High-Performance Graphene/Carbon Nanotube-Based Adsorbents for Treating Diluted o-Cresol in Water in a Pilot-Plant Scale Demo

Graphene/carbon nanotube (CNT)-based adsorbents were fabricated on a kilogram scale by extrusion processing (where graphene is used as the major adsorption material and CNTs make up the backbone to enhance the mechanical strength) and then mixed and bonded with poly(tetrafluoroethylene). Kilogram-scale adsorbents were used to treat the content of o-cresol in wastewater to be <1.12 mg/kg in a continuous and reversible adsorption–desorption apparatus, which could last for 99 h with a space velocity of 30 h–1 and a total wastewater capacity of 5 tons per day. Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and Raman spectroscopy all suggested that the surface properties and pore structure of the spent adsorbents remain unchanged after recycling at both low-temperature adsorption and high-temperature desorption in vacuum. These results provided an effective reversible adsorbent system for removing aromatic organics and prompted the scaled-up applications of carbon nanomaterials in the treatment of wastewater.