| dc.description.abstract | An increase in demand for air-conditioning is evident due to the rise in global temperatures through the advent of global warming, coupled with Earth's growing population. An estimation of about 65% of the worldwide population in 2050 will require an air conditioner for the comfort of life and survival. Current air conditions are too energy and resource extensive. Membrane-based air-dehumidification air-cooling has been proposed as a solution in the form of disruptive technology. The importance of the membrane in membrane-based air-dehumidification air-cooling cannot be understated. Therefore, the thesis aims to fabricate novel membranes incorporating nanofillers. In this thesis, polyether block amide (Pebax) membranes are manufactured in freestanding and supported membranes. Pebax has shown good performance in gas separation, especially water permeance. However, the restraints of the transport properties remain. Sulfonated GO (SGO) was targeted as the nanofiller of choice to be incorporated into the Pebax-MMM and supported Pebax membranes. The supported membranes are supported on an ultrafiltration PES membrane and its MMM containing SGO. The synthesis of SGO occurs with the grafting of sulfanilic salt on GO with oxygen-based functional groups, which was synthesized using Tour’s method. GO and SGO was characterized by wettability, crystal structure, and elemental analysis to incorporate the best performing nanofiller in the mixed matrix membranes. SGO retained a contact angle of 26°, making it an ideal candidate for a nanofiller in water/nitrogen separation. The support of PES membranes was fabricated incorporating SGO at 0.05, 0.10, 0.20, and 0.40 wt.% loadings, and they were characterized to determine the most favorable support. PES-0.2%SGO showed the lowest contact angle in relation to the loading amount with a water contact angle of 60.6°, a 10° decrease from 70.6° attained from the PES control membrane. The supported Pebax membrane used the PES-0.2%SGO support. The N₂ permeance was measured to study the effect of the number of coating layers, the substrate type, and the thickness of the active layer. The substrates used to fabricate the active Pebax layer were 0.5 wt.% Pebax and 0.5 wt.% Pebax-0.5%SGO-0.5%SGO. These membranes were characterized by studies regarding wettability, topography, and surface imaging—the active layer of each coat of 0.5 wt.% Pebax yielded around 200 nm, with a surface roughness of 11 and 12 nm for the coating substrates of 0.5 wt.% Pebax and 0.5 wt.% Pebax-0.5 wt.% SGO. Furthermore, freestanding Pebax membranes incorporating SGO in a mixed matrix were fabricated and characterized with wettability, topography, and surface imaging, where the incorporation of SGO in the 12 μm thick membranes resulted in a twice fold increase in average roughness to 18 nm with a 2° decrease in the contact angle to 72°. In the nitrogen permeance performance tests, asymmetric Pebax membranes were governed by the active layer coating thickness. One layer of coats (200 nm) gave N₂ permeance of 84 GPU, and the 2 layers membrane (400 nm) gave 34 GPU. In contrast, the free-standing Pebax membranes permeance increased five-fold from 176 GPU to 555 GPU with 0.5 wt.% SGO. | |
