Preparation of waste plastic-based nitrogen-doped carbon materials for removal of hexavalent chromium from wastewater

Low-density polyethylene waste plastic is used as the carbon source, and graphitic carbon nitride is used as the self-sacrificing soft template and nitrogen source to successfully prepare the nitrogen-doped carbon material (PSCN) for Cr(VI) wastewater purification. Characterization analysis result shows that PSCN has a developed pore structure and rich surface functional groups such as -NH- and C-OH with surface area of 601.0 m
2
/g. Effect of experiment conditions on Cr(VI) removal by PSCN is investigated. The intrinsic connection between removal conditions and Cr(VI) removal amount is established, and removal mechanism is investigated. The removal amount of Cr(VI) is 109.7 mg/g at 298 K, calculated based on Hill model. The coexisting impurity ions have a relatively minor impact on Cr(VI) removal process. The removal mechanism analysis indicates that the synergistic effect between pore structure and surface functional groups of PSCN promotes Cr(VI) adsorption and reduction. Approximate production cost of PSCN has been calculated with the $3.6/kg.