凹凸棒石与酸反应纳米尺度研究——反应机理和表面积变化

凹凸棒石与酸反应纳米尺度研究——反应机理和表面积变化

陈天虎1, 徐惠芳2, 彭书传1, 汪家权1, 徐晓春1

1. 合肥工业大学资源与环境工程学院，合肥 230009; 2. 美国新墨西哥大学地球与行星科学系， USANM 87131

收稿日期:2004-03-20 修回日期:2004-03-20 出版日期:2004-03-20 发布日期:2004-03-20

Nanometer Scale Study on Reaction of Palygorskite with Acid: Reaction Mechanism and Change of Specific Surface Area

CHEN Tian-hu1, XU Hui-fang2, PENG Shu-chuan1, WANG Jia-quan1, XU Xiao-chun1

1. College of Resources and Environment Engineering, Hefei University of Technology, Hefei 230009, China; 2. Department of Earth and Planetary Sciences, University of New Mexico, NM 87131, USA

Received:2004-03-20 Revised:2004-03-20 Online:2004-03-20 Published:2004-03-20

摘要/Abstract

摘要： 利用高分辨透射电子显微镜(HRTEM)和BET-比表面积分析(BET-SSA)技术调查了沉积型凹凸棒石与酸作用过程中形态和比表面积变化，并探讨了凹凸棒石与酸反应机理。对不同条件下凹凸棒石与酸反应产物纳米尺度观察表明，凹凸棒石的酸溶反应既表现出棒状晶体端部四面体和八面体一致溶解，也表现出柱面位置四面体和八面体不一致溶解。纳米尺度观察揭示出凹凸棒石与酸反应机制是质子从外表面扩散渗透，而不是质子从晶体孔道的渗透，反应速率主要受穿过酸溶产物硅酸层扩散速率控制。凹凸棒石的酸溶反应过程中，酸处理凹凸棒石的纳米孔结构现象与柱面位置四面体硅局部溶蚀有关。酸处理凹凸棒石比表面积增加归因于凹凸棒石中八面体不均匀、不连续溶解和局部四面体硅的溶蚀导致凹凸棒石孔道开放和直径扩大，从而使N2分子更多的进入凹凸棒石的孔道。部分八面体残留对四面体片起支撑作用，当凹凸棒石中八面体阳离子近于完全溶解时，四面体片失去支撑，结构塌陷，内孔孔道消失，比表面积再度下降。

Abstract: morphology and specific surface area (SSA)for n1e products after acid treatment of palygorskite were investigated by TEM and BET-SSA and the reaction mechanism between palygorskite and acid was discussed. The results indicate that the reaction between palygorskite and acid be longs to a reaction of proton diffusion from exterior surface rather than from channels. The rate of reaction is controlled by diffusion through the file of silicon acid which is formed by the reaction. The reaction yields concurrent dissolution of tetrahedron and octahedron cations from two ends of the palygorskite crystals and variant dissolution of the tetrahedron and octahedron cations from the columns. The mesoporous structure of palygorskite after acid treatment is caused by the partial dissolution of tetrahedral silicon from the columns. SSA increase of palygorskite is resulted from asymmetrical and discontinuous dissolution of octahedral cations and local dissolution of tetrahedral silicon, which results in opening of channels and enlargement of aperture diameter.

陈天虎, 徐惠芳, 彭书传, 汪家权, 徐晓春. 凹凸棒石与酸反应纳米尺度研究——反应机理和表面积变化[J]. J4.

CHEN Tian-hu1, XU Hui-fang2, PENG Shu-chuan1, WANG Jia-quan1, XU Xiao-chun1. Nanometer Scale Study on Reaction of Palygorskite with Acid: Reaction Mechanism and Change of Specific Surface Area[J]. J4.