Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada.
Catalysis and Microporous Materials Laboratory, Vasile-Alecsandri University of Bacau, Romania.
J Hazard Mater. 2019 Feb 15;364:356-366. doi: 10.1016/j.jhazmat.2018.09.070. Epub 2018 Oct 6.
Catalytic ozonation of Methylene Blue, Methyl Green, Methyl Orange and Methyl-thymol Blue was investigated in the presence of ion-exchanged montmorillonite (NaMt and Fe(II)Mt), crude bentonite and acid-activated counterparts. An original approach never tackled so far consisted in correlating the basicity and hydrophilic character to the dye-catalyst interactions occurring on the catalyst surface. This was achieved through CO and water thermal programmed desorption. Kinetics study revealed that ozonation starts in the bulk solution, and dye adsorption turns out to be an essential requirement for high catalytic effectiveness. On NaMt, dye molecules appear to adsorb mainly via hydrophobic interaction. On Fe(II)Mt, the contributions of hydrophobic interaction, cation-exchange and Fe mobility to the catalytic activity prevail. Acid activated clay catalysts exhibited lowest hydrophilic character favoring adsorption through organophilic interaction and affording thorough and fast dye mineralization. This was explained in terms of increased number of silanols and -Si-O-Si- groups. For all catalysts, short ozonation of all dye molecules resulted in similar end-chain products, which were totally eliminated after prolonged reaction times. This result is of great importance because it provides valuable theoretical findings that allow envisaging total mineralization of organic molecules by recyclable metal-free clay catalysts.
在离子交换蒙脱石（NaMt 和 Fe(II)Mt）、天然膨润土和酸活化对应物的存在下，研究了亚甲基蓝、甲基绿、甲基橙和甲基百里酚蓝的催化臭氧化作用。目前为止，我们采用了一种独特的方法，将碱性和亲水性与催化剂表面发生的染料-催化剂相互作用联系起来。这是通过 CO 和水的热程序解吸来实现的。动力学研究表明，臭氧化作用首先在本体溶液中发生，而染料吸附是获得高催化效果的必要条件。在 NaMt 上，染料分子主要通过疏水相互作用吸附。在 Fe(II)Mt 上，疏水相互作用、阳离子交换和 Fe 迁移对催化活性的贡献占主导地位。酸活化的粘土催化剂表现出最低的亲水性，有利于通过亲有机物相互作用进行吸附，并提供彻底和快速的染料矿化作用。这可以用增加的硅醇和-Si-O-Si-基团数量来解释。对于所有催化剂，所有染料分子的短臭氧化作用都会导致类似的端链产物，这些产物在延长反应时间后完全消除。这一结果非常重要，因为它提供了有价值的理论发现，允许通过可回收的无金属粘土催化剂实现有机分子的完全矿化。
