Synthesis Of Modified Composite Superabsorbent Resins And Its Lead Ion Adsorption Properties

These superabsorbents were prepared with2-Acrylamide-2-methyl propane sulfonicacid as the main monomer, three kinds of high hygroscopicity resins were2-acrylamido-2-methyl propanesulfonic acid/acrylamide; Na-bentonite/poly-2-acry-lamido-2-methyl propanesulfonic acid and shell powder/acrylic/acrylamide/2-acry-lamido-2-methylpropane sulfonic acid, respectively. The adsorption performance of resinwas studied by physical and chemical modified methods.The2-acrylamido-2-methyl propanesulfonic acid/acrylamide superabsorbent wasmodified by non-thermal plasma （NTP） under ambient temperature and pressureconditions. The results showed that NTP treatment can improve the adsorption property ofsuperabsorbent obviously, as well as the optimal modified conditions were as fellows:discharge power was40W, duration of discharge was3min. ΔG was more negative andΔS was more positive with NTP modified absorbent material, it indicated that theadsorption properties was enhanced and activation energy decreased by NTP treatment,which was due to available adsorption sites increased.The adsorption process followed thepseudo second-order kinetic model.The poly-2-acrylamido-2-methyl propanesulfonic acid superabsorbent was modifiedby adding Na-bentonite using aqueous polymerization. The adsorption capacity ofNa-bentonite/PAMPS was studied.The results showed that the optimum ratio ofNa-bentonite and AMPS were2:1, the initiator（potassium persulfate） dosage used is0.02%（wt） of total monomer, the cross-linking agent （N,N-methylene double acrylamide）dosage used is0.04%（wt） of total monomer, polymerization temperature is60℃andreaction time is6h. The equilibrium adsorption data were well described by the Freundlichisotherms. Adsorption kinetics data were modeled using the pseudo-first-order,pseudo-second-order and intraparticle diffusion models. Kinetics studies proved that thedynamic behavior of Pb²⁺adsorption by Na-bentonite/PAMPS could be well described bypseudo-second-order kinetic model.The superabsorbent polymer was prepared by aqueous solution polymerization, using shell powder, acrylic acid （AA）, acrylic amide（AM）,2-acrylamide-2-methyl propanesulfonic acid（AMPS） as raw material, N N’-methylene bisacrylamide as cross-linker,and K2S2O8as initiator. The effects on Pb²⁺absorbency were investigated, such as theamount of shell powder, neutralization, cross linker and initiator. The equilibriumadsorption data of Pb²⁺on resin were analyzed by Langmuir, Freundlich andDubinin-Radushkevich models. The equilibrium adsorption data fitted very well to theFreundlich model. Adsorption kinetics data were modeled using the pseudo-first-order,pseudo-second-order and intraparticle diffusion models. The results indicated that theadsorption kinetic data were well represented by pseudo-second-order model.