Hydrothermal Conversion of Spent Sugar Beets into High-Value Platform Molecules

Abstract

The growing importance of bio-based products, combined with the desire to decrease the production of wastes, boosts the necessity to use wastes as raw materials for bio-based products. A waste material with a large potential is spent sugar beets, which are mainly used as animal feeds or fertilizers. After hydrothermal treatment, the produced chars exhibited an H/C ratio of 1.2 and a higher heating value of 22.7 MJ/kg, which were similar to that of subbituminous coal and higher than that of lignite. Moreover, the treatment of 25 g/L of glucose and 22 g/L of fructose by heating up to 160 °C led to a possible application of spent sugar beets for the production of 5-hydroxymethylfurfural. In the present study, the maximum concentration of 5-hydroxymethylfurfural was 3.4 g/L after heating up to 200 °C.

Evaluation of the Char Formation During the Hydrothermal Treatment of Wooden Balls

“…Via dehydration, up to three water molecules can be split‐off from the sugar molecules to form furfurals like HMF (Figure 11 ). [ 58 ] The furfurals can perform aromatization, e.g., by Diels‐Alder reactions in the presence of a dienophile, which also could be furfurals. On the other hand, acids are formed by the dehydration and partial rehydration of hexoses (Figures 10 and 11 ).…”

“…In Scanning electron microscopy (SEM), the surface was analyzed concerning the morphology of the hydrothermally treated balls and precipitated material by using a FEI Inspect F at the Queen Mary University in London. The dust, scratched from the outer surface of the balls, as well as ground parts of the precipitate were fixed on a carbon tab, respectively, and sputtered with gold for 90 s. Sample preparation for the liquid analysis was done according to Pfersich et al [25,58] The Ultra Performance Liquid Chromatography (UPLC) with an UPLC gradient device of Waters Acquity as well as the Ion chromatography with both, an Integrion-RFIC and ICS 5000, of Thermo Scientific.…”

Biomass carbon mining to develop nature-inspired materials for a circular economy

“…Table 2 summarizes the functional groups found in hydrochars from HTC at different processing conditions of different model compounds. Most studies focus on cellulose and lignin, although HTC of other materials like spent sugar beets, 192 or even some mixtures of components like glucose and egg white ovalbumin, 193 has been performed.…”

“… 160 Fibers of spent sugar beets produce high-value platform molecules like glucose, fructose, sucrose, HMF, furfural, formic acid, levulinic acid, and acetic acid. 192 In addition, functionalized carbon nanoparticles with low cytotoxicity and photoluminescent properties can also be obtained from chitosan under mild conditions and applied as a bioimaging material. 166 Nevertheless, the yield of these carbon nanoparticles is only 7.8%.…”

Olive Mill by-Products Thermochemical Conversion via Hydrothermal Carbonization and Slow Pyrolysis: Detailed Comparison between the Generated Hydrochars and Biochars Characteristics

“…Indeed, the surface of hydrochars exhibits interconnected sphere-like particles with different diameters. The formation of these structures is attributed to the degradation mechanism of cellulosic structure into small chained polymers such as hydroxymethylfurfural (5-HMF) and furfural through dehydration reaction [26,65]. For extended carbonization time, these short aldehydes were repolymerized on the surface of the carbon material leading to spherical carbon condensates with hydrophilic outer shell (high content in oxygen groups) and a hydrophobic porous core [66].…”