Permeability and Stability of Hydrophobic Tubular Ceramic Membrane Contactor for CO₂ Desorption from MEA Solution

Ceramic membrane contactors hold great promise for CO₂ desorption due to their high mass transfer area as well as the favorable characteristics of ceramic materials to resist harsh operating conditions. In this work, a hydrophobic tubular asymmetric alpha-alumina (α-Al₂O₃) membrane was prepared by grafting a hexadecyltrimethoxysilane ethanol solution. The hydrophobicity and permeability of the membrane were evaluated in terms of water contact angle and nitrogen (N₂) flux. The hydrophobic membrane had a water contact angle of ~132° and N₂ flux of 0.967 × 10^-5 mol/(m²∙s∙Pa). CO₂ desorption from the aqueous monoethanolamine (MEA) solution was conducted through the hydrophobic tubular ceramic membrane contactor. The effects of operating conditions, such as CO₂ loading, liquid flow rate, liquid temperature and permeate side pressure, on CO₂ desorption flux were investigated. Moreover, the stability of the membrane was evaluated after the immersion of the ceramic membrane in an MEA solution at 373 K for 30 days. It was found that the hydrophobic α-Al₂O₃ membrane had good stability for CO₂ desorption from the MEA solution, resulting in a <10% reduction of N₂ flux compared to the membrane without MEA immersion.