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几种聚电解质的合成及絮凝性能研究 总被引:3,自引:0,他引:3
合成了5种水溶性聚电解质:①丙烯酰胺-二甲基二烯丙基氯化铵共聚物(AM-DM);②丙烯酰胺-三甲基烯丙基氯化铵共聚物(AM-TM);③水解聚丙烯酰胺(HPAM);④阳离子化聚丙烯酰胺(CPAM)和⑤丙烯酰胺-二甲基二烯丙基氯化铵-丙烯酸(AM-DM-AC)共聚物。对它们的结构进行了红外表征,并就絮凝能力进行了研究。结果表明:5种聚合物均具有絮凝能力且出现两个聚沉点,絮凝能力与聚合物的链结构有关。 相似文献
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Tina Heger Anna T. Pahl Zoltan Botta-Dukát Francesca Gherardi Christina Hoppe Ivan Hoste Kurt Jax Leena Lindström Pieter Boets Sylvia Haider Johannes Kollmann Meike J. Wittmann Jonathan M. Jeschke 《Ambio》2013,42(5):527-540
Invasion ecology has much advanced since its early beginnings. Nevertheless, explanation, prediction, and management of biological invasions remain difficult. We argue that progress in invasion research can be accelerated by, first, pointing out difficulties this field is currently facing and, second, looking for measures to overcome them. We see basic and applied research in invasion ecology confronted with difficulties arising from (A) societal issues, e.g., disparate perceptions of invasive species; (B) the peculiarity of the invasion process, e.g., its complexity and context dependency; and (C) the scientific methodology, e.g., imprecise hypotheses. To overcome these difficulties, we propose three key measures: (1) a checklist for definitions to encourage explicit definitions; (2) implementation of a hierarchy of hypotheses (HoH), where general hypotheses branch into specific and precisely testable hypotheses; and (3) platforms for improved communication. These measures may significantly increase conceptual clarity and enhance communication, thus advancing invasion ecology. 相似文献
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In this study, a new and facile route was employed for synthesis of polyamidine with abundant cations and attractive five-membered ringlike structural unit. N-vinylformamide and acrylonitrile copolymerized firstly to form intermediates, and the intermediates were processed with hydrochloric acid to produce polyamidine. A series of polymerization conditions (e.g. polymerization time, temperature and dosage of initiator) were optimized through productivity, viscosity and cationic degree as evaluation. SEM analysis illustrated that the amidinization process could reduce the size of spaces between molecular and created compact structure, which would contribute to good flocculation performance and high viscosity. FT-IR, XPS and NMR spectra presented a rather clear structure of polyamidine. 34.3% of sludge was sedimentated through the flocculation of polyamidine in the early stages. In contrast, only 6.8% of sludge was sedimentated by polyacrylamide. The moisture content in dehydrated floc could be reduced to 77.7% when 60 mg/L polyamidine was added. These results demonstrated that the polyamidine showed a great potential in the practical application of sludge dewatering. 相似文献
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Trichoderma spp. biosynthesize 6-pentyl-2H-pyran-2-one (6-PP), a natural antifungal pyrone which could be used as biological control agent (BCA). Unfortunately, biotechnical processes are limited by inhibition of biomass at high concentration of 6-PP. We report herein a new easy synthesis of this natural pyrone, using readily available starting materials. This synthesis, compatible with a large production scale, permit to obtain overweight amounts of 6-PP that in biotechnological routes. 相似文献
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The synthesis of distributed wastewater treatment plants (WTPs) has been studied to reduce capital and operating costs associated with wastewater treatment. In this study, the environmental and economic feasibility of a total wastewater treatment network system (TWTNS) including distributed and terminal WTPs was estimated using life cycle assessment (LCA) and life cycle costing (LCC) methods. Wastewater sources and existing distributed and terminal WTPs in an iron and steel plant were networked. The TWTNS was generated from the optimal solution to a mathematical optimization model and compared to a conventional wastewater treatment system (CWTS). The environmental effect scores of the TWTNS were from 29.6% to 68.3% higher than those of the CWTS because of higher electricity consumption required to pump wastewater to the networked WTPs. However, the life cycle cost of the TWTNS was lower than that of the CWTS by 10.1% because of the decrease of the labor cost resulting from the closing of three distributed WTPs. Overall, the TWTNS was no more eco-efficient than the CWTS because the increase of environmental burdens outweighed the decrease of economic costs. 相似文献
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Mojtaba Mirfendereski Mohtada Sadrzadeh Toraj Mohammadi 《International Journal of Greenhouse Gas Control》2008,2(4):531
In this research, nanoporous zeolite T membranes were synthesized at three levels of synthesis temperature: 100, 120 and 140 °C and synthesis time: 15, 30 and 50 h and characterized by gas permeation. Effects of synthesis parameters on CO2 and CH4 permeances and CO2/CH4 ideal separation factors were studied. All experiments were conducted at 1 bar feed pressure and 30 °C module temperature. Normally, it is anticipated that increasing synthesis temperature and synthesis time increase gas permeances and consequently decrease ideal separation factor. This prediction was not observed in the case of synthesis temperature increase from 100 to 120 °C as well as synthesis time increase from 15 to 30 h, due to the dual effect of increasing synthesis temperature and synthesis time on gas permeances and ideal separation factor. More zeolites are deposited and larger crystals are formed at higher synthesis temperatures and times. Forming the larger crystals accelerates the rate of zeolite layer integration, which is responsible for gas separation, in one hand and reduces the density of deposited zeolite layer on the support, due to the formation of more voids, on the other hand. In terms of maximizing the CO2/CH4 ideal separation factor, medium synthesis temperature and synthesis time (120 °C and 30 h) can be selected, however, maximum gas permeances are obtained at low levels of synthesis temperature and time (100 °C and 15 h). According to the ranges of gas permeances (10−11 to 10−6 mol/m2 s Pa) and CO2/CH4 ideal separation factors (1.4–70.3), it is concluded that the zeolite T membranes synthesized at optimum conditions can be employed for membrane separation of CO2/CH4 mixtures. 相似文献
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Teza Mwamulima Xiaolin Zhang Yongmei Wang Shaoxian Song Changsheng Peng 《Frontiers of Environmental Science & Engineering》2018,12(2):2
In the present study, a novel approach was used to control zero valent iron aggregation and separation problems by fixing zero valent iron (ZVI) on bentonite-fly ash pellets. For this purpose, porous low cost bentonite-fly ash (BFA) pellets with size of 2.00 cm in length and 0.35 cm in diameter were prepared and fixed with ZVI to manufacture zero valent iron bentonite-fly ash (ZVI-BFA) pellets. Importantly, unlike powdered adsorbents, ZVI-BFA can easily be separated from final effluents when exhausted without any disintegration. The performance of the developed novel adsorbent was investigated for the removal of Pb2+ and Cd2+ from aqueous media. At 100 mg·L–1 and 1 g adsorbent, a maximum of 89.5% of Cd2+ and 95.6% of Pb2+ was removed by ZVI-BFA as compared to 56% and 95% removal by BFA. At 200 mg·L–1, Cd2+ and Pb2+ removal by ZVI-BFA was 56% and 99.8% respectively as compared to only 28% and 96% by BFA. Further, the removal kinetics was best fitted for pseudo-second order model. The study provides the basis for improving the removal capacity of porous materials by iron fixation while taking separation ability into consideration.
相似文献
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Chemical synthesis and physical properties of two mercapturic acids suggested as urinary metabolites of m- and p-xylenes ace described. These compounds may be used for the identification and quantivative determination by high-performance liquid chromatography of the corresponding mercapturic acids in urine. 相似文献