Hydrothermal Pyrolysis of Sargassum Marine Macroalgae: "Synthesis and Characterization of Products"

Abstract

Abstract In recent years, there has been an explosive growth and overabundance of pelagic Sargassum macroalgae in the North Atlantic Ocean, which wash up on the beaches in the United States, Mexico and the Caribbeans, causing both environmental and health issues in those coastal regions. Hydrothermal carbonization (HTC) process was investigated as a potential solution by converting this wet algae biomass into solid and liquid products, namely hydrochar and organic process water, respectively. In this study, the effects of HTC reaction temperatures on the yields and physicochemical properties of hydrochar and organic process water derived from Sargassum algae sample obtained from a coastal region in South Florida were evaluated by using various analytical techniques, including SEM, TGA, BET, FTIR and GC-MS. As a result of the increase in temperature, hydrochar yield decreased, while the yield of bio-oil increased. During the heating process, the volatile matter in hydrochar decreases, whereas the fixed carbon increases. Ash content in hydrochar increases as temperature increases. There were some interconnected pores on the surfaces of all three temperatures. It has been shown that a change in temperature has a significant effect on the chemical composition of bio-oils. In some cases, certain compounds increased as the temperature increased, but in others, it was temperature dependent. This study demonstrated that HTC technology could be a potential solution for mitigating Sargassum pollution issue by converting it into value-added bio-based products.