Performance of Polymer-based Titanium and Zirconium Oxides Composite Adsorbent for Simultaneous Removal of Phosphorus and Fluorine from Water

A novel composite adsorbent (Ti-Zr-D201) for simultaneous removal of phosphate and fluoride from water was prepared by loading nanosized titanium and zirconium oxides on the anion exchange resin named D201. Combining with the characterization of the adsorbent, adsorption isotherm experiments, effect of solution pH experiments, competitive tests, kinetic experiments and fixed bed column adsorption experiments were performed to explore the adsorption performance and mechanism. The maximum adsorption capacity of Ti-Zr-D201 for phosphorus and fluorine was 34.9mg·g^-1 and 35.1mg·g^-1respectively, when the pH value was 5.8 and the temperature was 308K. Adsorption behavior was spontaneous, and higher temperature was favorable for phosphorus and fluoride adsorption. The effect of pH on the adsorption of fluoride was more significant compared with the adsorption of phosphorus. SO₄^2-, NO₃^- and Cl^-were selected as the competitive ions for competition experiments, and the results indicated that Ti-Zr-D201 exhibited favorable sorption selectivity for phosphorus and fluoride compared with the host material D201. The fitting results of the internal diffusion model showed that there were two different adsorption stages before the adsorption equilibrium of Ti-Zr-D201. Column adsorption experiments showed that Ti-Zr-D201 had a stable structure, excellent dynamic adsorption performance, and could be recycled, which showed the potential of practical application.