Synthesis and Application of Positively Charged and Magnetically Separable Magnetite/Silica-Ammonium as an Effective Platinum(IV) Adsorbent

Platinum is a valuable metal that is widely used in industry, electronics, and catalysts. The use of Platinum has a significant impact on the production of waste, necessitating effective metal recovery. This study investigated Platinum (IV) recovery from wastewater using a positively charged and magnetically separable Magnetite/Silica-Ammonium (MSA). The MSA was prepared by co-precipitation procedure of silica-decorated quaternary ammonium in the Fe3+/Fe2+ solution. The characterization result of the MSA by FT-IR, X-ray diffraction (XRD), SEM-EDX, and Vibration Sample Magnetometer (VSM) demonstrated the success of MSA synthesis. The application of MSA to the Pt (IV) solution occurred at pH optimum 6,0 with the easy and quick retraction of MSA-loaded Pt (IV) by 29.3 emu/g magnetic strength of an external magnet. The adsorption isotherm study followed the Freundlich model (R2=0.9895) with the KF=2.57×10-2 mol/g. The monolayer capacity by Langmuir showed the remarkable performance of 139.09 mg/g adsorption capacity through the ion exchange interaction mechanism based on the Dubinin-Radushkevich energy (ED-R=8,3 kJ/mol). The kinetics study was fitted well to the Pseudo-second-order model indicated the fast adsorption of Pt (IV) into the MSA surface.