Gas permeation through water‐swollen polysaccharide/poly(vinyl alcohol) membranes

Abstract

ABSTRACT:The effect of Na-alginate content on the gas permeation properties of water-swollen membranes prepared by varying Na-alginate and poly(vinyl alcohol) (PVA) content in membranes was investigated. The influences of water content and crystallinity of the membranes on the gas permeation performance of the water-swollen membranes were studied. The gas permeation rate and selectivity of Na-alginate/PVA water-swollen membranes were compared with those of the dry membranes. The permeation rates of nitrogen and carbon dioxide through water-swollen membranes were in the range of 0.4 -7.6 ϫ 10 Ϫ7 to 3.7-8.5 ϫ 10 Ϫ6 cm 3 (STP)/cm 2 s Ϫ1 cmHg Ϫ1 , which were 10,000 times higher than those of dry-state membranes. The permeation rates of mixture gases through water-swollen Naalginate/PVA membranes were found to increase exponentially with the increase of Na-alginate content, whereas carbon dioxide concentration in permeates was decreased linearly. It was found that the gas permeance of the waterswollen membranes increased with increasing the Na-alginate content in the membrane. Gas permeation rates of the water-swollen Na-alginate/PVA membranes increased with increasing the water content in the membrane and decreasing the crystallinity of the membrane.

Characterization of sericin protein recovered from silk wastewaters

“…The ash contents of SC and SN were slightly Similarly, the silk sericin shows a peak absorbance at around 280 nm of wavelength (35). The UV absorbance spectrum of reference and recovered sericin samples showed that the maximal absorption wavelength was around 220 nm for all sericin samples, which is attributed to the absorbance by the peptide bonds.…”

Hollow fiber contained hydrogel-CA membrane contactor for carbon dioxide removal from the enclosed spaces

“…Owing to the existence of hydrophilic -COOH, -COONa and -CONH 2 groups, poly(AA-co-AM) superabsorbent has the capacity to absorb large amount of water. As shown in Table 2, the deionized water absorbency of the superabsorbent is up to 800 g g −1 , which is much higher than the maximum PVA absorbency of 100 g g −1 [12,13], albeit it is lower than that prepared by 60 Co ␥-source irradiation [15]. It is expected that the more water absorbency, the greater gas permeability the hydrogel will possess when poly(AAco-AM) is used to be the contained substance as shown in Section 3.3.3.…”

“…These membranes were stable at least up to 12 h [11]. Another two waterswollen hydrogel membranes for gas separation were also prepared with PVA-glutaraldehyde (GA) and Na-alginate-PVA-GA, respectively, followed by the crosslinking of the active layer by a solutionbased method [12,13]. According to the concept of CO 2 facilitated transport separation, a CA immobilized PVA hydrogel membrane had been prepared and studied by Xu et al in our group [14].…”

“…Although, PVA is a well known material having good mechanical property and hydrophilicity, its swelling ratio is found generally no more than 100% [12,13]. Note that the behavior of gas permeation properties of hydrogel membrane was reported to be parallel to the swelling behavior of the coating layer in water [12,13], it is expected that the CO 2 permeation rates through membranes might increase exponentially if the water content in the membranes can be increased significantly, thereby alleviating the sensitivity of the CLM to the relative humidity of inlet feed and sweep gases. Therefore, an effective CO 2 extracting system calls for a proper hydrogel.…”

Time domain NMR evaluation of poly(vinyl alcohol) xerogels

“…When polymeric gels are not filled with fluids, they are dubbed xerogels [14] . This class of polymeric material has many applications, such as in tissue engineering, drug delivery, prosthetics and membranes applied in separation processes [14][15][16] .…”