Synthesis And Properties Of Humic Intelligent Hydrogel And The Adsorption Of Metal Ions

In recent years, the pollution of heavy metal ions in water is more serious as therapid development of industrial economy. Since the adsorption is normally used intreating the pollution of heavy metal in water, then the absorbent material research hasbecome an important research direction. Through the modification of acrylic polymer byusing to humic acid organic polymer prepare the hydrogel absorbent the conventionalabsorbent material usually aimed at one single or two kinds of heavy metal ions, smartselective adsorption material has been reported very little.The humic acid intelligent hydrogels P(HA-AA-NIPA) were obtained via inversesuspension polymerization method with HA-Na, AA, NIPA. KPS as the initiator, MBAas a crosslinking agent, cyclohexane as the continuous phase, Span-65as dispersing agent.The effects of the amount and the monomer mass ratio of KPS, MBA and Span-65on theswelling properties of the hydrogel were studied. The optimal conditions for the synthesisof P(HA-AA-NIPA) through the single factor experiment, and the microstructure ofP(HA-AA-NIPA) were characterized by infrared spectroscopy (IR) and scanning electronmicroscopy (SEM). The results showed that optimum reaction conditions, the molefraction of KPS is0.5%, MBA mole fraction of AA5%, m(HA):m(AA):m(NIPA) molarratio is1:3:0.4, the neutralization degree of AA is80%(sodium hydroxide as neutralizer).IR analysis showed that P(HA-AA-NIPA) is the a graft copolymer of HA-Na, AA, andNIPA. SEM analysis showed that P(HA-AA-NIPA) owned multi-surface pore structureand large surface area, which is beneficial for the adsorption of metal ions.The factors of P(HA-AA-NIPA) affecting the adsorption of Pb2+, Ni2+were furtherexamined. Optimum adsorption conditions is that Pb2+, Ni2+concentration was50mg/L,adsorption time was6h, dosage of water is0.5g/L and the temperature is35?. In thiscondition, when the pH=4, the adsorption capacity for Pb2+was49.5mg/g; when pH=7,the adsorption capacity for Ni2+reached47.7mg/g. Further investigation of Pb2+, Cr3+,Mn2+, Ni2+competitive adsorption, the result is:Pb2+>Ni2+>Mn2+>Cr3+. P(HA-AA-NIPA)mixed metal ion adsorption selectivity, when pH=4, the preferential adsorption of Pb2+;When pH=5, the preferential adsorption of Cr3+; When pH=6, the preferential adsorptionof Mn2+; When pH=7, the preferential adsorption of Ni2+.The mechanism of P(HA-AA-NIPA) adsorbing Pb2+, Ni2+was discussed. Theresults show that, P(HA-AA-NIPA) on Pb2+, Ni2+adsorption are in line with two kineticmodels.The fitting results of Isotherm equations show that the adsorption of P(HA-AA-NIPA) on Pb2+, Ni2+is more in line with the Langmuir adsorption model.Figure21; Table15; Reference60...