A Prospective Study of the Exploitation of Pelagic Sargassum spp. as a Solid Biofuel Energy Source

Abstract

This study presents a prospective study for the potential exploitation of pelagic Sargassum spp. as a solid biofuel energy source. It was carried out in three stages. First we conducted a morphological, physical-chemical, and structural characterization using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (DRX), respectively. Second we evaluated the material’s functional properties as a solid biofuel based on its calorific value and the quantification of polymeric components like hemicellulose, cellulose, and lignin, as well as thermogravimetric and differential analysis to study the kinetics of its pyrolysis and determine parameters like activation energy (Ea), reaction order (n), and the pre-exponential factor (Z). Third we analyzed the energetic potential considering the estimated volume of pelagic Sargassum spp. that was removed from beaches along the Mexican Caribbean coast in recent years. Results of the kinetic study indicate that Sargassum spp. has an enormous potential for use as a complement to other bioenergy sources. Other results show the high potential for exploiting these algae as an energy source due to the huge volumes that have inundated Caribbean, West African, and northern Brazil shorelines in recent years. As a solid biofuel, Sargassum spp. has a potential energy the order of 0.203 gigajoules (GJ)/m3. In the energy matrix of the residential sector in Mexico, its potential use as an energy source is comparable to the national consumption of firewood. The volume of beachcast Sargassum spp. that was removed from ~8 km of coastline around Puerto Morelos, Mexico in 2018–2019, could have generated over 40 terajoules/year of solid biofuel.

Presence of Polyphenols Complex Aromatic “Lignin” in Sargassum spp. from Mexican Caribbean

“…In order to carry out the thermogravimetric analysis (TGA) on Sargassum samples, three stages were selected (Figure 1). The first stage indicated a loss of 12% in mass, in the range of 50 to 150 • C, which is attributed to the loss of water as was reported by Davis et al Al et al [19,36] also found a loss of mass in the range of 8-15% in samples of these same species collected in the Caribbean Sea. The second stage is comprised between 180 to 360 • C with a loss of mass of 35% and is seen in the DTGA curves as two strong peaks at 250 and 320 • C. The overlapping of the peaks indicates the complexity of degradation reaction in this zone that is attributed to the decomposition of hemicellulose and cellulose, respectively.…”

The Use of Sargassum spp. Ashes Like a Raw Material for Mortar Production: Composite Performance and Environmental Outlook

“…The exception is the metallic component beryllium (Be), which may be related to metal adsorption by sargassum algae. Additionally, the EDS results are similar to those found in the research by López-Sosa et al, (2020) [36], due to the presence of the same chemical elements in sargassum stems and leaves from Mexico. The large amount of carbon, calcium, and oxygen elements may be related to the calcite phase [33].…”

Electron Microscopy Characterization of Sargassum Spp. from the Mexican Caribbean for Application as a Bioconstruction Material

“…Figure 1 shows the characterization by scanning electron microscopy of Sargassumspp, the morphology of the vesicles, stems and leaves is observed. As a result of the chemical analysis, different concentrations are identified, mainly of C, O, Ca, S and K. The large amount of C, Ca and O is associated with the presence of calcite that we have reported in previous investigations and that has been corroborated in scientific literature [1,6]. This compound can be visualized in the structures shown in Figure 1 (c).…”

“…In recent years, the influx of Sargassum spp. on the coasts of the Mexican Caribbean has increased considerably [1][2][3], generating effects on the marine ecosystem and the tourism sector. Recently, various applications of these algae have been explored, for example energy production, biofertilizers and as a bioconstruction material [1,4].…”