Adsorption Characteristics of Anionic Surfactant Sodium Dodecylbenzene Sulfonate on the Surface of Montmorillonite Minerals

Abstract

The adsorption characteristics of sodium dodecylbenzene sulfonate (SDBS) on the surface of montmorillonite can lay a foundation for obtaining the optimum concentration of the anionic surfactant. The best absorption wavelength of SDBS was determined using an ultraviolet spectrophotometer. The standard curves of concentration and absorbance of SDBS were established. The amount of SDBS adsorbed on the surface of montmorillonite at various concentrations was calculated by stirring adsorption method. Scanning electron microscopy–energy dispersive X-ray spectrometry (SEM-EDS), X-ray diffraction (XRD), zeta potentiometer, and Fourier transform infrared (FTIR) spectroscopy were used to observe the changes of the structure, main ions, interlayer spacing, potential, and main functional groups on the montmorillonite surface before, and after, adsorption. The test results of SEM with EDS (SEM–EDS) showed that the surface of the montmorillonite after SDBS adsorption was rougher, and the adsorption capacity of the surface was enhanced as the SDBS concentration increased. The XRD results indicated that SDBS adsorbed on the interlayer of montmorillonite repulsed interlayer water and reduced the interlayer water content. With the increase of SDBS concentration, the interlayer spacing of the montmorillonite available for adsorbing SDBS decreased further. Additionally, interlayer adsorption and surface adsorption exist simultaneously in montmorillonite in SDBS solution. The distribution of total adsorption capacity of SDBS in the layers and on the surface of montmorillonite accords with the adsorption result simulated by a pseudo-second-order kinetic model. The increase in concentration of SDBS adsorbed by montmorillonite is the main reason for the decreased initial adsorption rate. The zeta potential test showed that the addition of H+ to the SDBS solution could reduce electrostatic repulsion and promote the adsorption of SDBS on montmorillonite. The results of this study provide an experimental basis for the study of the mechanism of SDBS adsorption on montmorillonite.

Vinyl Phosphate-Functionalized, Magnetic, Molecularly-Imprinted Polymeric Microspheres’ Enrichment and Carbon Dots’ Fluorescence-Detection of Organophosphorus Pesticide Residues

“…The adsorption capacity increased with the increase of temperature; perhaps the reason was that the MMIPs could be swollen easily under higher temperature so that more binding sites were exposed. Thus, the adsorption capacity at a higher temperature was greater than that at low temperature, which is consistent with the results of relevant literature [28,30,40].…”

The adsorptive behaviour of kaolinite to sodium dodecyl benzene sulphonate and the structural variation of kaolinite

“…The upper clear solution was filtered after stirring for 0 min, 20 min, 40 min, 60 min, 90 min, and 120 min, respectively, then the absorbance of the filtrate was measured by 201 UV spectrophotometer (The test wavelength of the ultraviolet spectrophotometer ranged from 190 to 1100 nm and the wavelength accuracy was ± 0.8 nm). Adsorptive capacity calculation The absorbance peak of SDBS occurs at about 223 nm, and when the solution concentration is 3–5 mmol/L, the absorbance peak has a good linear relationship with the concentration of SDBS 5 : where, C is concentration of SDBS, mmol/L; A represents the peak wavelength of absorbance. According to the absorbance test results of filtered filtrate, in combination with formula ( 1 ), the adsorptive capacity can be calculated as follows: where, q t is the adsorptive capacity at time t , mmol/g; C 0 represents the initial concentration, mmol/L; C t is the concentration at time t , mmol/L; V is the volume of the solution, L; m is the mass of the kaolinite, g. Determination of the adsorptive behaviour of kaolinite to SDBS The adsorptive behaviour of kaolinite to SDBS was investigated mainly by comparing the adsorption process with the classical adsorption kinetic model.…”

“…According to the absorbance test results of filtered filtrate, in combination with formula ( 1 ), the adsorptive capacity can be calculated as follows: where, q t is the adsorptive capacity at time t , mmol/g; C 0 represents the initial concentration, mmol/L; C t is the concentration at time t , mmol/L; V is the volume of the solution, L; m is the mass of the kaolinite, g. Determination of the adsorptive behaviour of kaolinite to SDBS The adsorptive behaviour of kaolinite to SDBS was investigated mainly by comparing the adsorption process with the classical adsorption kinetic model. Wherein, the fitting formula of pseudo-first-order adsorption dynamics equation to characterise physical adsorption is as follows 5 : where, q e is the equilibrium absorption capacity, mmol/g; k 1 is the first-order adsorption constant, min −1 . The fitting formula of pseudo-second-order kinetic model to characterise chemical adsorption is as follows 5 : where, k 2 is the second-order adsorption constant, g·mmol −1 ·min −1 ; k 2 q e 2 is the initial adsorption time, mmol·g −1 ·min −1 .…”

“…Wherein, the fitting formula of pseudo-first-order adsorption dynamics equation to characterise physical adsorption is as follows 5 : where, q e is the equilibrium absorption capacity, mmol/g; k 1 is the first-order adsorption constant, min −1 . The fitting formula of pseudo-second-order kinetic model to characterise chemical adsorption is as follows 5 : where, k 2 is the second-order adsorption constant, g·mmol −1 ·min −1 ; k 2 q e 2 is the initial adsorption time, mmol·g −1 ·min −1 .…”

Influence of Emulsifier on Surface Mass Transfer Based on Molecular Dynamics Simulations

“…The results showed that the proper oil phase can make the interface SDBS and its isomers more compact and orderly, providing better interfacial activity. Ni et al (2018) investigated the adsorption characteristics of anionic surfactant sodium dodecylbenzene sulfonate on the surface of montmorillonite minerals. It showed that the addition of H+ to the SDBS solution could reduce electrostatic repulsion and promote the adsorption of SDBS on montmorillonite.…”