大孔钙铝石块体材料的制备及表征

doi:10.15541/jim20140323

摘要/Abstract

摘要：

以无机盐二水氯化钙(CaCl₂·2H₂O)和六水氯化铝(AlCl₃·6H₂O)为原料, 1,2-环氧丙烷(PO)为凝胶促进剂, 粘均分子量M_w= 100000的聚氧化乙烯(PEO)为相分离诱导剂, 乙二醇为络合剂, 甲酰胺为干燥控制化学添加剂(DCCA), 采用溶胶-凝胶伴随相分离制备了大孔钙铝石块体。利用扫描电镜(SEM)、压汞、X射线衍射(XRD)等测试技术对所得的块体进行了表征。结果表明: 加入PEO能诱导体系发生相分离; PEO用量和溶剂中醇水比会对多孔结构产生明显影响; 在合适凝胶温度下, 当加入适量PEO和溶剂时, 可以获得共连续大孔结构的钙铝石块体; 1000℃热处理后, 干凝胶由无定型转变为钙铝石晶型Ca₁₂Al₁₄O₃₂Cl₂, 块体的共连续大孔结构在热处理后被完整保留, 其大孔孔径分布在1~2 μm, 孔隙率为73.0%; 热处理前后的钙铝石块体均能保持光滑且致密的骨架。

关键词: 大孔块体, 钙铝石, 溶胶-凝胶, 相分离

Abstract:

Macroporous mayenite monoliths were successfully prepared via Sol-Gel process accompanied by phase separation using calcium chloride dihydrate and aluminum chloride hexahydrate as raw materials, propylene oxide (PO) as a gelation agent, and poly (ethylene oxide) with average molecular weight of 100,000 as a phase separation inducer. In addition, glycol was used as a chelating agent and formamide as a drying control chemical additive. Macroporous monoliths were characterized by scanning electron microscope(SEM), mercury porosimetry, and X-ray diffraction (XRD). The result shows that the addition of PEO induces phase separation; the amount of PEO and the ratio of ethanol to water have an important effect on porous structure, and monolithic mayenite with co-continuous marcoporous structure is obtained at appropriate addition of PEO and solvent as well as gelation temperature. The dried gels are amorphous, and transform to Ca₁₂Al₁₄O₃₂Cl₂ after heat-treatment at 1000℃ in air, while the co-continuous macropores are retained. The monolith after heat-treatment has narrow pore size distribution of 1-2 μm and porosity of 73.0%. The monoliths before and after heat-treatment possess smooth and dense skeletons.

Key words: macroporous monolith, mayenite, Sol-Gel, phase separation

中图分类号:

TQ174

郭兴忠, 蔡晓波, 宋杰, 杨辉. 大孔钙铝石块体材料的制备及表征[J]. 无机材料学报, 2015, 30(2): 141-146.

GUO Xing-Zhong, CAI Xiao-Bo, SONG Jie, YANG Hui. Preparation and Characterization of Macroporous Mayenite Monoliths[J]. Journal of Inorganic Materials, 2015, 30(2): 141-146.

图/表 8

表1 试样的原料组成

Table 1 Starting compositions of samples

	(CaCl₂/AlCl₃) /(g·g^-1)	(EtOH/H₂O) /(mL·mL^-1)	EG^a /mL	FA^b /mL	PO^c /mL	PEO^d /g
CA01	1.044 / 2.000	3.00 / 3.00	0.40	0.50	1.50	0
CA02	1.044 / 2.000	3.00 / 3.00	0.40	0.50	1.50	0.100
CA03	1.044 / 2.000	3.00 / 3.00	0.40	0.50	1.50	0.200
CA04	1.044 / 2.000	3.00 / 3.00	0.40	0.50	1.50	0.400
CA05	1.044 / 2.000	3.50 / 2.50	0.40	0.50	1.50	0.200
CA06	1.044 / 2.000	4.00 / 2.00	0.40	0.50	1.50	0.200
CA07	1.044 / 2.000	2.50 / 3.50	0.40	0.50	1.50	0.200
CA08	1.044 / 2.000	2.00 / 4.00	0.40	0.50	1.50	0.200

图1 不同PEO用量制备的钙铝石干凝胶的SEM照片

Fig. 1 SEM images of gels prepared with varied WPEO (a) 0; (b) 0.100 g; (c) 0.200 g; (d) 0.400 g

图2 醇水比较高时制备的钙铝石干凝胶的SEM照片

Fig. 2 SEM images of dried gels prepared with high volume ratios of ethanol to water (a) 1/1, (b) 7/5, (c) 2/1. Time inserted each image indicates the length of gelation time

图3 醇水比较低时制备的钙铝石干凝胶的SEM照片

Fig. 3 SEM images of dried gels prepared with low volume ratios of ethanol to water (a) 1/1, (b) 5/7, (c) 1/2. Time inserted each image indicates the length of gelation time

图4 不同凝胶温度得到的钙铝石干凝胶的SEM照片

Fig. 4 SEM images of dried gels prepared at different gelation temperatures (a) 20℃; (b) 40℃; (c) 60℃; (d) 80℃

图5 钙铝石试样CA03在1000℃热处理前后的XRD图谱

Fig. 5 XRD patterns of sample CA03 before and after heat-treated at 1000℃

图6 试样CA03热处理前(a)和1000℃热处理后(b)的宏观形貌和(c)热处理后的SEM照片

Fig. 6 Appearance of sample CA03 (a) before and (b) after heat-treatment at 1000℃; (c) SEM image of sample CA03 after heat-treatment at 1000℃

图7 热处理前后试样CA03的大孔孔径分布

Fig. 7 Macropore size distribution of sample CA03 before and after heat-treatment at 1000℃

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