Photochemical oxidation of arsenic by oxygen and iron in acidic solutions

被引:185
作者
Emett, MT [1 ]
Khoe, GH [1 ]
机构
[1] Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia
关键词
arsenic; photochemical oxidation; removal; iron; reaction mechanism;
D O I
10.1016/S0043-1354(00)00294-3
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The rate of oxidation of As(III) to As(V) by oxygen is increased by several orders of magnitude by the presence of dissolved Fe(III) and illumination with near ultraviolet light. The oxidation reaction has been studied in acidic conditions in the absence and presence of dissolved oxygen. A reaction mechanism has been postulated in which Fe(III)-hydroxide and -chloride complexes first absorb photons to produce highly oxidising hydroxyl and dichloro radicals. A series of rapid competing reactions involving free radicals then occur in which As(III) is oxidised via the As(IV) intermediate. The observed arsenic oxidation rate is controlled by the rate of photon absorption and the fraction of As(IV) which undergoes oxidising lather than reducing reactions. The use of iron compounds as a photo-oxidant is advantageous because Fe(III) hydroxide precipitate is an excellent adsorbent for As(V). (C) 2001 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:649 / 656
页数:8
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