Application of polyethylenimine multi-coated adsorbent for Pd(II) recovery from acidic aqueous solution: batch and fixed-bed column studies

PEI imilti-coated PSBF (PEI-M-PSBF) wth high adsorption efficiency and good reusability for Pd(II) recovery was prepared by a PEI multi-coating method. The results of FT-IR and FE-SEM showed that the PEI-M-PSBF was successfully prepared. Batch experiments were conducted to study the adsorption/desorption performance of PEI-M-PSBF to Pd(II). The Langmuir and pseudo-second-order models were well suited for the batch experiment isotherm and kinetic data, respectively. The adsorption capacity of Pd(II) by Langmuir model was 327.14 mg/g, and the initial adsorption rate of 3-PEI-PSBF was 37.19mg/g min. As a resut, the increase in amine groups on the PEI-M-PSBF surface through the PEI multi-coating directly influenced the adsorption amount of the biosorbent. The effects of initial concentration, bed column depth, and flow rate were determined in a column system and the breakthrough curves were detected by Thomas model. In addition, the recycle of the adsorbent was examined by multiple time performing adsorption/desorption cycles up to ten times in a fixed-bed column.