Article
Version 1
This version is not peer-reviewed
Chemical and Electrochemical Coagulation of Wastewater from UCG
Version 1
: Received: 6 August 2024 / Approved: 7 August 2024 / Online: 7 August 2024 (11:32:49 CEST)
How to cite: Szul, M.; Rychlewska, K.; Iluk, T.; Billig, T. Chemical and Electrochemical Coagulation of Wastewater from UCG. Preprints 2024, 2024080474. https://doi.org/10.20944/preprints202408.0474.v1 Szul, M.; Rychlewska, K.; Iluk, T.; Billig, T. Chemical and Electrochemical Coagulation of Wastewater from UCG. Preprints 2024, 2024080474. https://doi.org/10.20944/preprints202408.0474.v1
Abstract
This article compares chemical coagulation with electrocoagulation, two popular methods for the primary treatment of wastewater generated in the process of Underground Coal Gasification (UCG). The primary aim was to determine which method is more effective in the removal of cyanide and sulphide ions, metals and metalloids, as well as organic compounds. In both cases, experiments were conducted in batch 1 dm³ reactors, and the coagulation/flocculation process was carried out using iron ions. Four types of coagulants were tested during the chemical coagulation study: FeCl₂, FeSO₄, Fe₂(SO₄)₃, and FeCl₃. In the electrocoagulation experiments, pure iron Armco steel was used to manufacture the sacrificial iron anode. Both processes were tested under a wide range of operating conditions (pH, time, Fe dose) to determine their maximum efficiency for treating UCG wastewater. It was found that, through electrocoagulation, a dose as low as 60 mg Fe/dm³ leads to >60% cyanide reduction and >98% sulphide removal efficiency, while for chemical coagulation, even a dose of 307 mg Fe/dm³ did not achieve more than 24% cyanide ion removal. Moreover, industrial chemical coagulants, especially when used in very high doses, can be a substantial source of cross-contamination with trace elements.
Keywords
chemical coagulation; electrocoagulation; iron; underground coal gasification; UCG
Subject
Environmental and Earth Sciences, Water Science and Technology
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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