Removal of heat stable salts from methyldiethanolamine aqueous solution using anion adsorptive membranes

In this study, an adsorptive polyethersulfone (PES) membrane was used to remove the heat stable salts (HSS) from ۴۰ wt.% methyldiethanolamine (MDEA). The synthesized membranes were characterized using SEM, FTIR, porosity and mean pore size calculations, contact angle measurement, pure water and amine flux tests in order to examine their morphology. It was observed that Langmuir equilibrium isotherm best explained the ion exchange process with the highest capacity reaching ۲۲.۶۳ mg/g. The surface of the optimized M۲ membrane was coated with a polyamide (PA) layer via interfacial polymerization (IP) method to examine Donnan effect on salts rejection. The study demonstrated that the membranes' ability to reject ions was influenced by the membrane's surface charge. The highest removal efficiency was reported for phosphate ions, which was ۸۲.۲% for M۲/IP. Divalent ions like sulfate and oxalate were rejected more effectively than monovalent ions like chloride and nitrate. The results suggest that adsorptive membranes offer a cost-effective and efficient alternative for amine recovery benefiting refineries and related industries.

Keywords:

Heat stable salts (HSS) , Amine purification , MDEA reclamation , Adsorptive membrane , Polyethersulfone , Activated carbon nanoparticles