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Effective adsorption of sodium dodecylsulfate (SDS) by hydrocalumite (CaAl-LDH-Cl) induced by self-dissolution and re-precipitation mechanism

Zhang, Ping, Qian, Guangren, Xu, Zhi Ping, Shi, Huisheng, Ruan, Xiuxiu, Yang, Jing, Frost, Ray L.
Journal of colloid and interface science 2012 v.367 no.1 pp. 264-271
Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, adsorption, aluminum, calcium, calcium chloride, ions, rehydration, scanning electron microscopy, sodium dodecyl sulfate, sorption isotherms, transmission electron microscopes, transmission electron microscopy
Hydrocalumite (CaAl-LDH-Cl) was synthesized through a rehydration method involving a freshly prepared tricalcium aluminate (C₃A) with CaCl₂ solution. To understand the intercalation behavior of sodium dodecylsulfate (SDS) with CaAl-LDH-Cl, X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectrometer (ICP), and elemental analysis have been undertaken. The sorption isotherms with SDS reveal that the maximum sorption amount of SDS by CaAl-LDH-Cl could reach 3.67mmolg⁻¹. The results revealed that CaAl-LDH-Cl holds a self-dissolution property, about 20–30% of which is dissolved. And the dissolved Ca²⁺ and Al³⁺ ions are combined with SDS to form CaAl-SDS or Ca-SDS precipitation. It has been highlighted that the composition of resulting products is strongly dependent upon the SDS concentration. With increasing SDS concentrations, the main resulting product changes from CaAl-SDS to Ca-SDS, and the value of interlayer spacing increased to 3.27nm.