Development of an Activated Carbon-Based Electrode for the Capture and Rapid Electrolytic Reductive Debromination of Methyl Bromide from Postharvest Fumigations.
Due to concerns surrounding its ozone depletion potential, there is a need for technologies to capture and destroy methyl bromide (CH3Br) emissions from postharvest fumigations applied to control agricultural pests. Previously, we described a system in which CH3Br fumes vented from fumigation chambers could be captured by granular activated carbon (GAC). The GAC was converted to a cathode by submergence in a high ionic strength solution and connection to the electrical grid, resulting in reductive debromination of the sorbed CH3Br. The GAC bed was drained and dried for reuse to capture and destroy CH3Br fumes from the next fumigation. However, the loose GAC particles and slow kinetics of this primitive electrode necessitated improvements. Here, we report the development of a cathode containing a thin layer of small GAC particles coating carbon cloth as a current distributor. Combining the high sorption potential of GAC for CH3Br with the conductivity of the carbon cloth current distributor, the cathode significantly lowered the total cell resistance and achieved 96% reductive debromination of CH3Br sorbed at 30% by weight to the GAC within 15 h at -1 V applied potential vs standard hydrogen electrode, a time scale and efficiency suitable for postharvest fumigations. The cathode exhibited stable performance over 50 CH3Br capture and destruction cycles. Initial cost estimates indicate that this technique could treat CH3Br fumes at ∼$5/kg, roughly one-third of the cost of current alternatives.
Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States.
Yuanqing
Y
Li
Department of Materials Science and Engineering, Stanford University , McCullough Building, Stanford, California 94305, United States.
Chong
C
Liu
Department of Materials Science and Engineering, Stanford University , McCullough Building, Stanford, California 94305, United States.
Yi
Y
Cui
Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, USDA , 9611 South Riverbend Avenue, Parlier, California 93648-9757, United States.
Spencer S
SS
Walse
Department of Agricultural and Resource Economics, Giannini Hall, University of California at Berkeley , Berkeley, California 94720, United States.
Ryan
R
Olver
Department of Agricultural and Resource Economics, Giannini Hall, University of California at Berkeley , Berkeley, California 94720, United States.
David
D
Zilberman
Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States.
William A
WA
Mitch
D000327:Adsorption; D002606:Charcoal; D004566:Electrodes; D004572:Electrolysis; D005651:Fumigation
D002606:Charcoal