芦苇是多年生湿地植被,其根系具有向根际环境释放氧气和氧化性物质,并在根表和根际形成铁氧化物膜状包被的特性。本文针对芦苇根表生物成因的铁氧化物具有两性胶体的性质,以直接和高温炭化得到的芦根表面的铁氧化物为吸附材料,采用等温平衡法研究了该吸附材料对外部溶液中五价砷的吸附效果。结果表明,在酸性条件下芦根根表获取的铁氧化物对五价砷的吸附能力明显强于中性及碱性条件；两种方式获取的铁氧化物材料对砷的吸附性能如下：随着外部介质溶液中砷添加浓度的增加,铁氧化物材料对砷的吸附量逐渐增加,最高可达16.70 mg.g-1,但并未达到铁氧化物的最大吸附量平台。由此可见,生物成因的铁氧化物材料对五价砷有很强的吸附能力。综合考虑芦根根表铁氧化物对砷的吸附能力及其对处理砷污染水体的可行性,且该生物成因材料的高温炭化处理方式优于直接获取的处理方式。
Abstract
Reed is perennial wetland vegetation, whose root has the ability to release oxygen and oxidants into
the rhizosphere, and form iron oxides at the root surface or rhizosphere. According to the amphoteric colloid
ability of reed root biogenic iron oxides, the iron oxides were used as adsorbing material obtained by the
methods of both direct obtaining and high temperature carbonization, the adsorption effect of this material to
pentavalent arsenic [As (V)] was studied by isotherm method. The results showed that the As (V) adsorption
ability of iron oxides under acidic condition was significantly higher than that in neutral or alkaline condition.
The adsorption content increased with the increase of As concentration in the external medium solution, when
the As concentration was 200 mg/L, the adsorption content of two iron oxides treatments reached (17.00±3.25)
and (12.82±1.01) mg/g, respectively. The adsorption of As by iron oxides could be well described by Langmuir
and Freundlich isothermal adsorption model. The maximum adsorption amounts of As obtained by Langmuir
isotherm equation were (17.72±1.09) and (21.94±6.74) mg/g, respectively. Therefore, the biogenic iron oxides
had strong absorption ability to As (V). Overall consideration of the adsorption ability and the feasibility of
polluted water management, iron oxides treated by high temperature carbonization were better than that of
direct obtaining.
关键词
芦根;铁氧化物;五价砷;高温炭化;吸附
{{custom_keyword}} /
Key words
reed root; iron oxides; pentavalent arsenic; high temperature carbonization; adsorption
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] Pontius J F W. A current load at the federal drinking water regulations[J]. Journal American Water Works Association, 1992, 84: 36-42.
[2] 段桂兰,王利红,陈玉等. 植物超富集砷机制研究的最新进展[J]. 环境科学学报, 2007, 27(5)：714-720.
[3] 梁慧锋,刘占牛,马子川. 新生态二氧化锰悬浊液的制备及对三价砷氧化吸附机理的探讨[J]. 河北大学学报(自然科学版),2005, 25(9)：515—519.
[4] El-Hadri F, Morales-Rubio A, Guardia M. Determination of total arsenic in soft drinks by hydride generation atomic fluorescence spectrometry[J]. Food Chemistry, 2007(105): 1195-1200.
[5] 张西科,张福锁,毛达如. 植物根表铁、锰氧化物胶膜及其在植物营养中的作用[J]. 土壤学进展,1995,23(6)：1-8.
[6] 张西科,张福锁,毛达如. 根表铁氧化物胶膜对水稻吸收Zn的影响[J]. 应用生态学报,1996,7(3)：262-266.
[7] 鲁安怀,卢晓英,任子平等. 天然铁锰氧化物及氢氧化物环境矿物学研究[J]. 地学前缘,2000, 7(2)：473-483.
[8] Benjamin M M .Sorption and f ilt ration of metals using iron-oxide-coat ed sand[ J].Water Res, 1996, 30(11):2609～2620 .
[9] 刘文菊, 朱永官. 湿地植物根表的铁锰氧化物膜[J]. 生态学报,2005,25 (2)：358-369.
[10] Weis J S, Weis P. Metal uptake, transport and release by wetland plants: implications for phytoremediation and restoration[J]. Environment International, 2004, 30(5): 685-700.
[11] 彭先佳. 高效复合型吸附材料的研制及其环境吸附行为研究[D]. 2005. 77-90
[12] 魏显有,王秀敏,刘云惠等. 土壤中砷的吸附行为及其形态分布研究[J]. 河北农业大学学报, 1999, 22(3)：29-30
[13] Hansel C M, La Force M J, Fendorf S, et al. Spatial and temporal association of As and Fe species on aquatic plant roots[J]. Environmental Science and Technology, 2002, 36: 1988-1994.
[14] Liu W J, Zhu Y G, Smith F A. Effects of iron and manganese plaques on arsenic uptake of by rice seedlings (Oryza sativa L.) grown in solution culture supplied with arsenate and arsenite[J]. Plant Soil, 2005. 277: 127-138.
[15] Chen Z, Zhu Y G, Liu W J, et al. Direct evidence showing the effect of root surface iron plaque on arsenite and arsenate uptake into rice (Oryza sativa L.) roots[J]. New Phytologist, 2005. 165: 91-97.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
PDF(660 KB)
