Effect of fly ash/silica fume ratio and curing condition on mechanical properties of fiber-reinforced geopolymer
บทความในวารสาร
ผู้เขียน/บรรณาธิการ
กลุ่มสาขาการวิจัยเชิงกลยุทธ์
รายละเอียดสำหรับงานพิมพ์
รายชื่อผู้แต่ง: Sukontasukkul P., Chindaprasirt P., Pongsopha P., Phoo-Ngernkham T., Tangchirapat W., Banthia N.
ผู้เผยแพร่: Elsevier
ปีที่เผยแพร่ (ค.ศ.): 2020
วารสาร: Applied Clay Science (0169-1317)
Volume number: 9
Issue number: 4
หน้าแรก: 218
หน้าสุดท้าย: 232
จำนวนหน้า: 15
นอก: 0169-1317
eISSN: 1872-9053
ภาษา: English-Great Britain (EN-GB)
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บทคัดย่อ
In this study, a magnesium (Mg) and aluminum (Al) layered double hydroxide (LDH) was used as a precursor in the preparation of calcium (Ca), Mg and Al ternary mixed oxides for selective conversion of glycerol into diglycerols via solvent-free glycerol etherification. The LDH-derived MgAl mixed oxide was saturated with an aqueous solution of Ca citrate complexes, followed by calcination at 700 °C, to obtain the Ca-MgAl mixed metal oxide (MMO) catalysts. The effects of the citric acid addition and Ca loading levels on the physicochemical and catalytic properties of the resulting Ca-MgAl MMO were investigated. The Ca-MgAl MMO series were characterized by a high Ca dispersion, high total basicity (236–482 μmol g −1 ), an enhanced amount of strong basic sites and a new mesoporosity. The highest diglycerols selectivity of 78.3 mol% was achieved at a glycerol conversion of 40.4 mol% when the reaction was performed over the Ca-MgAl MMO catalyst synthesized with a 7.5 wt% Ca loading level, at a 3 wt% catalyst loading, 220 °C for 24 h. The formation of ternary mixed oxides improved the structural stability of the pristine MgAl mixed oxide. The catalytic performance of Ca-MgAl MMO was compared with that of commercial MgAl mixed oxides and homogeneous base (Na 2 CO 3 ). The presence of strong basicity in the MMO catalysts was a key part in the selective synthesis of diglycerols. © 2019 Elsevier B.V.
คำสำคัญ
Ca–Mg–Al mixed oxides, Diglycerols, Etherification, Layered double hydroxides