In this study, diethylene glycol (DEG) as an absorbent was used for gas dehydration. For this purpose, hollow fiber membrane contactor was fabricated from polyvinyl chloride. The effect of surface modification with polydimethylsiloxane in the presence of calcium carbonate nanoparticles, relative humidity percentage of inlet air, variation in the gas and liquid flow rates in a dehydration process were investigated. The surface modification of the membranes increased the contact angle from 64 degrees to 101 degrees and a liquid entry pressure of as high as 7 bar was achieved. Moreover, increasing the gas flow rate led to a significant enhancement in absorption performance. Conversely, it was observed that the liquid flow rate had marginal effect on the mass transfer efficiency and flux i.e. RM+L/RM+G = 0.001-0.01. This revealed that the mass transfer resistance was not controlled by the liquid phase. Although higher fluxes were observed for the unmodified membrane contactor, the membrane modified with polydimethylsiloxane and calcium carbonate nanoparticles (i.e. M0.5-1) was more effective compared to the neat membrane (M0) in a 35-day long-term performance test i.e. eta(M0.5-1) approximate to 0.12 versus eta(M0) =1.0. The results show that the applied technique for fabricating the hollow fiber membrane contactor can be a promising technique in gas conditioning. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.