The efficacy of carbon nanotubes (CNTs) adsorbents in complex aquatic environments depends on the synergistic interaction between their surface chemistry and surrounding environmental factors. Using first-principles calculations, we systematically investigated the adsorption of p-aminobenzoic acid (PABA) on functionalized CNTs (G/O/H/N-CNTs) in the presence of metal ions (Na+, Mg2+, Ca2+, Fe3+), the explicit water environment, and dual iron sites. The results indicated that on O-/N-/H-CNTs surfaces, charge-assisted hydrogen bonding (CAHB) became the dominant and more stable interaction compared to ordinary hydrogen bonding (OHB), which significantly enhanced adsorption efficiency. Moreover, anionic PABA− exhibited higher electron density, rendering it more readily adsorbed than PABA. The study further revealed metal ions (particularly Ca2+), improved adsorption efficiency by promoting CAHB reinforcement, cation-π interactions, and metal-O/N coordination. This process was regulated by the spatial position and introduction order of ions. The aqueous environment significantly enhances adsorption by forming hydrogen-bond networks and hydrophobic effects, and narrowing the adsorption performance gap between PABA and PABA−. Particularly, the coexistence of doped iron atoms and free Fe3+ at the solid-liquid interface generated a strong synergistic effect, enhancing the adsorption energy by nearly threefold compared to the single Fe@CNT system. This work reveals the adsorption mechanism involving multiple factors at the atomic scale, providing a theoretical basis for designing high-performance carbon nanotube adsorbents.
碳纳米管（CNTs）吸附剂在复杂水生环境中的作用取决于其表面化学与周围环境因子之间的协同相互作用。利用第一性原理计算，我们系统地研究了在金属离子（Na+、Mg2+、Ca2+、Fe3+）、外显水环境和双铁位点存在下，对氨基苯甲酸（PABA）在功能化碳纳米管（G/O/H/N-CNTs）上的吸附。结果表明，在O-/N-/H-CNTs表面，电荷辅助氢键（CAHB）成为比普通氢键（OHB）更稳定的主要相互作用，显著提高了吸附效率。此外，阴离子PABA−表现出更高的电子密度，使其比PABA更容易吸附。研究进一步揭示了金属离子（特别是Ca2+）通过促进CAHB增强、阳离子-π相互作用和金属- o /N配位来提高吸附效率。这一过程受离子的空间位置和引入顺序的调控。水环境通过形成氢键网络和疏水效应显著增强了吸附，缩小了PABA和PABA−之间的吸附性能差距。特别是，在固液界面处掺杂铁原子和自由Fe3+共存产生了很强的协同效应，吸附能比单一Fe@CNT体系提高了近三倍。本研究揭示了碳纳米管在原子尺度上多因素的吸附机理，为设计高性能碳纳米管吸附剂提供了理论依据。
{"title":"Synergistic regulation of environmental factors on the adsorption of p-aminobenzoic acid on functionalized carbon nanotubes: A first-principles study","authors":"Yu Zhang, Yuxin Zhou, Yuhui Ma, Nuan Wen, Qingyuan Gu, Meichao Chen, Chongwen Sun, Chenglin Wang, Maoxia He","doi":"10.1016/j.cej.2026.175507","DOIUrl":"https://doi.org/10.1016/j.cej.2026.175507","url":null,"abstract":"The efficacy of carbon nanotubes (CNTs) adsorbents in complex aquatic environments depends on the synergistic interaction between their surface chemistry and surrounding environmental factors. Using first-principles calculations, we systematically investigated the adsorption of <em>p</em>-aminobenzoic acid (PABA) on functionalized CNTs (G/O/H/N-CNTs) in the presence of metal ions (Na<sup>+</sup>, Mg<sup>2+</sup>, Ca<sup>2+</sup>, Fe<sup>3+</sup>), the explicit water environment, and dual iron sites. The results indicated that on O-/N-/H-CNTs surfaces, charge-assisted hydrogen bonding (CAHB) became the dominant and more stable interaction compared to ordinary hydrogen bonding (OHB), which significantly enhanced adsorption efficiency. Moreover, anionic PABA<sup>−</sup> exhibited higher electron density, rendering it more readily adsorbed than PABA. The study further revealed metal ions (particularly Ca<sup>2+</sup>), improved adsorption efficiency by promoting CAHB reinforcement, cation-π interactions, and metal-O/N coordination. This process was regulated by the spatial position and introduction order of ions. The aqueous environment significantly enhances adsorption by forming hydrogen-bond networks and hydrophobic effects, and narrowing the adsorption performance gap between PABA and PABA<sup>−</sup>. Particularly, the coexistence of doped iron atoms and free Fe<sup>3+</sup> at the solid-liquid interface generated a strong synergistic effect, enhancing the adsorption energy by nearly threefold compared to the single Fe@CNT system. This work reveals the adsorption mechanism involving multiple factors at the atomic scale, providing a theoretical basis for designing high-performance carbon nanotube adsorbents.","PeriodicalId":270,"journal":{"name":"Chemical Engineering Journal","volume":"2 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147501939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-23DOI: 10.1016/j.cej.2026.175477
Yating Lu, Huixia Zhu, Yue Han, Yu Tian, Xiaoxia Liang, Dongyu Nie, Tingming Ye, Yixu Peng, Xia Yang
The simultaneous photocatalytic synthesis of high-value carbonyl compounds and hydrogen peroxide (H2O2) represents a highly promising yet challenging strategy for green and sustainable manufacturing. In our work, a series of photocatalysts was constructed by coupling chitosan-citric acid (CSCA) with NH2-UiO-66 via amidation, which named as CSCA/NU. Among them, 1CSCA/NU exhibited benzaldehyde (BAD) and H2O2 production rates of 875.9 and 1012.1 μmol·g−1·h−1, respectively, accompanied by a high BAD selectivity of 94.5% under simulated sunlight irradiation for 2 h. The AQY of BAD and H2O2 production over 1CSCA/NU were approximately 21.1% and 24.3% at 360 nm. NH2-UiO-66 demonstrated excellent structural stability and avoided the generation of strong free radicals that could cause over-oxidation, thereby ensuring high selectivity toward BAD. Moreover, the incorporation of CSCA expanded the light absorption range. The experimental and DFT results revealed that the CSCA integration establishes a directed charge-transfer pathway. Furthermore, radical trapping experiments and EPR spectroscopy collectively corroborate a dual mechanism, which consists of a hole-mediated direct conversion and a superoxide radical-involved chain process. As expected, 1CSCA/NU exhibited good catalytic universality toward a variety of alcohol substrates. Our work established an efficient, stable MOF-based photocatalytic platform for the co-production of valuable chemicals and green oxidants.
{"title":"Directed charge transfer in a chitosan-citric acid/NH2-UiO-66 hybrid via an amide bond bridge for photocatalytic co-production of benzaldehyde and H2O2","authors":"Yating Lu, Huixia Zhu, Yue Han, Yu Tian, Xiaoxia Liang, Dongyu Nie, Tingming Ye, Yixu Peng, Xia Yang","doi":"10.1016/j.cej.2026.175477","DOIUrl":"https://doi.org/10.1016/j.cej.2026.175477","url":null,"abstract":"The simultaneous photocatalytic synthesis of high-value carbonyl compounds and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) represents a highly promising yet challenging strategy for green and sustainable manufacturing. In our work, a series of photocatalysts was constructed by coupling chitosan-citric acid (CSCA) with NH<sub>2</sub>-UiO-66 via amidation, which named as CSCA/NU. Among them, 1CSCA/NU exhibited benzaldehyde (BAD) and H<sub>2</sub>O<sub>2</sub> production rates of 875.9 and 1012.1 μmol<strong>·</strong>g<sup>−1</sup><strong>·</strong>h<sup>−1</sup>, respectively, accompanied by a high BAD selectivity of 94.5% under simulated sunlight irradiation for 2 h. The AQY of BAD and H<sub>2</sub>O<sub>2</sub> production over 1CSCA/NU were approximately 21.1% and 24.3% at 360 nm. NH<sub>2</sub>-UiO-66 demonstrated excellent structural stability and avoided the generation of strong free radicals that could cause over-oxidation, thereby ensuring high selectivity toward BAD. Moreover, the incorporation of CSCA expanded the light absorption range. The experimental and DFT results revealed that the CSCA integration establishes a directed charge-transfer pathway. Furthermore, radical trapping experiments and EPR spectroscopy collectively corroborate a dual mechanism, which consists of a hole-mediated direct conversion and a superoxide radical-involved chain process. As expected, 1CSCA/NU exhibited good catalytic universality toward a variety of alcohol substrates. Our work established an efficient, stable MOF-based photocatalytic platform for the co-production of valuable chemicals and green oxidants.","PeriodicalId":270,"journal":{"name":"Chemical Engineering Journal","volume":"15 1","pages":""},"PeriodicalIF":15.1,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147496446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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