Preparation And Property Study Of Adsorbent Crosslinked-amphoteric Polymer

Highly crosslinked amphoteric polymer can be used to separate and enrich metal ions, so it plays an important role in treating the wastewater; slightly crosslinked amphoteric polymer can be used as water absorbents. They are mainly applied in many fields, such as industry, agriculture, medicine, healthcare, architecture and etc. On the basis of reviewing the synthesis and application of crosslinked amphoteric polymer, a series of crosslinked amphoteric starches and water absorbents was synthesized, as well as their capacity were studied. The main contents of this thesis were as follows:Adsorption behaviors between metal ions (M2+=Zn2+, Pb2+) and crosslinked amphoteric starches (CAS) were investigated. The results showed that the adsorption capacity for Zn2+ is 9.59, 26.49, 43.48 mg/g, respectively for DS 0.12, 0.20,0.33, when initial concentration of Zn2+ is 60 mg/L, the dose of CAS is 40 mg and pH =4- 6. While the adsorption capacity for Pb2+ ion is 19.2, 61.66, 152.74 mg/g, respectively for DS 0.12, 0.20,0.33, with initial concentration of Pb2+60-110 mg/L, 40 mg CAS and pH = 4-6. The adsorption processes of two metals were both endothermic; the adsorptions followed the Langmuir isotherm.Amphoteric water absorbents CAS/AA were synthesized by aqueous polymerization with cationic starch (CAS) and acrylic acid (AA) as grafting monomer, N, N'-methylenebis-acrylamide as crosslinker and ammonium persulfate as initiator. Various factors, including initiator concentration, crosslinker concentration, reaction temperature, dose of AA, concentration of AA were discussed in detail. The results showed that synthesized amphoteric water absorbent under optimal condition can absorb water as high as 464 g/g, and 0.9 %NaCl solution 75 g/g. Besides, the absorbing capacity in different temperature, saltsolution, and pH solution was studied. As well as absorbing reversibility and swelling kinetics of CAS/AA were investigated.Amphoteric water absorbents DMDAAC/AA were synthesized by aqueous polymerization with cationic monomer diallyldimethylammonium chloride (DMDAAC) and anionic monomer acrylic acid, N, N'-methylenebis-acrylamide as crosslinker and ammonium persulfate as initiator. Effect of dose of AA was discussed in detail. The results showed that amphoteric water absorbent can absorb water as high as 800g/g, and 0.9 %NaCl solutin 82 g/g. The absorbing behaviors in different conditions were investigated. Its application in germination rate of winter wheat was also studied.Amphoteric water absorbents CDAH/AA were synthesized by aqueous polymerization with amphoteric monomer N-carboxymethyl-N,N -dimethyl-N allylammonium (CDAH) and acrylic acid, N, N'-methylenebis-acrylamde as crosslinker and ammonium persulfate as initiator. When monomer weight ratio AA : CDAH=1.4 .' l,The results showed that amphoteric water absorbent can absorb water as high as 773 g/g, 0.9%NaCl %) 48 g/g. The absorbing behaviors in different conditions were investigated. Its application in germination rate of winter wheat was also studied.