Highly Salt Resistant Polymer Supported Ionic Liquid Adsorbent for Ultrahigh Capacity Removal of p-Nitrophenol from Water

The exploration of new adsorbents is still highly desirable, especially those with ultrahigh adsorption capacity, super anti-interference ability, and excellent regeneration power. Herein, a novel chloromethyl polystyrene resin supported task-specific ionic liquid adsorbent was prepared by chemical grafting and its performance to remove p-nitrophenol (PNP) from water was systematically investigated by both batch process and dynamic column elution method. It was shown that the adsorbent not only exhibited excellent adsorption performance toward high concentration PNP with an ultrahigh adsorption capacity of 1269.8 mg/g within 30 min but also could effectively remove trace PNP from water at the concentration as low as 0.0025 mg/L. Common interfering ions and neutral molecules in water, especially K+, Na+, Ca2+, Mg2+, NO3-, and Cl-, did not interfere with the removal of PNP even if their concentrations (1 mol/L) were 1 000 000 times higher than that of PNP, which indicates its potential in removal of PNP from high salinity wastewater. The adsorbent could be easily regenerated and recycled at least 10 times with no loss in separation performance. The possible adsorption mechanism was investigated in various approaches. In addition, the adsorbent was applied to remove PNP in real water samples, and promising results were reported.