Design of mechanically stable polyacrylamide/cellulose hydrogel with high performance for biodiesel dehydration

Author(s)

Arthus, Leticia ; Estevam, Bianca Ramos ; Maciel, Maria Regina Wolf ; Fregolente, Leonardo Vasconcelos

• Document type: Journal article
• Source: INDUSTRIAL CROPS AND PRODUCTS; v. 218, p. 13-pg., 2024-06-08.

Abstract

Hydrogel presents great potential for dehydrating fuel, although several challenges must be addressed to advance this technology for commercial use. The essential attributes for industrial application include robust mechanical strength, high hydrophilicity, and rapid water removal kinetics. This study aimed to design composite hydrogels that concurrently meet these requirements. The introduction of cellulose significantly enhanced the compressive strength of polyacrylamide (PAM), with microfibrillated cellulose (MFC) demonstrating superior performance compared to cellulose nanocrystals (CNC). This enhancement resulted in a fivefold increase in compressive strength. Notably, the inclusion of MFC had no significant impact on water removal from biodiesel, as supported by a 95% confidence level. To enhance hydrophilicity, ionizable charges were introduced through hydrolysis of the composite. This process substantially improved water removal from biodiesel, increasing it from 36% to 49%. Moreover, the swelling degree increased from 27 to 714 g.g -1 when using the hydrolyzed composite and ovendried hydrogel compared to non-hydrolyzed polyacrylamide. The drying method influenced the water uptake kinetics, with freeze-dried hydrogels exhibiting better initial performance but ultimately reaching equilibrium values similar to oven-dried hydrogels. Equilibrium was achieved after 1440 minutes for hydrolyzed composite hydrogels, with the kinetic data fitting the pseudo-second-order model. With approximately 190 mg of hydrogel per mL of biodiesel, the water content in the biodiesel decreased from 1,497 -303 ppm, meeting regulatory agency specifications. Furthermore, the material proved to be reusable for at least three cycles of biodiesel treatment. Summing up, this research demonstrates that cellulose-polyacrylamide composite hydrogels are a promising solution for effectively removing trace amounts of water from biodiesel, achieving efficiency comparable to established technologies. (AU)

• FAPESP's process: 21/03472-7 - Design of new separation processes for water removal from biodiesel and diesel/biodiesel mixtures applying synthetic hydrogels grafted with cellulose nanocrystals
• Grantee: Leonardo Vasconcelos Fregolente
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• FAPESP's process: 21/08438-1 - Development of beds of hidrogel grafted with cellulose nanomaterials obtained by additive manufacturing for removal of water from biodiesel and diesel
• Grantee: Letícia Arthus
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 15/20630-4 - Biorefinery development integrated to a bioethanol sugar cane plant with zero CO2 emission: routes to convert renewable resources to bio-products and bio-electricity
• Grantee: Rubens Maciel Filho
• Support Opportunities: Research Projects - Thematic Grants