División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), San Luis Potosí, SLP, México.
Environ Sci Technol. 2012 Sep 4;46(17):9577-83. doi: 10.1021/es204696u. Epub 2012 Aug 21.
The surface area of iron oxyhydroxides is a key factor when removing As from water. However, research related to this matter shows that this issue has not been explored in detail. The use of capping agents is a viable method to synthesize ferric oxyhydroxide nanoparticles; however, this method to our knowledge has not been applied for the anchorage of iron oxyhydroxide nanoparticles on activated carbon (AC). In the present work, the addition of PO(4) (as a capping agent) in forced hydrolysis of FeCl(3) in AC was investigated. Results revealed that the surface area of modified materials reached a maximum of about 900 m(2)/g with a molar ratio PO(4)/Fe of 0.1. Moreover, microscopy studies indicate a size range of iron nanoparticles from 2 to 300 nm, where the smallest particles are attained with the highest concentration of PO(4). The surface charge distribution of modified samples became less positive; however, the As removal increased, indicating that electrostatic interaction is not the controlling sorption mechanism. Modified samples showed a 40% increase on As(V) adsorption capacity when using a molar ratio PO(4)/Fe of 1.5. The proposed method allowed anchoring of iron oxyhydroxides nanoparticles on AC, which have a high As(V) adsorption capacity (5 mg/g).
铁的水合氧化物的表面积是从水中去除砷的关键因素。然而，相关研究表明，这个问题尚未得到详细探讨。使用封端剂是合成三价铁水合氧化物纳米粒子的可行方法；然而，据我们所知，这种方法尚未应用于将铁的水合氧化物纳米粒子锚定在活性炭（AC）上。在本工作中，研究了在 AC 中强制水解 FeCl3 时添加 PO(4)（作为封端剂）的情况。结果表明，用 PO(4)/Fe 的摩尔比为 0.1 时，改性材料的表面积达到最大值约 900 m(2)/g。此外，显微镜研究表明，铁纳米粒子的尺寸范围为 2 至 300nm，其中 PO(4)浓度最高时获得最小的颗粒。改性样品的表面电荷分布变得不那么正，但砷的去除量增加，表明静电相互作用不是控制吸附机制。当使用 PO(4)/Fe 的摩尔比为 1.5 时，改性样品对 As(V)的吸附容量增加了 40%。所提出的方法允许将铁的水合氧化物纳米粒子锚定在具有高 As(V)吸附容量（5mg/g）的 AC 上。
