Magnetic vs. non-magnetic colloids – A comparative adsorption study to quantify the effect of dye-induced aggregation on the binding affinity of an organic dye
| Autor: | Cory A. Diemler, Jenny Lee, Mahamud Subir, Tyler A. Williams |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Aqueous solution
Analytical chemistry Nanoparticle 02 engineering and technology 010501 environmental sciences 021001 nanoscience & nanotechnology 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Biomaterials chemistry.chemical_compound Colloid Colloid and Surface Chemistry Adsorption chemistry Magnetic nanoparticles Particle Malachite green 0210 nano-technology Spectroscopy 0105 earth and related environmental sciences |
| Zdroj: | Journal of Colloid and Interface Science. 481:20-27 |
| ISSN: | 0021-9797 |
| Popis: | Hypothesis Due to attractive magnetic forces, magnetic particles (MPs) can exhibit colloidal instability upon molecular adsorption. Thus, by comparing the dye adsorption isotherms of MPs and non-magnetic particles of the same size, shape and functional group it should be possible to characterize the influence of magnetic attraction on MP aggregation. Experiments For a range of particle densities, a comparative adsorption study of malachite green (MG+) onto magnetic and non-magnetic colloids was carried out using a combination of a separation technique coupled with UV–vis spectroscopy, optical microscopy, and polarization dependent second harmonic generation (SHG) spectroscopy. Findings Significant MP aggregation occurs in aqueous solution due to MG+ adsorption. This alters the adsorption isotherm and challenges the determination of the adsorption equilibrium constant, K ads . The dye-induced aggregation is directly related to the MG+ concentration, [MG+]. A modified Langmuir equation, which incorporates loss of surface sites due to this aggregation, accurately describes the resulting adsorption isotherms. The K ads of 1.1 (±0.3) × 107 and a loss of maximum MP surface capacity of 2.8 (±0.7) × 103 M−1 per [MG+] has been obtained. Additionally, SHG has been established as an effective tool to detect aggregation in nanoparticles. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect