Performance evaluation of sodium alginate–Pebax polyion complex membranes for application in direct methanol fuel cells

Abstract

A novel polyion complex membrane was synthesized for direct methanol fuel cell application through the blending of the natural biopolymer sodium alginate (SA) with the synthetic polymer Pebax [poly(ether-block-amide)]. The blend was covalently crosslinked with glutaraldehyde (GA) and sulfonated with sulfuric acid (H 2 SO 4 ), after which characterization by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, and universal testing machine techniques was carried out. The SA-Pebax-GA-H 2 SO 4 membrane exhibited a high ion-exchange capacity of 2.1 mequiv/g, an optimum water sorption of 17.3%, and a low methanol sorption of 9.5%. A desirably low methanol permeability of 9.25 3 10 28 cm 2 /s and a high proton conductivity of 0.067 S/cm were obtained as against corresponding values of 1.82 3 10 26 cm 2 /s and 0.077 S/cm reported for a commercial Nafion 117 membrane. Moreover, a high selectivity of 6.5 3 10 5 Ss/cm 3 with a power density of 0.17 W/ cm 2 was achieved with the indigenous blend membrane at a potential of 0.34 V. Molecular dynamics simulation was performed along with the estimation of fractional free volume to explain the transport behavior of water and methanol molecules through the membrane.

Green Synthesis of Cation Exchange Membranes: A Review

“…Sodium alginate is the most common modification [ 98 ]. Nagar et al [ 116 ] blended sodium alginate with a synthetic polymer Pebax, performed crosslinking with glutaraldehyde and sulfonated with sulfuric acid. They also investigated membranes that were not sulfonated with sulfuric acid.…”

Development and Utilization of Polyelectrolyte Membranes Based on Biomass and Agricultural Waste

“…Traditional power generation methods mainly rely on nonrenewable resources, which results in some environmental problems such as air pollution and climate change. Therefore, developing clean and efficient new energy technologies is crucial. , Direct methanol fuel cell (DMFC), as an electrochemical power generation device that can directly convert the chemical energy stored in the fuel into electrical energy, has the advantages of high energy conversion efficiency, environmental friendliness and stable operation, and hence is considered to be an ideal green energy alternative technology. , However, some important scientific, technical, and economic issues need to be addressed before large-scale commercialization can be achieved.…”

Promising Fluorine-Free Ion Exchange Membranes Based on a Poly(ether-block-amide) Copolymer and Sulfonated Montmorillonite: Influence of Different Copolymer Segment Ratios

“…Poly(ether-block-amide) membranes, under the tradename of PEBAX ® [ 11 , 12 ], are advantageous because they have attractive properties including high permeability, and high selectivity and durability. The mechanical stability of the copolymer is controlled by the crystalline structure of the polyamide segments, while the amorphous structure of the polyether segments ensures the high permeability of organic substances [ 13 , 14 ].…”