Zinc oxide nanoparticles functionalized with chelating nitrogenous groups for the adsorption of methyl violet in aqueous solutions

In this study, a potent material for adsorption of methyl violet (MV) in water was developed. This material was synthesized from silica coated zinc oxide nanoparticles. The material was obtained after functionalization of silica coated zinc oxide nanoparticles with pyrene ligand. Fourier transform infrared spectrometer (FTIR), Brunauer-Emmett-Teller analyzer, energy dispersive X-ray spectrometer, scanning electron microscope (SEM), X-ray diffratometer, transmission electron microscope (TEM) and thermogravimetric analyser were used for characterization of the synthesized materials. Moreover, the ligand was initially characterized with proton and carbon 13 nuclear magnetic resonance spectroscope and FTIR. The results showed characteristic Zn-O stretch in all synthesized nanoparticles' FTIR spectra. Also, the nanoparticles showed crystalline morphology and spherical geometry in the SEM and TEM analyses respectively. The potent adsorbent showed a reasonable adsorption maximum capacity (qmax) (31.5 mg/g) in comparison with other MV adsorbents. Efficiency test of the adsorbent for MV was carried via batch adsorption experiments. The highest adsorption efficiency and adsorption capacity were found to be 87.7 % and 57.4 mg/g respectively. Kinetic and isotherm studies showed applicability of pseudo-first order and Langmuir isotherm models respectively. These result showed that this special adsorbent can serve as another high efficient adsorbent for MV in wastewater. Further, these results also implied that this adsorbent could be considered for other toxic contaminants in wastewater and can be considered for industrial usage. This is due to its high efficiency and capacity as observed in the study and its reusability and recyclability properties for cost effectiveness.