Adsorption of Platinum and Palladium from Hydrochloric Acid Media by Hydrothermally Treated Garlic Waste Gel

摘要

A new approach of recovering platinum and palladium from electronic wastes by hydrochloric acid leaching followed by selective adsorption on low-cost and environmentally benign biomass sorbent prepared from easily available agriculture waste is suggested. The obtained adsorbents were prepared by a combination of chemical modification and hydrothermal carbonization process with (NH_4)_2C_2O_4. It was found that the maximum adsorption capacity of hydrothermal carbonized garlic peel for Pt(Ⅳ) and Pd(Ⅱ) was 1.64 and 0.42 mol/kg respectively. The Langmuir adsorption isotherm was applied to describe the adsorption process. Kinetics of the Pt(Ⅳ) and Pd(Ⅱ) ions adsorption was found to follow pseudo-second-order rate equation. The adsorbents were examined by scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). Based on the characterization results, a possible mechanism of Pt(Ⅳ) and Pd(Ⅱ) ions adsorption with the hydrothermal carbonized garlic peel was proposed. This study provides a promising adsorbent with efficient adsorption property for platinum and palladium recovery from the leach solution of electronic wastes.