TY - JOUR
T1 - Electrochemical sulfide removal by low-cost electrode materials in anaerobic digestion
AU - Lin, Hongjian
AU - Williams, Nicholas
AU - King, Amelia
AU - Hu, Bo
N1 - Publisher Copyright:
© 2016 Elsevier B.V.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 2016/8/1
Y1 - 2016/8/1
N2 - Hydrogen sulfide removal is usually a necessary but costly step following the anaerobic digestion (AD) in order to upgrade biogas quality. Mitigating sulfide levels of biogas and digestate simultaneously in AD process will decrease the capital cost by eliminating standalone biogas upgrading facility. However, current in situ remediation methods, for instance, dosing of magnesium/sodium hydroxide, oxygen gas, iron salts, and nitrite or nitrate, potentially cause interference to biogas production and may intensively consume energy and chemicals. Here, an electrochemical remediation method was studied to use low-price electrode materials of carbon cloth and stainless steel AISI 304. These electrode materials at 3 V showed a complete removal of sulfide in 2 days in synthetic media of 10 mM sulfide solution. Operating conditions for carbon cloth and stainless steel electrodes as well as major intermediates of electrochemical reactions in bench-scale digester fed with dairy manure were examined to study the performances in sulfide removal and biomethane production. Based on the results, it was concluded that carbon cloth at 2 and 3 V, and stainless steel anodes at both 1 and 2 V have a potential of significantly removing hydrogen sulfide from biogas under continuous operation given sufficient electrode surface area. Intermittent 3 V voltage application (15 minutes per day) of stainless steel can remove most biogas hydrogen sulfide. The electrochemical sulfide oxidation and removal showed no/little negative effect on biomethane production, and therefore can be a promising technology for the AD industry to develop a cost-effective approach to producing sulfide free biogas.
AB - Hydrogen sulfide removal is usually a necessary but costly step following the anaerobic digestion (AD) in order to upgrade biogas quality. Mitigating sulfide levels of biogas and digestate simultaneously in AD process will decrease the capital cost by eliminating standalone biogas upgrading facility. However, current in situ remediation methods, for instance, dosing of magnesium/sodium hydroxide, oxygen gas, iron salts, and nitrite or nitrate, potentially cause interference to biogas production and may intensively consume energy and chemicals. Here, an electrochemical remediation method was studied to use low-price electrode materials of carbon cloth and stainless steel AISI 304. These electrode materials at 3 V showed a complete removal of sulfide in 2 days in synthetic media of 10 mM sulfide solution. Operating conditions for carbon cloth and stainless steel electrodes as well as major intermediates of electrochemical reactions in bench-scale digester fed with dairy manure were examined to study the performances in sulfide removal and biomethane production. Based on the results, it was concluded that carbon cloth at 2 and 3 V, and stainless steel anodes at both 1 and 2 V have a potential of significantly removing hydrogen sulfide from biogas under continuous operation given sufficient electrode surface area. Intermittent 3 V voltage application (15 minutes per day) of stainless steel can remove most biogas hydrogen sulfide. The electrochemical sulfide oxidation and removal showed no/little negative effect on biomethane production, and therefore can be a promising technology for the AD industry to develop a cost-effective approach to producing sulfide free biogas.
KW - Biogas cleaning
KW - Carbon cloth
KW - Electrochemical oxidation
KW - Stainless steel
KW - Sulfide removal
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U2 - 10.1016/j.cej.2016.03.086
DO - 10.1016/j.cej.2016.03.086
M3 - Article
AN - SCOPUS:84963571374
SN - 1385-8947
VL - 297
SP - 180
EP - 192
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -