Volatilization characteristics of organic compounds in the coagulation process

The emissions of two types of organic solutes during the coagulation process were simulated using Jar Test equipment and two additives, coagulant and polymer, to evaluate the volatilization characteristics under various operating conditions. The solute volatilization rates were found to be a function of the liquid mixing intensity, the chemical properties of the additives, and the properties of solutes, including molecular weight (M), Henry's law constant (H), and water solubility (S). The volatilization rates of the high H solutes increased sharply as the mixing intensity increased. Moreover, the volatilization rates of selected compounds were only slightly dependent on the coagulant concentrations due to the inorganic property of the coagulant. On the other hand, the effective volatilization reduction of the high H solutes in the existence of organic flocculant was a result of the enhancement of solutes solubility in water solutions. However, the above inhibition effects decreased significantly when the mixing intensity increased. Finally, the emission rates of the low H solutes were weakly correlated with both the solution properties and the operating parameters, due to their high affinity with the solution and the major volatilization resistance existing in the gas phase. Two different approaches, i.e., the two-film theory and the modified Knudsen diffusion equation, were used to explain the solute volatilization characteristics in the simulation process. CE Database subject headings: Coagulation; Volatile organic chemicals; Volatilization; Polymers; Emissions; Organic compounds.