Adsorbents with high effective adsorption capabilities have attracted extensive interest and are promising for the removal of heavy metal ions from wastewater. Herein, we prepared well-dispersed ZnOHF microspheres with efficient adsorptive removal toward Pb²⁺ in an aqueous environment via an amino acid assisted hydrothermal method. The obtained microspheres were self-assembled by numerous nanotubes with an outer diameter of ∼10 nm and a wall thickness of about 3.5 nm. By taking advantage of the large specific surface areas of nanotube-assembled microspheres (271.06 m² g⁻¹), the maximum adsorption capacity for Pb²⁺ was up to 285.7 mg g⁻¹ in solution. Further analysis revealed the key role of the geometry structure of fine nanotube-assembled microspheres in boosting their adsorption ability. Furthermore, we proposed a potential growth mechanism of the as-prepared microspheres. The thermodynamic study of Pb²⁺ adsorbed on nanotube-assembled ZnOHF microspheres suggests that it is an endothermic and spontaneous process. This finding may open a new avenue to design efficient sorbents with high surface areas and effective heavy metal or organic dye removal ability in solution.

中文翻译：

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用于高效去除Pb2 +的ZnOHF纳米管组装的微球吸附剂的合理结构设计

具有高有效吸附能力的吸附剂引起了广泛的兴趣，并有望用于从废水中去除重金属离子。在这里，我们制备了分散良好的ZnOHF微球，通过氨基酸辅助水热法在水性环境中对Pb ²⁺具有有效的吸附去除作用。所获得的微球由外径约为10 nm，壁厚约为3.5 nm的许多纳米管自组装而成。通过利用纳米管组装的微球的大比表面积（271.06 m ² g ^-1），Pb ²⁺的最大吸附容量高达285.7 mg g ^-1在解决方案中。进一步的分析揭示了细纳米管组装的微球的几何结构在提高其吸附能力中的关键作用。此外，我们提出了所制备的微球的潜在生长机理。纳米管组装的ZnOHF微球上吸附的Pb ²⁺的热力学研究表明，这是一个吸热和自发过程。这一发现可能为设计具有高表面积和有效去除溶液中重金属或有机染料能力的高效吸附剂开辟一条新途径。