Enhanced removal of Cr(VI) by cerium oxide polyaniline composite: Optimization and modeling approach using response surface methodology and artificial neural networks

•A cost effective adsorbent is proposed for Cr(VI) removal from water.•Removal efficiency of the adsorbent is studied over a wide range of pH (2–10).•The removal of hexavalent chromium is 93.9% at obtained optimum condition.•The adsorption capacity for Cr(VI) ions was 357mg/g at pH 6.•Prediction of removal percentage by ANN was found to be best than RSM model.