Cyanide Removal from Aqueous Solutions with Magnetic Silica Nanoparticles Modified with Olive Leaves

Today, the technology advancements and industrial developments have led large amounts of pollutants to make their way to aquatic environments. Cyanide compounds are a pollutant, found mainly in the gold and silver mines sewage, which should be refined due to high toxicity for human beings and the environment before discharging. In this study, silica magnetic nanoparticles were synthesized in the main accordance with the Stober method with a slight synthetic change and modified with bitter olive leaves ash; the aim was to assess the capability of the proposed method in the removal of the cyanide compounds from aqueous solutions. To determine the synthesized nanocomposite specifications, the following methods were used: X-ray diffraction pattern, Fourier transform infrared spectrometer, scanning electron microscopy, and parametric magnetometer. The experimental design in this study was one factor at a time and the effect of pH, the duration of contact, the amount of adsorbent, and the initial concentration of cyanide were investigated. Based on the results, up to 81.41% of the cyanide was excluded under the optimal conditions of PH at 5, absorbent amount of 750 mg /L, contact duration of 30 minutes, and initial concentration of 50 mg /L cyanide.  The results also revealed that the iso-thermic absorption models basically follow the Langmuir model with a correlation coefficient of 0.981. Conducting a traditional absorption study showed the speed of the absorption of the cyanide ions on Fe3O4/SiO2 adsorbent is better matched with a second-order kinetic model. Correspondingly, the study findings showed silica magnetic nanoparticles modified with bitter olive leaves ash are good in absorbing cyanide contaminants in aqueous solutions.