RE(Hsal)2•(tch)•2H2O配合物与大肠杆菌作用的热动力学研究

用TAM air微量热仪测定了新合成的稀土水杨酸硫代脯氨酸配合物RE(Hsal)2•(tch)•2H2O (RE＝La, Sm; Hsal＝C7H5O3; tch＝C4H6NO2S)在37.00 ℃时对大肠杆菌作用的产热曲线; 根据产热曲线求算了在稀土水杨酸硫代脯氨酸配合物作用下, 大肠杆菌生长代谢的最大发热功率Pmax、速率常数k、传代时间tG、抑制率I和半抑制浓度cI,50等热动力学参数. 结果表明: 稀土水杨酸硫代脯氨酸配合物在低浓度下对大肠杆菌有刺激作用, 高浓度下为抑制作用, 即稀土配合物对微生物的生长具有双向生物效应, 也称为Hormesis效应. 配合物La(Hsal)2•(tch)•2H2O和Sm(Hsal)2•(tch)•2H2O的半抑制浓度cI,50分别为7.60和1.62 mg•L－1. 即配合物Sm(Hsal)2•(tch)•2H2O的抑制效果优于La(Hsal)2•(tch)•2H2O.     

钇(III)离子印迹聚合物的制备及性能研究

以钇(III)离子作为模板, 以4-乙烯吡啶(4-VP)、乙酰丙酮(Hacac)和钇(III)形成的三元配合物为功能单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂, 采用本体聚合法合成了钇(III)离子配位分子印迹聚合物. 系统研究了印迹聚合物对钇(III)离子的吸附性和选择性. 结果表明, 印迹聚合物对钇(III)离子有很好的亲和性, 达到吸附平衡的时间为60 min, 最大吸附量为12.4 mg•g−1, 重复使用时性能稳定, 而且印迹聚合物对钇(III)离子具有较强的选择性识别能力.     

纳米Au粒子作为直接硼氢化钠-过氧化氢燃料电池阴极催化剂

采用浸渍还原法制备了纳米Au/C, 并将其用作直接硼氢化钠-过氧化氢燃料电池阴极催化剂. 通过X-射线衍射(XRD)和透射电镜(TEM)对催化剂进行结构和形貌分析, 结果表明10～20 nm的纳米Au粒子均匀地分散在Vulcan XC-72R碳黑表面上. 循环伏安测试表明, 在0.5 mol•L－1 H2SO4和2 mol•L－1 H2O2混合溶液中, 纳米Au/C在0.85 V处表现较强的不可逆还原电流. 以纳米Au/C为阴极催化剂, AB5储氢合金为阳极催化剂制成直接硼氢化钠-过氧化氢燃料电池. 电池在30 ℃下的最大功率密度可达到78.6 mW•cm－2. 当电池工作温度升高至50 ℃时, 电池的最大功率密度超过120 mW•cm－2. 此外, 研究了阴极溶液中H2SO4和H2O2浓度对电池性能的影响. 当阴极溶液中H2SO4浓度小于0.5 mol•L－1时, 酸浓度对电池性能影响较大; H2O2浓度对电池性能影响较小. 确定了阴极溶液中H2SO4和H2O2的最佳浓度分别为0.5和2 mol•L－1.     

碘乙醇在Ni(100)表面的化学热反应

利用热脱附(TPD)实验和X射线光电子能谱(XPS)研究了碘乙醇在Ni(100)表面的吸附和热反应过程. 实验结果表明, 碘乙醇在100 K温度下以两种分子的形式吸附在Ni(100)的表面, 既有碘原子端的吸附也有碘原子端和羟基端同时吸附在表面. 热分解反应发生在140 K, 伴有少量的乙烯和水产生. 碘乙醇在150 K经过C—I键断裂形成−O(H)CH2CH2−和羟乙基两种中间产物. 在160 K温度下−O(H)CH2CH2−脱去氢形成−OCH2CH2−氧金属环. 中间产物经过进一步分解氧化反应分别在210和250 K产生乙醛, 一部分乙醛从表面脱出, 而其余的则分解成氢气、水和CO.     

普鲁士蓝类配位聚合物KCd[Cr(CN)6]•H2O的合成、 结构及多孔性能研究

以Cd2＋和[Cr(CN)6]3－为建筑基元通过自组装合成普鲁士蓝类配位聚合物KCd[Cr(CN)6]•H2O (1•H2O), 并用红外光谱、元素分析、单晶X射线衍射、粉末X射线衍射、热重分析和氮气吸附脱附等手段对其进行了表征. 配位聚合物1•H2O属于面心立方晶系, 空间群Fm-3m, 晶胞参数: a＝b＝c＝1.09059 mn, α＝β＝γ＝90°. 配位聚合物1•H2O是由K＋, Cd2＋, [Cr(CN)6]3－离子和一个结晶水分子组成的三维多孔结构. 热重分析结果表明失水样品1的骨架结构在120～ 200 ℃之间保持稳定. 氮气吸附脱附研究表明: 失水样品1具有683.6 m2•g－1的比表面积, 氮气最大吸附量为8.83 mmol•g－1.     

3-(4-β-D-吡喃阿洛糖苷苯基)-4-胺羰基-5-甲氧羰基异噁唑衍生物的 合成及其镇静活性的研究

4-(β-D-吡喃阿洛糖苷)-α-氯代苯甲醛肟与N-芳基马来酰亚胺在三乙胺作用下, 以甲醇为溶剂, 通过1,3-偶极环加成, 合成了一系列未见文献报道的3-(4-β-D-吡喃阿洛糖苷苯基)-4-胺羰基-5-甲氧羰基异噁唑衍生物; 其结构经1H NMR, IR, MS (HRMS)加以确证. 并对4a～4h和5a进行了药理活性筛选, 结果表明, 部分化合物具有良好的镇静活性. 其中, 化合物4b (200 mg•kg－1), 4c (200 mg•kg－1), 4h (200 mg•kg－1), 与豆腐果苷相比较具有更强的活性.     

超声-伏安法对饮用水中痕量铅(II)和铜(II)的检测研究

以金纳米粒子修饰玻碳电极为工作电极, 采用超声-微分脉冲阳极溶出伏安法连续测定饮用水中痕量铅(II)和 铜(II). 通过原子力显微镜(AFM)对金纳米粒子的形貌和大小进行表征, 对超声波提高伏安检测信号的工作机理作了比较详细的探讨. 实验结果表明, 超声波-伏安法提高了方法的灵敏度, 与传统的微分脉冲伏安法相比, Pb(II)和Cu(II)的峰电流分别增大10倍和8倍. Pb(II)和Cu(II)离子在质量浓度10～250 µg•L－1和5～200 µg•L－1范围内成良好的线性关系, 相关系数分别为0.9943和0.9985. 在含有50 µg•L－1 Pb(II)和20 µg•L－1 Cu(II)的溶液中重复测定9次, 其相对标准偏差为3.5%和2.2%, Pb(II)和Cu(II)的检出限分别为0.3 ng•mL－1和0.1 ng•mL－1. 该方法成功应用于饮用水中痕量Pb(II)和Cu(II)的检测, 方法简便可靠, 具有实际应用意义.     

La 0.9 M 0.1 Ga 0.8 Mg 0.2 O 3 -α的中温质子导电性及其在常压合成氨中的应用

采用水热沉淀法制备了La0.9M0.1Ga0.8Mg0.2O3-α (M＝Ca2＋, Sr2＋, Ba2＋)陶瓷样品的前驱体, 沉淀剂来自尿素在水热条件下的水解产物. 前驱体经煅烧和烧结后得到陶瓷样品. XRD显示样品具有单一的斜方晶LaGaO3钙钛矿结构. 同位素效应和氢的电化学透过(氢泵)实验证明陶瓷样品具有质子导电性. 用AC阻抗谱法测定了样品在300～600 ℃、氢气气氛中的质子电导率, 其大小取决于La位掺杂的碱土金属离子: σ(M＝Sr2＋)＞σ(M＝Ba2＋)＞σ(M＝Ca2＋). 以La0.9M0.1Ga0.8Mg0.2O3-α为固体电解质进行了常压合成氨, 最佳合成温度为520 ℃. 当施加的电流密度为1 mA•cm－2、合成温度为520 ℃时, 氨产率分别为: 1.63×10–9 mol•s－1•cm－2 (M＝Ca2＋), 2.53×10－9 mol•s－1•cm－2 (M＝Sr2＋)和2.04× 10－9 mol•s－1•cm－2 (M＝Ba2＋).     

mPAM/mCMC双极膜电解槽中MnO2电催化氧化制备甘油醛

分别以FeCl3和戊二醛等对羧甲基纤维素(CMC)和聚丙烯酰胺(PAM)进行改性, 制备了mPAM/mCMC双极膜. 测定了PAM、CMC胶体的电荷密度, mPAM/mCMC双极膜离子交换能力、I-V工作曲线等参数. 用扫描电镜和红外光谱对膜形貌与成分作表征, 膜厚≈260 μm, 中间界面层厚为纳米级. 热重分析表明膜具有较好的热稳定性. 以mPAM/mCMC双极膜为电解槽的隔膜, 间接电氧化甘油为甘油醛. 在电场的作用下, 双极膜中间层中的水离解产生H＋和OH−, OH−及时地传输入阳极室, 中和了电生成甘油醛时生成的H＋, 促进了正向反应的进行. 槽电压稳定, 产率达91.6%, 电流效率为65.5%.     

HNCO + CN反应途径的从头计算

在6-311G(d, p)基组水平上, 采用全电子的UMP2方法对HNCO和CN自由基的反应途径进行了研究, 结果表明, 反应存在如下两条反应通道: HNCO + CN→NCO + HCN (1); HNCO + CN→HNCN + CO (2). 其中反应(1)是吸氢反应, 氢转移过程在分子间以协同方式进行, UMP2(full)/6-311G(d, p)计算位垒是 20.80 kJ/mol, 在反应的温度区间(1000~2100 K), 传统过渡态理论得出的速率常数值范围是0.32×10^−11~6.9×10^−11 cm³·mol^−1·s^−1, 支持了实验预测结果. 反应(2)是分步反应, 在反应途径上存在分子中间体, UMP2(full)/6-311G(d, p)计算位垒为83.42 kJ/mol. 反应通道(2)的位垒大于反应通道(1).     

Carboxymethyl Chitosan-Fe3O4 Nanoparticles: Preparation and Adsorption Behavior toward Zn2+ Ions

A novel magnetic nanoadsorbent was prepared by the covalent binding of carboxymethyl chitosan (CMC) onto the surface of Fe₃O₄ magnetic nanoparticles, which was developed using a coprecipitating method. This nanoadsorbent was characterized by transmission electron microscopy (TEM) and X-ray diffraction patterns (XRD), etc. Moreover, the adsorption performance of the nanoadsorbent toward Zn²⁺ ions was investigated. The results showed that the mean diameter of the magnetic nanoadsorbent was 18 nm and the amount of CMC was about 5%. The nanoadsorbent showed high efficiency for the removal of Zn²⁺ ions. The adsorption rate was so rapid that the equilibrium was achieved within 2 min. The isotherm adsorption data obeyed the Langmuir model, with a maximum adsorption capacity of 20.4 mg·g^?1 and an adsorption equilibrium constant of 0.0314 L·mg^?1. The thermodynamic calculations indicated that the adsorption process was exothermic and that the enthalpy change was ?5.68 kJ·mol^?1.     

水溶液中六价铬在碳纳米管上的吸附

针对用碳纳米管对水溶液中六价铬的吸附净化进行了研究, 考察了溶液浓度、溶液pH值、共存的三价铬离子等因素对吸附行为的影响. 实验结果表明, 碳纳米管在室温下对于六价铬的吸附量随着平衡浓度的增大而升高, 在铬浓度为493.557 mg•L−1时碳纳米管吸附量达到最大值为532.215 mg•g−1; 六价铬的浓度在300~700 mg•L−1的范围内, 碳纳米管对铬的吸附量变化不大；大于700 mg•L−1时, 随着铬的平衡浓度的升高碳纳米管对铬的吸附量降低, 铬浓度为961.074 mg•L−1时, 碳纳米管吸附量降至194.631 mg•g−1. 在pH值为2~7的范围内, 碳纳米管对六价铬的吸附量随着溶液pH值的减小而增大; 而在碱性条件下, pH值对碳纳米管吸附六价铬的影响不大. 溶液中存在三价铬时, 碳纳米管对六价铬的吸附量明显降低, 表明三价铬与六价铬有竞争吸附. 此外, 活性炭的对比吸附实验表明, 在低浓度时, 譬如在六价铬浓度为190 mg•L−1吸附时, 碳纳米管对铬的吸附量约为活性炭的6倍；而在高浓度下, 譬如六价铬浓度为493 mg•L−1时, 碳纳米管对铬的吸附量约为活性炭的2倍.     

Pt纳米粒子修饰的多孔硅电极的制备及其电催化性能

通过循环伏安法电沉积使直径约为7 nm的Pt纳米粒子均匀地分散于多孔硅表面, 拟用作微型质子交换膜燃料电池的催化电极. 与刷涂法相比较, 电沉积Pt纳米粒子的多孔硅电极(Pt/Si)呈现出高的Pt利用率和增强的电催化活性. 当Pt载量为0.38 mg•cm−2时, 其电化学活性比表面积高达148 cm2•mg−1, 是刷涂相近质量的纳米Pt/C催化剂的多孔硅电极Pt-C/Si的2倍多；该修饰电极对甲醇氧化也呈现了增强的催化性能和好的稳定性, 在0.5 V(vs SCE)极化1 h后电流密度为4.52 mA•cm−2, 而刷涂了相近Pt量的Pt-C/Si电极的电流密度只有0.36 mA•cm−2.     

Chemically modified kapok fiber for fast adsorption of Pb2+, Cd2+, Cu2+ from aqueous solution

Kapok fiber, a natural hollow fiber with thin shell and large cavity, has rarely been used as adsorbent for heavy metal ions. In this paper, kapok fibers were modified with diethylenetriamine pentaacetic acid (DTPA) after hydrophilicity treatment. The adsorption behavior of the resultant kapok-DTPA influenced by pH, adsorption time and initial concentration of metal ion was investigated. The results demonstrate that adsorption equilibrium was reached within 2 min for Pb²⁺ and Cd²⁺. Adsorption kinetics showed that the adsorption rate was well fitted by pseudo-second-order rate model. The adsorption isotherms were studied, and the best fit was obtained in the Langmuir model. The maximum adsorption capacities of kapok-DTPA were 310.6 mg g^?1 for Pb²⁺, 163.7 mg g^?1 for Cd²⁺, 101.0 mg g^?1 for Cu²⁺, respectively. After eight desorption and re-adsorption loops, the lost adsorption capacities for Pb²⁺ and Cu²⁺ were less than 10 %. Because of the large specific area derived from the hollow fiber structure, kapok-DTPA exhibited much better adsorption capacity compared with many other reported adsorbents based on natural materials.     

Adsorption of Cu(II) and Zn(II) ions from aqueous solutions onto fine powder of Typha latifolia L. root: kinetics and isotherm studies

Fine powder of Typha latifolia L. root was used for adsorption of copper and zinc ions from buffered and nonbuffered aqueous solutions. The adsorption reached equilibrium in 60 min. During this time, more than 90 % of the adsorption process was completed. The effect of initial pH, initial concentration of metal ion, and contact time was investigated in a batch system at room temperature. The optimum adsorption performance was observed at pH 5.00 and 4.25 for nonbuffered solutions of Cu(II) and Zn(II), respectively, while for buffered solutions it occurred at pH 6.00. The total metal uptake decreased on application of ammonium acetate buffer, from 37.35 to 17.00 mg g^?1 and 28.80 to 9.90 mg g^?1 for Cu(II) and Zn(II) solutions, respectively, with 100 mg L^?1 initial concentration. The pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models were used to describe the adsorption kinetics. The experimental data followed the pseudo-second-order kinetic model. The biosorption equilibrium was well described by Langmuir and Freundlich isotherm models.     

Preconcentration of Pb2+ by iron oxide/amino-functionalized silica core–shell magnetic nanoparticles as a novel solid-phase extraction adsorbent and its determination by flame atomic absorption spectrometry

The use of iron oxide/amino-functionalized silica core–shell magnetic nanoparticles for preconcentration of Pb²⁺ followed by its consecutive atomic absorption spectrometry determination is described. Effects of various operating variables, namely, solution pH, initial Pb²⁺ concentration, contact time, adsorbent dosage, sample volume, concentration and volume of desorbing solution, and co-existing ions on solid-phase extraction (SPE) of Pb²⁺ were studied by batch equilibrium technique. The experimental adsorption data were well fitted to the Langmuir isotherm model. The Langmuir adsorption capacity and equilibrium time were found to be 100 mg g^?1 and 20 min, respectively. The adsorption data were also fitted to kinetic pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption followed pseudo-second-order model. Under the optimal SPE conditions, the enrichment factor, detection limit and relative standard deviation for determination of Pb²⁺ were found to be 211, 1 μg L^?1, and 3.7 % for 50 μg L^?1, respectively. The proposed method was successfully applied to the determination of lead in a real sample with satisfactory results.     

乙醇在Pt/nanoTiO2-CNT复合催化剂上的电催化氧化

通过前驱体Ti(OEt)4直接水解和电化学扫描电沉积法制备在Ti基体上的纳米TiO2-碳纳米管复合膜载Pt(Pt/nanoTiO2-CNT)复合催化剂. 透射电镜 (TEM) 和X射线衍射 (XRD) 结果表明, 锐钛矿型纳米TiO2粒子和Pt纳米粒子(粒径均为5~10 nm)均匀地分散在碳纳米管表面. 通过循环伏安和计时电流法研究表明, Pt/nanoTiO2-CNT 复合催化剂(Pt载量为0.32 mg•cm−2) 具有高达51.8 m2•g−1的电化学活性比表面积, 常温常压下对乙醇的电化学氧化具有高催化活性和稳定性, 乙醇氧化峰电位分别为0.59、0.96和0.24 V, 氧化峰电流密度分别达到−115、−113和−75 mA•cm−2. 复合催化剂对乙醇电氧化的高催化活性可归因于nanoTiO2、CNT和Pt纳米粒子的协同催化作用.     

Synergistic and antagonistic effects between halide ions and carboxymethyl cellulose for the corrosion inhibition of mild steel in sulphuric acid solution

The corrosion and corrosion inhibition effect of carboxymethyl cellulose (CMC) for mild steel in sulphuric acid medium was investigated using chemical (weight loss and hydrogen evolution) techniques at 30–60 °C. The effect of addition of halide ions (Cl⁻, Br⁻, and I⁻) was also studied. It was found that CMC functions as an inhibitor for acid induced corrosion for mild steel. Inhibition efficiency increases with increase in immersion time but decreases with increase in temperature. Addition of halide ions reveals that chloride ions (Cl⁻) antagonize the inhibition process whereas iodide ions (I⁻) exert synergistic effect on the corrosion inhibition by CMC. Corrosion inhibitive effect was afforded by adsorption of CMC molecules onto the mild steel surface both in the absence and presence of halide ions which was found to follow Langmuir adsorption isotherm model. The phenomenon of physical adsorption is proposed from decrease in inhibition efficiency with increase in temperature. The inhibition mechanism was further corroborated by the values of thermodynamic and kinetic parameters obtained from the experimental data.     

Fast recovery of Au (III) and Ag(I) via amine-modified zeolitic imidazolate framework-8

In this paper, zeolitic imidazolate framework-8 modified by the ethanediamine (NH₂-ZIF-8) was employed for adsorbing Au (III) and Ag(I) from aqueous solutions. The adsorption capacities of NH₂-ZIF-8 towards Au (III) and Ag(I) were found to be significantly affected by the pH values of the solution. The adsorption kinetics studies show that NH₂-ZIF-8 presents a fast adsorption property towards metals, attaining 93% of adsorption equilibrium uptake for Au (III) within the first 30 min. This phenomenon can be ascribed to the coordination interaction between the amino group and Au (III). The thermodynamic data suggest that the adsorption of NH₂-ZIF-8 towards Au (III) is endothermic process, while that for Ag(I) is exothermic. The maximum adsorption capacities of NH₂-ZIF-8 toward Au (III) and Ag(I) can be achieved to 357 mg·g⁻¹ and 222.25 mg·g⁻¹, respectively. The metal ions interference results show that Cu (II) and Ni (II) hardly have no interference on Au (III) adsorption in e-waste containing 1500 mg·l⁻¹ Cu (II),100 mg·l⁻¹ Ni (II) and 10 mg·l⁻¹ Au (III); while for Ag(I), Cd (II) and Zn (II) have little interference on Ag(I) adsorption in the hybrid solutions containing Ag(I), Ni (II), Cd (II) and Zn (II) with equal concentration (50 mg·l⁻¹), but Ni (II) interference most. The XPS study shows that partial Au (III) was reduced to Au(I), and that Ag(I) was completely reduced to Ag(0) during the adsorption process. The abundant of active sites of NH₂-ZIF-8 containing C=N, N-H, and Zn-OH groups play a key role in the adsorption of Au (III) and Ag(I). In addition, electrostatic interaction can be responsible for the adsorption of Au (III) by NH₂-ZIF-8. The regeneration experiments results show that the adsorption capacities of NH₂-ZIF-8 towards Au (III) and Ag(I) can maintain after three cycles. This work provides a reliable method to improve the adsorption kinetics for metal ions.     

多色蓝在核酸分子上的Langmuir聚集吸附

用微相吸附-光谱修正（MPASC）新技术研究核酸与多色蓝(PCB)探针分子间的相互作用，分析核酸分子内双静电膜的形成与Langmuir吸附的关联性.通过pH 7.24的介质核酸-PCB反应的光谱研究，测定了结合产物的物理化学参数：结合比1PCB:2DNA-PCB、1PCB:3RNA-PCB, 平衡常数KDNA-PCB=5.42×104， KRNA-PCB=2.82×104,摩尔吸收系数ε(DNA-PCB, 625 nm)=5.65×103（mo1－1•L ）•cm－1， ε(RNA-PCB, 625 nm)=3.85×103 （mol－1•L）•cm－1.结果表明， RNA分子仅形成约60％双螺旋结构链，核酸双螺旋每一周期的负静电沟最大聚集10个PCB分子.该吸附反应用于核酸样品测定，结果良好.