Removal of heat stable salts from aqueous MDEA solution via electrosorption using carbon-based electrodes

Capacitive Deionization (CDI), an emerging desalination technique, was explored for the removal of heat stable salts (HSS) from the industrial lean methyldiethanolamine (MDEA) solutions. Various carbon-based materials, commercially available and synthetically prepared, were screened for the CDI application. Among different biochar materials, biochar prepared from date palm was the most efficient material for the removal of HSS. The activated biochar from date palm prepared at 550 degrees C (DPAC550) showed the highest HSS removal with about 20% removal efficiency. The date palm activated carbon was characterized by BET, XRD, SEM, FTIR and Elemental Analysis. Kinetic studies were also performed to determine the uptake capacity of DPAC550. The kinetic studies revealed that the electrosorption of HSS by DPAC550 followed pseudo-first order model. Electrochemical analysis supported the electrosorption behavior of DPAC550 which exhibited a specific capacitance of 269 F g(-1) at 10 mV s(-1) in 6M KOH solution. This study clearly demonstrated the potential application of biochar electrodes for the removal of HSS from aqueous MDEA solutions using CDI cells.