Ammonium pyrrolidine dithiocarbamate anchored Symphoricarpus albus biomass for lead(II) removal: Batch and column biosorption study

► S. albus was successfully modified with APDC. ► Biosorbent has higher capacity for lead(II) about 3 fold than natural biosorbent. ► Biosorbent was effectively used in both batch and continuous systems. ► Pseudo-second-order and Langmuir models best described the lead(II) biosorption. ► More than one mechanism was played role in lead(II) biosorption process. The biosorption properties of APDC modified S. albus were tested in batch and column conditions. Effective experimental parameters such as pH, biosorbent dosage, contact time, temperature, initial lead(II) ion concentration, flow rate and bed height were investigated. The biosorption capacity of modified biosorbent was at maximum when lead(II) solution pH and biosorbent dosage were 5.5 and 2.0gL−1, respectively. The biosorption equilibrium was established in 20min. Langmuir isotherm fitted well to the equilibrium data and kinetics is found to fit pseudo-second-order model. Increase in ionic strength of lead(II) solutions caused a slight decrease in the biosorption yield of APDC-modified biosorbent. Co-ions affected the biosorption performance of modified biomass up to maximum 20.81% reduction. Column biosorption of lead(II) showed higher biosorption yields at lower flow rates. Required time of breakthrough point was found to be 200min. The recommended mechanism was found to depend mainly on electrostatic interaction, ion-exchange and complex formation. The ion-exchange mechanism for lead(II) biosorption onto the modified biosorbent is verified from the ionic strength effect and EDX analysis. Carbonyl, phosphate and CN groups on the modified surface of S. albus were found to responsible for complexation with lead(II).