催化学报 ›› 2023, Vol. 53: 13-30.DOI: 10.1016/S1872-2067(23)64530-9

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利用有机超分子光催化剂在太阳光下处理污水的研究进展

刘伟旭a,1, 贺唱a,1, 朱博文b, 朱恩伟c, 张亚宁d, 陈云宁a, 李军山e, 朱永法a,*()   

  1. a清华大学化学系, 北京100084
    b北京建筑大学环境与能源工程学院, 北京100044
    c吉林师范大学环境友好材料制备与应用教育部重点实验室, 吉林长春130052
    d江南大学光响应功能材料研究中心, 江苏无锡214122
    e成都大学高等研究院化学系, 四川成都610106
  • 收稿日期:2023-09-05 接受日期:2023-10-06 出版日期:2023-10-18 发布日期:2023-10-25
  • 通讯作者: *电子信箱: zhuyf@tsinghua.edu.cn (朱永法).
  • 作者简介:

    1共同第一作者.

  • 基金资助:
    国家重点研发计划(2020YFA0710304);国家自然科学基金(22136002);江苏省碳达峰碳中和科技创新专项资金(BK20220023)

Progress in wastewater treatment via organic supramolecular photocatalysts under sunlight irradiation

Weixu Liua,1, Chang Hea,1, Bowen Zhub, Enwei Zhuc, Yaning Zhangd, Yunning Chena, Junshan Lie, Yongfa Zhua,*()   

  1. aDepartment of Chemistry, Tsinghua University, Beijing 100084, China
    bSchool of Environmental and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
    cKey Laboratory of Preparation and Applications of Environmental Friendly Materials, Jilin Normal University, Changchun 130052, Jilin, China
    dInternational Joint Research Center for Photoresponsive Molecules and Materials, Jiangnan University, Wuxi 214122, Jiangsu, China
    eInstitute for Advanced Study, Chengdu University, Chengdu 610106, Sichuan, China
  • Received:2023-09-05 Accepted:2023-10-06 Online:2023-10-18 Published:2023-10-25
  • Contact: *E-mail: zhuyf@tsinghua.edu.cn (Y. Zhu).
  • About author:Prof. Yongfa Zhu is currently a full professor of Tsinghua University. He received his BA degree in 1985 from Nanjing University and obtained his master degree in 1988 from Peking University. He had studied and worked at Tsinghua University from 1992 to now and received a PhD degree in 1995. His current research is focused on photocatalysis and application on environmental, energy conversion and anti-tumor. He is the author and co-author of 498 original research papers published in SCI journals. The total cited numbers reached about 46000 and the H-index arrived at 120. About 50 papers were selected as High-Cited Papers by Essential Science Indicators. He is Elsevier highly cited scholar from 2014 to now, and Clarivate highly cited scientist from 2018 to now. Besides, he has written about 5 books and applied about 24 patents. He also serves as the creative editor of Science for Energy and Environment (SEE), the associate editor of Applied Catalysis B, the associate editor of Green Carbon, the vice chairman of China Photosensitive Society and the director of Photocatalytic Committee, and the president of Beijing Indoor and Indoor Environmental Purification Industry Association.

    1 Contributed equally to this work.

  • Supported by:
    The National Key Research and Development Project of China(2020YFA0710304);National Natural Science Foundation of China(22136002);Special Fund Project of Jiangsu Province for Scientific and Technological Innovation in Carbon Peaking and Carbon Neutrality(BK20220023)

摘要:

对水体中酚类等难降解有机污染物进行深度矿化处理, 实现无毒无害排放, 是提高环境质量, 实现可持续发展的关键. 如何高效去除水体中难降解有机污染物不仅是环境化学污染控制的研究热点, 也是制约工业废水回用的技术瓶颈. 光催化可直接利用太阳光实现污染物的深度矿化和无毒无害排放, 为该难题的解决提供了新思路. 但对传统无机光催化剂而言, 光利用率低、降解速率慢和净化通量低制约了其实际应用. 本文总结了本课题组在利用有机光催化剂降解污染物时提出的三个策略,以进一步推动光催化污水处理技术的实际应用.

针对可见光利用效率低的难题, 发展了一系列有机超分子等新型光催化剂. 通过对共轭结构(生色基团)和侧链基团(助色基团)的调控, 实现了对最高被占分子轨道(HOMO)和最低未占分子轨道(LUMO)能级位置以及吸光能力的调控, 有机半导体光催化剂的降解催化活性可拓展到近红外段, 实现了污染物在太阳光下的降解和深度矿化. 光生空穴可将酚类和抗生素等难降解污染物完全矿化成CO2和水, 建立了可见光下有机半导体光催化剂深度矿化净化水中难降解有机污染物的新方法. 通过构建分子内供体受体(DA)结构和分子间供体-受体(D-A)界面, 将卟啉和苝二酰亚胺类光催化反应活性拓展到近红外段, 太阳光利用效率达70%.

针对难降解有机污染物降解去除速率慢的问题, 建立了通过光催化剂的分子偶极作用调控内建电场及构建超短迁移路径, 进而促进光生电荷的分离和传输, 提升污染物降解和矿化动力学. 通过支链基团种类和位置调控, 发现强极性取代基如羧基、羟基、磺酸基等可以增强偶极作用, 而分子偶极在催化剂内有序排列又可以产生强内建电场, 从而促进光生电荷的快速分离和迁移到表面, 加速污染物的降解反应动力学. 通过提升苝二酰亚胺超分子和聚合物光催化剂的结晶度, 增强了分子间π-π堆积和氢键的有序度, 显著提升了内建电场, 实现了光催化氧化反应活性数量级的提高. 通过光催化剂尺度和多孔结构调节, 电荷迁移距离缩短到纳米和亚纳米量级, 增强了电荷迁移到表面的速率. 发现并证实了π-π堆积间距的缩短可促进电荷传输, 光催化降解活性提高了5-10倍.

针对光催化法降解通量低和芬顿法矿化度低的难题, 提出了在光催化剂上耦合芬顿催化剂的新思路, 创立了光催化原位自芬顿高通量矿化水中有机污染物的新方法. 利用光催化的氧化还原反应特性, 促进了产双氧水中间体的氧化还原循环, 实现了可见光下从纯水到双氧水的高效合成. 四羧基卟啉光催化剂产双氧水的活性从可见拓展到1100 nm的红外段, 太阳能到双氧水的能量转换效率达1.2%, 10 h双氧水积累浓度达到1 wt%, 实现了光催化产双氧水性能的新进展. 通过在氮化碳光催化剂中引入氧源, 使得富氧氮化碳表面生成了大量的酚基和醌基, 产双氧水性能可提高3.5倍. 通过将g-C3N4、苝-3,4,9,10-四羧酸二亚胺等光催化剂耦合芬顿催化剂, 对酚类等难降解污染物的降解活性可提高20倍以上, 矿化度提高到90%, 解决了传统芬顿法需要外加H2O2的难题.

本课题组通过以上三种策略, 解决了光催化去除水体污染物过程中太阳光利用率低、矿化度不足和处理通量有限等缺点. 未来如何增强超分子光催化剂的稳定性、提高光催化效率以及构建非均相自芬顿体系仍是光催化污水处理技术的研究重点.

关键词: 光催化, 污水处理, 有机半导体, 超分子光催化剂, 内建电场

Abstract:

Semiconductor photocatalysis offers a promising and sustainable avenue for wastewater treatment due to its ease of separation and recyclability. However, their practical application is currently hampered by limited energy utilization, insufficient mineralization, and low treatment capacity under sunlight. This account summarizes our progress in developing broad-spectrum responsive (extended to 950 nm) supramolecular organic photocatalysts capable of sunlight-driven over 95% pollutant mineralization. Through modulation of molecular dipole and crystallinity, we enhance the built-in electric field, thereby improving charge separation and photodegradation rates. Furthermore, to overcome the low-flux constraints of traditional photocatalysis, we integrated the Fenton catalyst to construct photo-self-Fenton systems, realizing a 29.63 L m-2 h-1 high-flux mineralization under sunlight. Finally, a brief conclusion and outlook on organic photocatalysts have also been presented.

Key words: Photocatalysis, Wastewater treatment, Organic semiconductor, Supramolecular photocatalyst, Built-in electric field