Enhanced degradation of BDE209 in spiked soil by ferrous-activated persulfate process with chelating agents.

In order to maintain the quantity of ferrous ions, two eco-friendly chelating agents (CAs), i.e., sodium citrate (Citrate) and sodium gluconate (Glu), have been introduced into a traditional iron activated sodium persulfate (PS) system (Fe2+/PS). The results indicated that the PS/CA/Fe2+ oxidation could be an effective method for BDE209 removal. Effects of the chelating agents, reagents dosage, and pH were evaluated in batch experiments. Glu was observed to be more effective than citrate. In addition, the rate constants (k 1) of BDE209 removal indicated a quadratic curve relationship with initial persulfate concentrations (k 1 = -0.019 × [PS]02 + 0.031 × [PS]0 + 0.007, R 2 = 0.933, [PS]0 = 0.1-1.0 M) and a good linear relationship with initial ferrous contents (k 1 = 0.109 × [Fe2+]0 + 0.002, R 2 = 0.943). Furthermore, as a reducing agent, ascorbic acid (H2A) could enhance the degradation rate of BDE209, which might be because H2A accelerated the transformation process from Fe3+- to Fe2+-gluconate complexes.