Boix Gerard, Troyano Javier, Garzón-Tovar Luis, Camur Ceren, Bermejo Natalia, Yazdi Amirali, Piella Jordi, Bastus Neus G, Puntes Victor F, Imaz Inhar, Maspoch Daniel
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
ICREA, Pg. Lluıs Companys 23, 08010 Barcelona, Spain.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10554-10562. doi: 10.1021/acsami.9b23206. Epub 2020 Feb 21.
Pollution of water with heavy metals is a global environmental problem whose impact is especially severe in developing countries. Among water-purification methods, adsorption of heavy metals has proven to be simple, versatile, and cost-effective. However, there is still a need to develop adsorbents with a capacity to remove multiple metal pollutants from the same water sample. Herein, we report the complementary adsorption capacities of metal-organic frameworks (here, UiO-66 and UiO-66-(SH)) and inorganic nanoparticles (iNPs; here, cerium-oxide NPs) into composite materials. These adsorbents, which are spherical microbeads generated in one step by continuous-flow spray-drying, efficiently and simultaneously remove multiple heavy metals from water, including As(III and V), Cd(II), Cr(III and VI), Cu(II), Pb(II), and Hg(II). We further show that these microbeads can be used as a packing material in a prototype of a continuous-flow water treatment system, in which they retain their metal-removal capacities upon regeneration with a gentle acidic treatment. As proof-of-concept, we evaluated these adsorbents for purification of laboratory water samples prepared to independently recapitulate each of two strongly polluted rivers: the Bone (Indonesia) and Buringanga (Bangladesh) rivers. In both cases, our microbeads reduced the levels of all the metal contaminants to below the corresponding permissible limits established by the World Health Organization (WHO). Moreover, we demonstrated the capacity of these microbeads to lower levels of Cr(VI) in a water sample collected from the Sarno River (Italy). Finally, to create adsorbents that could be magnetically recovered following their use in water purification, we extended our spray-drying technique to simultaneously incorporate two types of iNPs (CeO and FeO) into UiO-66-(SH), obtaining CeO/FeO@UiO-66-(SH) microbeads that adsorb heavy metals and are magnetically responsive.
重金属对水的污染是一个全球性环境问题，在发展中国家其影响尤为严重。在水净化方法中，重金属吸附已被证明是简单、通用且具有成本效益的。然而，仍需要开发能够从同一水样中去除多种金属污染物的吸附剂。在此，我们报道了金属有机框架材料（这里是UiO - 66和UiO - 66-(SH)）与无机纳米颗粒（iNPs；这里是氧化铈纳米颗粒）在复合材料中的互补吸附能力。这些吸附剂是通过连续流喷雾干燥一步生成的球形微珠，能高效且同时从水中去除多种重金属，包括As(III和V)、Cd(II)、Cr(III和VI)、Cu(II)、Pb(II)和Hg(II)。我们进一步表明，这些微珠可作为连续流水处理系统原型中的填充材料，在经过温和的酸性处理再生后，它们仍保持金属去除能力。作为概念验证，我们评估了这些吸附剂对为独立模拟两条重度污染河流（印度尼西亚的博内河和孟加拉国的布林甘加河）而制备的实验室水样的净化效果。在这两种情况下，我们的微珠都将所有金属污染物的水平降低到了世界卫生组织（WHO）规定的相应允许限值以下。此外，我们还证明了这些微珠能够降低从意大利萨尔诺河采集的水样中的Cr(VI)水平。最后，为了制备在用于水净化后能够通过磁力回收的吸附剂，我们扩展了喷雾干燥技术，将两种类型的iNPs（CeO和FeO）同时掺入UiO - 66-(SH)中，得到了对重金属具有吸附作用且具有磁响应性的CeO/FeO@UiO - 66-(SH)微珠。
