Removal of phosphate from aqueous solution by zeolite synthesized from fly ash

Fifteen Chinese fly ashes were converted hydrothermally into zeolites, and phosphate immobilization capacity (PIC) of the synthesized zeolites and the corresponding raw fly ashes were determined using an initial phosphate concentration of 1000 mg/L. Results showed that there was a remarkable increase in PIC (from 1.2 to 7.6 times) following the synthesis process. Fractionation of immobilized phosphorus indicated that Fe+Al-P increased most significantly and consistently among all the phosphorus fractions following the conversion of fly ash to zeolite. The PIC and Ca+Mg-P were closely related to Ca content (with r values of 0.9683 and 0.9651, respectively) rather than Mg content (with r values of 0.3920 and 0.3212, respectively). The r values of PIC and Fe+Al-P with Fe content (with r values of 0.4686 and 0.6385, respectively) were higher than those with Al content (with r values of -0.7857 and -0.3770, respectively). Although calcium and iron components were mainly involved in phosphate immobilization, there was no significant change of Ca and Fe content following the conversion of fly ash to zeolite. Increase in dissociated Fe(2)O(3) and specific surface area probably accounted for the enhancement in PIC of synthesized zeolites compared with corresponding fly ashes. The PIC value of zeolites showed a significant correlation with dissociated Fe(2)O(3) (r=0.6186). The specific surface area increased 26.0-89.4 times as a result of the conversion of fly ash to zeolite. The maximum removal of phosphate occurred within different pH ranges for zeolites which were synthesized from high, medium and low calcium fly ashes and this behavior was explained by the reaction of phosphate with calcium and iron components.     

H原子与CO2分子碰撞的化学反应与能量转移

Collisions between hot H atoms and CO2 molecules were studied experimentally by time-resolved Fourier transform infrared emission spectroscopy. H atoms with three translational energies, 174.7, 241.0 and 306.2 kJ/mol respectively, were generated by UV laser photolysis to initiate a chemical reaction of H+CO2!OH+CO. Vibrationally excited CO (v≤2) was observed in the spectrum, where CO was the product of the reaction. The highly efficient T-V energy transfer from the hot H atoms to the CO2 was verified too. The highest vibrational level of v=4 in CO2 (v≤3) was found. Rate ratio of the chemical reaction to the energy transfer was estimated as 10.     

Si(CH3)3Cl分子电离电势和化学键能的测定

The photoionization spectroscopy of Si(CH3)3Cl in the range of 50 -130 nm was studied with synchrotron radiation source. The adiabatic ionization potentials of molecule Si(CH3)3Cl and radical Si(CH3)3 are 10.06 ±0.02 eV and 7.00±0.03 eV respectively. In addition, the appearance potentials of Si(CH3)2Cl+, Si(CH3)3+, SiCl+ and SiCH3+ were determined:
AP(Si(CH3)2Cl+) ＝10.49±0.02eV, AP(Si(CH3)3+) ＝ 11.91 ±0.02eV
AP(SiCl+) ＝ 18.64 ±0.06eV, AP(SiCH3+)＝ 18.62 ±0.02eV
From these, some chemical bond energies of Si(CH3)3Cl+ were calculated:
D(Si(CH3)2Cl+ - CH3) ＝0.43 ±0.02eV, D(Si(CH3)3+ - Cl) ＝ 1.85 ± 0.02eV
D(SiCH3+ - (2CH3 ＋ Cl)) ＝ 8.56 ± 0．06eV, D(SiCH3+ - 2CH3) ＝6.71±0．06eV
D(SiCl+ - 3CH3) ＝ 8.58 ± 0.06eV, D(SiCl＋- 2CH3) ＝ 8.15 ±0.06eV
D(SiCH3+- (CH3 ＋ Cl)) ＝8.13 ±0.06eV     

铅硫二元团簇Pb~nS~n~-~1^+ (n=2～4)的从头算研究

用密度泛函方法,对铅硫团簇Pb~nS~n~-~1^+(n=2～4)的各种可能的异构体进行计算。结果表明异构体Pb~S^+(C~2~v)、Pb~3S~2^+(C~2~v)和Pb~4S~3^+(C~3~v)最为稳定,是该类团簇系列中最稳定的存在形式。同时,该类团簇的最低空轨道(LUMO)能量较低,容易得到电子,表明其相应的中性团簇也能稳定存在。     

铝硫二元团簇的组分及其光解规律

硫与金属元素所形成的二元团簇具有很多重要的特性,已受到人们的普遍重视.用激光-串级飞行时间质谱仪,我们曾研究了硫与过渡金属钽、铁等的二元团簇.最近我们选取主族金属元素铝,研究了铝硫团簇的形成及其光解,实验结果表明,与钽硫或铁硫团簇相比,铝硫团簇无论在其组份构成还是在其光解方面,都表现出鲜明的特有规律性.实验的主要参数如下:溅射用激光为Nd:YAG 二倍频,其输出强度控制在约10~7W·cm~(-2),激光的重复频率10Hz 样品位于激光束的焦点附近,由焦距f=50cm 的透镜调整其聚焦状     

Thermal stability and flame-retardancy mechanism of poly(ethylene terephthalate)/boehmite nanocomposites

The thermal stability and flame-retardancy properties of poly(ethylene terephthalate)/nano-boehmite composites (PET/AlOOH) were investigated using composites prepared in situ. Combustion behaviour and flammability were assessed using the limiting oxygen index (LOI) and cone calorimetry. The incorporation of nano-boehmite increased the LOI of PET from 18 to greater than 25. Cone calorimetry showed that the heat release rates and total smoke production values of PET/AlOOH composites were significantly less than those of pure PET. It also showed that PET/AlOOH combustion produced greater quantities of char residues than did PET combustion. These results showed that nano-boehmite is an effective flame-retardant for PET. Combustion residues were examined using scanning electron microscopy, indicating that nano-boehmite addition produced consistent, thick char crusts. Thermal stability and pyrolysis were investigated using thermogravimetric analysis and pyrolysis-gas chromatography-mass spectrometry, showing that thermal stability of PET/AlOOH was superior to that of pure PET, fewer cracking products were produced in nanocomposite combustion than in pure PET combustion, and pyrolysis of the flame-retardant polyester was incomplete. We propose a condensed phase mechanism for the PET/AlOOH flame-retardancy effect.     

IVSPlat 1.0: an integrated virtual screening platform with a molecular graphical interface

Background  

The virtual screening (VS) of lead compounds using molecular docking and pharmacophore detection is now an important tool in drug discovery. VS tasks typically require a combination of several software tools and a molecular graphics system. Thus, the integration of all the requisite tools in a single operating environment could reduce the complexity of running VS experiments. However, only a few freely available integrated software platforms have been developed.     

红外辐射多相复合粉体常温发射率的提高及波段宽化

通过多相成分分析, 以镁铝硝酸盐、正硅酸乙酯、钛酸四丁酯和氧氯化锆等为原料, 采用溶胶\|凝胶燃烧法合成了新型复相氧化物粉体, 研究了Ni和Fe离子掺杂及粉体细化对红外辐射率的提高及波段宽化的影响. XRD物相分析发现, 在1100～1200 ℃范围内煅烧可获得结晶良好的氧化物粉体, 该粉体的结构为堇青石及金红石等多相结构. 采用碳酸氢铵为pH调节剂与使用氨水相比, 粒子中位粒径有显著减小. 红外辐射性能显示, 在1～22 μm的宽波段内, 该复合粉体均具有很高的红外发射率, 在10 μm附近其红外发射率达到98%. 同时Ni及Fe离子的掺杂及粉体细化可引起堇青石晶格畸变, 增强了材料的非简谐效应, 从而有利于复合粉体红外辐射率的提高.     

固相萃取-气相色谱-质谱联用检测地沟油中胆固醇

建立了固相萃取-气相色谱-质谱联用(SPE-GC-MS)检测地沟油样品中胆固醇的分析方法。样品用硅胶固相萃取小柱前处理净化,先用20 mL含0.6%乙醚的正己烷溶液淋洗,再用10 mL含15%乙醚的正己烷溶液洗脱,胆固醇萃取率达97%。净化后的样品用配备电子轰击离子源的气相色谱-质谱联用仪进行测定,以保留时间和特征碎片离子定性,在选择离子监测模式下用外标法定量,选择离子为m/z 213、275、301、368、386,目标离子为m/z 386,参考离子为m/z 213和275。不同加标水平下的加标回收率为91.7%～101%,相对标准偏差(RSD)小于6%,检出限为0.01 mg/L。胆固醇质量浓度在0.24~6.0 mg/L范围内有良好的线性关系(相关系数为0.9996)。该法可精确检测油脂中胆固醇的含量,检测结果可作为判断其中是否掺有地沟油的依据之一。     

A hierarchical porous carbon membrane from polyacrylonitrile/polyvinylpyrrolidone blending membranes:Preparation,characterization and electrochemical capacitive performance

Novel hierarchical porous carbon membranes were fabricated through a simple carbonization procedure of well-defined blending polymer membrane precursors containing the source of carbon polyacrylonitrile （PAN） and an additive of polyvinylpyrrolidone （PVP）, which was prepared using phase inversion method. The as-fabricated materials were further used as the active electrode materials for supercapacitors. The effects of PVP concentration in the casting solution on structure feature and electrochemical capacitive performance of the as-prepared carbon membranes were also studied in detail. As the electrode material for supercapacitor, a high specific capacitance of 278.0 F/g could be attained at a current of 5 mA/cm2 and about 92.90% capacity retention could be maintained after 2000 charge/discharge cycles in 2 mol/L KOH solution with a PVP concentration of 0.3 wt% in the casting solution. The facile hierarchical pore structure preparation method and the good electrochemical capacitive performance make the prepared carbon membrane particularly promising for use in supercapacitor.