Pan Siyuan, Shen Jialin, Deng Ziniu, Zhang Xiaolin, Pan Bingcai
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China; Research Center for Environmental Nanotechnology (ReCENT), Nanjing University, Nanjing 210023, China.
J Hazard Mater. 2022 Feb 5;423(Pt B):127158. doi: 10.1016/j.jhazmat.2021.127158. Epub 2021 Sep 6.
Nanotechnology has provided a new opportunity for water decontamination from trace heavy metals, yet the relatively poor acidic stability remains a major obstacle for the nano-adsorbents, given that acidic treatment is frequently used to regenerate the heavy metal-saturated adsorbents. Zirconium phosphate (ZrP) is very promising for water treatment due to its absolute insoluble nature, though it interacts with heavy metals mainly through the non-specific electrostatic attraction. Herein, we prepared the ultrafine ZrP (~3.9 nm) inside the commercially available gel-type cation exchanger (N001), i.e., the sulfonated poly(styrene-co-divinylbenzene) bead. The resultant nanocomposite ZrP@N001 contained the amorphous nanoparticles (NPs) with metastable γ-ZrP structure as the main phase, unlike the layered α-ZrP formed inside the macroporous cation exchanger D001 (referred to as ZrP@D001). As a result, ZrP@N001 could selectively adsorb heavy metals through inner-sphere coordination, possessing a much stronger adsorption affinity than ZrP@D001, as confirmed by XPS analysis. In both batch and column assays on the Pb(II)-polluted water, ZrP@N001 exhibited superior adsorption performance over ZrP@D001. After adsorption, the exhausted ZrP@N001 was fully refreshed by acidic treatment for a 5-cyclic adsorption-regeneration run with constant removal efficiencies. This study may open a door for the rational design of highly efficient water purifiers for heavy metal control.
纳米技术为去除水中痕量重金属提供了新机遇，然而鉴于酸性处理常用于再生重金属饱和的吸附剂，纳米吸附剂相对较差的酸稳定性仍是一个主要障碍。磷酸锆（ZrP）因其绝对不溶性，在水处理方面很有前景，尽管它与重金属的相互作用主要通过非特异性静电吸引。在此，我们在市售凝胶型阳离子交换剂（N001），即磺化聚（苯乙烯 - 共二乙烯基苯）珠粒内部制备了超细微的ZrP（约3.9纳米）。所得的纳米复合材料ZrP@N001含有以亚稳态γ-ZrP结构为主相的无定形纳米颗粒（NPs），这与在大孔阳离子交换剂D001内部形成的层状α-ZrP（称为ZrP@D001）不同。结果，ZrP@N001能够通过内球配位选择性吸附重金属，具有比ZrP@D001更强的吸附亲和力，XPS分析证实了这一点。在对含Pb(II)污染水的批量和柱式试验中
