Elbayoumy Elsayed, El-Bindary Ashraf A, Nakano Tamaki, Aboelnga Mohamed M
Chemistry Department, Faculty of Science, Damietta University, New Damietta, 34517, Egypt.
Institute for Catalysis and Graduate School of Chemical Sciences and Engineering, Hokkaido University, N21 W10, Kita-ku, Sapporo, 001-0021, Japan.
Sci Rep. 2025 Jan 3;15(1):717. doi: 10.1038/s41598-024-82183-3.
The removal of toxic nitrophenols from the industrial wastewater is urgently needed from health, environmental and economic aspects. The present study deals with the synthesis of crosslinked vinyl polymer Poly(divinylbenzene) (poly(DVB)) through free radical polymerization technique using AIBN as initiator and acetonitrile as solvent. The prepared polymer was used as a support for silver nanoparticles via chemical reduction of silver nitrate on the polymer network. The prepared poly(DVB) and Ag/poly(DVB) composite were characterized by different techniques including Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brunauer Emmett-Teller (BET) analysis. The results exhibit that silver metal was well distributed on the surface of poly(DVB) without any aggregation as a nanocrystals with an average size 13 nm. Also, BET analysis confirm that Ag/poly(DVB) composite is a meso porous material with a surface area 127.428 m²/g. This composite was also applied as a heterogenous catalyst for the reduction of toxic nitrophenol in the industrial wastewater into a less toxic aminophenol with the aid of NaBH as reductant. In addition, Ag/poly(DVB) catalyst regards as one of the most active catalyst that exhibits an advantage over the other catalysts showing similar activities in the aspects that it can be more readily prepared than the competitors and that it works at the lowest concentration of NaBH. Interestingly, DFT calculations were conducted to provide atomistic insights into the reduction mechanism and a detailed catalytic pathway have been proposed. Furthermore, the reusability experiment confirm that Ag/poly(DVB) was stable and can be removed from the reaction mixture by centrifuge and reused for four successive cycles with a slight decrease in their catalytic activity.
从健康、环境和经济角度来看，迫切需要从工业废水中去除有毒的硝基酚。本研究涉及通过自由基聚合技术，以偶氮二异丁腈（AIBN）为引发剂、乙腈为溶剂，合成交联乙烯基聚合物聚二乙烯基苯（聚（DVB））。通过在聚合物网络上化学还原硝酸银，将制备的聚合物用作银纳米颗粒的载体。采用傅里叶变换红外（FTIR）光谱、热重分析（TGA）、透射电子显微镜（TEM）、X射线衍射（XRD）和布鲁诺尔-埃米特-泰勒（BET）分析等不同技术对制备的聚（DVB）和Ag/聚（DVB）复合材料进行了表征。结果表明，银金属以平均尺寸为13nm的纳米晶体形式均匀分布在聚（DVB）表面，无任何聚集现象。此外，BET分析证实Ag/聚（DVB）复合材料是一种介孔材料，比表面积为127.428m²/g。该复合材料还用作多相催化剂，在硼氢化钠作为还原剂的辅助下，将工业废水中有毒的硝基酚还原为毒性较小的氨基酚。此外，Ag/聚（DVB）催化剂被认为是最具活性的催化剂之一，与其他具有相似活性的催化剂相比，它具有优势，因为它比竞争对手更容易制备，并且在硼氢化钠浓度最低的情况下仍能发挥作用。有趣的是，进行了密度泛函理论（DFT）计算，以提供对还原机理的原子层面见解，并提出了详细的催化途径。此外，可重复使用性实验证实，Ag/聚（DVB）是稳定的，可以通过离心从反应混合物中分离出来，并连续重复使用四个循环，其催化活性略有下降。
