Electrochemical Oxidation of Organic Pollutants Powered by a Silicon-Based Solar Cell

Abstract

Currently available (photo-)electrochemical technologies for water treatment establish a trade-off between low-pollutant concentration and costs. This paper aims at decoupling these two variables by designing a photo-oxidation device using earth abundant materials and an electronic-free approach. The proposed device combines a graphite/graphite electrochemical system with a silicon-based solar cell that provides the necessary electrical power. First, the optimum operational voltage for the graphite/graphite electrochemical system was found to be around 1.6 V. That corresponded closely to the voltage produced by an a-Si:H/a-Si:H tandem solar cell of approximately 1.35 V. This configuration was shown to provide the best pollutant degradation in relation to the device area, removing 70% of the initial concentration of phenol and 90% of the methylene blue after 4 h of treatment. The chemical oxygen demand (COD) removal of these two contaminants after 4 h of treatment was also promising, 55 and 30%, respectively. Moreover, connecting several solar cells in series led to higher pollutant degradation but lower COD removal, suggesting that the degradation of the intermediate components is a limiting factor. This is expected to be due to the higher currents achieved by the series-connected configuration, which would favor other reactions such as polymerization over the degradation of intermediate species.

Electrocatalytic Oxidation Processes for Treatment of Halogenated Organic Pollutants in Aqueous Solution: A Critical Review

“…This model can be used to predict the mineralization level of clopyralid effluent once the solar radiation is known. A graphite/graphite electro­catalytic oxidation system powered by an a-Si:H/a-Si:H tandem solar cell can degrade 70% of phenol after a treatment time of 4 h at the optimum voltage of 1.6 V, and the COD removal ratio was higher than that powered by a DC-stabilized power supply at the same voltage . Electro­catalytic oxidation of aniline was fully powered by solar photovoltaic panels without input of any other energy .…”

“…A graphite/graphite electrocatalytic oxidation system powered by an a-Si:H/a-Si:H tandem solar cell can degrade 70% of phenol after a treatment time of 4 h at the optimum voltage of 1.6 V, and the COD removal ratio was higher than that powered by a DC-stabilized power supply at the same voltage. 140 Electrocatalytic oxidation of aniline was fully powered by solar photovoltaic panels without input of any other energy. 141 Total mineralization of aniline can be achieved without passivation of the anode.…”

Fabrication of Hydroxyl‐Carboxyl Bifunctional Hyper‐Crosslinked Polymers for Selective Adsorption of Methylene Blue

“…Physical treatment techniques mainly include coprecipitation [9], filtration [10], and others. Chemical treatment techniques include photocatalysis [11], ultrasonic degradation [12], electrochemical oxidation [13], Fenton catalytic oxidation [14], and adsorption. Adsorption is one of the most effective techniques since it has high uptake capacity, simple operation and design, and no additional harmful substances.…”