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研究了混合办公废纸脱墨的选择性凝聚技术,在废纸浆中添加分散在水中并不与水相溶的长链烷作凝聚剂,这些凝聚剂选择性地将印刷墨粉通过液桥连结在一起,且形成大颗粒的球形聚团,再分选脱除。研究表明只需要加入占纸重量4%的廉价长链烷,即可获得95%以上的脱墨率。因此在混合办公废纸脱墨时加入凝聚剂进行液桥凝聚,可降低脱墨浆中的尘埃度并增加产品的白度。 相似文献
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在水处理技术中,各种铝盐化合物作为无机凝聚剂而广泛应用于从天然水和废水中去除各种胶体微粒和溶解性有机杂质,向水中投加铝盐化合物,首先发生水解反应而生成各种羟基铝离子。大量的研究及水处理实践都证实,水解羟基铝离子是促使胶体微粒凝聚脱稳的活性形态,不同的羟基铝离子可能具有不同的凝聚能力。许多现代凝聚理论都是基于水解铝络离子与胶体微粒间的相互作用来阐述铝的凝聚机理。因此,铝的水化学反应及其形态组成的研究,是深入探讨和研究铝凝聚机理,控制最优凝聚剂量的基础,它始终是水处理界讨论和研究的 相似文献
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1、高分子凝聚剂 高分子凝聚剂可以定义为:“分子量由数万至一千万左右具有水溶性的线状化合物。分子中有许多活性基,吸附于水中悬浮固体颗粒之上,在颗粒之间起架桥作用并不断形成大块凝聚的物质”。 约在五十年前,这些高分子凝聚剂还 相似文献
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预处理垃圾焚烧飞灰作为碱胶凝材料混合材的研究 总被引:1,自引:0,他引:1
试验分析了垃圾焚烧飞灰的主要化学成分及矿物组成,探讨了预处理垃圾焚烧飞灰作为碱胶凝材料混合材的可能性.研究表明,垃圾焚烧飞灰主要由黏土类矿物组成,飞灰直接作为混合材参与水化过程会产生明显膨胀现象,加入30%(质量分数)飞灰制成的矿渣/飞灰试块在成型1 d脱膜时膨胀率达到15.7%,标准养护28 d后无侧压抗压强度只有12.4 MPa.对飞灰进行热活化预处理,900℃条件下活化效果最佳,同样的飞灰掺量下,试块在标准养护28 d后无侧压抗压强度达到46.0 MPa,膨胀现象消失,且碱胶凝材料中重金属稳定性良好. 相似文献
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研究了吹脱-沸石吸附法处理荧光粉生产废水.正交试验结果表明:氨吹脱工艺中影响NH3-N去除率因素的重要性顺序为:pH>温度>气液比.当pH=11、气液比(V/V)=100:1、温度T=40℃、吹脱时间t=120 min,吹脱工艺对荧光粉生产废水中NH3-N的去除率为74.46%.试验确定的沸石吸附单元较佳的工艺参数为:滤速0.04 m/min、接触时间14min、pH=7.5,吹脱-沸石吸附工艺总NH3-N去除率96.04%.试验结果表明再生沸石氨吸附性能稳定,适于高氨氮的荧光粉生产废水处理. 相似文献
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在自制0.2 t/h气动超声吹脱实验装置中,通过自主研发的纳米复合脱氮剂(CT-601)与气动超声波的耦合作用,在不同氨氮初始浓度、吹脱时间、CT-601投加量、气液比等条件下对高浓度氨氮废水进行研究。结果发现,在常温下p H=11、气液比=900∶1、脱氮剂投加量为0.0848 g/L时,超声吹脱60 min,处理2 000 mg/L的模拟废水时,去除率可达到93%以上,处理浓度为2 156 mg/L的实际废水时,去除率达到90%以上,较普通吹脱法和超声吹脱法分别提高40%和10%。同时还发现,该装置对COD去除率为29.72%,运行成本也只有7.24元/m3。 相似文献
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为提高供气式低压射流曝气器中气液混合效果、提高氧传质速率,基于射流曝气器内部结构解析,提出了混合室增设分散孔板、双管进气等优化改进方案。应用FLUENT软件对射流曝气器改进前后混合室气液两相混合效果进行三维数值模拟研究,模拟结果表明,增设分散孔板可显著增加混合室湍流强度、提高气液两相混合效果,孔板设置于进气孔前更利于氧传质效率的提升;增设射流曝气器对称进气口可使气液两相在混合室内分布更加均匀,增大气液两相接触面积,促进气液两相混合。根据模拟结果加工改进型供气式射流曝气器,并进行清水充氧实验,在不同实验参数下,改进射流曝气器的标准氧传质系数、标准氧传质速率、标准氧传质效率和标准曝气效率与改进前相比分别提高19.81~20.30%、30.84%~41.87%、9.84%~25.97%、3.78%~20.56%。 相似文献
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《国际环境与污染杂志》2011,11(2):211-227
Egypt is facing a major crisis due to the 1997's 40% increase in the price of imported newsprint. This price increase not only affected the press and publishers, but also placed a burden on the educational system, because most of the government textbooks depend on this type of imported paper. This crisis can be solved entirely by recycling waste paper and depending on recycled paper instead of imported paper. An experimental test facility for paper recycling was designed, manufactured and tested at the American University in Cairo (AUC). The system consists of a shredder, a beater to produce pulp, a flotation cell to remove the ink mechanically, a hand-sheet machine to produce test paper and a press/dryer to dry the paper. The paper produced was tested for physical (tear and tension) and optical (brightness and opacity) properties at different times and temperatures. The system proved to be very efficient. 相似文献
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《Atmospheric environment (Oxford, England : 1994)》1999,33(15):2301-2312
This paper reports effects of reactions between ozone and selected terpenes on the concentrations and size distributions of airborne particles in a typical indoor setting. The studies were conducted in adjacent, identical offices. In the first set of experiments, known concentrations of ozone and a selected terpene (either d-limonene, α-terpinene, or a terpene-based cleaner whose major constituent is α-pinene) were deliberately introduced into one of the offices while the other office served as a control. Subsequent particle formation and redistribution were monitored with an eight-channel optical particle counter. Particle formation was observed in each terpene system, but was greatest in the case of d-limonene. The number of particles in the 0.1–0.2 μm diameter size range was as much as 20 times larger in the office with deliberately supplemented ozone and d-limonene than in the office serving as the control. The concentration differences in the larger size ranges developed with time, indicating the importance of coagulation and condensation processes in this indoor environment. In the second set of experiments, d-limonene was deliberately introduced into one of the offices, but ozone was not supplemented in either office; instead, the indoor ozone concentrations were those that happened to be present (primarily as a consequence of outdoor-to-indoor transport). In the office that contained supplemental d-limonene, the concentrations of the 0.1–0.2 μm particles tracked those of indoor ozone (the limiting reagent) and were as much as 10 times greater than levels measured in the comparable office that did not contain supplemental d-limonene. The results demonstrate that ozone/terpene reactions can be a significant source of sub-micron particles in indoor settings, and further illustrate the potential for reactions among commonly occurring indoor pollutants to markedly influence indoor environments. 相似文献
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Fenton氧化对制浆造纸废水分子量及可生化性变化的影响 总被引:1,自引:0,他引:1
以制浆造纸废水的初沉池出水为研究对象,对不同剂量的Fenton氧化试剂处理制浆造纸厂初沉废水的效果进行了研究,初沉废水中的分子量大于10 000的有机污染物含量占到83%,废水可生化性较差;在Fe2+与H2O2的摩尔比为1∶5,废水pH为3.5的条件下,H2O2(30%)投加量小于3.25 mL/L时,Fenton试剂的氧化效率更高;H2O2(30%)投加量为6.50 mL/L时,废水中污染物的去除率更高,其中废水COD的去除率为79.5%,AOX的去除率为75.3%,色度去除率为97.5%,同时处理后废水中分子量在500~3 000之间的有机物含量占到82.98%,废水的BOD5/COD值提高到0.56。Fenton氧化作为前置技术处理制浆造纸废水,可以降低废水中的有机物分子量,减少废水的生物毒性,增加废水生物降解性,有助于后续生物处理的正常运行。 相似文献
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Structure-activity relationships for association of linear alkylbenzene sulfonates with activated sludge 总被引:4,自引:0,他引:4
Sorption of linear alkylbenzene sulfonates (LAS) on sludge particles from wastewater treatment plants was studied. The effect of alkyl chain length and the water hardness were investigated. Sorption on sludge increases with increasing alkyl chain length in the LAS molecules. The results are interpreted in terms of a hydrophobic bonding mechanism being the critical micelle concentration a good index of the surfactant hydrophobicity. The increase in free energy of adsorption for the addition of successive methylene groups to the alkyl chain was estimated as 2.4 kJ/mol. Water hardness clearly enhances the sorption of LAS homologues on sludge and seems to promote cooperative sorption at high surfactant and calcium ion concentrations. An empirical equation was provided that allow to estimate the partition coefficient between aqueous and solid phases for LAS homologues as a function of the alkyl chain length and the water hardness. 相似文献
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Thacker NP Nitnaware VC Das SK Devotta S 《Environmental science and pollution research international》2007,14(4):225-226
Samples of effluents, sludge, pulp, final products (paper) and soil were collected from the identified pulp and paper mills
in India. The samples were analysed for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxin congeners and
precursors. Pulp and paper mills using chlorine for the bleaching process showed the presence of 2,3,7,8-TCDD in effluent
samples. In the effluent and pulp samples from mills where chlorine dioxide was used as a bleaching agent, the 2,3,7,8-TCDD
congener ranged from below the detection limit 0.05 to 0.12 ngL−1/ngg−1. The relative standard deviation of reproducibility and the percent recovery of 2,3,7,8-TCDD were 2.07 and 82.4% in pulp
and 2.8 and 92% in effluent, respectively. The 1,3,6,8-TCDD was the only other major dioxin congener found in the treated
and untreated effluent and sludge samples. However, dichlorobenzene, trichlorophenyl, and hexachlorobiphenyl were detected
in all samples. The formation of dioxins can be minimised by replacing chlorine with chlorine dioxide in bleaching processes
in pulp and paper mills. 相似文献
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M. Taheri S.A. Beg M. Beizaie 《Journal of the Air & Waste Management Association (1995)》2013,63(10):794-798
An attempt was made to demonslrate the utility of a wetted butterfly valve for cleaning flue gases from industrial wastes. Butterfly valves are extensively in use to control the gas pressures in various processes. A small pilot plant with a maximum airflow rate of 400 cfm and water flow rate of 4 gpm was constructed to provide the desired testing conditions. The results indicate that for a pressure drop greater than 30 in. water a collection efficiency of greater than 95% for submicron particles can be obtained. For particles larger than 1.7;u diameter efficiencies of greater than 99% were obtained. The exceptional suitability of wet butterfly valves for gas cleaning is demonstrated by the flexibility to adjust to large variations of gas and liquid flow rates. 相似文献
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A novel paper-based material containing titanium dioxide (TiO2) photocatalyst was successfully prepared by a papermaking technique with the internal addition of inorganic fibers on which TiO2 particles were supported. Photodegradation performance of acetaldehyde gas, an indoor pollutant, and the durability of the TiO2-containing papers were investigated under UV irradiation. Ceramic fiber suspension and polydiallyldimethylammonium chloride as a cationic flocculant were mixed, followed by the addition of TiO2 suspension and anionic polyacrylamide. Subsequently, the inorganic mixture was poured into a pulp suspension, and TiO2 handsheets then prepared by a papermaking method. The tensile strength of TiO2-containing paper without a ceramic carrier decreased by more than 30% after 240-h UV irradiation (2 mW/cm2), although the strength of the TiO2 sheet with ceramic fibers remained reasonably stable. The efficiency of acetaldehyde decomposition by the TiO2 paper containing an inorganic carrier was nearly equal to that of the carrier-free TiO2 paper. Scanning electron microscopic observation suggested that most TiO2 particles were predominantly supported on the inorganic fiber matrix, and were mostly out of contact with organic pulp fibers. The TiO2 paper with an inorganic carrier demonstrated both excellent photocatalytic performance and durability, which before had been mutually incompatible for organic materials containing TiO2 photocatalyst. The two-stage mixing procedure for TiO2 sheet-making is promising for the simple manufacture of high performance paper with photocatalytic ability. 相似文献
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Nitin R. Patel 《Journal of the Air & Waste Management Association (1995)》2013,63(4):291-292
Abstract Submicron particles play a major role in soiling processes and contribute to corrosion, current leakage and shorts in electronic equipment. For more than a year, optical particle counters have been used to continuously measure the concentrations of submicron particles at a telecommunications facility in Southern California. Separate instruments have simultaneously sampled at four locations: the outdoor air intake, immediately upstream of the HVAC filters, immediately downstream of the HVAC filters, and inside the office. The indoor concentrations can be explained in the context of a one-compartment mass balance model. Key parameters in the model (e.g., the air exchange rate) were monitored throughout the sampling period. In the latter part of this study, the particle counters were used as feedback elements in the HVAC system. An estimate of the concentration of indoor submicron particles, based on measurements of outdoor submicron particles, has been used as a control variable. When this variable exceeds a preset value, the outdoor air damper is partially closed, reducing the amount of outdoor air entering the building. That is, the position of the damper is based on the concentration of outdoor particles as well as the outdoor temperature. As a consequence, the average indoor concentration of submicron particles has been significantly reduced within this facility. 相似文献