Investigation of simultaneous adsorption properties of Cd, Cu, Pb and Zn by pristine rice husks using ICP-AES and LA-ICP-MS analysis
Investigation of simultaneous adsorption properties of Cd, Cu, Pb and Zn by pristine rice husks using ICP-AES and LA-ICP-MS analysis
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DOI：
10.1016/j.microc.2017.08.001
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发表时间：
2017-11-01
影响因子：
4.8
通讯作者：
Amarasiriwardena, Dulasiri
中科院分区：
文献类型：
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作者：
Alexander, David;Ellerby, Ryan;Amarasiriwardena, Dulasiri
稻壳是一种农业废弃物，具有独特的金属吸附能力，可修复重金属污染场地。它不溶于水，具有很强的化学稳定性和机械强度，二氧化硅含量高(接近20%)，具有高比表面积，具有颗粒状吸附结构，富含阳离子交换硅醇(-Si-OH)官能团。本研究的目的是为了确定原始稻壳(PRH)的吸附能力，以便在实际的田间应用。采用电感耦合等离子体原子发射光谱分析技术，研究了不同pH值、不同浓度、不同反应温度和不同最大吸附容量条件下稻壳对镉、铜、铅、锌的同时吸附。在与环境相关的pH为6.92的条件下，以10ppm的Cd、Cu2+、Pb2+和Zn作为吸附剂，通过增加PRH用量(0.1~2.0g)，确定了最佳的吸附剂用量为1.0g壳体。在竞争平衡条件下，当加入1.0g PRH时，Cd、Cu2+、Pb2+和Z2+的脱除效率(%R)按Pb值最高，Z值最低。吸附等温曲线符合Freundlich模型，而不符合Langmuir模型。铜和锌的吸附是吸热的，而镉和铅的吸附是放热的。用LA-ICPMS得到的空间元素分布图直观地证明了金属在稻壳富硅区域的吸附，并证明了污染土壤和酸性矿井水中Cd、Cu、Fe、Pb和Zn的成功分离能力。由于未经处理的稻壳是一种丰富的农业废弃物，而且成本低廉，显然，它作为一种可持续固定金属的介质，对金属污染的酸性矿井水和土壤具有巨大潜力。(C)2017爱思唯尔B.V.保留所有权利。
Rice husks are an agricultural waste product that has unique metal adsorption capabilities to remediate heavy metal contaminated sites. It is insoluble in water, has strong chemical stability and mechanical strength with a high silica content (similar to 20%), and possesses a high surface area with granular structure for adsorption that is rich with cation exchanging silanol (-Si-OH) functionalities. The purpose of this study is to determine the adsorption capabilities of pristine rice husks (PRH) for practical field applications. Sorption experiments were performed to evaluate simultaneous Cd, Cu, Pb, and Zn sorption by rice husk at varying pH, concentration, reaction temperature, and maximum adsorption capability using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Optimum adsorbent mass of 1.0 g of husk was determined by using increasing amounts of PRH (0.1-2.0 g) with 10 ppm concentration of Cd, Cu, Pb, and Zn at environmentally relevant pH 6.92. The resulting percent Cd, Cu, Pb and Zn removal efficiency (%R) order by 1.0 g of PRH was highest for Pb and lowest for Zn under competitive equilibration conditions. Isotherm model plots of Cd, Pb, and Zn adsorption follows better with the Freundlich model than Langmuir model. Copper and Zn adsorption is endothermic while Cd and Pb adsorption process is exothermic. Spatial elemental distribution plots obtained by LA-ICP-MS on the PRH visually demonstrate metals are adsorbed on the silica rich areas of the rice husk The ability to successfully sequester Cd, Cu, Fe, Pb and Zn in contaminated soils and acid mine water was demonstrated. Due to its abundance as an agricultural waste and its low cost it is clear that untreated raw rice husk has a great potential as a sustainable metal sequestering medium for metal contaminated acid mine water and soils. (C) 2017 Elsevier B.V. All rights reserved.