date most of the ELM-based extraction processes have used only organic solvents, such as kero-sene, hexane, heptane, as the main component of the organic phase. These solvents are toxic and volatile in nature, flammable, and uneconomic due to their limited resources [16]. Currently, vegetable oils are viewed as the best alternative to petroleum-based solvents being economic, renewable, nontoxic, inflammable, nonvolatile, and biodegradable.…”

Stability of Palm Oil-based Emulsion Liquid Membrane for Succinic Acid Extraction from Aqueous Solution

“…Alternatively, palm oil can be chosen as renewable organic diluent, as it is readily available and may contain natural surface-active agents, which improve the stability of an emulsion [29]. In addition, palm oil was proven to work well in extraction of heavy metal and phenol [30,31].…”