Upcycling of plastic membrane industrial scraps and reuse as sorbent for emerging contaminants in water

Scraps obtained as waste of the industrial production of polysulfone and polysulfone-graphene oxide hollow fiber membranes (PSU-HF and PSU-GO-HF, respectively) were converted into granular materials and used as sorbents of several classes of emerging and standard water contaminants, such as drugs, heavy metal ions, and a mixture of per- and poly-fluoroalkyl substances (PFASs). The millimetric sized granules (PSU and PSU-GO, respectively) outperformed granular activated carbon (GAC), the industrial sorbent benchmark, in the adsorption of lead, diclofenac, and PFOA from tap water. Adsorption mechanism insight was achieved by molecular dynamics simulations, demonstrating the key role of graphene oxide (GO) on PSU-GO material performance. With respect to GAC, PSU-GO adsorption capacity was two times higher for diclofenac and PFOA and ten times higher for lead. Material safety was assessed by surface enhanced Raman spectroscopy, excluding GO nanosheets leaching, and combined potability test. Overall, our work proves that scrap conversion and reuse is a valuable strategy to reduce plastic industrial waste disposal and to integrate standard technology for enhanced water purification. We describe a process for recycling scraps of graphene hollow fiber membranes into sorbent granules suitable for drinking water treatment.