Dynamic Reversible Adsorption and Desorption of Lead Ions Through a Packed Column of Poly(<i>m</i>-phenylenediamine) Spheroids

Abstract

Pb(II) solution has been treated by a column packed with 5 mm-diameter spheroids of poly(m-phenylenediamine) powder that has been entrapped in polyvinylalcohol, via dynamic adsorption. The effect of operation conditions on the adsorbability and desorbability has been investigated and optimized systematically. The results show that a lower flow rate gives a higher adsorptivity at a fixed Pb(II) concentration because of longer contact time, and higher Pb(II) concentration gives higher adsorptivity at a fixed flow rate. The highest adsorptivity reaches up to 75.9% for Pb(II) concentration of 500 mg·L–1 at the flow rate of 1 mL·min–1. The release of Pb(II) from the Pb(II)-adsorbing column has been revealed using 0.1 M HNO3 as an eluant, with an elution efficiency of 98.1%, effectively regenerating the column. The regenerated column could be circularly used several times. The Adams-Bohart and Wolborska sorption models have been used to describe the dynamic sorption of Pb(II) through the packed column. It is very interesting that the Pb(II) adsorptivity onto the regenerated column is 20% higher than that onto as-prepared column, making the poly(m-phenylenediamine) spheroids attractive and cost-effective as a potential sorbent for continuous removal of Pb(II) in large-scale operations.