Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, Université de Pau et des Pays de l'Adour, Hélioparc-2 Av. du Président Angot, F-64053 Pau Cedex 09, France.
J Hazard Mater. 2012 Apr 15;211-212:266-74. doi: 10.1016/j.jhazmat.2011.09.066. Epub 2011 Oct 1.
Transparent and porous silica xerogels containing various grafted photosensitizers (PSs) such as anthraquinone derivatives, Neutral Red, Acridine Yellow and a laboratory-made dicyano aromatics (DBTP) were prepared. In most cases, the xerogels were shown to be mainly microporous by porosimetry. The PSs were characterized in the powdered monoliths (form, aggregation, concentration) by electronic spectroscopy which also proved to be a useful tool for monitoring the material evolution after irradiation. These nanoporous xerogels were used as microreactors for gas/solid solvent-free photo-oxygenation of dimethylsulfide (DMS) using visible light and air as the sole reactant. All these PSs containing monoliths were efficient for gas-solid DMS oxidation, leading to sulfoxide and sulfone in varying ratios. As these polar oxidation products remained strongly adsorbed on the silica matrix, the gaseous flow at the outlet of the reactor was totally free of sulfide and odorless. The best results in term of yield and initial rate of degradation of DMS were obtained with DBTP containing xerogels. Moreover, as these materials were reusable without loss of efficiency and sensitizer photobleaching after a washing regeneration step, the concept of recyclable sensitizing materials was approved, opening the way to green process.
制备了含有各种接枝光敏剂（PS）的透明多孔硅胶干凝胶，例如蒽醌衍生物、中性红、吖啶黄和一种实验室制备的二氰基芳烃（DBTP）。在大多数情况下，通过孔隙率测定法证明干凝胶主要是微孔的。通过电子光谱法对粉末状整体（形态、聚集、浓度）中的 PS 进行了表征，该方法也被证明是监测辐照后材料演变的有用工具。这些纳米多孔干凝胶被用作微反应器，用于使用可见光和空气作为唯一反应物，对二甲基硫（DMS）进行气固无溶剂光氧化。所有这些含有整体的 PS 都能有效地进行气固 DMS 氧化，导致亚砜和砜以不同的比例生成。由于这些极性氧化产物仍强烈吸附在硅胶基质上，因此反应器出口处的气体流完全不含硫和气味。在 DBTP 含量的干凝胶中，以产率和 DMS 初始降解速率为衡量标准，得到了最佳结果。此外，由于这些材料在洗涤再生步骤后可以重复使用而不会损失效率和敏化剂光漂白，因此批准了可回收敏化材料的概念，为绿色工艺开辟了道路。
