混凝土拌合站废水沉淀性能研究

本文以商混站洗刷废水为研究对象,通过沉淀实验,利用数值模拟方法进行沉淀池设计,研究发现:商混站洗刷废水中悬浮物密度约1.4 g/cm~3,动力学直径为5.06×10~(-5)m,沉降速度为2 m/h,以不溶物浓度2000 mg/L为目标设计沉淀池,一般商混站修建面积为15 m~2的沉淀池即可满足回用要求。     

沉淀法回收废旧磷酸铁锂电池中的铁和锂

采用NaOH溶液浸泡法分离废旧磷酸铁锂电池的铝箔和正极材料,采用有机溶剂浸泡法分离正极活性物质和粘结剂,采用酸浸-沉淀法回收废旧磷酸铁锂电池中的铁和锂,考察了回收废旧磷酸铁锂电池中的铁和锂,考察了试剂浓度、固液比和反应时间等因素对处理效果的影响,实验结果表明:在NaOH溶液的浓度为0.4 mol/L,NaOH溶液与正极片的液固比(m L/g)为10的条件下,将正极废片在NaOH溶液中浸泡10 min,可以实现铝箔与正极材料的完全分离;在温度为60℃,有机溶剂与正极材料的液固比(m L/g)为10的条件下,将正极材料在有机溶剂NMP中浸泡30 min,可以实现正极活性物质与粘结剂的完全分离;在硫酸浓度为4 mol/L,液固比(m L/g)为10,反应温度为60℃的条件下,将正极活性物质在硫酸-双氧水体系中反应2 h,铁和锂的浸出率分别达到96.4%和97.0%;在浸出液的pH为3时,铁的沉淀率达到99.0%;在除去铁的浸出液中,碳酸钠的用量为200 g/L时,锂的沉淀率达到98.9%。     

660MW燃煤机组SCR流场模拟优化与喷氨优化运行

以某电厂660 MW亚临界燃煤机组SCR烟气脱硝系统为研究对象,对SCR反应器内烟气流动以及喷氨分布均匀性进行数值模拟研究。通过对比首层催化剂前烟气速度分布及NH_3浓度分布,研究了SCR反应器内均流部件对烟气流场均匀特性的影响,并且在数值模拟的基础上对喷氨方式进行了优化调整研究。研究结果表明:优化调整烟道内均流部件对速度、浓度均匀性有显著改善作用;通过分析流场不均匀性得到的分区喷氨方法能够进一步优化NH_3在烟道中分布;现场试验验证了调节喷氨格栅阀门可降低SCR反应器出口NO_x浓度。本文研究可为燃煤机组SCR系统导流板优化及实际电厂喷氨优化调试提供参考。     

Processing of alumina‐coated glass‐bonded silicon carbide membranes for oily wastewater treatment

Crack‐free γ‐Al₂O₃‐coated glass‐bonded SiC membranes were successfully prepared using a simple heat‐treatment and dip‐coating process at a temperature as low as 850°C in air. The changes in the porosity, flexural strength, flux, and oil rejection rate of the membranes were investigated while changing the initial SiC particle size. Larger SiC particles led to bigger pores, resulting in higher flux in the oily water and a lower oil rejection rate. The SiC membranes with a support prepared from 10 μm SiC powder showed an exceptionally high oil rejection rate (99.9%) with a feed oil concentration of 600 mg/L at an applied pressure of 101 kPa. The typical porosity, flexural strength, steady state flux, and oil rejection rate of the alumina‐coated SiC membrane were ~45%, ~81 MPa, 1.78×10^?5 m³ m^?2s^?1, and 99.9%, respectively.     

Graphene oxide/fluorhydroxyapatite composites with enhanced chemical stability,mechanical, and biological properties for dental applications

A novel graphene oxide‐based fluorhydroxyapatite (GO/FHA) composite is prepared using an in situ chemical synthesis method. The mechanical properties, chemical stability, in vitro bioactivity, and antibacterial properties of the as‐synthesized GO/FHA composites with different GO amounts are reported. The result shows that the mechanical properties of the composites are strongly dependent on the adding amount of GO. The result of chemical stability indicates that the substitution of fluorine (F) into the hydroxyapatite (HA) crystal has a positive effect on the dissolution resistance. The in vitro bioactivity assessment shows that the osteoblast proliferation and differentiation ability on GO/FHA composites are improved.     

Orthorhombic‐pseudocubic phase transition and piezoelectric properties of (Na0.5K0.5)(Nb1−xSbx)‐SrZrO3 ceramics

0.96(Na_0.5K_0.5)(Nb_1?xSb_x)‐0.04SrZrO₃ ceramics with 0.0≤x≤0.06 were well sintered at 1060°C for 6 hours without a secondary phase. Orthorhombic‐tetragonal transition temperature (T_O‐T) and Curie temperature (T_C) decreased with the addition of Sb₂O₅. The decrease in T_C was considerable compared to that in T_O‐T, and thus the tetragonal phase zone disappeared when x exceeded 0.03. Therefore, a broad peak for orthorhombic‐pseudocubic transition as opposed to that for orthorhombic‐tetragonal transition appeared at 115°C‐78.2°C for specimens with 0.04≤x≤0.06. An orthorhombic structure was observed for specimens with x≤0.03. However, the polymorphic phase boundary structure containing orthorhombic and pseudocubic structures was formed for the specimens 0.04≤x≤0.06. Furthermore, a specimen with x=0.055 exhibited a large piezoelectric strain constant of 325 pC/N, indicating that the coexistence of orthorhombic and pseudocubic structures could improve the piezoelectric properties of (Na_0.5K_0.5)NbO₃‐based lead‐free piezoelectric ceramics.     

Preparation of pH-sensitive amphiphilic block star polymers,their self-assembling characteristics and release behavior on encapsulated molecules

Poly(ethylene glycol) (PEG), a polymer with excellent biocompatibility, was widely used to form nanoparticles for drug delivery applications. In this paper, based on PEG, a series of pH-sensitive amphiphilic block star polymers of poly(ethylene glycol)-block-poly(ethoxy ethyl glycidyl ether) (PEG-b-PEEGE) with different hydrophobic length were synthesized by living anionic ring-opening polymerization method. The products were characterized using ¹H NMR and gel permeation chromatography. These copolymers could self-assemble in aqueous solution to form micellar structure with controlled morphologies. Transmission electron microscopy showed that the nanoparticles are spherical or rodlike with different hydrophilic mass fractions. The pH response of polymeric aggregates from PEG-b-PEEGE was detected by fluorescence probe technique at different pH. A pH-dependent release behavior was observed and pH-responsiveness of PEG-b-PEEGE was affected by the hydrophobic block length. These results demonstrated that star-shaped polymers (PEG-b-PEEGE) are attractive candidates as anticancer drug delivery carriers.     

化学实验中合作策略的研究

学生从实验中获得知识、发展培养各方面能力,在这个过程中,小组合作探究是最佳方式。相对个别学习,我们提出了小组合作学习,也就是学生进行分工合作在各自小组中共同完成学习任务,其本身也是一种学习的组织形式。作者就化学实验中如何发挥学生的合作能力进行了研究,旨在提高学生独立自主性的同时培养其团结合作能力,以适应现代教育改革的需要。     

HPLC法测定甲磺酸伊马替尼片的有关物质

目的：建立高效液相色谱法测定甲磺酸伊马替尼片有关物质的方法。方法：色谱柱为KromasilCl8（250mm×4．6mm,5肛m）,以含0．04％辛烷磺酸钠的20mmol／L磷酸二氢钠溶液（磷酸调至PH2．5）-甲醇为流动相,梯度洗脱,流速为1ml．min-1,检测波长为268nm,柱温为30℃。结果：在本方法中,甲磺酸伊马替尼的线性关系良好,r为0．9999;专属性强,甲磺酸伊马替尼与各中间体及各降解产物之间都能完全分离;精密度良好,RSD为1％。结论：该方法准确、简便、灵敏,可用于甲磺酸伊马替尼片有关物质测定。     

Effects of N,N′-Ethylenebis(stearamide) on the Properties of Poly(ethylene terephthalate)/Organo-montmorillonite Nanocomposite

Poly(ethylene terephthalate)/organo-montmorillonite (PET/OMMT) nanocomposites were melt-compounded using twin screw extruder followed by injection molding. N,N′-ethylenebis(stearamide) (EBS) was selected as a dispersing agent to improve the dispersibility and exfoliation of OMMT clay in PET matrix. Morphological properties of the PET/OMMT nanocomposites were examined by using X-ray diffraction analysis, transmission electron microscopy and atomic force microscopy. Thermal properties of the nanocomposites were characterized by using dynamic mechanical thermal analysis. It was found that the OMMT are well dispersed and exfoliated in the presence of EBS. Remarkable enhancement in impact strength and storage modulus of PET/OMMT was achieved by the addition of EBS.