Preparation Of A Paramagnetic Solid-phase Nano-extractant For Separating Pb²⁺ From Dilute Solution

In this paper, series of paramagnetic solid phase nano-extractant are firstly assembled for separating Pb2+ from diluted solution, in which Fe3O4 is their core, TEOS is modified layer, extraction with selective adsorption characteristics, or specially designed is adsorptive group, silane-coupling agents are linkers. Adsorption studies(including optimal pH, adsorption capacity Q, thermodynamics, kinetics, desorption conditions, reusability)are focused on laboratory simulation of a single heavy metal ions(such as Pb2+) wastewater, screening of excellent adsorbent with good performances of adsorption and desorption, adsorption capacity, selectivity, reusability, and also exploration of its adsorption, desorption mechanism during the whole study; on this basis, synthesis of organic active molecules with selectivity adsorption toward Pb2+, then self-assembly excellent adsorption properties of magnetic nano-solid phase extraction agent. 1. Preparation and Performance of dithizone magnetic solid-phase nano-extractantIn this chapter, a paramagnetic solid phase nano-extractant Fe3O4 @ SiO2 @ Clpr-silica @ dithizone is firstly constructed to extract Pb2+ from dilute solution. Morphology, Composition, magnetic properties and adsorption properties of nano-extractant were characterized by FTIR, SEM, VSM and AAS, respectively. The experimental results show a good absorption capacity more than 63.4 mg·g-1, rapid adsorption and desorption rate, and good reusable. 2. Preparation and performance of L-cysteine magnetic solid-phase nano-extractantIn this chapter, paramagnetic solid phase nano extractant Fe3O4 @ SiO2 @ Aminopropyl-silica @ L-Cysteine(FSAC), is firstly assembled for separating Pb2+ from diluted solution. The samples are characterized by FTIR, TEM and VSM. The extracting properties of some samples are measured by AAS. The experimental results show a good absorption capacity beyond 234 mg×g-1 within 30 minutes, rapid adsorption and desorption rate, good reusable. Experimental results also show that-SH is mainly functional group,-NH,-COOH are secondary functional groups in the complexation process of Pb2+. 3. Exploration of self-design and synthesis for novel adsorption ligands of Pb2+Some improvements are based on series of methods for preparation of magnetic nano-solid phase extraction agent and the mechanism of adsorption and desorption, as follows: 1. Choosing some excellent adsorbents with high selectivity toward Pb2+, and with addition of new active sites for linking magnetic nanocomposite without changing the adsorption groups and production of excellent adsorption properties of magnetic nano-solid phase extraction agent through modification and organic synthesis, thereby preparing a new type of small organic molecules which may have good adsorption toward Pb2+, and some preliminary results are obtained as follows:Bis-N-(mercapto Pro phenyl)-5-amino-1,3-isophthalamide, some important intermediates and so on. 2. Reducing the size of the magnetic core, choosing and preparing paramagnetic spherical ferrite nanoparticles with low coercivity and high magnetic response strength.