Linking the effect of temperature on adsorption from aqueous solution with solute dissociation.

Autor: Aumeier BM; RWTH Aachen University, Aachener Verfahrenstechnik, Chemical Process Engineering, Forckenbeckstrasse 51, 52074 Aachen, Germany; RWTH Aachen University, Institute of Environmental Engineering, Mies-van-der-Rohe-Strasse 1, 52074 Aachen, Germany. Electronic address: benedikt.aumeier@rwth-aachen.de., Augustin A; RWTH Aachen University, Aachener Verfahrenstechnik, Chemical Process Engineering, Forckenbeckstrasse 51, 52074 Aachen, Germany., Thönes M; RWTH Aachen University, Aachener Verfahrenstechnik, Chemical Process Engineering, Forckenbeckstrasse 51, 52074 Aachen, Germany., Sablotny J; RWTH Aachen University, Aachener Verfahrenstechnik, Chemical Process Engineering, Forckenbeckstrasse 51, 52074 Aachen, Germany., Wintgens T; RWTH Aachen University, Institute of Environmental Engineering, Mies-van-der-Rohe-Strasse 1, 52074 Aachen, Germany., Wessling M; RWTH Aachen University, Aachener Verfahrenstechnik, Chemical Process Engineering, Forckenbeckstrasse 51, 52074 Aachen, Germany; DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52074 Aachen, Germany. Electronic address: manuscripts.cvt@avt.rwth-aachen.de.
Jazyk: angličtina
Zdroj: Journal of hazardous materials [J Hazard Mater] 2022 May 05; Vol. 429, pp. 128291. Date of Electronic Publication: 2022 Jan 21.
DOI: 10.1016/j.jhazmat.2022.128291
Abstrakt: Imperative decarbonization of water purification processes entails alternative regeneration methods for activated carbon. Regeneration based on changing dissociation equilibria, i.e. a major influencing factor on adsorption, usually requires the addition of acids/bases, but may also be triggered by temperature swing. Although adsorption and dissociation are both temperature-dependent phenomena, their conjunction has received little attention regarding trace organic compounds (TrOCs) and large temperature intervals, in particular above ΔT ≥ 50  ∘ C. Therefore, we studied the adsorption equilibria of 16 TrOCs onto one granular activated carbon at temperatures ranging from 20 to 95  ∘ C. The majority of compounds (12/16) exhibited an exothermic apparent adsorption enthalpy, while 3 out of 16 exhibited an endothermic apparent enthalpy. The range spanned from - 46 to + 50 kJ mol -1 (median at - 17 kJ mol -1 ). The possible origins of endothermic adsorption were discussed. A rationale of shifting pK a and thus changing dissociation of TrOCs was introduced and traded off against existing rationales, i.e. changing solute solubility, changing adsorption heat capacity, and saturation effects of the adsorbates. This knowledge may allow designing temperature swing adsorption processes that unlock the dissociation switch. The augmented process efficiency can thus provide the foundation for low-carbon emission, circular water purification processes.
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Databáze: MEDLINE
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