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Seaweeds are large-scale multicellular marine algae categorized based on color as Chlorophyceae, Rhodophyceae, and Phaeophyceae. No information has been provided on the conditions affecting the production of mesoporous activated carbon from one member of the described aquatic plants, namely Sargassum sp. Therefore, this study aimed to determine the...
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... The experiment was modeled by a modified experimental design methodology [19,17] . ...
Anaerobic digestion (AD) is a potential solution to valorize invasive pelagic Sargassum spp. Sargassum spp. (SP) biomass is characterized by a low carbon/nitrogen (C/N) ratio, which, in addition to the presence of indigestible fiber, sulfide, salt, ash, and polyphenol content, are inhibitors to the AD process. Furthermore, its chemical composition depends on the season and region of harvesting. To increase biogas yields, biomass must be subjected to pre-treatment or an anaerobic co-digestion process with other waste biomass. In this paper results of co-digestion of Sargassum spp. and municipal solid waste (OFMSW) batches with different weight ratios are reported and compared with the mono-digestion of the two organic matrices. The objective is to provide an optimized SP to OFMSW ratio for the sustainable production of biogas in the Dominican Republic. Mono-digestion of Sargassum spp. showed the longest reaction time and the lowest biomethane yield as it lasted 30 days and provided a cumulative volume of biomethane equal to 79.68 NmLg−1VS. The addition of OFMSW led to the shortening of the reaction time to 10 days and to the increase of the yield and cumulative volume of biomethane. It can be attributed to the more favorable C/N ratio, to the presence of more readily digestible compounds and lower ash content of those batches. The reaction kinetics of all the investigated batches is properly fitted by the Modified Gompertz model. The system with a Sargassum spp.-OFMSW weight ratio of 33:67 allows to obtain a notable bio-methane volume of 327.27 ± 15.93 NmLg−1VS, ten times higher than from Sargassum spp. alone.
... Similarly, total pore volume and micropore volume illustrated enhancement with an increase in HTC temperature for the SAH up to 12.0% and 11.0% for SAH-260 from SAH-180 and SAH-220, respectively. Analogous porosity results were obtained from Prakoso et al. which investigated HTC and activation factors' effect on mesoporous activated carbon production from Sargassum sp. using a multilevel factorial design [53]. Prakoso et al. reported that for the Sargassum-derived activated carbon produced with a KOH activator resulted in S BET ranging from 1121 to 1799 m 2 g −1 based on the appropriate HTC temperature and KOH: biomass ratio [53]. ...
... Analogous porosity results were obtained from Prakoso et al. which investigated HTC and activation factors' effect on mesoporous activated carbon production from Sargassum sp. using a multilevel factorial design [53]. Prakoso et al. reported that for the Sargassum-derived activated carbon produced with a KOH activator resulted in S BET ranging from 1121 to 1799 m 2 g −1 based on the appropriate HTC temperature and KOH: biomass ratio [53]. Content courtesy of Springer Nature, terms of use apply. ...
Sargassum (brown seaweed) is free-floating brown algae found on ocean shores in large quantities littering shorelines and causing visual and olfactory nuisances affecting the tourism and fishery industries. In this study, Sargassum is valorized to ultraporous carbon material via hydrothermal carbonization (HTC) at temperatures 180, 220, and 260 °C followed by KOH activation. The synthesized ultraporous superactivated hydrochar (SAH) is then analyzed by physical (thermogravimetric analysis and ultimate analysis), morphological (Brunauer-Emmet-Teller surface area and scanning electron microscopy), and chemical characterizations (Fourier Transform Infrared Spectroscopy and Boehm titration). It was found that the SAH proved to be thermally stable, carbon-dense with very high BET surface area ranging from 1216.92 to 1404.09 m²/g, total pore volume ranging from 0.69 to 0.77 cm³/g and micropore volume ranging between 0.32 to 0.36 cm³/g. Substantial surface oxygen-containing acidic functional groups were present on the SAH extending from 356.04 to 452.82 μmol/g. These physical and morphological alterations made SAH an excellent adsorption material with Methylene blue adsorption where as high as 641.03 mg/g at room temperature and 714.29 mg/g at 37 °C. Influential adsorption parameters were investigated, showing high maximum adsorption at solution pH 12, 24 h contact time, and under 37 °C respectively. Additionally, SAH showed selective adsorption behavior towards methylene blue in the presence of methyl orange. The possible adsorption mechanisms associated with the uptake of methylene blue are pore filling and electrostatic attraction being the dominant adsorption mechanisms. From adsorption isotherm modeling, the Langmuir model has proven to be the best fit with R² at 0.99. A thermodynamic study was conducted confirming spontaneous adsorption (negative ΔG) favoring higher adsorption temperatures with an entropy-driven process (ΔH = 11.57 kJ/mol, ΔS = 169.94 J/mol). From kinetic modeling, Elovich model showed the best fit describing chemisorption characteristics.
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