School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Sci Total Environ. 2022 Jul 10;829:154540. doi: 10.1016/j.scitotenv.2022.154540. Epub 2022 Mar 14.
Conversion of food waste into valuable chemicals under mild conditions has attracted increasing attention. Herein, a series of nano-sized MgAl layered double hydroxides (LDHs) were firstly developed as solid base catalyst for the methyl lactate (MLA) production directly from glucose/food waste. Glucose, which could be easily obtained from cellulose or starch-rich food waste via hydrolysis, was thus selected as the model compound. It is inspiring to find that the metal hydroxide layer in prepared LDHs was highly stable and suitable enlarged interlayer distance was reconstructed owing to in-situ intercalation of formed aromatics during the reaction, which was demonstrated by Al magic angle spinning nuclear magnetic resonance and time-of-flight secondary ion mass spectrometry analysis. As a result, in-situ activation of the catalysts along with gradually enhanced catalytic activity was obtained in the recycling runs and the highest MLA yield of 47.6% from glucose was achieved over LDHs (5:1) after 5 runs at 150 °C. Most importantly, the scope was further extended to other typical substrates (e.g. Chinese cabbage and rice) and the results demonstrated the effectiveness of present conversion system for real food waste.
在温和条件下将食物垃圾转化为有价值的化学品引起了越来越多的关注。在此，首次开发了一系列纳米级 MgAl 层状双氢氧化物（LDHs）作为固体碱催化剂，可直接从葡萄糖/食物垃圾生产乳酸甲酯（MLA）。葡萄糖可通过水解作用从富含纤维素或淀粉的食物垃圾中轻易获得，因此被选为模型化合物。令人鼓舞的是，发现在反应过程中形成的芳烃原位插层会使制备的 LDHs 中的氢氧化物层高度稳定，并适合重建较大的层间距离，这通过 Al 魔角旋转核磁共振和飞行时间二次离子质谱分析得到了证实。结果，在回收利用过程中，催化剂得到了原位活化，并且在 150°C 下经过 5 次循环后，LDHs（5:1）的催化活性逐渐增强，可从葡萄糖获得最高 47.6%的 MLA 产率。最重要的是，该方法的适用范围进一步扩展到了其他典型的底物（如白菜和大米），结果表明了本转化体系对于实际食物垃圾的有效性。
