title: STEP wastewater treatment: a solar thermal electrochemical process for pollutant oxidation.
abstract: A solar thermal electrochemical production (STEP) pathway was established to utilize solar energy to drive useful chemical processes. In this paper, we use experimental chemistry for efficient STEP wastewater treatment, and suggest a theory based on the decreasing stability of organic pollutants (hydrocarbon oxidation potentials) with increasing temperature. Exemplified by the solar thermal electrochemical oxidation of phenol, the fundamental model and experimental system components of this process outline a general method for the oxidation of environmentally stable organic pollutants into carbon dioxide, which is easily removed. Using thermodynamic calculations we show a sharply decreasing phenol oxidation potential with increasing temperature. The experimental results demonstrate that this increased temperature can be supplied by solar thermal heating. In combination this drives electrochemical phenol removal with enhanced oxidation efficiency through (i) a thermodynamically driven decrease in the energy needed to fuel the process and (ii) improved kinetics to sustain high rates of phenol oxidation at low electrochemical overpotential. The STEP wastewater treatment process is synergistic in that it is performed with higher efficiency than either electrochemical or photovoltaic conversion process acting alone. STEP is a green, efficient, safe, and sustainable process for organic wastewater treatment driven solely by solar energy.
authors.affiliation: Institute of New Energy Chemistry and Environmental Science, College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing 163318, PR China. wangbh@nepu.edu.cn
authors.forename: Baohui
authors.initials: B
authors.lastname: Wang
authors.forename: Hongjun
authors.initials: H
authors.lastname: Wu
authors.forename: Guoxue
authors.initials: G
authors.lastname: Zhang
authors.forename: Stuart
authors.initials: S
authors.lastname: Licht
mesh_terms: D011211:Electric Power Supplies; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification; D012993:Solar Energy; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D010636:Phenols; D062065:Wastewater; D014874:Water Pollutants, Chemical