碱土金属掺杂对BiFeO3陶瓷多铁性的影响

为了探究碱土金属离子掺杂对BiFeO3陶瓷多铁性的影响,采用固相法成功制备了BiFeO3以及Bi0.9 A0.1 FeO3(A=Ca、Sr、Ba)陶瓷,并对其铁电、铁磁等性能进行了研究.X射线衍射结果表明:晶体均为六方钙钛矿结构,空间群为R3 c,晶胞参数随掺杂离子半径的增大呈现先增大后减小的现象.电学性能测试发现:Bi0.9 A0.1 FeO3陶瓷的铁电极化值和漏电流密度均随着掺杂离子半径的增大而增大.结合X射线光电子谱(X-ray photoelectron spectroscopy,XPS)铁离子价态分析表明:Bi0.9 A0.1 FeO3陶瓷铁电性会受掺杂带来的结构畸变和氧空位浓度变化的双重作用的影响.BFO、BCFO、BSFO和BBFO陶瓷的磁化强度依次增大,磁场强度为14 T时磁化强度分别为0.150、0.356、0.497和0.995 emu/g,其铁磁性随掺杂离子半径增大而增强,这与掺杂造成的结构畸变以及铁离子变价有关.     

锈蚀损伤混凝土管桩水平承载性状时变分析

为研究锈蚀损伤混凝土管桩的水平承载性状,依据Fick第二定律,建立了氯离子在混凝土管桩中的扩散方程,并结合初始和边界条件,得到扩散方程的解析解.依据厚壁圆筒模型,推导了钢筋混凝土管桩保护层锈胀开裂时的钢筋临界锈蚀深度.基于Faraday定律,对钢筋混凝土管桩保护层锈胀开裂时间进行了预测.并在此基础上,通过引入桩身抗弯刚度折减系数对海洋环境下锈蚀损伤钢筋混凝土管桩的桩身抗弯刚度的衰减规律进行了探讨,进而对海洋环境下锈蚀损伤钢筋混凝土管桩的水平承载性状的时变特性进行了分析.结果表明:海洋环境中氯离子侵蚀引起的钢筋锈蚀对钢筋混凝土管桩的水平承载性状有明显影响.随着暴露时间的延长,桩身抗弯刚度呈非线性衰减,桩身水平位移和桩身负剪力最大值逐渐增大,桩身弯矩逐渐减小.     

盐酸羟胺改性柚皮吸附剂的制备及对Cu~(2+)吸附性的研究

用盐酸羟胺改性柚子皮制备一种新型的生物质吸附剂,通过模拟废水吸附试验研究了其对Cu~(2+)的去除效果。从模拟废水的pH、吸附时间、吸附剂用量和反应温度4个方面分别考察了改性柚子皮吸附剂对铜离子去除的影响。以溶液的吸光度和电导率来表征吸附性能。实验结果表明:吸附反应时间、吸附剂加入量、反应温度和模拟废水的pH等4个因素对吸附剂性能均有明显影响,其中当Cu~(2+)的初始质量浓度为100mg/L,温度为35℃,溶液pH=4,吸附剂质量为吸附剂/吸附质质量的15%,吸附时间为25min时,吸附率最高。     

Selective removal of heavy metal ions from aqueous solutions with surface functionalized silica nanoparticles by different functional groups

The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as（3-Mercaptopropyl） triethoxysilane（MPTES） and（3-Amincpropyl） trithoxysilane（APTES）. Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared（FI-IR） and X-ray photoelectron spectroscopy（XPS）. The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2＋, Cu2＋, Hg2＋, Cd2＋ and Zn2＋ions in aqueous solutions. The results show that the（3-Mercaptopropyl） triethoxysilane functionalized silica nanoparticles（SiO2-MPTES） play an important role in the selective adsorption of Cu2＋ and Hg2＋, the（3-Amincpropyl） trithoxysilane（APTES） functionalized silica nanoparticles（SiO2-APTES） exhibited maximum removal efficiency towards Pb2＋ and Hg2＋, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2＋ at room temperature, respectively.     

Fabrication and adsorption property of novel adsorbent for potential application to wastewater with Fe（Ⅲ） ions

The spherical macroporous cellulose（SMC） was fabricated using medical absorbent cotton as raw material and nano CaCO3 as porogenic agents.And then,the phenylglycine was grafted onto the SMC to obtain the novel spherical macroporous cellulose derivative adsorbent（PSMC）.FT-IR and scanning electron microscope（SEM） were employed to characterize the adsorbents and Fe3＋ ions served as model solute to evaluate the adsorption property of the adsorbents.The experimental results show that the amount of porogenic agents and the value of pH have obvious influence on adsorption capacity of the adsorbents.The data of adsorption kinetic and isotherm display that the adsorbents possess excellent equilibrium adsorption capacity（348.94 mg/g） and have a bright prospect and considerable potential in the treatment of Fe3＋ ions in wastewater.     

D201负载Fe(Ⅲ)深度处理含As(Ⅲ)废水

研究了强碱性大孔型阴离子交换树脂D201负载Fe(Ⅲ)的纳米吸附材料在不同的试验条件下对含As(Ⅲ)废水深度处理效果的影响。结果表明:D201-Fe对As(Ⅲ)的最大静态吸附容量为43 mg/g;动态吸附容量为1 092 mg/L;动态吸附处理的最佳p H范围是7~8;当废水中含有一定量的硫酸根离子和氯离子时,D201-Fe(Ⅲ)对As(Ⅲ)仍具有较高的吸附能力;采用8%氢氧化钠和氯化钠混合溶液再生效果较好,再生度达到80%以上。     

Removal behavior and mechanism of silver from low concentration wastewater using cellulose aerogel modified by thiosemicarbazide

Due to the low concentration of silver in water, most of the cellulose adsorbents exhibited low removal efficiency, which greatly limited their practical applications. Herein, a cellulose aerogel modified by thiosemicarbamide (CAT) was fabricated for reducing and adsorbing silver ions from low concentration wastewater. The characterization results concluded that CAT owned a three-dimensional spongy structure with many circular microspheres and a better specific surface area (19.37 m² g⁻¹), as well as the functional groups of ─C═N⁺─H and ─(C═S)─N. The static batch adsorption experiments demonstrated that CAT could reached the maximum removal percentage of 94.94% and adsorption capacity of 42.12 mg g⁻¹ under the initial concentration of Ag(I) was 15 mg L⁻¹ and the pH value was 7. Meanwhile, the adsorption of Ag(I) on CAT was second-order reaction, and the Langmuir model could better fit the adsorption process. In addition, CAT exhibited wide pH values (1–9) adaptability and excellent adsorption performance for silver through electrostatic interaction, chelation, and reduction. This study probably provides a new method as well as important experimental data and theoretical reference for the removal of silver ions and other metals.     

An empirical molecular docking study of a di-iron binding protein with iron ions

Various molecular docking software packages are available for modeling interactions between small molecules and proteins.However,there have been few reports of modeling the interactions between metal ions and metalloproteins.In this study,the AutoDock package was employed to example docking into a di-iron binding protein,bacterioferritin.Each binding site of this protein was tested for docking with iron ions.Blind docking experiments showed that all docking conformations converged into two clusters,one for internal iron binding in sites within the metalloprotein and the other for external iron binding on the protein surface.Local docking experiments showed that there were significant differences between two internal iron binding sites.Docking at one site gave a reasonable root-mean-square deviation(RMSD) distribution with relatively low binding energy.Analysis of the binding mode quality for this site revealed that more than half of the docking conformations were categorized as having good binding geometry,while no good conformations were found for the other site.Further investigations indicated that coordinating water molecules contributed to the stability of binding geometries.This study provides an empirical approach towards the study of molecular docking in metalloproteins.