Theoretical limit of energy consumption for removal of organic contaminants in U.S. EPA Priority Pollutant List by NRTL, UNIQUAC and Wilson models

This paper quantifies the theoretical limit of energy consumption for the removal of 20 representative organic contaminants (9 chlorinated alkyl hydrocarbons, 3 chlorinated alkenes, 3 brominated methanes, 5 aromatic hydrocarbons and their derivatives) in the United States Environmental Protection Agency (U.S. EPA) Priority Pollutant List by physical procedures. The general rules of the theoretical limit of energy consumption with different initial concentrations at 298.15 K and 1.01325 × 105 Pa by NRTL, UNIQUAC and Wilson models are obtained from the thermodynamic analysis with our previously established method based on the thermodynamic first and second law. The results show that the waste treatment process needs a high energy consumption and the theoretical limit of energy consumption for organic contaminant removal increases with decreasing initial concentrations in aqueous solutions. The theoretical limit of energy consumption decreases with the more C–H bonds being replaced by C–Cl or C–Br bonds in chlorinated methanes, ethanes, ethenes or brominated methanes except for 1,1,2,2-tetrachloroethane, and the energy consumption for the removal of chlorinated methanes is higher than that of chlorinated ethanes with the same C–H bonds being replaced by C–Cl bonds. For the removal of chlorinated ethenes, brominated methanes and benzene and its derivatives studied, the energy consumption has corresponding relationship with solubility and the energy consumption is higher for the removal of organics with higher solubility.