Radially aligned hierarchical N-doped porous carbon beads derived from oil-sand asphaltene for long-life water filtration and wastewater treatment

The application of waste-derived highly efficient adsorbent for organic pollutants removal from water and wastewater is presented. Highly porous carbon beads with radially aligned macrochannels were prepared from asphaltene. Well -ordered inwardly aligned macrovoids favored solute diffusion and maximized the liquid accommodation capacity. A further N-doping could modulate the sorbent hydrophilicity leading to an outstanding absorption performance for a range of organic solvents and oily chemicals. N-doped carbon beads were effective sorbents of lopinavir (LNV) and ri-tonavir (RNV) from water and wastewater. The process of sorption was fast, and the highest removal was noted for RNV than LPV. N-doping favored LNV and RNV adsorption due to the increased porous structure of N-doped asphaltene beads. The chemisorption of both LPV and RTV was a rate-limiting step. The presence of co-pollutants in treated wastewater enhanced LPV and RNV removal and an up to 470 % increase was noted. The presence of LPV or RTV in distilled water was not toxic to Aliivibrio fischeri or even can stimulate their growth. However, after the ad-sorption process, the solution of RTV reduced its toxicity significantly and the final solution was not toxic. The opposite effect was noted for LPV. Given the repeatability, high removal performance, and cost-effectiveness of the asphaltene-based carbon microtubes when compared to other well-known sorbents such as carbon nanotubes, they demonstrated great potential as a low-cost and effective agent for long-life water filtration and wastewater treatment.

Automated summary

This study presents the application of waste-derived adsorbent for removing organic pollutants from water and wastewater. The adsorbent, made from asphaltene, consists of highly porous carbon beads with radially aligned macrochannels, which enhances solute diffusion and liquid accommodation capacity. N-doping further improves the hydrophilicity of the adsorbent and its absorption performance for organic solvents. The N-doped carbon beads effectively remove lopinavir (LNV) and ritonavir (RNV) from water and wastewater, with RNV exhibiting higher removal efficiency. The presence of co-pollutants in treated wastewater enhances the removal of LNV and RNV, and the toxicity of the solutions is reduced after the adsorption process.