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In this paper, magnetic polyethyleneimine lignin (M-Lignin-PEI) was prepared by a reversed-phase suspension crosslinking method to remove Pb (II) form aqueous solutions. SEM, FT-IR, TGA, XRD and VSM technology were employed to explain their structures. Batch adsorption experiments for Pb (II) were carried out to estimate their adsorption performance. Results showed that lignin successfully grafted with polyethyleneimine and coated on the surface of Fe 3 O 4 with a saturation magnetization of 24.08 emu/g, which could achieve good solid-liquid separation. In addition, the experiment results indicated that the adsorption of Pb (II) by M-Lignin-PEI was in line with Langmuir model, and the adsorption process could be described by a pseudo-second-order model, suggesting that Pb (II) adsorption onto sorbents were a chemical process and monolayer adsorption. The maximum adsorption capacity of M-Lignin-PEI for Pb (II) could reach 96.60 mg/g and the removal rate was 99.73%. Moreover，the lead-loading M-Lignin-PEI could be easily regenerated with only 15% decrease of adsorption capacity after five times regeneration., (Copyright © 2019. Published by Elsevier B.V.)

Novel magnetic hydrogel beads (m-CS/PVA/CCNFs), consisting of carboxylated cellulose nanofibrils (CCNFs), amine-functionalized magnetite nanoparticles and poly(vinyl alcohol) (PVA) blended chitosan (CS), were prepared by an instantaneous gelation method. SEM, XRD, and TGA techniques were applied to investigate the structure of the hydrogel materials. The magnetic hydrogels were employed as absorbents for removal of Pb(II) ions from aqueous solutions and the fundamental adsorption behavior was studied. Experimental results revealed that the m-CS/PVA/CCNFs hydrogels exhibit higher adsorption capacity with the value of 171.0mg/g, and the carboxylate groups on the CCNFs surface play an important role in Pb(II) adsorption. Moreover, adsorption isotherm data were reliably described by the Langmuir model and the adsorption kinetics closely followed pseudo-second order model. Additionally, the Pb(II)-loaded m-CS/PVA/CCNFs hydrogels could be easily regenerated in weak acid solution and the adsorption effectiveness of 90% can be maintained after the 4 cycles., (Copyright © 2013 Elsevier Ltd. All rights reserved.)