Preparation Of Hyperbranched PVDF / ATP-PAMAM Composite Membranes And Their Adsorption Properties Of Heavy Metal Ions

PVDF membrane is widely used in membrane science for its good chemical stability and thermal stability.As one of natural nano inorganic, attapulgite possesses extensive resources, low price, large surface area, good adsorption and has been applied in adsorption and catalytic research areas. Polyamide-amine (PAMAM) polymer has been gradually focused on because of its unique controllable highly branched structure, intramolecular cavity and free aminostate. But overall, the level of exploration to the depth of the modified polymer and composite materials is low. In this paper, three types of functional membranes were prepared by different routes, in which PVDF membrane is matrix, PAMAM organic is modifier and ATP is an inorganic filler.(1) Hyperbranched PAMAM/PVDF composite membrane through surface chemical modificationwas preparedby interfacial polymerization. Wherein the G3.0PAMAM as aqueous phase monomer was obtained by the divergent method, while trimesoyl chloride (TMC) is an oil phase monomer.Studies have shown that, PAMAM has hyperbranched macromolecules regular structure cavity tablets, diameter uniform and stable and free form amino surface increasing exponentially. The composite membrane presents a unique "category branched" porous structure, maintaining a surface branched layer with 0-5μm thickness,which greatly improved hydrophily. The initial momentary contact angle of PVDF/G3.0-PAMAM can reach 39.4°.The adsorption ability of the composite membrane has improved to some extent compared with pure PVDF membrane in adsorbing Ni2+、Cu2+、Cd2+. With the graft algebra increased,the adsorption equilibrium became higher. The adsorption kinetics study showed that the adsorption mechanism was in line with the proposed second order kinetic model.(2) After ATP surface was modified by hyperbranched PAMAM polymer modified sol-situ Polymerization, different algebra PVDF/ATP-PAMAM organic/inorganic hybrid membrane was prepared in sol-situ Polymerization. Structure and property characterization of the whole generation and a half generations ATP-PAMAM proved that ATP maintain a reasonablegrafting ratio which is successfully modified by PAMAM.In addition, ATP was well dispersed in an organic solvent, maintaining a bundle of spindle and spherical structure with 200nm. The filling of inorganicnano particles in hybrid membrane played a role of hole system. The introduction of ATP-G3.0 increased surface roughness of the membrane. The hydrophilicity of the hybrid membrane improved compared to pure membrane and simple blend of pure ATP. The adsorption capacity of Ni2+, Cu2+, Cd2+of the PVDF/ATP-G3.0 hybrid membranereached its peak 124.28 mg/g,155.19 mg/g and 125.55 mg/g. The adsorption kinetics study showed that the adsorption mechanism accorded with the proposed second order kinetic model.Mechanism was in line with the proposed second order kinetics model much better, but with a smaller difference between the proposed first-order kinetic model, namely the coexistence of physical and chemical adsorption process.(3) The PVDF/SA total fixed ATP composite membrane was prepared by PVDF "penetration" SA immersion phase inversion. Studies have shown that the introduction of SA increased utilization. The combination of PVDF/SA/ATP possesses bilayer membrane structure, showing that different sides of the membrane morphology and performance, and reflecting the excellent hydrophilic performance. Heavy metal ion adsorption experiments reflected this bilayer membrane has a good prospect.