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The degradation of polyacrylamide (PAM) in simulate wastewater was studied in UV/Fenton/C4H4O62? system. The factors such as molecular ratio of H2O2/Fe2+/C4H4O62?, pH, and the dosage of Fenton reagent that could affect the PAM degradation in the UV/Fenton/C4H4O62? system were investigated. The experimental results showed that adding C4H4O62? to UV/Fenton system could form photosensitive ferrous complexes, which led to higher degradation efficiency of PAM. The degradation rate of PAM could be up to 95.2% under the following conditions: the concentration of H2O2, Fe2+, and C4H4O62? were 22.5, 2.25, and 2.25 mmol/L, respectively (i.e., molecular ratio of H2O2/Fe2+/C4H4O62? was 10:1:1), the pH value was 3.0. 相似文献
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Mona Akbar Muhammad Farooq Saleem Khan Ling Qian Hui Wang 《Frontiers of Environmental Science & Engineering》2020,14(6):98
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Development of the DGT technique for Hg measurement in water: comparison of three different types of samplers in laboratory assays 总被引:1,自引:0,他引:1
The Diffusive Gradients in Thin films (DGT) technique is an operationally defined method to determine the dissolved fraction of trace elements in water. The aim of this study was to develop this technique for the measurement of the bioavailable mercury species in natural waters. For that purpose, three types of DGT units (commercial, manufactured with agarose diffusive gel (DG) and manufactured with polyacrylamide DG) were tested under controlled conditions using an Hg(II) solution both with and without dissolved organic matter (DOM). An acid digestion method using aqua regia was optimised to efficiently digest the resin gel discs prior to analysis. A good performance was obtained for the three DGT types when deployed in a DOM-free mercury solution in the laboratory, and it was demonstrated that polyacrylamide gel can be used as diffusive layer for mercury sampling. However, when the DGT units were deployed in a mercury solution containing DOM, performance differences were observed. Furthermore, the mass of background mercury (blanks) varied among the different DGT types. In the light of the results, the devices manufactured with polyacrylamide DG seemed to be the best choice for dissolved mercury determination. 相似文献
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UASB反应器中加入膨润土和聚丙烯酰胺培养颗粒污泥 总被引:9,自引:0,他引:9
使用一个反应体积255L的UASB反应器,处理啤酒生产废水.向接种厌氧污泥中加入膨润土和非离子型聚丙烯酰胺,采用室温下间歇式进料,4周内形成稳定颗粒污泥床.COD负荷6kg/m3·d,COD去除率为90%. 相似文献
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Column experiments and model simulations were employed to evaluate the processes involved in multicomponent solute transport in a system with heterogeneous flow. Column experiments were performed with goethite embedded in polyacrylamide gel beads. The gel forms an immobile water region that can be accessed by diffusion. A two-region transport model with diffusion into spheres was combined with a surface complexation model to predict reactive transport in the goethite-gel bead system. Chromate and sulphate breakthrough curves were measured in a set of transport experiments, along with corresponding changes in the pH of the effluent. Sorption and transport of sulphate and chromate in separate columns were predicted from independently measured sorption parameters. The model overestimated the pH changes in the effluent, possibly because of proton buffering by the polyacrylamide gel. The effect of competitive sorption on transport was examined in experiments with both anions present. The model predicted the effect of competition very well in a system initially equilibrated with sulphate, followed by infiltration with chromate. However, when sulphate was infiltrated after equilibration with chromate, chromate desorption and sulphate adsorption were clearly overestimated by the transport model. The exchange between the more strongly bound chromate and the sulphate added subsequently may be too slow to cause a substantial chromate peak in the effluent. This suggests that the local equilibrium assumption was not applicable in this case. 相似文献
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Wenzhe Song Yu Zhang Jianwei Yu Yingxin Gao Teruki Naito Gaku Oinuma Yasutaka Inanaga Min Yang 《环境科学学报(英文版)》2019,31(9):1-7
Due to the severe restrictions imposed by legislative frameworks, the removal of polyacrylamide(PAM) rapidly and effectively from produced wastewater in offshore oilfields before discharge is becoming an urgent challenge. In this study, a novel advanced oxidation process based on plasma operated in the gas–liquid interface was used to rapidly decompose PAM, and multiple methods including viscometry, flow field-flow fractionation multi-angle light scattering, UV–visible spectroscopy, and attenuated total reflectanceFourier transform infrared spectroscopy were used to characterize the changes of PAM.Under a discharge voltage of 25 kV and pH 7.0, the PAM concentration decreased from 100 to 0 mg/L within 20 min and the total organic carbon(TOC) decreased from 49.57 to1.23 mg/L within 240 min, following zero-order reaction kinetics. Even in the presence of background TOC as high as 152.2 mg/L, complete removal of PAM(100 mg/L) was also achieved within 30 min. The biodegradability of PAM improved following plasma treatment for 120 min. Active species(such as O_3 and H_2O_2) were produced in the plasma. Hydroxyl radical was demonstrated to play an important role in the degradation of PAM due to the inhibitory effect observed after the addition of an ·OH scavenger, Na_2CO_3. Meanwhile, the release of ammonia and nitrate nitrogen confirmed the cleavage of the acylamino group.The results of this study demonstrated that plasma, with its high efficiency and chemicalfree features, is a promising technology for the rapid removal of PAM. 相似文献
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Graft copolymers of polyacrylamide and various substrates were prepared by reactive extrusion in a twin screw extruder using ammonium persulfate as initiator. Substrates included unmodified starches (corn, waxy maize, wheat, and potato), cationic starches, dextrin, dextran, and polyvinyl alcohol (PVOH). The feed ratio of substrate to monomer was 2:1. Average conversion of monomer to polymer was 88.9% (±5.1%). Graft contents for the starch substrates were approximately 25% with grafting efficiencies of about 70%. Polyacrylamide graft molecular weights ranged from 317,000 to 769,000. Absorbencies at pH 7 for saponified graft copolymers prepared with unmodified starches were approximately 200 g/g and approximately 150 g/g for the cationic starches, dextran, and PVOH. In electrolyte solution (0.9% NaCl), absorbencies were in the range of 26–59 g/g, depending on substrate type. Saponified dextrin copolymers were essentially soluble with absorbencies of 6 g/g in water and 12 g/g in 0.9% NaCl.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献