Studies of Surface Acidity and Basicity of the Attapulgite

Abstract

Abstract: Attapulgite with the composition of [MgAlFe]₅Si₈O₂₀(OH)₂(OH)₂(OH₂)₄₄H₂Ohas beenwidely used as catalyst or catalyst support in various catalytic reactions.The surface acidityand basicity of attapulgite should play an important role, in particular, in the acid/base cat-alyzed reactions.In this paper, a Tian-Calvet type microcalorimeter was used to measurequantitatively the number and strength of acid/base sites on the surface of attapulgite sam-ple.The acid/base properties of the sample were also investigated with infrared spectroscopyand test reaction of isopropanol dehydration.The results indicated that the attapulgite dis-played the acidity with initial differential NH₃ adsorption heat of 130kJ/mol and saturatedNHs coverge of 1.5 pmol/m².The strength distributions of surface acid sites on attapulgiteand the calorometric results suggested that the attapulgite possessed only a few(<0.1 μmol/m²) very weak base sites with CO₂ adsorption heat lower than 5kJ/mol.The infrared spec-troscopy revealed that the attapulgite had both Brdnsted and Lewis acid sites-Moreover, theLewis acid sites(1619 cm^-1 ) were stronger than 90kJ/mol characteric of the NH, adsorptionheat.In summary, the attapulgite was a weak solid acid without any basicity compared tothe γ-Al₂O₃。

Key words: Microcalorimetry, Attapulgite, Surface acidity and basicity

TrendMD:

WANG Qing-Gen, TU Mai, WANG Wei-Dong, SHEN Jian-Yi. Studies of Surface Acidity and Basicity of the Attapulgite[J]. Chem. J. Chinese Universities, 1997, 18(4): 625.

References

Related Articles 15

[1]	WU Shanshan,WEI Chanling,ZHAO Lijuan,TIAN Yang,WANG Xia,GONG Bolin. Preparation and Enrichment Properties of Novel Magnetic Restricted Access Media-molecularly Imprinted Composites^† [J]. Chem. J. Chinese Universities, 2019, 40(6): 1150.
[2]	QUAN Yao, BI Erping. Adsorption Characteristics of Different Forms of Ofloxacin to Attapulgite^† [J]. Chem. J. Chinese Universities, 2017, 38(4): 622.
[3]	LIU Zuojiao, FAN Gaochao, HE Liangming, DIAO Kaisheng, HUANG Zaiyin, TAN Xuecai. Temperature and Morphology Effect on Surface Thermodynamic Functions of Ag₃PO₄ Microcrystals^† [J]. Chem. J. Chinese Universities, 2015, 36(7): 1385.
[4]	LI Xu, JIANG Jianhong, HAN Buxing, GU Huiwen, XIE Zhaofeng, CHEN Lan, XIAO Shengxiong, LI Chuanhua, LI Aitao, LI Xia, YAO Feihong, WANG Qun, LI Qiangguo. Synthesis and Biological Activities of o-Vanillin-histidine Schiff-base and Its Lanthanum Complex^† [J]. Chem. J. Chinese Universities, 2015, 36(5): 856.
[5]	LIU Xiaolin, WANG Lude, HUANG Zaiyin, LIU Zuojiao, LI Xingxing. Thermodynamic Functions of Nano Zinc Oxide Acquired by Microcalorimetry and Electrochemical Methods^† [J]. Chem. J. Chinese Universities, 2015, 36(3): 539.
[6]	FAN Gaochao, MA Zhao, HUANG Zaiyin, TAN Xuecai, YAO Xianchao. Surface Thermodynamic Properties of Micro/nano Peanut-shaped CaMo $O 4 †$ [J]. Chem. J. Chinese Universities, 2014, 35(5): 1007.
[7]	JIA Zhaopeng, HU Xingen, FANG Guoyong. Enthaplic Pairwise Self-associations of Nicotinamide and Isonicotinamide in Aqueous KCl Solutions by Microcalorimetry^† [J]. Chem. J. Chinese Universities, 2014, 35(2): 384.
[8]	LIU Hao, XU Fen, SUN Li-Xian, CAO Zhong, ZHOU Huai-Ying. Preparation and Hydrogen Generation for Al-LiBH₄ Composite Materials [J]. Chem. J. Chinese Universities, 2013, 34(8): 1953.
[9]	MA Yu-Jie, FAN Gao-Chao, CHEN Jie, HUANG Zai-Yin. In situ Thermokinetic Investigation on the Growth of MnMoO₄稨₂O Nanorods [J]. Chem. J. Chinese Universities, 2012, 33(08): 1813.
[10]	FAN Gao-Chao, HUANG Zai-Yin*, JIANG Jun-Ying, LI Yan-Fen, SUN Li. Preparation and Standard Molar Formation Enthalpy of Weed-like ZnO Nanostructures [J]. Chem. J. Chinese Universities, 2011, 32(5): 1016.
[11]	YANG Li-Ni^1,2, SUN Li-Xian¹, XU Fen¹, ZHAO Zong-Bao³, LIANG Jian-Guo⁴. A Study of the Influence of Cephalosporins on the Microbial Activity of E.coli* by Microcalorimetry [J]. Chem. J. Chinese Universities, 2008, 29(7): 1412.
[12]	YANG Xu-Wei*, ZHANG Xiao-Feng, KAN Qiu-Bin, FU Wei, Huang Jia-Hui, WU Tong-Hao. Application of Microcalorimetric Technique to the Synthesis of NH₂-SBA-15 [J]. Chem. J. Chinese Universities, 2007, 28(6): 1147.
[13]	GAO Sheng-Li, FANG Yan, HU Rong-Zu, CHEN San-Ping, SHI Qi-Zhen . Crystallization Kinetics of Zn(Val)SO₄·H₂O in Mixed Solvent of Water with Acetone [J]. Chem. J. Chinese Universities, 2003, 24(3): 381.
[14]	LI Xi, LIU Yi, WU Jun, QU Song-Sheng. Microcalorimetric Study of the Associated Action of Selenium to Arsenic on the Growth of Escherichia coli [J]. Chem. J. Chinese Universities, 2003, 24(1): 91.
[15]	LI Li, ZHANG Jia-Min, HU Yuan-Yang, FENG Ying, QU Song-Sheng . Experimentation on Induction of Tumor Cell Apoptosis by Temperature and Anti-tumor Medicine [J]. Chem. J. Chinese Universities, 2002, 23(7): 1379.