Preparation, characterization and investigation of their crystal violet dyestuff removal characteristics of biogeneic fe3o4 magnetic nanoparticles

Crystal violet (KV) is a cationic dye with a dark green, shiny crystalline structure. KV is used in printing, dyeing of paper and fibres (silk, wool, leather jackets, jute and cotton), printing ink, veterinary drugs and fertiliser production. Due to its cationic structure, it is a carcinogenic dyestuff with mutagenic properties that causes cell death by binding to negatively charged receptors on the cell. Consumption in small amounts (less than 1 mg/L) causes respiratory discomfort, shortness of breath, wheezing. In the present study, magnetic Fe3O4 nanoparticles (Z-MNP) were prepared using olive pits collected from olive wastes in order to develop a new biogenic adsorbent with low cost and high adsorption capacity for CV adsorption. The characterisations of the prepared Z-MNPs were carried out by means of Transform Infrared Spectroscopy (FTIR), Sample Vibrating Magnetometer (VSM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Spectrometry (EDX). Z-MNP magnetic nanoparticles were then used for the removal of KV from aqueous solution. In adsorption studies, parameters such as contact time, initial pH, pHpzc, initial concentration were studied. The contact time was 90 min, pH:6.0, pHpzc:5.978, initial dye concentration was 10 mg/L at 25 ºC. In Z-MNP desorption studies of KV, ethyl alcohol was found to be a better desorption agent than other desorbents for 2, 4 and 24 hours. Pseudo-second order (Ho-Mckey) kinetic model was found to be appropriate in kinetic studies. The Ea value for the adsorption of crystal violet on Z-MNP was calculated as 6.09 kJ/mol (25.50 kcal/mol). Activation enthalpy (ΔH#) and activation entropy (ΔS#) values were calculated as 0.23 kJ/mol and -176.84 J/molK, respectively. The activation free energy (ΔG#) was calculated as 52.72, 54.49 and 56.26 kj/mol at 298, 308 and 318 K, respectively.