研究背景

自然水体是一个多种物质组成的流动群落，其自净化依赖于内源性物质之间的相互作用。然而，新污染物（ECs）日益复杂且稳定的分子结构以及惰性的基态氧分子（O2）使得反应物端口活化速率缓慢。此外，反应物之间无序且随机的相互作用极大的限制了传质。这就导致自然水体自净化过程十分缓慢，往往需要几十甚至上百年时间。利用大量氧化剂和能量来打破“端口-通道”效应，实现污染物快速去除是工业界迫不得已的选择。这一做法与低碳可持续发展的理念背道而驰，因此开发低能耗水处理技术已成为环境领域的全球性挑战。

研究内容

针对上述科学挑战，吕来教授课题组在前期开发的双反应中心（DRC）水处理技术基础上，首次创新性地提出“水自净扩增理论与技术”。通过设计微势差（MPD）表面催化剂，在非消耗性H2O2的触发下实现内源性物质（ECs和O2等）的快速活化和利用，降低化学键断裂能垒的同时构建ECs与O2之间的快速反应通道，从而减少对外部能量和氧化剂（如H2O2）的依赖，成功突破惰性端口效应以及通道阻塞效应，实现水自净力扩增。

具体如下，构建的MPD表面扩增体系表明，H2O2可触发难降解有机物快速去除，而单独CZO几乎无法降解ECs。这一过程中绝大部分H2O2是非消耗性的，它通过吸附在MPD表面调控表面电子极化分布诱发反应，即降低内源性物质活化能垒的同时打开MPD表面的传质通道，从而降低氧化剂使用量。整个过程中H2O2的最大消耗量仅为2.6%，有时甚至为零，且H2O2的瞬时绝对量超过了100%，极大降低了有毒有机物脱毒过程的能耗。曝气实验和淬灭实验直接证明了溶解氧在H2O2调控的MPD表面活化生成活性氧物种（ROS，包括O2·−，·OH和1O2）和H2O2，并在ECs去除过程中起到关键作用。

上图MPD表面扩增体系效能及机制

（a）内分泌干扰素BPA的降解曲线；（b）各种ECs的降解曲线及相应H2O2消耗；（c）溶解氧含量对BPA降解的影响；（d）污染物在H2O2调控表面前后Cu位点和Zn位点的吸附能计算；（e）自净化扩增过程中产生的ROS；（f）内分泌干扰素BPA在CZO/H2O2体系的降解路径。

研究相关

该工作发表在环境领域顶刊Environmental Science & Technology上，通讯作者为吕来教授，第一作者为广州大学博士研究生卢超。该工作得到了广东省重点领域研发计划、国家自然科学基金、广东省珠江人才计划引进创新团队项目以及广州市基础与应用基础研究项目的资助。

文章来源

Chao Lu, Chun Hu, Junmei Wu, Hongwei Rong and Lai Lyu*. Endogenous Substances Utilization for Water Self-Purification Amplification Driven by Nonexpendable H2O2 over a Micro-Potential Difference Surface. Environ. Sci. Technol. 58, 23241–23250.

全文链接：https://doi.org/10.1021/acs.est.4c09385

Amplification of Water Self-Purification via a Micro-Potential Difference Surface with Nonexpendable H2O2 to Overcome Inert-Port and Channel-Blocking Effects

Research Background

Natural water environment is a flowing community composed of diverse substances. The natural self-purification of polluted-water mainly depends on the interaction of these endogenous substances. However, the increasingly complex and stable molecular structures of emerging contaminants (ECs) and the inert ground-state oxygen molecules (O2) result in slow activation rates at reactive ports. Furthermore, disordered and random interactions between reactants severely limit mass transfer, leading to extremely slow natural water self-purification processes that often require decades or even centuries. The utilization of extensive additive oxidants and energy to break the “port-channel” effect and achieve rapid pollutant removal is a compelling choice for industry. This practice runs counter to the concept of low-carbon sustainable development, and the development of low-energy water treatment technologies has therefore become a global challenge in the environmental field.

Research Content

To address the above scientific challenges, Prof. Lyu Lai's group innovatively proposed the "Theory and Technology of Water Self-Purification Amplification" for the first time on the basis of the previously established dual reaction center (DRC) water treatment technology. By designing a micro-potential difference (MPD) surface catalyst, rapid activation and utilization of endogenous substances (ECs and O2, etc.) is achieved under the trigger of nonexpendable H2O2. In this way, the rapid reaction channel between ECs and O2 is constructed while the energy barrier for chemical bond breaking is lowered. Thus, the dependence on external energy and oxidants (e.g., H2O2) is reduced, and the inert port effect as well as the channel blocking effect are successfully overcome to realize the water self-purification amplification.

Key Findings:

The constructed MPD surface amplification system demonstrates that H2O2 triggers rapid degradation of recalcitrant pollutants, whereas CZO alone barely degrades ECs. The majority of H2O2 in this process is nonexpendable, and it induces the reaction by adsorbing on the MPD surface to modulate the surface electron polarization distribution. In this way, the activation energy barrier of endogenous substances is lowered while the mass transfer channels on the MPD surface are opened, thus reducing the consumption of oxidant. Surprisingly, the rapid degradation of the pollutants is accompanied by H2O2 consumption of only 2.6% at most, sometimes even reaching zero consumption, with the instantaneous absolute amount of H2O2 exceeding 100%. This strategy significantly reduces the energy consumption in the ECs removal process. Aeration and quenching experiments directly demonstrate that dissolved oxygen is activated to generate reactive oxygen species (ROS，including O2·−，·OH and 1O2) and H2O2 on the H2O2-modulated MPD surface and plays a key role in the removal of ECs.

Above Figure: Performance and mechanism of theMPD surface amplification system.

(a) Degradation curve of BPA; (b) Degradation curves of various ECs and corresponding H2O2 consumption; (c) Impact of dissolved oxygen content on BPA degradation; (d) Adsorption energy calculations of pollutants at Cu/Zn sites on H2O2-modulated surfaces; (e) ROS generation in self-purification expansion process; (f) Degradation pathways of BPA in the CZO/H2O2 system.

Related Information

This work was published in Environmental Science & Technology, with Prof. Lyu Lai as the corresponding author and Dr. Lu Chao (Guangzhou University) as the first author. This work was financially supported by the Key-Area Research and Development Program of Guangdong Province, the National Natural Science Foundation of China, the Introduced Innovative R&D Team Project under the "Pearl River Talent Recruitment Program" of Guangdong Province, and the Basic and Applied Basic Research Project of Guangzhou.

Article Source

Chao Lu, Chun Hu, Junmei Wu, Hongwei Rong and Lai Lyu*. Endogenous Substances Utilization for Water Self-Purification Amplification Driven by Nonexpendable H2O2 over a Micro-Potential Difference Surface. Environ. Sci. Technol. 58, 23241–23250.

DOI：https://doi.org/10.1021/acs.est.4c09385