Revalorizing a Pyrolytic Char Residue from Post-Consumer Plastics into Activated Carbon for the Adsorption of Lead in Water

This work focuses on the use of a char produced during the pyrolysis of a mixture of non-recyclable plastics as a precursor for the preparation of porous activated carbon with high developed adsorption uptake of lead in water. Physical and chemical activation was used to enhance the porosity, surface area, and surface chemistry of char. The final activated carbon materials were deeply characterized through N-2 adsorption isotherms, scanning electron microscopy, Fourier transformed infrared spectroscopy, analysis of the metal content by inductively coupled plasma mass spectroscopy, and pH of point zero charge. The native char displayed a Pb adsorption uptake of 348 mg Pb center dot g(-1) and considerably high leaching of carbon, mainly organic, ca. 12%. After stabilization with HCl washing and activation with basic character activators, i.e., CO2, NaOH, and KOH, more stable adsorbents were obtained, with no organic leaching and a porous developed structure, the order of activation effectiveness being KOH (487 m(2)center dot g(-1)) > NaOH (247 m(2)center dot g(-1)) > CO2 (68 m(2)center dot g(-1)). The activation with KOH resulted in the most effective removal of Pb in water with a saturation adsorption uptake of 747 mg Pb center dot g(-1).

Automated summary

This study focuses on using char produced from the pyrolysis of non-recyclable plastic mixture as a precursor to prepare porous activated carbon with high adsorption capacity for removing lead from water. Physical and chemical activation techniques were utilized to improve the porosity, surface area, and surface chemistry of the char. The activated carbon materials obtained through HCl washing and activation with basic activators showed stable adsorption performance and developed porous structure, with KOH activation being the most effective in removing lead from water.