Efficient extraction of metals (Fe, Zn, Pb) from hazardous jarosite using ionic liquid and waste-derived solvents

The present study evaluated a solvo-metallurgical technique for metal extraction from industrial solid waste (jarosite) using ionic liquids (ILs) and waste-derived solvents. The jarosite contains a considerable amount of metal ions, namely iron, zinc, and lead. The jarosite was characterized by XRF, XRD, SEM, and FTIR techniques. The parameters affecting metal extraction, such as stirring time, acid molarity, and temperature, have been examined. Aliquat 336 was used to extract metals from fresh and roasted jarosite after equilibration with HCl. The response surface methodology (RSM) was used to optimize the parameters for the maximum metal extraction using [A336] [Cl]. Maximum extraction of iron (86.75%), zinc (51.96%), and lead (94.38%) from roasted jarosite was achieved at optimum conditions (125-min stirring time, 5 M acid molarity, and 20 ml/g liquid-to-solid ratio). Furthermore, the metal extraction was investigated using waste-derived solvents. The results show that waste-derived solvents, such as biomass and plastic pyrolysis oil, can effectively extract metals from fresh and roasted jarosite. Biomass pyrolysis oil achieved the highest extraction at 50 °C for 90 min, while plastic pyrolysis oil achieved the highest extraction at 50 °C for 60 min from roasted jarosite. These solvents are also cost-effective because they are made from waste plastic and biomass.