Removal of priority pollutants from water by means of dielectric barrier discharge atmospheric plasma

Abstract

Two different nonthermal plasma reactors at atmospheric pressure were assessed for the removal of organic micropollutants (atrazine, chlorfenvinfos, 2,4-dibromophenol, and lindane) from aqueous solutions (1-5 mg L(-1)) at laboratory scale. Both devices were dielectric barrier discharge (DBD) reactors; one was a conventional batch reactor (R1) and the other a coaxial thin-falling-water-film reactor (R2). A first-order degradation kinetics was proposed for both experiments. The kinetic constants (k) were slightly faster in R1 (0.534 min(-1) for atrazine; 0.567 min(-1) for chlorfenvinfos; 0.802 min(-1) for 2,4-dibromophenol; 0.389 min(-1) for lindane) than in R2 (0.104 min(-1) for atrazine; 0.523 min(-1) for chlorfenvinfos; 0.273 min(-1) for 2,4-dibromophenol; 0.294 min(-1) for lindane). However, energy efficiencies were about one order of magnitude higher in R2 (89 mg kW(-1) h(-1) for atrazine; 447 mg kW(-1) h(-1) for c hlorfenvinfos; 47 mg kW(-1) h(-1) for 2,4-dibromophenol; 50 mg kW(-1) h(-1) for lindane) than in R1. Degradation by -products of all four compounds were identified in R1. As expected, when the plasma treatment (R1) was applied to industrial wastewater spiked with atrazine or lindane, micropollutant removal was also achieved, although at a lower rate than with aqueous solutions (k = 0.117 min(-1) for atrazine; k = 0.061 min(-1) for lindane).