Nitrate adsorption by stratified wheat straw resin in lab-scale columns

A continuous adsorption study for nitrate removal was carried out by using pilot-scale produced wheat straw anion resin in batch lab-scale columns. Effect of resin widths on column adsorption was first evaluated and then a stratification-packed column with different widths of resins was applied. The nitrate uptakes by different bed depth (3.6, 5.6 and 9.8 cm) of stratified columns were 35.3, 28.1 and 23.2 mg/g, respectively. The better performance for this stratified column was observed at neutral condition, and marginally decreased with pH variation on both acidic and basic sides. The nitrate adsorption capacity was optimum at lower flow rates. In addition, Adams-Bohart and Thomas models were applied for analyzing all these parameters. The results showed that the Thomas model was suitable for the description of breakthrough curve at all experimental conditions, while Adams-Bohart model was only for an initial part of dynamic behavior of the column.