Sustainability-inspired upcycling of plastic waste into porous carbon nanobulks for water decontamination via peroxymonosulfate activation

Abstract

"White pollution" is regarded as one of the most serious problems in the natural environment. Thus greener recycling of plastic waste has attracted significant efforts in recent research. In this study, to kill two birds with one stone, a series of porous carbon nanobulks (PCNs) were synthesized from the pyrolysis of plastic waste (polyethylene terephthalate, PET) and inorganic salt (including NaHCO₃, Na₂CO₃, NaCl, and ZnCl₂) for sulfadiazine (SDZ) degradation via peroxymonosulfate (PMS) activation. PCNs-1 (co-calcinated from PET and NaHCO₃) with a large number of CO and COOH active sites, which were in favor of PMS activation and electron transfer during the catalytic process, had shown the best catalytic activity for SDZ degradation. Significantly, PCNs-1 exhibited excellent universality, adaptability, and stability. The degradation pathways of SDZ were identified by the total content of organic carbon (TOC), and high-resolution mass spectrometry (HR-MS). The possible mechanism was proposed according to the anion effect, quenching experiments, electron paramagnetic resonance (EPR), and electrochemical analysis, indicating that radical (OH, SO₄^-, O₂^-) and non-radical (¹O₂ and e) species were the catalytically active species for SDZ decomposition in the PCNs-1/PMS system. Moreover, Ecological Structure-Activity-Relationship Model (ECOSAR) program and wheat seed cultivation experiments clearly demonstrated that the biotoxicity of SDZ could be effectively reduced by the PCNs-1/PMS system. Here we successfully upcycled plastic waste into high-value materials for efficient water decontamination.

Keywords: PMS activation; Plastic waste; Porous carbon nanobulks; Upcycling; Water decontamination.