酸/热处理对海泡石吸附甲醛的影响及其机理分析  

Study on Effects of Acid Modification or Heat Treatment on Formaldehyde Adsorption of Sepiolite in Air and the Related Mechanisms

作　　者：梁凯[1] 罗莹华[2] 彭美勋 赵宏伟 LIANG Kai;LUO Yinghua;PENG Meixun;ZHAO Hongwei(School of Chemistry and Civil Engineering, Shaoguan College, Shaoguan 512000, Guangdong, China;School of Tourism and Geography, Shaoguan College, Shaoguan 512000, Guangdong, China;School of Material Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, Hunan, China)

机构地区：[1]韶关学院化学与土木工程学院,广东韶关512005 [2]韶关学院旅游与地理学院,广东韶关512005 [3]湖南科技大学材料科学与工程学院,湖南湘潭411201

出　　处：《矿产保护与利用》2022年第2期120-125,共6页Conservation and Utilization of Mineral Resources

基　　金：国家自然科学基金(22008060);广东省科技计划项目(2017A010103028);湖南省自然科学基金(2020JJ5196)。

摘　　要：为再生海泡石的甲醛吸附能力,分别对经质量分数15%盐酸于60℃搅拌8.5 h和于100~600℃热处理5 h的海泡石进行甲醛静态吸附研究,并结合X射线衍射、红外吸收光谱、热重、BET比表面积和扫描电镜分析研究吸附机理。结果表明:经≤450℃热处理的海泡石基本保持良好的甲醛吸附性能,但酸处理和≥500℃热处理均显著降低海泡石的甲醛吸附性能。推测海泡石相的结晶水对甲醛形成化学吸附,而其沸石孔洞为主的结构微孔有利于物理吸附的甲醛占位。酸处理使海泡石中大量的Al^(3+)和Mg^(2+)被H^(+)取代,使原本与Mg^(2+)结合的结晶水脱失,结构层拆解,其微孔面积则因结构微孔坍塌而显著减少,从而严重降低其甲醛吸附量;而经≥500℃热处理后,海泡石相的全部结晶水不可逆脱出,全部结构微孔坍塌消失,甲醛吸附能力消失。该研究支持海泡石通过合理温度的热处理消除吸附的甲醛并再生吸附功能持续去除空气中的甲醛。In order to regenerate HCHO adsorption,both types of sepiolite stirred at 15%HCl for 8.5 h or heated at 100~600℃for 5 h were applied to static adsorption experiments in high concentration HCHO to research the HCHO adsorption effects,and X-ray diffraction,infrared adsorption spectroscopy,thermogravimetry,BET specific surface area analysis and scanning electronic microscopy were adopted to research the adsorption mechanisms.The results revealed that the sepiolite heated at≤450℃held favorable HCHO adsorption capacities,while those modified by acid or heated at≥500℃had significantly reduced HCHO adsorption capacities.It is inferred that the crystalliferous water in sepiolite could chemically absorb HCHO and the structural microhole,basically composed of zeolite holes,could be occupied by HCHO through physical adsorption.Subjected to acid modification,large part of Al^(3+) and Mg^(2+) in the sepiolite structure were replaced by H^(+),then the crystalliferous water bonded with Mg^(2+) lost and the structural layers were dismantled.The micropore area significantly reduced due to the structural microhole collapsed,and the HCHO absorption capacity drastically declined.The sepiolite heated at≥500℃lost its HCHO adsorption ability for the sepiolite phase was decomposed with the crystalliferous water completely lost and the structural microhole collapsed also.The research affirmed continuously removing HCHO in the air with sepiolite by heating at reasonable temperature that could not only eliminate the absorbed HCHO and regenerate the adsorption capacity.

关 键 词：海泡石 甲醛吸附 热处理 酸化 吸附机理 

分 类 号：TD985[矿业工程—选矿] TQ424[化学工程]