Structure, surface chemistry, and DFT-based mechanistic insights of seafood-waste hydrochars for pollutant adsorption
Siddhartha, T.R.; Kashif, M.; Ranjbari, A.; Adhikary, K.K.; Kooy, E.; Anbari, A.P.; Che, C.A.; Ronsse, F.; Heynderickx, P.M. (2026). Structure, surface chemistry, and DFT-based mechanistic insights of seafood-waste hydrochars for pollutant adsorption. Biomass Bioenerg. 208: 108829. https://dx.doi.org/10.1016/j.biombioe.2025.108829
In: Biomass and Bioenergy. Pergamon: Oxford; New York. ISSN 0961-9534; e-ISSN 1873-2909, more
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| Author keywords |
Hydrochar; Hydrothermal carbonization; Adsorption; Marine biowaste; Kinetic model |
| Authors | | Top |
- Siddhartha, T.R.
- Kashif, M.
- Ranjbari, A.
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- Adhikary, K.K.
- Kooy, E.
- Anbari, A.P.
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- Che, C.A.
- Ronsse, F., more
- Heynderickx, P.M., more
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| Abstract |
Marine biowastes such as fish and shrimp residues represent abundant yet underutilized carbon precursors for adsorbent synthesis. This study evaluates hydrochars derived from fish and shrimp waste as sustainable adsorbents for multi-pollutant removal, benchmarked against corn hydrochar and commercial activated carbon. Seven model pollutants (acetaminophen, doxycycline hyclate, tetracycline, methylene blue, methyl orange, 4-nitrophenol, and potassium dichromate) were examined to elucidate adsorption behavior across different molecular polarities. Adsorption kinetics were best described by the Two-PFO model, confirming dual-phase uptake involving rapid surface binding and slower intraparticle diffusion. Fish hydrochar achieved the highest tetracycline affinity (7.5 mg g−1; KL = 0.077 L mg−1), while shrimp hydrochar exhibited the largest capacity (qmax = 81.3 mg g−1; KL = 0.015 L mg−1). Thermodynamic analysis revealed endothermic and entropy-driven adsorption (ΔH = +3.6 kJ/mol; ΔS = +20 J mol−1 K−1). Spectroscopic (FTIR, XPS) and textural (BET) analyses, supported by DFT-derived electronic descriptors (ΔE, μ, α), demonstrated that adsorption was governed by the interplay between oxygenated surface groups (–OH, C=O, –COOH) and pollutant polarity. The complementary adsorption traits of fish hydrochar (strong affinity) and shrimp hydrochar (high capacity) highlight the potential of marine-waste hydrochars as low-cost, renewable alternatives to activated carbon for multi-pollutant wastewater treatment. |
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