Ferrous-activated persulfate oxidation of arsenic(III) and diuron in aquatic system.
In situ chemical oxidation (ISCO) can be an effective technology for the remediation of soil and groundwater polluted by organic and inorganic contaminants. This study investigated the oxidation of arsenic(III) (As(III)) and diuron using ferrous activated persulfate-based ISCO. The results indicated that Fe(II)/persulfate oxidation could be an effective method to oxidize As(III) and diuron. Effects of pH, S2O8(2-) and Fe(II) amounts on the destruction of As(III) and diuron were examined in batch experiments. Acidic conditions favored the removal of As(III) and diuron. Four chelating agents, citric acid (CA), Na2S2O3, diethylene triamine pentaacetic acid (DTPA) and ethylene diamine tetraacetic acid disodium (EDTA-Na2) were used in attempt to maintain the quantity of ferrous ion in solution. In our experiments, CA and Na2S2O3 were found to be more effective than DTPA and EDTA-Na2. Our results also revealed a widely practical prospect of inorganic chelating agent Na2S2O3. Hydroxyl and sulfate radical were determined to play key roles in the oxidation process by using ethanol and tertiary butanol as molecular probes. Oxidation of As(III) yielded As(V) via the electron-transfer reaction. In the oxidation process of diuron, a stepwise nucleophilic substitution of chlorine by hydroxyl and a stepwise oxidation process of the methyl on the dimethylurea group by hydroxyl and sulfate radical were proposed.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
Lei
L
Zhou
Wei
W
Zheng
Yuefei
Y
Ji
Jinfeng
J
Zhang
Chao
C
Zeng
Ya
Y
Zhang
Qi
Q
Wang
Xi
X
Yang
D001151:Arsenic / Q000032:analysis*; D002614:Chelating Agents / Q000737:chemistry; D004237:Diuron / Q000032:analysis*; D004492:Edetic Acid / Q000737:chemistry; D004583:Electrons; D004784:Environmental Monitoring / Q000379:methods; D052918:Environmental Restoration and Remediation / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D004369:Pentetic Acid / Q000737:chemistry; D012964:Sodium / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
D002614:Chelating Agents; D013431:Sulfates; D014874:Water Pollutants, Chemical; D004369:Pentetic Acid; D004492:Edetic Acid; D004237:Diuron; D012964:Sodium; D007501:Iron; D001151:Arsenic; D010100:Oxygen
Arsenic(III); Chelating agent; Diuron; Ferrous-activated persulfate oxidation; In situ chemical oxidation