Jacobs KY, Schoonheydt RA
Department of Interphase Chemistry, Katholieke Universiteit Leuven, Kardinal Mercierlaan 92, Heverlee, B-3001, Belgium
J Colloid Interface Sci. 1999 Dec 1;220(1):103-111. doi: 10.1006/jcis.1999.6513.
Aqueoussuspensions of different Na-smectite type clay minerals were exchanged with methylene blue (Mb) and analyzed by visible spectroscopy. The spectra show bands of two types of monomers, protonated Mb, Mb-dimers, and higher aggregates. Their relative importance and the bandwidth was found to depend on parameters such as the particle morphology, the degree of dispersion, and the extent and location of the layer charge of the smectite. This can be qualitatively explained by the relative importance of three types of interactions, Mb-surface, H(2)O-surface, and Mb-Mb interactions. For hectorite and laponite at small loadings, H(2)O-surface interactions are dominant. Mb-islands are formed with a characteristic monomer absorption at 653 nm. Monomers at the surface absorb at 670 nm as found in barasym and saponite. Wyoming bentonite takes an intermediate position. As the loading increases Mb-Mb and Mb-surface interactions become dominant, giving rise to monomers absorbing at 670 nm, dimers, and higher aggregates. The bandwidths of the absorption bands reflect the structure of the clay particle associates. Copyright 1999 Academic Press.
将不同的钠蒙脱石型粘土矿物水悬浮液与亚甲基蓝（Mb）进行交换，并通过可见光谱法进行分析。光谱显示了两种类型单体、质子化Mb、Mb二聚体和更高聚集体的谱带。发现它们的相对重要性和带宽取决于诸如颗粒形态、分散程度以及蒙脱石层电荷的程度和位置等参数。这可以通过三种类型相互作用（Mb-表面、H₂O-表面和Mb-Mb相互作用）的相对重要性进行定性解释。对于少量负载的锂蒙脱石和合成锂皂石，H₂O-表面相互作用占主导。形成了Mb岛，在653 nm处有特征性单体吸收。如在绿脱石和皂石中发现的那样，表面的单体在670 nm处吸收。怀俄明膨润土处于中间位置。随着负载增加，Mb-Mb和Mb-表面相互作用占主导，产生在670 nm处吸收的单体、二聚体和更高聚集体。吸收带的带宽反映了粘土颗粒缔合体的结构。版权所有1999年学术出版社。
