Study on synthesis and adsorption performance of hydrophobic ZSM-5 zeolites for removal of toluene in high-humidity exhaust gas

doi:10.11949/0438-1157.20191253

Abstract

Abstract:

ZSM-5 zeolites with different Si/Al ratios were synthesized by hydrothermal in situ method. The effect of Si/Al ratio on the structure and hydrophobicity of ZSM-5 was studied. The adsorption performance of ZSM-5 zeolites for toluene was investigated on a dynamic adsorption experimental device, and the adsorption isotherm equation of toluene on hydrophobic ZSM-5 was studied. The results show that the high-silicon ZSM-5 has good hydrophobicity, and its static water adsorption capacity is 0.014 g·g^-1. Under high humidity conditions, the toluene concentration of 1800 mg·m^-3, the GHSV of 25000 ml·h^-1·g^-1and the temperature of 35℃, the breakthrough adsorption capacity of the synthesized ZSM-5 for toluene is 0.041 g·g^-1, and the toluene saturated adsorption capacity is 0.075 g·g^-1. The fitting of the adsorption isotherm showed that the adsorption of toluene on the hydrophobic ZSM-5 zeolites was in accordance with the Langmuir-Freundlich model.

Key words: hydrophobic, ZSM-5, hydrothermal in situ, toluene, adsorption isotherm

摘要：

采用水热原位法合成了不同硅铝比的ZSM-5分子筛，研究了硅铝比对ZSM-5分子筛结构和疏水性的影响。以典型的挥发性有机物甲苯为对象，在动态吸附实验装置上评价了ZSM-5分子筛吸附有机物的性能，并拟合了甲苯在疏水ZSM-5上的吸附等温线方程。结果表明，高硅铝比ZSM-5具有良好的疏水性，其静态水吸附容量为0.014 g·g^-1，在高湿度条件下，甲苯浓度为1800 mg·m^-3，GHSV为25000 ml·h^-1·g^-1，温度为35℃，甲苯穿透吸附容量为0.041 g·g^-1，甲苯饱和吸附容量为0.075 g·g^-1。吸附等温线的拟合显示，甲苯在疏水ZSM-5分子筛上的吸附符合Langmuir-Freundlich复合模型。

关键词: 疏水, ZSM-5, 水热原位法, 甲苯, 吸附等温线

CLC Number:

X 511

Jun an GAO, Wei WANG, Jie ZHANG, Zhigang LEI, Dongjun SHI, Lingduo QU. Study on synthesis and adsorption performance of hydrophobic ZSM-5 zeolites for removal of toluene in high-humidity exhaust gas[J]. CIESC Journal, 2020, 71(1): 337-343.

高君安, 王伟, 张傑, 雷志刚, 史东军, 曲令多. 用于高湿度废气中甲苯吸附净化的疏水型ZSM-5分子筛的合成及其吸附性能研究[J]. 化工学报, 2020, 71(1): 337-343.

Figures/Tables 9

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样品	RH=0			RH=60%
样品	q _甲苯/(g·g^-1)	穿透时间/min	穿透吸附量/(g·g^-1)	q _甲苯/(g·g^-1)	q _水/(g·g^-1)	穿透时间/min	穿透吸附量/(g·g^-1)
ZSM-5-50	0.058	46	0.016	0.011	0.037	28	0.008
ZSM-5（300）	0.071	76	0.031	0.069	0.001	71	0.029
ZSM-5（500）	0.077	82	0.042	0.075	0.001	79	0.041

样品	RH=0			RH=60%
样品	q _甲苯/(g·g^-1)	穿透时间/min	穿透吸附量/(g·g^-1)	q _甲苯/(g·g^-1)	q _水/(g·g^-1)	穿透时间/min	穿透吸附量/(g·g^-1)
ZSM-5-50	0.058	46	0.016	0.011	0.037	28	0.008
ZSM-5（300）	0.071	76	0.031	0.069	0.001	71	0.029
ZSM-5（500）	0.077	82	0.042	0.075	0.001	79	0.041

样品	S _BET/(m²·g^-1)	S _micro/(m²·g^-1)	平均孔径/nm	相对结晶度/%	实际硅铝比	投料转化率/%
ZSM-5-50	377.4	102.1	1.94	100	50	—
ZSM-5(100)	377.1	110.3	1.96	98	66.7	66.7
ZSM-5(300)	384.9	142.8	2.32	110	225	75.3
ZSM-5(500)	379.6	149.2	2.36	103	356	71.2
ZSM-5(800)	368.2	98.7	2.12	78.1	435	54.3
ZSM-5(1000)	364.7	97.1	2.11	76.3	538	53.8

样品	S _BET/(m²·g^-1)	S _micro/(m²·g^-1)	平均孔径/nm	相对结晶度/%	实际硅铝比	投料转化率/%
ZSM-5-50	377.4	102.1	1.94	100	50	—
ZSM-5(100)	377.1	110.3	1.96	98	66.7	66.7
ZSM-5(300)	384.9	142.8	2.32	110	225	75.3
ZSM-5(500)	379.6	149.2	2.36	103	356	71.2
ZSM-5(800)	368.2	98.7	2.12	78.1	435	54.3
ZSM-5(1000)	364.7	97.1	2.11	76.3	538	53.8

ZSM-5	Langmuir			Freundlich			Langmuir-Freundlich
ZSM-5	q _m/(mg·g^-1)	K _L×10⁵	R ²	n	K _F	R ²	q _m/(mg·g^-1)	K _a×10^-5	n	R ²
ZSM-5(300)	185.3	5.431	0.971	1.812	0.415	0.972	303.5	1.672	0.711	0.975
ZSM-5(500)	156.9	8.313	0.973	2.136	0.818	0.951	154.6	154.8	7.868	0.979