Papers by Keyword: Polyacrylamide

Abstract: Electrocatalytic oxidation of polyacrylamide (PAM) at Ti/PbO2 anode was studied in a three-electrode cell without any diaphragm but with a sandwich bath by galvanostatic electrolysis. Turbidimetry was used to determine the concentration of PAM. The change of degradation ratio with current density and reaction temperature was studied through single factor experiment in order to determine the optimal conditions. The optimal conditions of PAM degradation by electrocatalytic oxidation were: current density was 200 mA•cm-2, and reaction temperature was 60 °C. Under these conditions, the degradation ratio of PAM reached 88% after 3.0 h electrolysis. The total dissolved salts (TDS) and different ions affected on the degradation ratio of PAM by changing the size of PAM molecule and the viscosity of solution. The results of experiments showed that the degradation ratio increased firstly then decreased with the increasing of ion concentration. When TDS was 3000 mg•L-1, the degradation ratio reached the highest level. The high valence cation promoted the degradation of PAM. Cl- and HCO3- promoted the degradation of PAM because of the direct and indirect electrocatalytic oxidation and hydrolysis in alkaline solution respectively.

Abstract: The modified polyacrylamide/organic montmorillonite (PAM/OMMT) flocculant was prepared by in-situ intercalation polymerization with acrylamide monomer and OMMT under CO2 inert atmosphere. The OMMT was synthesized with MMT and cetyl trimethyl ammonium bromide (CTAB) as intercalation agent by cationic exchange reaction. This flocculant was used to deal with coalmine wastewater. The effects of the flocculant dose on turbidity removal rate and settling time, the influent of pH value, temperature on turbidity removal rate and the comparison with PAM was studied. Experimental results show that PAM/OMMT is a kind of high efficient compound flocculating agent, the formation of hydrophobic micro in polymer surface area has strong adsorption ability and dispersing capability. Then MMT increased the quality of flocculant body so that flocculating settling time is shorter. Its turbidity removal rate can be as high as 95.5%. Compared with PAM, PAM/OMMT presents many advantages with higher turbidity removal rate, higher settling velocity, lower relatively sludge water content and lower sensitivity of temperature and pH in wastewater treatment process. Flocculant dosage in 10 to 20 mg/L is the optimal flocculation condition. Sludge water content treated by PAM/OMMT (63.4%) is relatively lower than PAM (80.2%).

Abstract: In this study, a novel aluminum chloride-ploy(acrylamide) hybrid polymer has been synthesized by free radical solution polymerization of acrylamide (AM) onto aluminum chloride (AlCl₃) in the presence of ammonium persulphate and sodium hydrogen sulphite as polymerization’s initiators. On the other hand, the structure of hybrid polymer (AlCl₃-PAM) has been characterized by Fourier transform infrared spectroscopy (FTIR). The central composite design (CCD) and response surface methodology (RSM) have been applied in the flocculation process of wastewater treatment to achieve maximum removal efficiencies of total suspended solids (TSS), turbidity , and chemical oxygen demined (COD), as the other objectives of this study. The operating variables in this experiment were new hybrid polymer dose and wastewater pH. The maximum conditions have been found to be wastewater pH 7, and hybrid polymer dose 100 mg/l. Under these optimal conditions, the removal of turbidity, TSS, and COD in the effluent have been reached to 98.2%, 99.1%, and 90.6% respectively. According to these results, domestic wastewater treatment using (AlCl3-PAM) has proved to be an effective alternative in the administration of COD, TSS, and turbidity problems of municipality wastewater.

Abstract: Polyacrylamide/MgCl₂ hybrid hydrogel desiccant was prepared from magnesium chloride and polyacrylamide by aqueous solution polymerization. The hybrid hydrogel was synthesized and characterized by X-ray diffraction. The effect of the experimental factors such as content of magnesium chloride, concentration of cross-linking agent, initiator content on hygroscopic performance of the hybrid hydrogel were investigated, furthermore, the hygroscopic swelling kinetic process of the hybrid hydrogel was studied. The results indicate that hybrid hydrogel possessed preferable hygroscopic property under the optimum conditions, the hygroscopic swelling degree achieving 172%. The hygroscopic swelling process of the hybrid hydrogel follows the kinetic pseudo-second-order model, in addition, the swelling rate decreases with the increase of relative humidity.

Abstract: The copolymerization of acrylamide (AM), Dodecafluoroheptyl methacrylate (G04), acrylic acid and the polycondensate of maleic anhydride and Polyethyleneglycol (PEG400) was studied in detail with benzoyl peroxide (BPO) as initiator when supercritical CO₂ and the acetone solvent were presented. The functional fluoride hydrophobic associating polymer products have some special characters with excellent performance of gas storage The structure of the copolymer products was characterized by FTIR, MR, 1H-NMR and SEM analysis.

Abstract: A water soluble branched polyacrylamide has been synthesized through solution polymerization. The polymerization was initiated by potassium diperiodatocuprate, K₅[Cu(HIO₆)₂](Cu(III)), in alkaline medium and capable of initiating the self condensation vinyl polymerization of acrylamide monomer. The polymer obtained was characterized using Fourier-transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Its flocculation properties were evaluated with clay suspensions using standard jar tests. The concentration of monomers, concentration of initiators, reaction temperature and solution pH on the influence of intrinsic viscosity and flocculation properties of production were studied. The results demonstrate that the branched polymer can be used as a kind of novel flocculant in water and wastewater treatment.

Abstract: Through creep-recovery and dynamic experiments, the viscoelasticity of polyacrylamide solutions (in short polymer) with different mass concentration are studied, the proportions of elastic part and viscous part in the polymer solution are calculated and the limit of mass concentration called high concentration polymer solution is given. It is indicated that the elastic part of the polymer solution increases firstly and tends to be constant with the increase in mass concentration under low external force condition. The minimum mass concentration of the polymer solution keeping constant elastic part is 1500mg/L. Under low stress and low shear rate conditions, the viscous part of the polymer solution is greater than that of elastic part; but under oil reservoir shear rate (6.283s-1) condition, the elastic part is greater than viscous part, and its elastic part increases with the increase in mass concentrations and the increment becomes smaller.

Abstract: The pH and electric responsive composite hydrogels were prepared by in situ polymerization in the presence of graphene oxide (GO). Their structure and properties were characterized by scanning electron microscopy, Raman microscopy and mechanical testing. The results indicate that the GO is evenly dispersed in the composite hydrogels and the mechanical properties of the GO based composite hydrogels are significantly improved. Most importantly, the composite hydrogels were responsive to external stimuli such as pH and electric field.

Abstract: It is significant to make researches on drag reduction in two-phase transport pipeline because two-phase flow has high energy dissipation. API X 52 steel pipe with diameter of 40mm is used in this paper to simulate pipeline with different inclination geometry including horizontal, up-inclined and vertical sections. The up-inclined section has an inclination angle of eight degree. Experiments and theoretical analysis are carried out to study the drag reduction characteristics of gas-liquid two-phase flow in these three sections. The drag reducing agents used here is polyacrylamide. It is found that two-phase drag reduction varies with pipe inclination geometry. The largest drag reduction efficiency occurs in horizontal pipes and which is up to seventy percent. Drag reduction efficiency in up-inclined section is up to sixty percent. Drag reduction in vertical section is the lowest and which can be up to about thirty percent. A mechanistic drag reduction model is proposed to predict drag reduction in gas-liquid two-phase flow. The results predicted are in good agreement with the experiment data.

Abstract: A study was made on plasma-initiated polymerization of polyacrylamide (PAM) with high superabsorbent property. The viscosity-averaged molecular weight Mη of this PAM was 6.2×106g/mol in the measurement of viscosity by using water as solvent. Its conversion and water absorption calculated are 70% and 300g/g respectively. The effects of plasma discharge time, polymerization temperature and duration on the conversion and the molecular weight of the products were also investigated. The results of this study suggested that the method of plasma initiated polymerization could greatly enhance the molecular weight and water absorption property of the polymer.