Fabrication of Cellulose Acetate-Based Proton Exchange Membrane with Sulfonated SiO2 and Plasticizers for Microbial Fuel Cell Applications

Abstract

Developing a hybrid composite polymer membrane with desired functional and intrinsic properties has gained significant consideration in the fabrication of proton exchange membranes for microbial fuel cell applications. Among the different polymers, a naturally derived cellulose biopolymer has excellent benefits over synthetic polymers derived from petrochemical byproducts. However, the inferior physicochemical, thermal, and mechanical properties of biopolymers limit their benefits. In this study, we developed a new hybrid polymer composite of a semi-synthetic cellulose acetate (CA) polymer derivate incorporated with inorganic silica (SiO2) nanoparticles, with or without a sulfonation (–SO3H) functional group (sSiO2). The excellent composite membrane formation was further improved by adding a plasticizer (glycerol (G)) and optimized by varying the SiO2 concentration in the polymer membrane matrix. The composite membrane’s effectively improved physicochemical properties (water uptake, swelling ratio, proton conductivity, and ion exchange capacity) were identified because of the intramolecular bonding between the cellulose acetate, SiO2, and plasticizer. The proton (H+) transfer properties were exhibited in the composite membrane by incorporating sSiO2. The composite CAG–2% sSiO2 membrane exhibited a higher proton conductivity (6.4 mS/cm) than the pristine CA membrane. The homogeneous incorporation of SiO2 inorganic additives in the polymer matrix provided excellent mechanical properties. Due to the enhancement of the physicochemical, thermal, and mechanical properties, CAG–sSiO2 can effectively be considered an eco-friendly, low-cost, and efficient proton exchange membrane for enhancing MFC performance.

Advancing High-Temperature PEMFCs: Synthesis and Characterization of Poly(2,5-benzimidazole) Nanoclay/SPVC Composite Membranes

“…This modification not only increases water absorption but also improves ion conductivity, particularly for protons. Sulfonation induces the formation of ionic domains within the polymer, attracting and holding water molecules, contributing to higher water uptake. − …”

Investigating the Sulfonated Chitosan/Polyvinylidene Fluoride-Based Proton Exchange Membrane with fSiO2 as Filler in Microbial Fuel Cells

“…Increased water uptake values resulted in high proton conductivity values, which also causes undesirable effects on dimensional swelling, resulting in membrane mechanical deterioration. The rise in temperature enhances the polymer chain mobility resulted in the formation of additional room for water absorption [ 77 ]. Thus, an increase in temperature increases the membrane water uptake values.…”

“…The proton conductivity measurements for the pristine PVDF, PVDF/SiO 2 , PVDF/fSiO 2, and PVDF/sCS/fSiO 2 composite membranes were identified through Nyquist plots and exhibited in Figure 9 . Incorporating inorganic SiO 2 fillers into the polymer enhances the composite membrane’s proton conductivity through its hygroscopic properties [ 77 ]. The proton conductivity values of PVDF/SiO 2 , PVDF/f SiO 2 , and PVDF/sCS/fSiO 2 composite membranes were found to be 8.418 × 10 −3 S/cm, 9.56 × 10 −3 S/cm, and 1.0 × 10 −2 S/cm, respectively.…”

Development of a Novel Composite Polymer Electrolyte Membrane for Application as a Separator in a Dual Chamber Microbial Fuel Cell

“…A mixed-matrix organic–inorganic membrane such as Zirfon (ZrO 2 and polysulfone) has been shown to decrease oxygen crossover in an air-cathode MFC as compared to a Nafion membrane, yielding improved MFC performance with a gas-permeable cathode . Researchers have also focused on sustainable composite PEMs for MFC applications using biodegradable polymers such as poly­(vinyl alcohol) (PVA), chitosan, sodium alginate, polyhydroxyalkanoate, and cellulose . The advantages of using such polymers are their cost-effectiveness, ease of availability, and environmentally benign nature while yielding a performance comparable to that of synthetic PEMs.…”