Cr(VI) removal with rapid and superior performance utilizing cost-efficient waste-polyester-textile-based mesoporous carbon: Behavior and mechanism

As a typical heavy metal, Cr(VI) poses a serious threat to the environment and to human health. Here, waste-polyester-textile-based highly mesoporous carbon (mPC), synthesized by the pyrolysis method in the presence of MgCl2, was employed to rapidly remove Cr(VI) from water. The resultant product presented a high specific surface area (1289 m2·g−1), total pore volume (3.14 cm3·g−1) and mesoporosity (>95%) owing to the strong dehydrogenation and cross-linking effects of MgCl2 on polymers, as well as the pore-developing effect of MgO. In further adsorption trials, mPC exhibited excellent removal performance for Cr(VI). The removal efficiency was significantly enhanced under appropriate conditions (lower pH and ionic strength). Furthermore, mPC showed high adsorption rate (0.0029 g·mg−1·min−1) and distinguished adsorption capability (165.93 mg·g−1), and the uptake procedure was fitted well by the Freundlich isotherm and pseudo-second-order kinetics. Fourier-transform infrared and X-ray photoelectron spectroscopy confirmed that the electrostatic interaction and reduction effects were the predominant adsorption mechanisms, the ion exchange reaction also accounted for part of the Cr(VI) removal. This preparation technique of mPC offers a new means of textile waste re-utilization, and the resultant carbon material with excellent physicochemical characteristics has practical applications in the removal of Cr(VI) from wastewater.