Thin film composite sodium alginate membranes for dehydration of acetic acid and isobutanol

Abstract

Dehydration of widely used organic solvents such as acetic acid (AA) and isobutanol (IB) is challenging tasks, which form close boiling mixtures with water. Sodium alginate (SA) thin film composite membranes were prepared and crosslinked with 2,4-toluene diisocyanate (TDI) and glutaraldehyde for dehydration of IB and AA/water mixtures through pervaporation (PV). The crosslinked and uncrosslinked SA composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and universal testing machine for intermolecular interactions, crystalline nature, thermal stability, surface morphology, and tensile strength, respectively. At a feed composition of 98 wt % IB and 95 wt % AA aqueous solutions, the TDI crosslinked SA composite membrane exhibited separation factors of 3229 and 708 with reasonable fluxes of 0.021 and 0.012 kg m 22 h 21 , respectively. The results obtained in the study for IB and AA systems were compared with other SA membranes reported in the literature. The membranes appeared to have potential for commercial PV ability to dehydrate the solvents up to desirable purity levels (>99%) and feasibility of preparing them in a composite form which would enable scale-up into modular configurations.

Antifouling membrane based on sodium alginate coated polyamide thin film composite for desalination of brackish water

“…The membrane underwent complete thermal degradation at 727 C with a weight loss of about 26.5% due to the alginic acid formed during the de-polymerization process, followed by complete decomposition. This is comparable to the GA cross-linked SA membrane, which revealed an initial weight loss at 300 C with more significant loss reported above 450 C. [19] From the TGA and DTA analytical study, the membrane was thermally stable up to 727 C, thus revealing high glass transition energy.…”

“…Lack of hydroxyl ( OH group) peak at 1250 cm −1 and ether ( C O C linkage) peak found in the range of 1050 to 1150 cm −1 demonstrated that the SA was cross-linked with an aldehyde group ( CHO) of GA ( Figure 4C,D) schematically presented in Scheme 1. [19,25] 3.1.2 | X-ray diffraction studies The absence of sharp peaks of amide monomer suggests complete formation of polyamide membrane. [31] F Figure 6 shows the scanning electron microscopy (SEM) images of the membrane surface and cross-sectional views of the SA/PA-TFC membrane, which reveals small circular nodules on the membrane surface, indicating a thin layer of SA on polyamide substrate.…”

“…Pure SA was studied by Badiger et al [19] to compare structural, thermal, and mechanical stabilities besides ion exchange capacity and sorption behavior with and without cross-linking by GA and found that the cross-linking enabled enhanced stability and performance. [19,20] Conventionally, many researchers explored the SA-TFC membranes for dehydration of alcohols, especially azeotropic mixtures. [21][22][23][24][25] As per our knowledge, this work is the first attempt to enhance the membrane performance by casting a hydrophilic layer of SA on the PA-TFC membrane.…”

Development of bacterial cellulose/alginate nanocomposite membrane for separation of ethanol–water mixtures

“…Hydrophilic membranes 27 such as poly(vinyl alcohol) [14][15][16], polyamide [17,18], chitosan 28 [5, [19][20][21][22], and alginate have been used to remove water from this 29 ethanol-water azeotropic mixture. Alginate is highly hydrophilic 30 because of its carboxyl and hydroxyl groups, but it has poor 31 stability and mechanical strength in aqueous solutions [23][24][25][26][27][28]. On 32 the other hand, hydrophobic polymeric membranes composed of 33 polydimethylsiloxane (PDMS) were reported for the pervaporative 34 separation and concentration of ethanol and butanol in fermenta-35 tion broths [29,30].…”

Chemical Modifications of Alginate and Its Derivatives

“…Sodium alginate is a polymer that is hydrophilic in nature and can be made into membranes having potential applications in dehydrating aqueous organic solutions. Badiger prepared thin-film composite membranes of sodium alginate, cross-linked the membrane with a 2,4-toluene diisocyanate (TDI) and glutaraldehyde for the dehydration of IB and AA/water blends by means of pervaporation (PV) [95]. To assess polymer-liquid interactions, sorption studies were conducted at equilibrium in pure liquids with binary organic-water mixtures of diverse compositions.…”