Novel Magnetic Nanocomposites Based on Carboxyl-Functionalized SBA-15 Silica for Effective Dye Adsorption from Aqueous Solutions

Abstract

In this study, three novel magnetic nanocomposites based on carboxyl-functionalized SBA-15 silica and magnetite nanoparticles were prepared through an effective and simple procedure and applied for methylene blue (MB) and malachite green G (MG) adsorption from single and binary solutions. Structure, composition, morphology, magnetic, and textural properties of the composites were thoroughly investigated. The influence of the amount of carboxyl functional groups on the physicochemical and adsorptive properties of the final materials was investigated. The capacity of the synthesized composites to adsorb MB and MG from single and binary solutions and the factors affecting the adsorption process, such as contact time, solution pH, and dye concentration, were assessed. Kinetic modelling showed that the dye adsorption mechanism followed the pseudo-second-order kinetic model, indicating that adsorption was a chemically controlled multilayer process. The adsorption rate was simultaneously controlled by external film diffusion and intraparticle diffusion. It was evidenced that the molecular geometry of the dye molecule plays a major role in the adsorption process, with the planar geometry of the MB molecule favoring adsorption. The analysis of equilibrium data revealed the best description of MB adsorption behavior by the Langmuir isotherm model, whereas the Freundlich model described better the MG adsorption.

A Review of the Current State of Magnetic Force Microscopy to Unravel the Magnetic Properties of Nanomaterials Applied in Biological Systems and Future Directions for Quantum Technologies

“…These high-resolution 3D capabilities, combined with ongoing research on new precursor materials and post-processing approaches, make FEBID a promising candidate for novel MFM probes. For all the above-described reasons, the future prospects of MFM are excellent [ 358 , 359 ] to deal with the current challenges, not only in the field of quantum technologies, but also for drug delivery [ 360 ], tissue regeneration [ 361 ], and wastewater treatments [ 362 ].…”

Methylene Blue Dye Adsorption on Iron Oxide-Hydrochar Composite Synthesized via a Facile Microwave-Assisted Hydrothermal Carbonization of Pomegranate Peels’ Waste

“…The Langmuir model indicates that the adsorption of MB on FHC and FAC is that of monolayer adsorption on a homogenous surface [40]. The Freundlich fitting indicates that the surfaces of FHC and FAC may be heterogenous surfaces with nonuniform affinities and multilayer adsorption of MB dye on composites [41]. The blue squares in Figure 6c show the measured results of the equilibrium adsorption capacity of the iron oxide-hydrochar composite, the dashed green line represents the Langmuir fitting with correlation coefficient R 2 = 0.999, and the black dashed line represents the Freundlich fitting with correlation coefficient R 2 = 0.999.…”

“…The Langmuir model indicates that the adsorption of MB on FHC and FAC is that of monolayer adsorption on a homogenous surface [40]. The Freundlich fitting indicates that the surfaces of FHC and FAC may be heterogenous surfaces with nonuniform affinities and multilayer adsorption of MB dye on composites [41]. The parameters of these two models are represented in Tables 1 and 2.…”