Beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation, School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation, School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Environ Res. 2021 Oct;201:111596. doi: 10.1016/j.envres.2021.111596. Epub 2021 Jul 2.
Hydroxyl modified UiO-66 ((OH)-UiO-66-X%, X represents the mass content ratio of introduced 2,5-dihydroxyterephthalic acid) was prepared via a solvothermal reaction between zirconium tetrachloride, benzene-1,4-dicarboxylic acid (HBDC), as well as 2,5-dihydroxyterephthalic acid (HBDC-(OH)). It was found that hydroxyl groups can act as the intramolecular hole scavenger to boost the photo-induced charge carrier separation to enhance Cr(VI) reduction. The photocatalytic Cr(VI) reduction activities of (OH)-UiO-66-X% were investigated upon the irradiation of low-power ultraviolet LED light. The findings demonstrated that (OH)-UiO-66-20% with good cyclicity and stability exhibited superior photocatalytic performances to both UiO-66 and (OH)-UiO-66. The introduction of hydroxyl groups can also extend the light absorption region to longer wavelength in visible range, which provides possibility for displaying photocatalytic activities under sunlight. The effect of small molecule organic acid (SOAs), pH value, and co-existing inorganic ions on photocatalytic performances of (OH)-UiO-66-20% were investigated. Tartaric acid (TA) as typical SOAs was introduced to the reaction system to further boost the photocatalytic Cr(VI) reduction via acting as hole scavenger, constructing charge-transfer-complex for quick electron transportation, and producing COO· radicals. This work opened a new opportunity for modified MOFs for boosted elimination activities for environmental pollutants.
羟基改性 UiO-66((OH)-UiO-66-X%，X 代表引入的 2,5-二羟基对苯二甲酸的质量含量比)是通过四氯化锆、苯-1,4-二羧酸(HBDC)和 2,5-二羟基对苯二甲酸(HBDC-(OH))之间的溶剂热反应制备的。研究发现，羟基可以作为分子内空穴清除剂，促进光致载流子分离，从而增强 Cr(VI)的还原。在低功率紫外 LED 光照射下，研究了(OH)-UiO-66-X%的光催化 Cr(VI)还原活性。结果表明，具有良好循环稳定性的(OH)-UiO-66-20%表现出优于 UiO-66 和(OH)-UiO-66 的光催化性能。羟基的引入还可以将光吸收区域扩展到可见光范围内的长波长，这为在阳光下显示光催化活性提供了可能性。研究了小分子有机酸(SOAs)、pH 值和共存无机离子对(OH)-UiO-66-20%光催化性能的影响。将酒石酸(TA)等典型的 SOAs 引入反应体系，通过充当空穴清除剂、构建快速电子传输的电荷转移配合物以及产生 COO·自由基，进一步促进光催化 Cr(VI)还原。这项工作为改性 MOFs 提供了新的机会，以增强对环境污染物的消除活性。
