Hydrogen Production by Reforming of Sodium Alginate in the Liquid Phase over Pt/C Catalyst

• Published in: Industrial & engineering chemistry research Vol. 60; no. 27; pp. 9755 - 9763
• Main Authors: Kalekar, Vinayak N, Vaidya, Prakash D
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.07.2021
• Subjects: Kinetics, Catalysis, and Reaction Engineering
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.1c01252

Wet biomass such as macroalgae (or seaweeds) can be effectively converted into a H2-rich gaseous product by catalytic reforming in the liquid phase. Sodium alginate (SA)a major constituent of such biomasswas chosen as the model compound for this study on aqueous-phase reforming (APR). Trials were performed in the 200–230 °C range in a stirred batch reactor for up to 6 h using different alginate concentrations (0.5–2.5 wt %) in aqueous solutions. Low-molecular-weight organic acids such as acetic, propionic, lactic, and succinic acids and gaseous product comprising H2, CH4, CO, and CO2 were formed. Contrary to the noncatalytic process, H2 was selectively produced over commercial 5% Pt/C catalyst for loadings between 2 and 6 kg/m3. After 3 h of reaction over Pt/C at T = 225 °C, the values of carbon conversion into gas phase (X) and selectivity to H2 (S-H2) and H2 yield (Y-H2) were 9.7, 32.5, and 1.4% respectively. Other noble metals were also tested; however, Pt/C performed better than Ru/C and Pd/C. Several features of Pt/C were investigated using electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and NH3-temperature-programmed desorption techniques. A possible reaction scheme for alginate conversion to products was discussed. Despite the low H2 yield, this work provided the desired starting point for improved macroalgae-to-H2 conversions via APR.