Hualei Hu,Jinghui Lyu,Jie Cen,Qunfeng Zhang,Qingtao Wang,Wenwen Han,Jiayao Rui,Xiaonian Li
The effect of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for benzene alkylation with methanol was investigated. The results indicated that the introduction of MgO could reduce the Brönsted acid sites which suppressed the side reaction of methanol to olefins and in turn effectively promoted the alkylation of benzene. However, the single modification of MgO could not completely suppress the formation of ethylbenzene and coke. Doping a small amount of Pd had a positive effect on inhibiting the generation of ethylbenzene and coke, which could be attributed to the hydrogenation of ethylene into ethane on Pd. The dual modified catalyst (MgO and Pd) exhibited high benzene conversion (56%) and xylene selectivity (39.1%), and the lowest ethylbenzene selectivity (0.13%) and coke content (0.4 wt%).
Fu Yang,Wenhao Li,Xiu Zhong,Wenlong Tu,Jie Cheng,Lei Chen,Jun Lu,Aihua Yuan,Jianming Pan
The adsorption separation of volatile organic compounds affords an efficient potential solution to address VOC emission. In this work, we reported alkaline sites-modified biomass-carbon adsorbents through in situ implanting MgO for reinforcing the adsorption abatement of polar VOCs. We revealed that the dispersed MgO alkaline sites in situ formed over the activated carbon during the KOH activation process by placing the magnesium acetate and KOH into grapefruit peel-based biochar together, which avoids the repeated postmodification. By tuning the mass proportion of Mg precursor and KOH activator, the optimized loading of magnesium oxide in AC was explored and compared with the MgO post-modified AC using a two-step procedure. The physicochemical properties of MgO-modified AC were characterized by various techniques. Impressively, MgO occupied a higher surface formation ratio (82.6%) in whole Mg species of the in-situ synthesized 10MgO/C compared to that (51.4%) in postimpregnated 10MgO/C-P. The adsorption properties of polar acetic acid and nonpolar benzene over the above comparative adsorbents were systematically studied by the gas-static adsorption method. The results revealed that the optimal sample of 10MgO/C afforded excellent structural properties (S BET = 2646 m 2 g −1 , V total = 1.59 cm 3 g −1 ) and a large adsorption capacity of polar acetic acid reaching 16.64 mmol g −1 at 30 °C. More importantly, compared to unmodified and nitrogen-doped AC, 10MgO/C showed improved acetic acid adsorption capacity, reversible desorption behavior, and lower adsorption heat. The calculation of Ideal Adsorption Solution Theory (IAST) for selective adsorption separation of the CH 3 COOH/C 6 H 6 binary mixture(50/50) over 10MgO/C showed the highest selectivity (3.42). This work offers new insight into the in-situ modification of AC and polar VOCs selective adsorption separation.
Sier Sang,Zhi-Jian Zhao,Hao Tian,Zhao Sun,Hongfang Li,Suttichai Assabumrungrat,Tahir Muhammad,Liang Zeng,Jinlong Gong
This article describes the design and synthesis of MgO-modified Ni/CaO catalysts for sorption-enhanced steam reforming of ethanol. The results show that the introduction of MgO effectively increases the dispersion of CaO via forming MgCa(CO 3 ) 2 precursor. In the prepared MgO-modified Ni/CaO catalysts, metallic Ni exists around MgO supported on CaO. Both 100% ethanol conversion and >96% hydrogen purity can be stabilized in 10 cycles over the catalyst containing 20 wt% MgO. The interaction between metallic Ni and MgO enhances the sintering resistance of the catalyst. More importantly, reaction pathway studies have confirmed that the formation of CaCO 3 hinders the activation of H 2 O on the Ni/CaO catalyst surface, and thus inhibits the conversion of the reaction intermediates including HCO* and CH x *. MgO can dissociate H 2 O to form hydroxyl groups which participate in the conversion of the reaction intermediates, thereby the MgO-modified Ni/CaO catalysts have better catalytic performance and carbon deposition resistance.
危险品化学品经营许可证（带存储）