Speciation- and Matrix-Controlled Removal of Antimony from Water: A Review of Treatment Technologies

Antimony (Sb) contamination in groundwater, drinking water, and industrial wastewater is of growing concern because its mobility, toxicity, and treatability depend strongly on oxidation state and water chemistry. This review examines Sb occurrence and aqueous speciation, the effects of water-matrix constituents, and the main technologies investigated for its removal. Particular attention is given to the contrasting behavior of Sb(III) and Sb(V) and to the influence of pH, competing ions, natural organic matter (NOM), and redox conditions on treatment performance. Biological processes, oxidation, adsorption, coagulation–precipitation, electrochemical methods, membrane separation, and hybrid systems are assessed in terms of effectiveness, practical limitations, and residual generation. By considering Sb speciation, matrix effects, and residual fate together, this review shows that treatment suitability cannot be judged from removal efficiency alone. Oxidation is best regarded mainly as a speciation-control step rather than a stand-alone removal process, whereas adsorption and coagulation remain important for dissolved Sb capture and bulk removal. Membrane and electrochemical processes offer options for high-quality separation and recovery, while hybrid systems can combine transformation and capture. Future studies should emphasize realistic matrices, environmentally relevant conditions, continuous operation, regeneration, and long-term residual stability.