Nitrate removal by quaternized mesoporous silica gel in ternary anion solutions: Flow-through column experiments and artificial neural network modeling

•Silica gel was quaternized for nitrate removal in fixed-bed column experiments.•Central composite design method was used to design column experimental conditions.•Column experiments were conducted in the ternary solutions of nitrate, phosphate, and sulfate.•Competitive breakthrough curves of competing anions were obtained and analyzed.•ANN model was developed to predict the removal rates of anions in column experiments.