Comparison of the effect of PANI/TiO2, Dow resins and activated carbon in removing model dissolved organic matter (DOM) and phosphorus

Abstract

Seven typical adsorbents were adopted to remove phosphorus and dissolved organic matter (DOM), including humic acid (HA), protein and polysaccharides from simulated wastewater (SW) and secondary effluent (SE). The corresponding adsorption behavior and mechanism were explored in this work. Results showed that the ideal optimal dosage and reaction time of seven adsorbents were 2 g/L and 300 min respectively. Three adsorbents (PANI/TiO2, IRA4200Cl, and IRA900Cl) were selected for the subsequent wastewater treatment because of their excellent adsorption and regeneration performance. After 10 cycles of adsorption-desorption process, the removal rates of TP and DOM could reach more than 80% for both SW and SE. The adsorption behavior on synthetic wastewater was well described by the pseudo-second-order model and Freundlich model, which meant that the adsorption of pollutants by these three adsorbents was ascribed to chemical and homogeneous adsorption. Moreover, it was found that the three selected adsorbents could selectively adsorb pollutants from wastewater through chemical adsorption, π-π stacking, hydrogen bonding and ion selectivity. All these findings revealed that the potential application of PANI/TiO2, IRA4200Cl, and IRA900Cl in the removal of phosphorus and DOM from SE due to their excellent thermal stability, excellent adsorption performance, and regeneration capability, among which PANI/TiO2 exhibited the most outstanding performance among them, especially in terms of regeneration capacity.