Treatment of Water with Water:N, P Co‐Doped and Post‐Loaded Magnetic Hydrochar for Sustainable Water Pollution Control

even with salt ions, coexisting adsorbates, and light. LSH-NPFe rapidly removed MB (within 15 min), and adsorption equilibrium is achieved within 30 min. During dynamic adsorption experiments, LSH-NPFe removed >90% of MB from wastewater within ≈6 h. After adsorption, LSH-NPFe is pyrolyzed to immobilize pollutants and mixed with high-density polyethylene to form a carbon-plastic composite. This research explains the interfacial interaction mechanism between heteroatom doping and loading, and proposes practical strategies for using aquatic plants in wastewater treatment and resource recycling. These findings can broaden the applications of biomass - derived carbon materials and advance the industrialization of advanced carbon materials.