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201.
202.
液膜技术及其应用研究进展 总被引:1,自引:0,他引:1
文中综述了液膜技术的传质机理、类型、特点和在废水处理领域的研究,为使该项技术能实现大规模的工业应用,目前需要解决的问题,以及近年来液膜分离技术的研究进展。 相似文献
203.
无皂乳液聚合改性废聚苯乙烯 总被引:1,自引:0,他引:1
以聚(甲基丙烯酸丁酯—丙烯酸钠)(P (BMA- AANa))为乳化剂,采用无皂乳液聚合技术,利用BMA对废聚苯乙烯(PS)泡沫塑料进行接枝改性.实验得出适宜的工艺条件:P(BMA - AANa)质量分数为51.5%,m(BMA)∶m(丙烯酸)=4∶6,PS和BMA质量分数之和为10.0%;m(PS)∶m(BMA) =... 相似文献
204.
Stability of titania nanoparticles in soil suspensions and transport in saturated homogeneous soil columns 总被引:2,自引:0,他引:2
Jing Fang Bei Wen Jin-ming Lin 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1101-1109
The stability of TiO2 nanoparticles in soil suspensions and their transport behavior through saturated homogeneous soil columns were studied. The results showed that TiO2 could remain suspended in soil suspensions even after settling for 10 days. The suspended TiO2 contents in soil suspensions after 24 h were positively correlated with the dissolved organic carbon and clay content of the soils, but were negatively correlated with ionic strength, pH and zeta potential. In soils containing soil particles of relatively large diameters and lower solution ionic strengths, a significant portion of the TiO2 (18.8-83.0%) readily passed through the soils columns, while TiO2 was significantly retained by soils with higher clay contents and salinity. TiO2 aggregate sizes in the column outflow significantly increased after passing through the soil columns. The estimated transport distances of TiO2 in some soils ranged from 41.3 to 370 cm, indicating potential environmental risk of TiO2 nanoparticles to deep soil layers. 相似文献
205.
Mehdi Mazaheri Jamal Mohammad Vali Samani Hossein Mohammad Vali Samani 《Environmental Forensics》2015,16(4):310-321
Release of pollution into rivers is required to be handled with special consideration to environmental standards. For this purpose, it is essential to specify the contribution of each pollution source in contamination of water resources. In this study, a mathematical model is proposed for determining locations and concentration release histories of polluting point sources using measured downstream river concentrations via an inverse problem framework. The inverse solution is based on the integral equation obtained from applying the Green's function method on the one-dimensional advection-dispersion contaminant transport equation. Discretization of this integral equation results in a linear, over-determined and ill-posed system of algebraic equations that are solved by using the Tikhonov regularization method. Several examples and some real field data are investigated to illustrate the abilities of the proposed model. Results imply that the proposed method is effective and can identify the pollution sources in rivers with acceptable accuracy. 相似文献
206.
采用Fenton法处理湿法腈纶聚合废水,考察了H2O2投加量、Fe2+投加量、p H和反应时间等因素对氧化和混凝作用去除废水污染物的影响,并分析了废水可生化性和特征污染物的变化。结果表明,Fenton法可以有效去除废水中有机污染物,在初始p H为3.0,Fe2+投加量为15.0 mmol/L,H2O2投加量为90.0 mmol/L的条件下,反应120 min后废水COD去除率可以达到56.8%,其中氧化和混凝作用对应的去除率分别为43.3%和13.5%;处理后废水的BOD5/COD由0.24升高至0.43;处理后废水中丙烯腈以及其他多数有机污染物能被有效去除。 相似文献
207.
采用水溶液聚合法,以丙烯酸、丙烯酰胺及改性蒙脱土为原料,纳米腐植酸为基体,N,N’-亚甲基双丙烯酰胺为交联剂,过二硫酸钾为引发剂,制备了丙烯酸-蒙脱土-丙烯酰胺/纳米腐植酸复合树脂(简称复合树脂)。考察了溶液pH、吸附时间、吸附温度、初始离子浓度等因素对复合树脂分别吸附Ni~(2+)和Cd~(2+)的影响。实验结果表明:在吸附温度35℃、吸附时间90 min、溶液pH为7、初始Ni~(2+)和Cd~(2+)的浓度分别为0.02 mol/L、复合树脂加入量16.7 g/L的条件下,Ni~(2+)和Cd~(2+)的吸附量分别为383.02 mg/g和359.27 mg/g;复合树脂吸附Ni~(2+)和Cd~(2+)的吸附等温线均满足Langmuir等温吸附方程;吸附过程均符合准二级动力学方程;复合树脂重复使用6次,其对Ni~(2+)和Cd~(2+)的吸附量分别降低了17.1%和9.3%。 相似文献
208.
K.M.S. Sundaram 《Journal of environmental science and health. Part. B》2013,48(3):541-579
Abstract Two formulation concentrates of the insecticide, RH‐5992 [N'‐t‐butyl‐N'‐(3,5‐dimethylbenzoyl)‐N‐(4‐ethylbenzoyI) hydrazine], an aqueous flowable (2F) and an emulsion‐suspension (ES), were diluted with water to provide spray mixes containing dosage rates ranging from 35 to 150 g of the active ingredient (AI)/ha. The mixes were sprayed in a laboratory chamber, onto balsam fir branch tips collected from field trees and greenhouse‐grown seedlings. Droplet spectra and spray mass recovery were determined on artificial samplers. Simulated rainfall of two different intensities was applied at different rain‐free periods, and rain droplet sizes were determined. Foliar washoff of RH‐5992 was assessed after application of different amounts of rain, and the increase in soil residues was evaluated. A direct relationship was indicated between the amount of rainfall and RH‐5992 washoff. The larger the rain droplet size, the greater the amount washed off. Longer rain‐free periods made the deposits more resistant to rain. Regardless of the amount of rainfall, rain droplet size and rain‐free period, foliar deposits of the 2F formulation were washed off to a greater extent than the ES formulation. The increase in soil residues due to foliar washoff was greater for the 2F than for the ES formulation. The deposits of the emulsion‐suspension were consistently more resistant to rain‐washing than those of the aqueous flowable formulation. 相似文献
209.
侧入式搅拌槽中多相流流场特性的数值模拟 总被引:1,自引:0,他引:1
运用计算流体力学(CFD)技术对不同安装偏角的侧入式搅拌反应器中单相及多相流场进行了数值模拟。模拟结果表明,典型安装偏角下,搅拌槽内流场是由内部围绕搅拌槽中心的高速环形上升流和外部沿搅拌槽壁面的低速下降流组成的大循环流。水平偏角既增加了整个搅拌槽流场的平均速度,有利于固体颗粒在整个搅拌槽内的悬浮性能,又增大了槽底高速流体区域的面积,因而改善了槽底固相沉积状况。竖直偏角增大了槽底高速流体区域的面积,并对槽底施加一定的冲刷作用,从而进一步降低了槽底固相沉积的可能性。无安装偏角时槽底固含率最多的地方主要积聚在搅拌器下方区域。搅拌器在水平偏角θ=10°,竖直偏角φ=5°时槽底大部分区域的固含率分布较均匀,仅在槽底搅拌器右侧的壁面区域存在小面积的固含率较高区域,在该安装偏角下整个搅拌槽的固液悬浮性能及防止底部固相沉积性能达到最佳。 相似文献
210.
进行了高浓度悬浮液的混凝实验研究。为研究混合阶段渐变剪切速率对混凝沉降效果的影响,在混合阶段分别采用固定搅拌转速和渐变搅拌转速进行实验。在混合阶段采用固定搅拌转速,当搅拌转速为210r/min时,絮体二维分形维数最高为1.8847,悬浮液浊度最低为118NTU。采用渐变搅拌转速的方法,由210r/min开始逐渐降低搅拌转速,絮体二维分形维数最大,为1.9205,处理后悬浮液浊度最小,为107NTU。在一般混凝沉降过程的规律及模型的基础上,提出了高浓度悬浮液混凝沉降过程的物理模型。 相似文献