The adsorptive removal of highly toxic metal oxyanions such as arsenic from water remains challenging, and metal–organic frameworks (MOFs) with structural diversity have been regarded as promising adsorbents. Herein, three La-MOF adsorbents, La-p-PTAs, La-m-PTAs and La-o-PTAs with different morphologies, are designed by altering the locations of the –COOH group for efficient removal of As(III). In particular, the maximum As(III) adsorption capacity of La-o-PTAs reaches 233.2 mg g⁻¹ within 30 min, which is 22.3% and 51.7% higher than those of La-m-PTAs and La-p-PTAs, respectively. Due to more abundant accessible adsorption sites distributed in the surface and edge regions confirmed by TPO-O₂ measurements and stronger interaction demonstrated by XPS analysis, La-o-PTAs have increased utilization of adsorption sites, contributing to the removal of As(III). Additionally, based on density functional theory (DFT) calculations, the adsorption energy of La-o-PTAs is −0.74 eV, 7.2% and 27.6% lower than those of La-m-PTAs and La-p-PTAs, indicating the superior As(III) adsorption performance of La-o-PTAs. This work highlights the critical importance of adsorption site utilization for efficient metal oxyanion remediation.

中文翻译：

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通过空间位阻效应调节 La-MOFs 中吸附位点的有效利用，以增强 As(III) 去除

从水中吸附去除砷等剧毒金属氧阴离子仍然具有挑战性，具有结构多样性的金属有机框架 (MOF) 被认为是有前途的吸附剂。在此，通过改变-COOH 基团的位置来设计三种不同形态的La-MOF 吸附剂 La- p- PTA、La- m- PTA 和 La- o- PTA，以有效去除 As( III )。特别是，La- o -PTA的最大 As( III ) 吸附容量在 30 min 内达到 233.2 mg g ^-1，分别比 La- m -PTA 和 La- p高 22.3% 和 51.7%。-PTA，分别。由于 TPO-O ₂测量证实分布在表面和边缘区域的更丰富的可及吸附位点和XPS 分析证明的更强相互作用，La- o- PTA 增加了吸附位点的利用率，有助于去除 As( III ) . 此外，基于密度泛函理论 (DFT) 计算，La- o -PTA的吸附能为 -0.74 eV，比 La- m -PTA 和 La- p -PTA的吸附能低 7.2% 和 27.6% ，表明其优越性As( III )对La- o的吸附性能-PTA。这项工作强调了吸附位点利用对有效金属氧阴离子修复的关键重要性。