Fabrication And Characterization Of Polyethyleneimine Immobilized On Chloropropyl And Silica-coated Magnetic Nanoparticles For Pb²⁺ Removal From Aqueous Solution

Nowadays,the spread of a wide range of metal ions contaminants in surface water and ground water has become a critical issue worldwide.Pb²⁺ is one of such kind of contaminants and has been extensively used in metal processing,electroplating and electronics leading to large releasing into aquatic environment.Therefore,increasing demands for clean and safe water make it greatly important to develop reliable methods for the removal of Pb²⁺ from environmental waters.Adsorption is regarded as the most attractive method in practical application owing to its simple operation and superior efficiency.In adsorption processes,the choice of an appropriate adsorbent is the key factor to achieve high adsorption capacity,good selectivity and short analytical time.This thesis aims at synthesizing a kind of high adsorption capacity,high efficient,low cost,renewable and environmentally friendly adsorption material.This thesis is divided into two parts:Part ?:A new surface polymeric functionalized magnetic adsorbent was synthesized through the grafting polyethyleneimine onto chloropropyl and silica coated magnetic nanoparticles and characterized by TEM,XRD,FT-IR,EA and TGA.The relationship between grafting reaction conditions,such as solvent,reaction time,reaction temperature and the polyethyleneimine amount added,and grafting percentage was investigated systematically.Part ?:Under the optimized conditions,the magnetic adsorbent was fabricated and used for the removal of Pb2 from the solutions for the first time.Batch experiments were carried out to examine the influence of different sorption parameters,for example,solution pH,initial concentration of Pb²⁺,contact time and adsorbent dosage.The equilibrium sorption data fitted Langmuir adsorption isotherm well and the adsorbent-adsorbate kinetics followed pseudo second order model with a maximum adsorption capacity of 131 mg·g-1,which revealed that the prepared polymeric magnetic adsorbent was attractive and effective material with high uptake capacity.The Pb²⁺can be desorbed from the magnetic adsorbent by 0.1 ?mol·L^-1 EDTA and reused 5 cycles without remarkable loss of adsorption performance.