Metal-loaded porous materials made from gold tailings: preparation and application in pollutants adsorption

In this study, gold tailings were modified as a carrier and loaded with iron oxides. The composites with different Fe₂O₃ doping were prepared by adjusting the mass ratio of Fe₂O₃/modified slag (Fe₂O₃/MS) to obtain porous materials with larger specific surface area and more adsorption sites. The adsorption of Levofloxacin hydrochloride (LEV) from aqueous solutions over Fe₂O₃/MS samples was investigated. The process of adsorption was studied in terms of a number of variables, such as adsorbent dosage, LEV concentration, solution pH. The results showed that the optimal mass ratio of Fe₂O₃ to MS was 3:10. The ionic strength and coexisting ions had little influence on the adsorption effect of the composite material, so the material had a strong anti-interference ability. However, the pH of the initial solution and the ion phosphate had a significant effect on the adsorption effect, indicating that electrostatic and coordination interaction were the main adsorption mechanisms. The adsorption process of Fe₂O₃/MS to LEV can be better described by quasi secondary rate equation with a faster adsorption rate (K₂ = 4.43 × 10⁻³g/(mg·min)) and the maxmium adsorption capacity (Q_e= 57.65 mg/g). In a wide temperature range (288–308 K), the adsorption behavior of LEV can be well described by the Langmuir isothermal model. Moreover, the ecyclability and stability of the material was explored. This study provides a new idea for the recycling of gold tailings. While solving the problem of water pollution, it realizes the high value reuse of solid waste resources and achieves the purpose of using waste to curb pollution.