Madan Shubhangi, Thapa Urvashi, Tiwari Sangeeta, Tiwari Sandeep Kumar, Jakka Suresh Kumar, Soares Manuel Jorge
Amity Institute of Applied Sciences, Amity University, Noida, 201303, India.
Council of Scientific and Industrial Research, New Delhi, 110001, India.
Environ Sci Pollut Res Int. 2021 May;28(18):22474-22487. doi: 10.1007/s11356-020-11692-1. Epub 2021 Jan 8.
The present study encompasses a unique concept involving the formation of core-shell particles with surface-activated fly ash (FA) as core and nanoscale zerovalent iron (nZVI) particles as shell, which not only imparts high adsorption efficiency for Cr(VI) but also contributes to fruitful utilization of FA while overcoming the drawbacks associated with ZVI nanoparticles (aggregation, rapid oxidation and less durability). The otherwise inert surface of FA has been modified and activated to achieve a uniform and stable layer of nZVI over FA. The functionalized particles were studied using FE-SEM/EDAX, HR-TEM, XRD and FT-IR studies for its physical, functional and morphological characteristics. The results indicate the strong adsorption ability of nZVI@FA particles, with 100% removal efficiency within 10 min at low initial concentrations of Cr(VI), which is appreciably higher than that of pure fly ash (26%) after 60 min of reaction. Besides, the so-formed structure of composite aids to improve its life, as the synthesized nZVI@FA particles could be efficiently regenerated and reused up to 5 subsequent adsorption-desorption cycles, which is in contrast with the ability of fly ash considering its low desorption potential. Hence, the composite material proves to be an effective and sustainable alternative for treatment of a waste using a waste.
本研究包含一个独特的概念，即形成以表面活化粉煤灰（FA）为核、纳米级零价铁（nZVI）颗粒为壳的核壳颗粒，这不仅赋予了对Cr(VI)的高吸附效率，还有助于粉煤灰的有效利用，同时克服了与ZVI纳米颗粒相关的缺点（团聚、快速氧化和耐久性较差）。已对原本惰性的粉煤灰表面进行改性和活化，以在粉煤灰上实现均匀且稳定的nZVI层。使用场发射扫描电子显微镜/能谱仪（FE-SEM/EDAX）、高分辨率透射电子显微镜（HR-TEM）、X射线衍射仪（XRD）和傅里叶变换红外光谱仪（FT-IR）研究了功能化颗粒的物理、功能和形态特征。结果表明，nZVI@FA颗粒具有很强的吸附能力，在低初始浓度的Cr(VI)下，10分钟内去除效率可达100%，这明显高于纯粉煤灰在反应60分钟后的去除效率（26%）。此外，如此形成的复合材料结构有助于延长其使用寿命，因为合成的nZVI@FA颗粒可有效再生并重复使用多达5个后续吸附-解吸循环，这与粉煤灰因其低解吸潜力而具有的能力形成对比。因此，该复合材料被证明是一种利用废物处理废物的有效且可持续的替代方案。
