Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Tehran, Iran.
Department of Chemistry, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Tehran, Iran.
Chemosphere. 2017 Mar;171:502-511. doi: 10.1016/j.chemosphere.2016.12.106. Epub 2016 Dec 23.
This research presents an efficient system for removing aqua's arsenic based on in situ zero valent iron doping onto multiwall carbon nanotube (MWCNT) through MWCNT growth onto the natural α-FeO surface in chemical vapor deposition (CVD) reactor. The as-synthesized magnetic nanohybrid was characterized by XRD, VSM, FE-SEM and TEM techniques. The result of XRD analysis revealed that MWCNT has been successfully generated on the surface of zero valent iron. Moreover, the material showed good superparamagnetic characteristic to be employed as a magnetic adsorbent. The hematite, nanohybrid and its air oxidized form were used for removing aqueous arsenite and arsenate; however, non oxidized material exhibited greater efficiency for the analytes uptake. Equilibrium times were 60 and 90 min for arsenate and arsenite adsorption using nanohybrid and oxidized sorbent but the equilibrium time was 1320 min using hematite. The adsorption efficiencies of hematite and oxidized sorbent were 18, 74% and 26, 77% for arsenite and arsenate, respectively, at initial concentration of 10 mg L. At this situation, the removal efficiencies were 96 and 98.5% for arsenite and arsenate adsorption using raw nanohybrid. Thermodynamic study was also performed and results indicated that arsenic adsorption onto nanohybrid and oxidized sorbent was spontaneous however hematite followed a nonspontaneous path for the arsenic removal.
本研究提出了一种基于原位零价铁掺杂多壁碳纳米管（MWCNT）的高效除砷系统，该系统通过化学气相沉积（CVD）反应器中 MWCNT 在天然α-FeO 表面上的生长来实现。所合成的磁性纳米复合材料采用 XRD、VSM、FE-SEM 和 TEM 技术进行了表征。XRD 分析结果表明，MWCNT 已成功地生成在零价铁表面上。此外，该材料表现出良好的超顺磁特性，可作为磁性吸附剂使用。赤铁矿、纳米复合材料及其空气氧化形式被用于去除水中的亚砷酸盐和砷酸盐；然而，未氧化的材料对分析物的吸附效率更高。使用纳米复合材料和氧化吸附剂吸附砷酸盐和亚砷酸盐的平衡时间分别为 60 和 90 分钟，但使用赤铁矿的平衡时间为 1320 分钟。在初始浓度为 10mg/L 时，赤铁矿和氧化吸附剂对亚砷酸盐和砷酸盐的吸附效率分别为 18%和 74%、26%和 77%。在这种情况下，使用原始纳米复合材料对砷酸盐和亚砷酸盐的去除效率分别为 96%和 98.5%。还进行了热力学研究，结果表明，砷酸盐在纳米复合材料和氧化吸附剂上的吸附是自发的，而赤铁矿则遵循非自发的砷去除途径。
