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1.
Yun‐Hwei Shen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(5):581-586
A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na+‐saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm?3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face‐to‐face interactions of platelets and effectively entrapped TiO2 particles in band‐type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO2 particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry 相似文献
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Poly (vinyl butyral) (PVB) hollow fiber membranes were fabricated via thermally induced phase separation (TIPS). The effects of coagulation bath temperature (CBT) on the structure and performance of membranes were investigated in detail. The morphologies of the membranes were studied by scanning electron microscopy (SEM), the performances of water permeability, rejection, breaking strength and elongation were measured, respectively. The results indicate that all the membranes have the asymmetric morphology and the thickness of the skin layer decreases and the pore size of the outer layer increases with the increase of CBT. The permeability of membranes prepared at air gap 1.0 cm and take-up speed 0.253 m/s increases from 1.047×10-7 to 5.909×10-7 m3/(m2·s-kPa) with the CBT increasing from 20 ℃ to 40℃, and sharply increases to 35.226×10 7 m3/(m2.s.kPa)once the CBT arrives at 50 ℃. While the carbonic ink rejections have no significant decrease, totally exceed 98%, but that of acid-maleic acid copolymer greatly decreases with the increase of CBT. Both the breaking strength and elongation decrease with the increase of CBT. 相似文献
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通过比较不同混凝剂对西流湖水的混凝效果,找出最佳混凝剂和最佳投混凝条件,从而达到提高混凝效率和出水水质的目的。 相似文献
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本文阐述了结团凝聚的基本原理及优越性。认为在结团工艺中,PAC的主要作用是使水中颗粒脱稳凝聚形成理想的初始粒子;而PAM的主要作用是增强初始粒子同结团体间的结合强度,由此亦决定了PAC和PAM投加位置的不同。通过实验研究,得出了PAC和PAM对分析指标Ct、ρe、dp的影响规律和它们的适宜范围。 相似文献
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Dong Liang Wenqia Wang Yu Cheng 《International journal for numerical methods in engineering》2009,80(3):338-354
In the paper we consider the non‐linear aerosol dynamic equation on time and particle size, which contains the advection process of condensation growth and the process of non‐linear coagulation. We develop an efficient second‐order characteristic finite element method for solving the problem. A high accurate characteristic method is proposed to treat the condensation advection while a second‐order extrapolation along the characteristics is proposed to approximate the non‐linear coagulation. The method has second‐order accuracy in time and the optimal‐order accuracy of finite element spaces in particle size, which improves the first‐order accuracy in time of the classical characteristic method. Numerical experiments show the efficient performance of our method for problems of log‐normal distribution aerosols in both the Euler coordinates and the logarithmic coordinates. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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YIN Zhao-qin LIN Jian-zhong 《水动力学研究与进展(B辑)》2007,19(5):533-541
The Large Eddy Simulation (LES) method has been used to solve the fluid momentum equations coupled with a convection-diffusion equation to study the formation of pollutant nanoparticles in a vehicular exhaust with impinging twin-jet. The functions of the space (S) between the two jets and the distance (H) from the exit of nozzle to the impingement plane are evaluated according to the distributions of pollutant nanoparticles. The results show that the nucleation produces a large number of nanoparticles, and gas-to-nanoparticle conversion mostly takes place in the interface region of the two jets, the circumambience of the jets, and region near the plane. The maximal particle size and maximal number concentration produced by both nucleation and coagulation appear around the region of free jet and the region near the plane, respectively. The significant differences for various spaces between the two jets are the number concentration and size distributions in the interface region of the two jets. For the case with larger space, more nanoparticles are produced by nucleation and coagulation. The more the distance from the exit of nozzle to the impingement plane, the lower is the number concentration and the fewer the particles distribute near the plane. Increasing the distance from nozzle to plane is beneficial to the reduction of nanoparticle formation. 相似文献
10.
Algane Waungana Harjinder Singh Rodney J. Bennett 《Food research international (Ottawa, Ont.)》1996,29(8):715-721
Skim milk and ultrafiltered milk were heated at temperatures in the range 80–140 °C for 4s in a UHT plate heat exchanger. The extent of denaturation of β-lactoglobulin and its association with the casein micelles increased with increase in heating temperature; the extent of association was markedly less than the amount that denatured. There was no noticeable difference in the extent of denaturation and association of β-lactoglobulin between skim milk and the corresponding ultrafiltered milk. The coagulation properties of renneted heated milks were measured by dynamic oscillation rheometry. Gelation times and storage modulus (G′) could be related to the extent of denaturation of β-lactoglobulin and its association with the casein micelles. Denaturation of β-lactoglobulin up to 60% had no effect on the gelation time, but additional denaturation markedly increased the gelation times. In contrast, G' decreased gradually with increase in the extent of denaturation of β-lactoglobulin and its association with casein micelles. The effects of β-lactoglobulin denaturation and association on coagulation properties were less pronounced in ultrafiltered milk. G' values for ultrafiltered milk were markedly higher than the corresponding skim milks under all heating conditions. 相似文献