Heavy metals and their compounds, among other things, cause significant damage to the world's oceans and marine ecosystems. The use of an organic sorbent based on buckwheat husk may be a solution to this problem. This study examined the sorption capacity of a buckwheat husk-based sorbent modified with 0.1 N oxalic and acetic acid solutions for Fe3+, Cu2+, and Pb2+ anions. Studies of the resulting sorbent showed that it may be suitable for treating liquid wastewater from various pollutants.