沥青基活性炭纤维复合活化工艺的研究

以沥青基炭纤维为原料，研究了用铵盐作为化学活化剂对其进行浸渍预处理，然后采用（H2O＋CO2）活化的方法制备活性炭纤维，讨论了工艺条件对活性炭纤维性能的影响并通过光电子能谱XPS探讨了活化过程中炭纤维表面官能团的变化。结果表明：采用这种物理和化学复合活化工艺，可以在较高得率下提高活性炭纤维比表面积。同时浸渍处理、H2O流量、活化温度和活化时间等工艺参数显著影响活性炭纤维的比表面积和得率，优化的工艺为：经铵盐浸渍6h，炭纤维在水蒸气与CO2流量比3：1的混合气氛中900℃活化30min。XPS研究表明，活化后炭纤维表面的含氧官能团C－O明显减少，铵盐浸渍未能增加活性炭纤维表面的含氮基团。     

Thermodynamic properties of the system NH4NO3 + (NH4)2SO4 + H2O at 298.15 K

In this investigation, the mixed aqueous electrolyte system of nitrate and sulfate with common ammonium cation has been studied with the hygrometric method at the temperature 298.15 K. The water activities of the system [yNH₄NO₃ + (1 − y)(NH₄)₂SO₄](aq) are measured at total molalities from 0.4 mol kg⁻¹ up to saturation for different ionic-strength fractions y of NH₄NO₃ with y = 0.2, 0.5 and 0.8. The obtained data allow the deduction of osmotic coefficients. The experimental results are compared with the predictions of the Zdanovskii–Stokes–Robinson (ZSR), Leitzke and Stoughton (LSII), Kusik and Meissner (KM), and Pitzer models. From these measurements, new Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture. The obtained results are used to calculate the excess Gibbs energy at total molalities for different ionic-strength fractions y.     

A new series of heteroaromatic receptors containing the 1,3-bis(6-oxopyridazin-1-yl)propane unit: their selective transport ability towards NH4 in relation to Na, K and Ca

The synthesis of a new series of heteroaromatic macrocycles 6-9 containing the 1,3-bis(6-oxopyridazin-1-yl)propane and pyridine units is reported. The acyclic compounds 11-15 had to be prepared as the intermediates in the synthetic sequence. Evaluation of the ionophoric properties of 6-9 and 11-15 shows that 8 and 13 behave as good ammonium ion carriers and exhibit a high selectivity for ammonium with respect to spherically symmetric metallic ions like Na⁺, K⁺, and Ca²⁺. Molecular modelling of the ammonium complexes suggests that the host's oxyimino groups play a more relevant part in effective complexation than the pyridine unit, and that the high complexating efficiency of 13 might be related to the formation of a pseudocavity by intramolecular hydrogen bonding.     

Synthese und Struktur von Hydrogensulfaten des Typs M(HSO4)(H2SO4) (M = Rb,Cs und NH4)

Synthesis and Structure of Hydrogen Sulfates of the Type M(HSO₄)(H₂SO₄) (M = Rb, Cs and NH₄) From the binary systems M₂SO₄/H₂SO₄ (M = Rb, Cs, NH₄), three new hydrogen sulfates of the type M(HSO₄)(H₂SO₄) could be synthesized and structural characterized. The rubidium and caesium compounds are isotypic whereas NH₄(HSO₄)(H₂SO₄) is topologically very similar to both. All three compounds crystallize with nearly identical cell parameters [Rb: a = 7.382(1), b = 12.440(2), c = 7.861(2), β = 93.03(3); Cs: a = 7.604(1), b = 12.689(2), c = 8.092(2), β = 92.44(3); NH₄: a = 7.521(3), b = 12.541(5), c = 7.749(3), β = 92.74(3)], in the monoclinic space group P2₁/c, There exist two kinds of SO₄-tetrahedra: HSO₄^? anions (S1) and H₂SO₄-molecules (S2). The HSO₄^? anions form hydrogen bridged zigzag chains. In the case of the Rb and Cs compounds, the H₂SO₄ molecules connect these chains forming double layers. The metal atoms are coordinated by 9 O-atoms with M? O-distances of 2.97 – 3.39 Å (Rb) and 3.13 – 3.51 Å (Cs). In the ammonium compound additional hydrogen bonds are formed originating from the NH₄⁺ cation. This finally leads to the formation of S2? NH₄⁺ chains (parallel to the S1 chains) as well as to a three-dimensional connection of both kinds of chains.     

Ammonium polyphosphate-aluminum trihydroxide antagonism in fire retarded butadiene-styrene block copolymer

In this paper the effect of aluminum trihydroxide (Al(OH)₃—ATH) on the surface protection from fire for a styrene butadiene rubber (SBR) provided by ammonium polyphosphate ([NH₄PO₃]_n—APP) is studied.The combustion behaviour is studied by means of Cone Calorimetric tests: a maximum fire retardant effect is observed with 10-12 wt.% of APP. ATH, less effective as fire retardant, has been added at 60 wt.% to reach comparable results as measured by cone calorimetry for 12 wt.% APP.Replacement of ATH in the best performing SBR + 12 wt.% of APP shows an antagonistic effect with as little as 1 wt.% of ATH.The combustion behaviour is explained with the mechanism of interaction between SBR, APP and ATH, in which formation of aluminum phosphates negatively affects the surface protection provided by the ultraphosphate surface coating formed on heating APP in SBR.     

HPLC of aminoacids on silica coated with ammonium tungstophosphate

Summary The chromatographic behaviour of aminoacids on columns of silica coated with different percentages of ammonium tungstophosphate at several buffer phosphate concentrations is reported. The stationary phase shows a high selectivity towards aminobutyric acids and methyl derivatives of tryptophan due to the distance between the carboxylic group and the –NH ₃ ⁺ group involved in the cation-exchange process and/or to the steric hindrance by a methyl substituent. A relationship between HPLC and HPTLC data has been verified and applied to the prediction of the separation of six aminoacids.     

Formation of copper oxide through NaNO3–KNO3 eutectic melt and its catalytic activity in the decomposition of ammonium perchlorate

The decomposition of basic copper carbonate in the presence and absence of NaNO₃–KNO₃ eutectic melt has been studied by employing isothermal TG and dynamic TG/DSC techniques. The rate constants for the decomposition in the presence of eutectic melt were found to be higher than when carbonate was heated alone. In both the cases copper oxide was found to be the end product. Catalytic activity of copper oxide obtained by the two methods were tested for the decomposition of ammonium perchlorate.     

催化动力学光度法测定微量银

依据在H2SO4介质中,Ag+对(NH4)2S2O8氧化Mn2+的强烈催化作用,建立了测量微量Ag+的新动力学光度法。方法的线性范围为0.05~2.0μg/mL,检出限为1.5×10-5mg/mL,表观摩尔吸光系数为7.1×104L.moL-1.cm-1。测定了反应的动力学参数。用本法测定了矿样和废水样中的银。     

ICP-AES法测定钼酸铵及多钼酸铵中14个杂质元素

提出了用浓硝酸沉淀并分离大量基体钼，ICP-AES同时测定钼酸铵中14个杂质元素的方法，考虑了钼基体、酸度、谱线干扰及背景影响等情况。在未引入其它任何试剂的情况下，用硝酸既除去了大量的钼基体，又调整了溶液的酸度，用标准加入法测定钼酸铵中的杂质元素，无需加入高纯基准试剂进行基体匹配，有效降低了分析成本，又消除了由于忽略基准物质中杂质元素的含量给分析测定带来的误差。回收率在85％～112％之间。