Aqueous phosphate uptake is needed to reduce global eutrophication. Negatively charged adsorbent surfaces usually give poor sorption. Chemically- and thermally-modified lignite (CTL) was prepared by impregnating low-cost (RL) with Ca2+ Mg2+ cations, basified KOH (pH ̴ 13.9), followed a 1 h 600 °C pyrolysis under nitrogen. CTL has positive surface (PZC = 13) due basic Ca Mg compounds, facilitatin...