间位芳纶溶解及凝固性能研究

以二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)、1-甲基-2-吡咯烷酮(NMP)为溶剂,分别加入LiCl和CaCl_2制备溶解体系,研究了间位芳纶在这几种溶解体系中的溶解性能。再以H_2O-DMAc、H_2O-DMF、H_2O-DMSO、H_2O-NMP为凝固浴,研究了溶剂种类、芳纶溶液质量分数、离子浓度等对间位芳纶溶液的凝固性能的影响。结果显示:Li Cl-DMAc溶解体系具有更强的溶解性能;凝固值随凝固浴中凝固剂H_2O的含量的增加不断减小,而临界浓度几乎没有变化;随着凝固浴温度的增加,凝固值增大,临界浓度减小;凝固值随凝固浴中离子浓度的升高而增大,但临界质量分数则不断降低。另外,间位芳纶溶液的扩散系数随着凝固浴中H_2O的含量的减少不断减小,随着芳纶浓度的增加不断减小。     

Mathematical simulation of wet spinning coagulation process: Dynamic modeling and numerical results

A dynamic model of polymer wet spinning coagulation process is proposed in this article. The model is based on the double diffusion phenomenon, phase separation process, continuity balance, and momentum balance of the entire coagulation process. The uniqueness of the model lies in its dynamic feature. The model can simulate the system's dynamic response to variations in system inputs/parameters. Steady‐state system solutions can also be produced as the long‐time solutions of the dynamic model; a settling time can be observed at the same time. This paper employs a computationally efficient method of lines numerical algorithm for solving the dynamic model. A simulation experiment on a selected non‐solvent‐solvent‐polymer ternary system is carried out to verify the model as well as the numerical method. The dynamic simulation results are analyzed and discussed. At the end of the article, h‐refinement and p‐refinement are used to confirm the spatial convergence of the numerical solutions. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3432–3440, 2016     

Simulation,model‐reduction,and state estimation of a two‐component coagulation process

The issue of state estimation of an aggregation process through (1) using model reduction to obtain a tractable approximation of the governing dynamics and (2) designing a fast moving‐horizon estimator for the reduced‐order model is addressed. The method of moments is first used to reduce the governing integro‐differential equation down to a nonlinear ordinary differential equation. This reduced‐order model is then simulated for both batch and continuous processes and the results are shown to agree with constant Number Monte Carlo simulation results of the original model. Next, the states of the reduced order model are estimated in a moving horizon estimation approach. For this purpose, Carleman linearization is first employed and the nonlinear system is represented in a bilinear form. This representation lessens the computation burden of the estimation problem by allowing for analytical solution of the state variables as well as sensitivities with respect to decision variables. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1557–1567, 2016     

混凝—磁分离—电化学技术处理压裂返排液研究

对页岩气开采中压裂返排液的组成、特性及处理现状进行分析,提出采用破胶混凝—磁分离—电化学催化氧化技术处理压裂返排液。研究得到各处理单元优化工艺,其中破胶混凝工艺采用高铁酸钾破胶剂、投加量2 500 mg/L,混凝剂聚合氯化铝铁投加量为2 000 mg/L,反应p H为11.0,反应时间40 min;磁分离工艺采用纳米磁铁粉,投加量4 000 mg/L,高分子絮凝剂阴离子聚丙烯酰胺投加量为20 mg/L;电化学催化氧化工艺采用Ti/Ti O_2作阳极,不锈钢作阴极,氧化电压10.0 V,电流密度1.6×10-2 A/cm2,体系p H为11.0,反应时间30 min。研究结果表明,采用上述技术及优化工艺处理压裂返排液,处理后COD、SS、油、色度、p H等主要指标均达到GB 8978—2002的一级排放标准要求。     

食品添加剂废水综合处理

通过分析食品添加剂废水成分,探讨了现有混合废水处理工艺存在的问题,提出了在现有混合废水处理工艺前增设预处理工序的方案。对混合废水通过Fenton氧化、混凝沉淀等方法进行预处理后,现有污水处理工艺可以正常运行。工艺改造后的运行结果表明:经过预处理的混合废水再经原废水站处理后,出水水质能达到工业园区废水接管标准。由于混合废水得到综合利用,废水排放量也相应减少。     

发制品废水处理技术研究进展

阐述了在发制品废水处理中常用的单元技术,包括微电解法、混凝法、吸附法、高级氧化法和生物处理法,分析了它们的处理机制、处理效果及优缺点,并对处理发制品废水的组合工艺进行了分析。在此基础上指出优化适合发制品废水特点的高效混凝、高效厌氧、强化硝化、高级氧化等单元技术,并进行合理的技术集成是今后发制品废水处理的发展方向。     

Reliable high strength alumina fabricated by DCC-HVCI using submicron calcium citrate complex

Ceramics with high strength and reliability are highly demanded in engineering applications. In this paper, a modified direct coagulation casting via high valence counter ions (DCC-HVCI) method for alumina using calcium citrate complex assisted by glycerol diacetate was investigated. Calcium citrate complex suspensions were prepared by mixing tri-ammonium citrate and calcium chloride in water. Effect of reaction time on the chelating properties of the prepared suspensions was investigated. Concentrated alumina suspensions with a solid loading of 50 vol% were prepared by mixing the calcium citrate complex suspensions and alumina powder at pH of 10.5. Then the suspensions were coagulated by adding 3–6 vol% glycerol diacetate at temperatures of 40–70 °C for 2–6 h. The compressive strength of the coagulated wet samples is in the range 1.1–2.4 MPa. Alumina ceramics sintered at 1550 °C shows homogeneous microstructures with flexural strength and Weibull modulus of 455±17 MPa and 30, respectively.     

A novel approach to prepare large-scale and narrow-dispersed latex particles by emulsion polymerization based on particle coagulation mechanism

In order to understand the mechanism of narrow particle size distribution of the final latex during particle coagulation, a series of experiments were performed to investigate the effect of polymer nature on particle coagulation capability. In particular, thermodynamics and kinetics in aqueous phase were considered to illustrate the detail process of particle coagulation. The final particle size decreased with the increasing side chain length of alkyl methacrylate from 181.5 nm in MMA to 131.6 nm in EMA, 119.3 nm in PMA, and 115.1 nm in BMA, indicating that the particle coagulation capability was proportional to the hydrophilicity of polymer. With increasing polymer hydrophilicity, the affinity between surfactant molecules and particle surface decreased, thus enhancing the particle coagulation capability. Moreover, the critical length of oligomer radical also increased with increasing hydrophilicity and the efficiency of radical capture decreased, thus increasing the saturation of monomer concentration in the inner part of particle, promoting particle coagulation. Combining these results and the La Mer Diagram, a novel approach was developed to prepare large-scale, narrow-dispersed, and high solid content polymer latex based on particle coagulation mechanism. Three criteria, namely, rapid nucleation, fast coagulation, and a long growth period, should be met to produce latex with a narrow particle size distribution.     

新型多功能季铵化抗菌材料的制备与应用

综述了近年来在抗污、超滑/超亲水、可降解、促凝血、促细胞生长等新型多功能季铵化抗菌材料的分子设计和潜在应用方面取得的研究进展,指出在抗菌的同时并具有以上所提及的多种功能是抗菌材料发展的一大趋势。举例说明通过原子转移自由基聚合（ATRP）技术,合成的星状聚合物（POSS-g-PDMA）,在季铵化后具有了极高的抗菌活性、相对非血溶性和可降解性。高度季铵化的基于二甲基癸基铵壳聚糖-接枝-聚(乙二醇)甲基丙烯酸酯(DMDC-Q-g-EM)和聚(乙二醇)二丙烯酸酯的抗菌水凝胶兼具抗菌和抗真菌活性、生物相容性和可重复使用性。最后对新型多功能季铵化抗菌材料的未来发展方向进行了展望。