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As(III) oxidation using chemical and solid‐phase oxidants
Author(s) -
Ghurye Ganesh,
Clifford Dennis
Publication year - 2004
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.2004.tb10536.x
Subject(s) - chemistry , permanganate , oxidizing agent , inorganic chemistry , chlorine , arsenite , chlorine dioxide , sulfite , arsenate , ferrous , manganese , cerium , redox , oxygen , arsenic , organic chemistry
The effectiveness of seven oxidants—chlorine (Cl 2 ), permanganate (MnO 4 − ), ozone (O 3 ), monochloramine (NH 2 Cl), chlorine dioxide (ClO 2 ), a manganese dioxide‐based solid‐oxidizing media, and 254‐nm ultraviolet radiation—for arsenite [As(III)] oxidation to arsenate was studied. The effect of water chemistry variables including pH, temperature, and interfering reductants (manganous and ferrous ions, sulfide, and total organic carbon [TOC]) was investigated. Cl 2 and MnO 4 − provided complete oxidation in less than 1 min under all conditions tested. The effectiveness of O 3 was significantly attenuated in the presence of TOC. Both ClO 2 (an otherwise powerful oxidant) and NH 2 Cl were ineffective for As(III) oxidation. When dissolved oxygen (DO) was not limiting, the solid‐oxidizing media provided complete oxidation. However, with low DO and interfering reductants, incomplete oxidation was observed. The adverse effect of interfering reductants was eliminated either by supplying enough DO or reducing the flow rate. UV light alone (254 nm) was not effective, but complete As(III) oxidation was observed when the feedwater was spiked with 1 mg/L of sulfite.