Multifunctional Loblolly Pine-Derived Superactivated Hydrochar: Effect of Hydrothermal Carbonization on Hydrogen and Electron Storage with Carbon Dioxide and Dye Removal

Abstract

Pore modulation via hydrothermal carbonization (HTC) needs investigation due to its crucial effect on surface that influences its multirole utilization of such ultraporous sorbents in applications of energy storage- hydrogen and capacitive- as well as for pollutant abatement- carbon capture and dye removal. Hence, loblolly pine was hydrothermally carbonized followed by KOH activation to synthesize superactivated hydrochars (SAH). The resulting SAHs had specific surface area (SSA) 1462–1703 m2/g, total pore (TPV) and micropore volume (MPV) of 0.62–0.78 cm3/g and 0.33–0.49 cm3/g, respectively. The SAHs exhibit excellent multifunctional performance with remarkably high atmospheric CO2 capture of 145.2 mg/g and high pressure cryogenic H2 storage of 54.9 mg/g. The fabricated supercapacitor displayed substantial specific capacitance value of maximum 47.2 Fg−1 at 1 A g−1 in 6 M KOH and highest MB dye removal of 719.4 mg/g. Higher HTC temperature resulted in increased surface porosity as higher SSA, TPV benefitted H2 storage and MB dye removal while superior MPV favored CO2 capture. Moderate HTC temperature ensured higher mesopore-to-macropore volume ratio favoring electrochemical performance. Isotherm modelling of the adsorbates was compared using models: Langmuir, Freundlich, Langmuir- Freundlich and Temkin.

High Surface Area Microporous Activated Carbon from Corn Fiber Using Graphene Oxide-Assisted Hydrothermal Carbonization

“…The hydrochars exhibit peaks indicating the presence of CC alkenes (1600 cm –1 ) when produced at 240 °C, revealing the increased aromatization at higher temperatures which is consistent with the increased carbon content and thermal stability that was experienced for these samples . C–H stretching (1450 cm –1 ) corresponding to alkanes, and C–O stretching or O–H bending vibrations (1000-1470 cm –1 ) corresponding the ether, ester, carbonyl, or carboxyl functional groups were also observed for the hydrochars. , Due to the use of GO and the high nitrogen content in the CF which is sustained in the hydrochar, it is also possible that the graphene structures could have become functionalized with nitrogen, as a new peak is formed at 1100 cm –1 which corresponds to C–N stretching vibrations in amine groups. , …”

“…With the global transition away from fossil fuels and towards green technology comprising of zero or negative carbon emissions, the suitability of porous carbon materials as the most environmentally sustainable and affordable options for adsorbent applications has become apparent. , Thermochemical conversion processes which produce these materials have further progressed emission and cost reduction efforts through the incorporation of hydrothermal technologies as an initial carbonization step. These technologies, such as hydrothermal carbonization (HTC), entail many advantages over pyrolysis as an initial pre-treatment method for activated carbon (AC) production and promote the utilization of biomass as carbonaceous feedstock by eliminating the need for drying feedstock, reducing ash content, requiring lower energy inputs, and producing higher solid yields. ,− Utilizing biomass for AC production over conventional coal-based precursors that are produced commercially help to reduce waste from agricultural and food residues, produce less emissions, and can be valorized into high-value carbon products for various applications …”

“…The subsequent activation of hydrochar produced from biomass using chemical activating agents like KOH has been shown to be effective in producing high surface area porous carbons with considerable microporosity. − Especially for adsorbent applications, a maximum surface area with well-developed porosity is required and is something that hydrochar is lacking on its own . Several researchers have studied the synthesis of high surface area AC via the chemical activation of hydrochar produced from lignocellulosic waste residues.…”

Prospective life cycle assessment of activated carbon production derived from banana peel for methylene blue dye removal

“…The BFA surface showed more irregularity and more development of the dark regions. When evaluating the morphology and functionality of activated hydro char, Sultana et al [54] observed this trend. Maia et al [41] also reported similar behavior when studying potential banana peels for activated carbon fabrication.…”

An Exploratory Study of Hydrochar as a Matrix for Biotechnological Applications

“…The flourishing literature has reviewed the advanced, non-energy applications of hydrochars from disparate waste biomass. − HTC of lignocellulosic materials, an environmentally benign process, yields a carbonaceous solid likely to undergo further transformation to functional matrices that can be applied to green, sustainable industrial processes of catalysis, electrical energy storage, and adsorption . Accordingly, HC recently came to the attention of researchers dealing with superperforming, hybrid materials. ,− Innovative adsorption processes make up a vast area for HC applicability because the carbonaceous matrix allows for surface modification in situ , i.e., during the HTC reactions , and postreaction. , Gas-phase separations exploit the affinity of hydrochar for acidic compounds. The literature primarily focuses on capturing CO 2 in the HC matrix, which is understandable considering the environmental relevance of this specific topic.…”