Valorization of poly(ethylene)terephthalate wastes into nanoporous carbons for the adsorption of 1,3-diphenylguanidine from an aqueous solution

Abstract

1,3-Diphenylguanidine (DPG) in an aqueous solution can endanger human health and also cause environmental pollution. A series of nanoporous carbons (called NPC-1–4) were prepared using a MgO-template method and KOH activation with an MgO template to absorb 1,3-diphenylguanidine (DPG) in aqueous solution. In addition, the carbon precursor of the template carbon uses poly(ethylene)terephthalate (PET) waste which is difficult to deal with. Meanwhile, commercially available absorbents comprising NCC-9, XCC-4 and macroporous resin (MR) were also studied in this work as controls. All absorbents were characterized by SEM and N₂ physical absorption–desorption isotherm analysis. DPG solution onto all absorbents is more inclined to fit PSO by experimental data. Except for NCC-9 and MR, the adsorption isotherms could be correlated to the Freundlich model, and the related parameters of PSO (K_s and Q_es) for NPC-4 are higher than other absorbents fitting with Freundlich. NPC-4 was able to be reused for DPG removal for at least five consecutive cycles without any obvious efficiency loss. The results indicated that the self-made nanoporous carbon could be a potential adsorbent for the removal of DPG from aqueous solutions.