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“Self-cleaning” electrochemical regeneration of dye-loaded activated carbon

A low maintenance, “self-cleaning” electrochemical approach is evaluated for regeneration of dye-loaded granular activated carbon (GAC). To do so, batch experiments were conducted using a low-cost granular activated carbon/stainless steel mesh (GACSS) composite cathode and a stable Ti/mixed metal ox...

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Bibliographic Details
Published in:Electrochemistry communications 2019-03, Vol.100, p.85-89
Main Authors: Zhou, Wei, Meng, Xiaoxiao, Ding, Yani, Rajic, Ljiljana, Gao, Jihui, Qin, Yukun, Alshawabkeh, Akram N.
Format: Article
Language:English
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Summary:A low maintenance, “self-cleaning” electrochemical approach is evaluated for regeneration of dye-loaded granular activated carbon (GAC). To do so, batch experiments were conducted using a low-cost granular activated carbon/stainless steel mesh (GACSS) composite cathode and a stable Ti/mixed metal oxides (Ti/MMO) anode without the addition of oxidants or iron catalysts. The GACSS cathode supports simultaneous H2O2 electrogeneration via the in situ supplied O2 from Ti/MMO anode and the subsequent H2O2 activation for OH generation, thus enabling the cracking of dye molecules adsorbed on GAC and regenerating the GAC's sorption capacity. Results show that a prolonged electrochemical processing for 12 h will achieve up to 88.7% regeneration efficiency (RE). While RE decreases with multi-cycle application, up to 52.3% could still be achieved after 10 adsorption-regeneration cycles. To identify the mechanism, experiments were conducted to measure H2O2 electrogeneration, H2O2 activation, and OH generation by various GAC samples. The dye-loaded GAC and GAC treated after 10 adsorption-regeneration cycles were still capable of OH generation, which contributes to effective “self-cleaning” and regeneration over multi-cycles. [Display omitted] •Saturated GAC was “self-cleaned” by electrochemical method without any reagents addition.•H2O2 was in-situ electrogenerated and activated to generate hydroxyl radicals by GAC.•The prolonged regeneration time resulted in a higher regeneration efficiency within 10 cycles.•Organic pollutants pre-adsorbed on GAC can be partially mineralized by this novel process.
ISSN:1388-2481
1873-1902
DOI:10.1016/j.elecom.2019.01.025