Highly efficient and rapid purification of organic dye wastewater using lignin-derived hierarchical porous carbon.

Coating manufacturing, textile processing, and plastic industry have led to dramatical release levels of hazardous organic dye pollutants threatening public health and the environment. To solve this problem, porous carbon materials are being developed following with the United Nations initiative on water purification. However, conventional porous carbon materials face many challenges, such as limited removal rates, low adsorption capacity, and high chemicals consumption, hampering their large-scale utilization in dye wastewater treatment. Herein, we demonstrate a high-performance lignin-derived hierarchical porous carbon (LHPC) material directly prepared from renewable lignin through a low-cost activation procedure. The large specific surface area (1824 m/g) enables the rapid and effective adsorption of organic dyes. Therefore, the LHPC exhibits an ultrahigh adsorption ability (1980.63 mg/g) and removal rate (99.03% in 10 min) for Azure B, superior to that of other adsorbents. Additionally, the LHPC adsorbent, organic dyes, eluting agent, and water all can be recycled and reused in a designed close-looped system. Its high removal ability and rate, strong retrievability, low-cost and scalable production combined with high dyes adsorption universality, positions our LHPC as a promising commercial adsorbent candidate for the purification of harmful organic dye wastewater, especially for heavily polluted area with an insistent demand for clear water.