Sidaraite Ramune, Baltakys Kestutis, Jaskunas Andrius, Naslenas Nedas, Slavinskas Darius, Slavinskas Edvinas, Dambrauskas Tadas
Department of Silicate Technology, Kaunas University of Technology, Radvilenu 19, LT-50270 Kaunas, Lithuania.
Department of Physical and Inorganic Chemistry, Kaunas University of Technology, Radvilenu 19, LT-50270 Kaunas, Lithuania.
Materials (Basel). 2024 Jul 14;17(14):3489. doi: 10.3390/ma17143489.
Volatile organic compounds (VOCs) are pollutants that pose significant health and environmental risks, necessitating effective mitigation strategies. Catalytic oxidation emerges as a viable method for converting VOCs into non-toxic end products. This study focuses on synthesizing a catalyst based on calcium silicate hydrates with chromium ions in the CaO-SiO-Cr(NO)-HO system under hydrothermal conditions and evaluating its thermal stability and catalytic performance. A catalyst with varying concentrations of chromium ions (10, 25, 50, 100 mg/g Cr) was synthesized in unstirred suspensions under saturated steam pressure at a temperature of 220 °C. Isothermal curing durations were 8 h, 16 h, and 48 h. Results of X-ray diffraction and atomic absorption spectroscopy showed that hydrothermal synthesis is effective for incorporating up to 100 mg/g Cr into calcium silicate hydrates. The catalyst with Cr ions (50 mg/g) remained stable up to 550 °C, beyond which chromatite was formed. Catalytic oxidation experiments with propanol and propyl acetate revealed that the Cr catalyst supported on calcium silicate hydrates enhances oxygen exchange during the heterogeneous oxidation process. Kinetic calculations indicated that the synthesized catalyst is active, with an activation energy lower than 65 kJ/mol. This study highlights the potential of Cr-intercalated calcium silicate hydrates as efficient catalysts for VOC oxidation.
挥发性有机化合物（VOCs）是对健康和环境构成重大风险的污染物，因此需要有效的缓解策略。催化氧化是一种将VOCs转化为无毒终产物的可行方法。本研究聚焦于在水热条件下，在CaO-SiO-Cr(NO)-H₂O体系中合成一种含铬离子的硅酸钙水合物催化剂，并评估其热稳定性和催化性能。在220℃的饱和蒸汽压力下，于未搅拌的悬浮液中合成了具有不同铬离子浓度（10、25、50、100mg/g Cr）的催化剂。等温养护时间分别为8小时、16小时和48小时。X射线衍射和原子吸收光谱结果表明，水热合成对于将高达100mg/g的Cr掺入硅酸钙水合物是有效的。含50mg/g Cr离子的催化剂在550℃以下保持稳定，超过该温度则形成铬铁矿。用丙醇和乙酸丙酯进行的催化氧化实验表明，负载在硅酸钙水合物上的Cr催化剂在多相氧化过程中增强了氧交换。动力学计算表明，合成的催化剂具有活性，其活化能低于65kJ/mol。本研究突出了铬插层硅酸钙水合物作为VOC氧化高效催化剂的潜力。
