一种二价季铵盐在粘土矿物上的吸附

研究了一种不显著降低界面张力的二价季铵盐化合物(MD膜驱剂)在粘土矿物上的吸附. 选取蒙脱土(Su-M)和膨润土(B)两种粘土矿物作为研究对象，其阳离子交换容量(CEC)分别为0.44和0.88 mmol•g^-1. 研究结果表明，MD膜驱剂在低的加入浓度下，MD膜驱剂分子在两种粘土矿物上能全部被吸附，此外，其在Su-M上的饱和吸附量达到100% CECSu-M，而在B上仅为77%CECB. MD膜驱剂只能吸附在粘土矿物的负电荷点上，而不能吸附在单元层外表面的Si-OH中性点上. XRD数据显示，随MD膜驱剂添加浓度的增大，两种粘土矿物的干态层间距略有减小，并根据分子的理论空间尺寸，认为MD膜驱剂在粘土层间只能以单层平卧方式排列.

Adsorption of a Divalent Quaternary Ammonium Cation on Clay Mineral

Adsorption of a divalent quaternary ammonium named molecular deposition film flooding agent (MDFFA) on clay was studied. It is characterized by its surface non-activity. Two source clays were selected： montmorillonite (Su-M) and bentonite (B), and their cation exchange capacities (CEC) are 0.44 and 0.88 mmol•g^-1 clay, respectively. At low ionic strength, all cations were completely adsorbed on the clay. Besides, the absorbed amounts of MDFFA on Su-M reach 100% of the CEC, while the absorbed amounts of MDFFA on B only reach 77% of the CEC. From FT-IR spectra, we deduced that the MDFFA only binds to the electronegative adsorption sites and does not bind to the external Si－OH groups which act as neutral adsorption sites. XRD data show that the basal spacings of the two kinds of clay decreased slightly with added amount of MDFFA. Based on the theoretical size of molecules, we think that only horizontal monolayer of MDFFA exists in clay interlayer.