【期刊】马德里自治大学Belver、Bedia团队杂环接枝NH2-MIL-125太阳能光催化降解新兴污染物研究 | SPT

马德里自治大学Belver、Bedia团队近日于国际分离纯化领域著名期刊Separation and Purification Technology（JCR 1区Top，中科院2021升级版分区：工程技术1区Top期刊）上发表了题为“Solar photocatalytic degradation of emerging contaminants using NH2-MIL-125 grafted by heterocycles”的文章（Volume 297，15 September 2022，121442，Available online 7 June 2022）。

图文摘要

研究亮点

• 成功合成杂环甲醛接枝的 NH2-MIL-125。

• 接枝改善了光吸收、电荷转移和水稳定性。

• 对乙酰氨基酚的光催化消除比裸 MOF 增加了两倍。

• 首次使用接枝-MOF 以连续流动模式去除对乙酰氨基酚。

• Successful synthesis of NH2-MIL-125 grafted by heterocyclic carboxaldehydes.

• Grafting improves light absorption, charge transference and water stability.

• Photocatalytic elimination of acetaminophen twofold increased respect to bare MOF.

• Acetaminophen removal in continuous flow mode using grafted-MOF for the first time.

文章简介

不同化合物不受控制地排放到水源中，引起了越来越多的关注。药物 (EC)是在废水和水生生态系统中检测到的常见新兴污染物，来自家庭污水、工业活动和医院服务等。接触 EC 可能会对人类健康和环境产生有害影响，例如破坏性影响或细胞损伤。对乙酰氨基酚 (ACE) 可以被认为是全球最常见的镇痛解热药物之一，也以不同的商品名称出售，例如对乙酰氨基酚。在法国、西班牙、丹麦和英国等欧洲国家，ACE 的消费量在每 1000 名居民 (DDD) 60-70 日剂量之间，远高于其他常见镇痛药，如乙酰水杨酸，具有报告的消耗量低于 10 DDD。消耗后，约有 2-5% 的 ACE 在没有任何代谢变化的情况下被排出并进入废水。这些新兴污染物的不完全消除会增加它们的总体浓度，从而带来潜在的环境风险。因此，有必要改进废水处理策略，以便在最终排放前完全去除这些 EC。The uncontrolled discharge of different compounds into aquatic sources constitutes an increasing concern. Pharmaceuticals are common emerging contaminants (ECs) detected in wastewaters and aquatic ecosystems, coming from household effluents, industrial activities, and hospital services, among others . Exposure to ECs may produce harmful effects on human health and the environment, such as disruptive effects or cellular damage . Acetaminophen (ACE) can be considered among the most common analgesic-antipyretic pharmaceuticals worldwide, also sold under different trade names, such as paracetamol. The consumption of ACE is situated among 60-70 daily doses per 1000 inhabitants (DDD) in European countries such as France, Spain, Denmark, and the United Kingdom, much higher than that of other common analgesics, such as acetylsalicylic acid, with a reported consumption below 10 DDD . After consumption, about 2-5% of ACE is excreted without any metabolic shift and reaches wastewater . The incomplete elimination of these emerging contaminants would increase their overall concentration, thus representing a potential environmental risk. Therefore, it is necessary to improve strategies in the treatment of wastewaters for the complete removal of these ECs before their final discharge.金属有机框架 (MOF) 因为具有良好的光学、结构和电子特性，正在研究用于光催化处理污染水，可以通过使用不同的金属节点进行定制或有机接头。杂环化合物可以在席夫碱反应后通过醛基成功地接枝到NH2 基团上。这些杂环化合物提供了额外的电荷并提高了它们的迁移率，似乎是改善 MOF 光催化性能的一种有前途的方法。然而，据我们所知，还没有关于 MOFs 接枝用于太阳能光催化降解 ECs 的研究报道。Metal organic frameworks (MOFs) are being investigated for the photocatalytic treatment of contaminated water , as a consequence of their good optical, structural, and electronic properties that can be tailored through the use of different metal nodes or organic linkers. Heterocyclic compounds can be successfully grafted to the NH2 group following a Schiff base reaction through an aldehyde group. These heterocyclic compounds provide additional charges and improve their mobility, appearing as a promising approach to improving the photocatalytic properties of MOFs. However, to the best of our knowledge, no studies have been reported dealing with the grafting of MOFs for the solar photocatalytic degradation of ECs.这是第一项报告使用这些接枝-NH2-MIL-125 降解 EC 用于水净化的工作。在 ACE 的光降解中测试了接枝的 MOF。最好的接枝-NH2-MIL-125 的光催化性能在不同的水基质下和在水性流出物中存在的新兴污染物（对乙酰氨基酚、磺胺甲恶唑和安替比林）的混合物中进行了进一步研究。此外，在连续流动测试中的新分析下评估了稳定性和光催化性能。值得注意的是，以前的工作没有证明接枝-NH2-MIL-125 在连续流动测试或具有不同化学结构的新兴污染物的混合物中的性能。This is the first work reporting the degradation of ECs for water purification using these grafted-NH2-MIL-125. The grafted-MOFs were tested in the photodegradation of ACE. The photocatalytic performance of the best grafted-NH2-MIL-125 was further investigated under different water matrices and with a mixture of emerging contaminants (acetaminophen, sulfamethoxazole, and antipyrine) whose presence in aqueous effluents has been also frequently reported . Besides, the stability and photocatalytic performance were evaluated under a novel analysis in continuous flow tests. Remarkably, no previous works have demonstrated the performance of grafted-NH2-MIL-125 in continuous flow tests or with a mixture of emerging contaminants with different chemical structures.由紫外-可见光谱测定所有合成材料的光学性质。图1显示了吸收光谱。由于钛氧簇的存在,所有材料在200-300纳米的范围中显示相同的吸收带。位于较高波长的谱带是由于在用杂环接枝后，连接体的吸收从390略微移动到400 nm。因此，接枝材料显示出对可见光范围的一些吸收偏移，表明杂环分子有利于光的吸收。接枝过程也显示出对带隙值的影响，从Tauc图获得，其值在接枝后稍微降低。所有合成材料的形态可以在图2所示的SEM图像中观察到。所有样品都呈现出了薄的盘状颗粒，且具备类似于NH2-MIL-125 的光滑表面，平均尺寸为400-650 nm。因此，可以看出接枝处理后不影响颗粒形态。The optical properties of all synthesized materials were determined by UV–vis spectroscopy. Figure 1 represents the absorbance spectra. All materials show the same absorption bands in Adsorbed volume (cm3/g STP)the 200-300 nm range due to the presence of the Ti-oxo-clusters. The band located at higher wavelengths is due to the linker absorption that shifts slightly from 390 to 400 nm after grafting with heterocycles. Thus, the grafted materials show some shift of absorption to the visible range, suggesting that the heterocycle molecules act as an antenna favouring light absorption . The grafting process also showed an effect in the band gap values , obtained from the Tauc plot (Figure S5), whose values are slightly reduced after grafting. The morphology of all synthesized materials can be observed in the SEM images shown in Figure 2. All samples describe thin and disk-like particles with a smooth surface similar to that of NH2-MIL-125 ,with a mean size of 400-650 nm. Thus, the grafting posttreatment does not affect the particle morphology.

图1.原始NH2-MIL-125和接枝后的NH2-MIL-125紫外-可见光谱

Figure 1. UV-visible spectra of the bare NH2-MIL-125 and the grafted materials

图2.原始NH2-MIL-125和接枝后的NH2-MIL-125 SEM

Figure 2. SEM images of the bare NH2-MIL-125 and the grafted materials

本文合成的所有材料的在模拟太阳光照射下对ACE降解获得光催化性能。图3显示了在黑暗中达到吸附平衡后ACE浓度随照射时间的变化。全部接枝材料描述了比裸MOF更好的光催化性能，3PA-MIL-125最具活性，在90分钟内实现了几乎完全的ACE降解。所有降解曲线都较好地符合准一级动力学反应。值得说明的是，3PA-MIL-125的动力学常数比原始NH2-MIL-125高2.4倍。将这些值与NH2- MIL-125 MOF在相同反应条件下进行其他修改(即Zr掺杂和Pt修饰)时已经报道的值进行了比较。ATA配体与杂环的接枝比其它改性更大程度地促进了光催化反应。The photocatalytic performance of all materials herein synthesized was evaluated for ACE degradation under simulated solar light irradiation. Figure 2 shows the evolution of ACE concentration with irradiation time after reaching the adsorption equilibrium in the dark. All grafted materials describe a better photocatalytic performance than the bare MOF, being 3PA-MIL-125 the most active, achieving almost total ACE degradation in 90 min. All degradation profiles were successfully fitted to a pseudo-first order kinetic reaction, being the kinetic constant values collected in Table2. It is noteworthy that the kinetic constant of 3PA-MIL-125 is 2.4 times higher than that of the original NH2-MIL-125. These values have been compared with those already reported under the same reaction conditions with NH2- MIL-125 MOF with other modifications, i.e., Zr-doping and Pt decoration.

图3. 裸露的 NH2-MIL-125 和接枝材料在太阳辐射下的 ACE 降解演变（[ACE]0 = 5 mg⋅L–1；光催化剂负载 = 250 mg⋅L–1；强度 = 600 W⋅ m-2)

Figure 3. Evolution of ACE degradation with the bare NH2-MIL-125 and the grafted materials under solar irradiation ([ACE]0 = 5 mg⋅L–1; Photocatalyst load = 250 mg⋅L–1;Intensity = 600 W⋅m−2)

     间歇操作系统有一个巨大的缺点，因为它需要从处理过的水中分离光催化剂。因此，3PA-MIL-125的光催化性能在16小时连续流动系统中进行评估。图4显示了在该测试过程中ACE和沥滤的配体在流中的时间进程。一旦达到稳态(约6小时)，光催化性能保持恒定，实现了ACE的完全转化，从而证明了3PA-MIL-125的稳定性。还监测了配体浸出情况，观察到低浓度的浸出液(< 4mg·L–1)，该浓度从反应8小时开始持续下降，实际上在运行16小时后消失。反应后，回收光催化剂并表征以分析其结构稳定性。XRD和N2吸附-脱附结果非常相似，如上所述的纯3PA-MIL-125。仅检测到表面积的轻微减少，这可能与副产物的沉积有关，副产物的沉积可能轻微堵塞多孔网络。因此，3PA-MIL-125似乎是一种活性较高和相对稳定的光催化剂，可以在连续流动系统中接受可见光照射去除水中出现的污染物。

  Batch systems present a huge disadvantage since it is necessary to separate the photocatalyst from the treated water. Thus, the photocatalytic performance of 3PA-MIL-125 was evaluated in a 16 h continuous flow system .Figure 4 shows the time-course of ACE and leached ligand on stream during this test. Once the steadystate was reached (about 6 h), the photocatalytic performance remained constant, achieving a total conversion of ACE, and thus demonstrating the stability of 3PA-MIL-125. Ligand leaching was also monitored, and a low concentration of leachate was observed (< 4 mg·L–1), which continuously decreases from 8 hours of reaction and practically disappeared after 16 h on stream. After reaction, the photocatalyst was recovered and characterized to analyze its structural stability. XRD and N2 adsorption-desorption results were very similar to those described above for the neat 3PA-MIL-125. Only a slight reduction of the surface area was detected, which may be associated with the deposition of by-products, which can slightly block the porous network. Thus, 3PA-MIL-125 appears as an active and stable photocatalyst to remove emerging contaminants from water under solar irradiation in a continuous flow system.

图4.在用3PA-MIL-125的连续实验中ACE和配体沥滤液在流中的时间过程

Figure 4. Time-course of ACE and ligand leachate on stream in a continuous experiment with 3PA-MIL-125.

主要结论

NH2-MIL-125的光催化性能通过用杂环接枝胺配体而得到改善，杂环作为可见光吸收的介质。3PA-MIL-125在对乙酰氨基酚降解方面表现出最佳性能，这是由于其高比表面积和微孔性、稍低的带隙、改善的光吸收、更好的界面电荷转移和减少的电子-空穴复合。用猝灭剂进行的捕获实验实验得出结论，超氧化物自由基在对乙酰氨基酚的光降解中起主要作用，尽管电子和羟基自由基也部分参与。水中常见的无机离子减少了对乙酰氨基酚的光降解。3PA- MIL-125能够去除其他新出现的污染物，即磺胺甲恶唑和安替比林，甚至它们的混合物，尽管反应速率取决于目标化合物的性质。在连续流动过程中，对乙酰氨基酚的降解在6小时后达到几乎完全去除，并且在随后16小时实验内保持不变。目前的结果揭示了接枝-NH2-MIL-125与3-吡啶甲醛光催化剂的稳定性和活性，用于在太阳光照射下去除水中的药物分子。The photocatalytic performance of NH2-MIL-125 was improved by grafting the amine ligand with heterocycles that act as an antenna for visible light absorption.3PA-MIL-125 exhibited the best performance in acetaminophen degradation due to its high specific surface area and microporosity, slightly lower band gap, improved light absorption, better interfacial charge transference, and reduced electron-hole recombination. Experiments with scavengers lead to the conclusion that superoxide radicals play a major role in the photodegradation of acetaminophen, although electrons and hydroxyl radicals are also partly involved. The inorganic ions commonly found in water reduced the acetaminophen photodegradation. 3PAMIL-125 was able to remove other emerging contaminants, i.e. sulfamethoxazole and antipyrine, and even a mixture of them, although the reaction rate depends on the nature of the target compound. In a continuous flow regime, total degradation of acetaminophen was reached after 6 h and then maintained for the rest of the 16 h experiment. The current results revealed the stability and activity of the grafted-NH2-MIL-125 with 3-pyridinecarboxaldehyde photocatalyst for the remediation of pharmaceuticals in water on stream under solar irradiation.

 原文信息

 原文链接

https://doi.org/10.1016/j.seppur.2022.121442

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主要作者介绍

通讯作者

卡罗来纳贝尔弗博士

Carolina Belver, PhD

工作单位：马德里自治大学，马德里，西班牙

employer:Autonomous University of Madrid, Madrid, Spain

通讯邮件：[e-mail] (C.B.)

Communication email:[e-mail] (C.B.)

通讯作者：Carolina Belver博士现任西班牙马德里自治大学化学工程系副教授，化工知名期刊Chemical Engineering Journal (SCI IF = 10.652)副主编、Materials Science for Energy Technologies期刊编委，并担任国际碳大会（Carbon）等多个国际会议委员。Carolina Belver 博士是国际知名的水资源循环领域的专家，主要研究方向为光催化水处理技术开发，主持参与了20余项科研项目，发表SCI期刊论文70余篇，并撰写著作10余部。

Corresponding Author:Dr. Carolina Belver is currently an associate professor in the Department of Chemical Engineering of the Autonomous University of Madrid, Spain, an associate editor of Chemical Engineering Journal (SCI IF = 10.652), a well-known chemical journal, an editorial board member of Materials Science for Energy Technologies, and serves as a number of international conferences such as the International Carbon Conference (Carbon). member. Dr. Carolina Belver is an internationally renowned expert in the field of water resources recycling. His main research direction is the development of photocatalytic water treatment technology. He has presided over and participated in more than 20 scientific research projects, published more than 70 SCI journal papers, and wrote more than 10 books.

豪尔赫·贝迪亚博士

Jorge Bedia, PhD

工作单位：马德里自治大学化学工程系，马德里，西班牙

employer:Autonomous University of Madrid, Chemical Engineering Department, Madrid, Spain

通讯邮件：[e-mail] (J.B.)

Communication email:[e-mail] (J.B.)

通讯作者：Jorge Bedia，2008年毕业于西班牙马拉加大学（UMA）毕业，获工程博士学位（杰出毕业生），现任西班牙马德里自治大学（UAM） 副教授，化工知名期刊Separation & Purification Technology (SCI IF = 5.774)期刊的编辑（2020年至今），Chemical Engineering Journal (SCI IF = 10.652)编辑委员会成员（2017年至今）。Bedia博士是水处理领域的国际知名专家，主要研究方向为高级氧化水处理技术开发、吸附和催化的碳基材料开发、水处理MOFs材料开发、挥发性氯化有机化合物的气相加氢脱氯、离子液体和负载型离子液体的分离和催化过程等。先后在 Advanced Materials、Applied Catalysis B: Environmental等化学工程专业期刊上发表多篇学术论文。近年来主持/参与20余项与欧盟与中国、美国、俄罗斯等多个国家合作项目。

Corresponding Author:Jorge Bedia, graduated from the University of Malaga (UMA) in Spain in 2008 with a doctorate in engineering (distinguished graduate), is currently an associate professor at the Autonomous University of Madrid (UAM) in Spain, and is a well-known chemical journal Separation & Purification Technology (SCI IF = 5.774) Editor of the journal (2020-present), member of the Editorial Board of Chemical Engineering Journal (SCI IF = 10.652) (2017-present). Dr. Bedia is an internationally renowned expert in the field of water treatment. His main research directions are the development of advanced oxidation water treatment technology, the development of carbon-based materials for adsorption and catalysis, the development of MOFs materials for water treatment, gas-phase hydrodechlorination of volatile chlorinated organic compounds, Separation and catalytic process of ionic liquids and supported ionic liquids, etc. He has published many academic papers in chemical engineering professional journals such as Advanced Materials and Applied Catalysis B: Environmental. In recent years, he has hosted/participated in more than 20 cooperation projects with the European Union, China, the United States, Russia and other countries.

本期编辑：张梦琳，徐熙焱（[e-mail]）

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