一步热解法制备Cu/Fe双金属生物炭复合材料及其高效吸附Pb2+性能

使用一步热解法制备了 Cu/Fe双金属生物炭复合材料(BC@Cu/Fe-X,X=3、5、10)和 Fe生物炭复合材料(BC@Fe)。考察了Cu掺杂量对BC@Cu/Fe-X吸附Pb²⁺的影响,确定最佳掺杂比例。结果显示BC@Cu/Fe-5吸附Pb²⁺性能最好。考察了吸附时间、Pb²⁺浓度、pH、背景离子、空气中老化等实验条件对 BC@Cu/Fe-5 吸附 Pb²⁺的影响。通过动力学、热力学数据拟合分析了BC@Cu/Fe-5吸附Pb²⁺的行为,利用X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)等表征手段解析了BC@Cu/Fe-5吸附Pb²⁺前后特征峰变化。BC@Cu/Fe-5吸附Pb²⁺的机理如下：大约42%的Pb²⁺被还原为Pb⁰,33%的Pb²⁺形成PbO/Pb(OH)₂,25%的Pb²⁺与O—H、C—O、C=O、COO、Fe—O等官能团形成配合物。Cu掺杂可以提高Fe还原Pb²⁺的能力。     

H2在K0-MWCNTs上储存和吸附/脱附特性研究

利用高压容积法辅以卸压升温脱附排水法, 测定金属K修饰多壁碳纳米管对H₂的吸附储存容量. 结果表明, 在室温(25 ℃), 7.25 MPa实验条件下, x%K⁰-MWCNTs (x%＝30%～35%, 质量百分数)对H₂的吸附储存容量可达3.80 wt%(质量百分数), 是相同条件下单纯MWCNTs氢吸附储量的2.5倍; 室温下卸至常压的脱附氢量为3.36 wt%(占总吸附氢量的～88%), 后续升温至673 K的脱附氢量为0.41 wt%(占总吸附氢量的～11%). 利用LRS和H₂-TPD-GC/MS等谱学方法对H₂/K⁰-MWCNTs吸附体系的表征研究表明, H₂在K⁰-MWCNTs上吸附存在非解离 (即分子态)和解离(即原子态)两种吸附态; 在≤723 K温度下, H₂/K⁰-MWCNTs体系的脱附产物几乎全为H₂气; 723 K以上高温脱附产物不仅含H₂, 也含有CH₄, C₂H₄和C₂H₂等C₁/C₂-烃.     

卤化银添加剂对125I在北山花岗岩岩粉中的吸附作用研究

利用柱法实验和批次实验研究了卤化银(AgCl、AgBr、AgI)对¹²⁵I在甘肃北山花岗岩中的吸附现象。结果表明在无载体的情况下,卤化银添加剂有利于¹²⁵I在北山花岗岩岩粉中的吸附,有效分配系数(K_d,e)均大于1.0×10³ mL·g^-1。在有载体的情况下,氯化银和溴化银仍然对¹²⁵I在北山花岗岩岩粉中有良好的吸附作用,K_d,e大于1.0×10³ mL·g^-1。其中,溴化银的吸附效果最好,这可能与其晶体结构和光解性质有关。     

改性硅藻土负载亚铁氰化铜复合物的制备及其对Cs+的吸附性能

采用水热法、以氯化铝为铝源对硅藻土(De)进行改性,通过浸渍法将亚铁氰化铜(KCuHCF)纳米颗粒负载于改性De表面,制备出γ-AlOOH/De-KCuHCF和γ-Al₂O₃/De-KCuHCF两种复合吸附剂,对所制备的吸附剂进行了表征,并研究了其对Cs⁺的吸附性能。结果表明,所制备吸附剂具有优异的Cs⁺吸附性能,γ-AlOOH/De-KCuHCF和γ-Al₂O₃/De-KCuHCF最高吸附容量分别可达75.44、84.02 mg·g^-1,γ-Al₂O₃/De-KCuHCF对模拟卤水中Cs⁺的吸附率高达97.55%;以3 mol·L^-1 NH₄NO₃为脱附剂,经3级连续脱附后,γ-Al₂O₃/De-KCuHCF的Cs⁺脱附率可达81.88%,经过5次吸附-脱附循环后仍保持了较高的吸附量。     

膨润土纳米复合材料的制备、表征及吸附性能研究

用有机螯合剂(CA)和十六烷基三甲基溴化铵(HDTMAB)共同改性膨润土(IMB)，制得一系列膨润土纳米复合材料IMB-HDTMA-CA。X射线衍射(XRD)、热分析(TG-DTA)、红外光谱(FTIR)以及N₂-吸附脱附技术等研究发现，HDTMA⁺和CA已稳定柱撑在膨润土的片层结构中，其层间距增大、比表面积减小而疏水性增强。吸附实验表明，IMB-HDTMA-CA能协同吸附水中有机物对硝基苯酚(PNP)和重金属镉(Cd²⁺)。对水中对硝基苯酚的吸附源于PNP在膨润土层间有机相中分配作用的增加，其吸附容量和膨润土内有机碳含量和层间距大小一致，而与比表面积无关，依次为IMB-HDTMA-TEPA>IMB-HDTMA-TETA>IMB-HDTMA-En>IMB-HDTMA 》IMB；FTIR图谱显示，IMB-HDTMA-CA吸附Cd²⁺后的N-H吸收峰向低频方向移动，其吸附能力和所形成配合物的稳定性一致。     

苯乙烯三嗪衍生物的合成及在重金属离子识别中的应用

合成了2,4-二(2-噻吩乙烯基)-6-(4'-N,N-二甲氨基苯乙烯基)-1,3,5-均三嗪(2)并鉴定了其结构。在乙腈-水混合介质中,化合物2在355和416nm处呈现双吸收峰,加入Cu²⁺,Hg²⁺ 和Fe³⁺ 后,均在520nm附近形成新的吸收峰。化合物2与Cu²⁺、Hg²⁺ 和Fe³⁺ 均形成1:1型配合物,其结合常数分别为1.9×10⁵L·mol^-1,6.6×10³L·mol^-1,2.7×10³L·mol^-1。对照化合物4与金属离子的光谱响应与化合物2相似,仅吸收峰的位置不同。因此,可认为化合物2和4中三嗪环中的N和噻吩环中的S与Cu²⁺、Hg²⁺ 和Fe³⁺ 共同配位形成了稳定的金属配合物。     

MOF-1和Tb@MOF-1荧光探针的设计、 合成及对痕量Cr2O72-、 S2O82-离子的识别

采用5-((4-吡啶基)甲氧基)-异烟酸(H₂PLIA)、1,3,5-三(1-咪唑基)-苯(TIB)合成了金属有机骨架[Cd(PLIA)(TIB)]_n (MOF-1),MOF-1是具有理想一维孔道的二维结构化合物,其一维孔道由柔性三角形PLIA^2-配体和刚性三角形TIB配体间隔形成。利用MOF-1 易掺杂的优势,采用后修饰合成策略制备了Tb@MOF-1。对MOF-1 和Tb@MOF-1 进行了基本表征及荧光探针性能研究。2种探针材料具有相同的结构。MOF-1和Tb@MOF-1分别对水溶液中的Cr₂O₇^2-和S₂O₈^2-离子具有较强荧光识别能力,均有响应时间快,稳定性、选择性、灵敏度高的特点。研究了MOF-1和Tb@MOF-1对Cr₂O₇^2-和S₂O₈^2-的荧光识别机理,其不同可能与Tb³⁺离子掺杂有关。     

Li＋在PC＋DMF混合溶剂中优先溶剂化的13C NMR研究

利用¹³C NMR光谱技术研究了Li^＋在碳酸丙烯酯(PC)＋N,N-二甲基甲酰胺(DMF)混合溶剂中的优先溶剂化现象. 根据溶剂分子中碳原子的化学位移随锂盐浓度的变化关系, 确定了与Li^＋发生配位的原子. 碳原子的配位位移值随混合溶剂组成的变化关系表明, 在LiClO₄＋PC＋DMF混合物中, DMF分子对Li^＋的溶剂化作用较PC分子强. 定量计算得到, 在n(PC)∶n(DMF)＝1∶1(摩尔比)的混合溶剂中, PC与DMF分子数在Li^＋第一溶剂化层中的比率为0.12, 说明Li^＋优先被DMF分子溶剂化.     

激发态Ti＋(3d14s2)与丙炔醇气相反应理论研究

用量子化学密度泛函(DFT)方法研究了激发态Ti^＋(3d¹4s²)与丙炔醇(PPA)气相反应的机理. 在B3LYP/DZVP水平上, 优化了反应的两个通道的反应物、中间体、过渡态和产物的几何构型, 并在MP4/[6-311＋G**(C,H,O)＋Lanl2dz (Ti)]水平上计算了各驻点的单点能量. 为了确证过渡态的真实性, 在B3LYP/DZVP水平上进行了内禀坐标(IRC)计算和频率分析, 获得了二重态反应势能面, 确定了反应机理. 研究结果表明生成产物为[C₃H₃O]^＋和Ti—H的通道是主要反应途径.     

人宫颈癌细胞(Hela)内的31P核磁共振研究

建立了无损伤性³¹P NMR研究细胞内物质的实验方法, 并对人宫颈癌细胞(Hela)的³¹P NMR谱中含磷小分子代谢物的谱峰进行了分析; 细胞内无机磷(Pi)的化学位移对pH非常敏感, 通过测定其化学位移可间接确定细胞内的pH, Hela细胞内Pi峰的化学位移为5.88±0.01 (n＝3), 计算得到细胞内 pH值为7.05±0.01; 通过测量Hela细胞的³¹P NMR谱中ATP的α磷和β磷及γ磷的化学位移差值, 得出Hela细胞内Mg^2＋与ATP结合的复合物MgATP和整个ATP量的比值, 计算得到Hela细胞内游离Mg^2＋浓度为(253.3±0.13) mmol/L (n＝3), 与其它分析方法相比, ³¹P NMR测定细胞内游离Mg^2＋浓度具有对细胞样品无损伤的优点.     

硝化纤维素对肌酐吸附机理的研究

利用IR，~(13)C NMR和XPS等技术研究了硝化纤维素（CN-1.15）对肌酐（Cr） 的吸附行为，并提出了可能的吸附路线。光谱分析的结果充分表明，碱性条件下， CN-1.15对Cr的吸附是通过碱化的硝酸酯基与Cr的胍基碳生成离子复合物而达到的。     

Infrared electroabsorption spectroscopy of N,N-dimethyl-p-nitroaniline in acetonitrile/C2Cl4: solvation of the solute and self-association of acetonitrile

Solvated structures of N,N-dimethyl-p-nitroaniline (DMPNA), an analog of p-nitroaniline (PNA), and self-associated structures of acetonitrile (ACN) in mixed solvents of ACN and C(2)Cl(4) were studied using infrared (IR) electroabsorption and FTIR spectroscopies. IR electroabsorption spectroscopy measures changes in IR absorption intensity upon application of external electric field modulation, which are a sensitive probe for permanent dipole moments. In ACN/CCl(4), PNA has been shown to occur as two distinct solvated forms, namely, 1:1 and 1:2 forms, which have one and two ACN molecule(s), respectively, associated with PNA. The IR electroabsorption and FTIR measurements on DMPNA show that, unlike PNA, DMPNA occurs as a monomer in ACN/C(2)Cl(4) rather than as specific solvated structures analogous to the 1:1 and 1:2 forms because of the substitution effect. Not only does the N,N-dimethyl substitution in DMPNA hamper solvation of ACN at the N(CH(3))(2) group, but it also indirectly blocks strong interactions with ACN at the NO(2) group. Furthermore, by using the ΔA signal of DMPNA as an internal intensity standard, it was found that the dipole moment of ACN in the DMPNA/ACN/C(2)Cl(4) system is about 1.5 times larger than that of the ACN monomer in dilute CCl(4) solution. This large value of the dipole moment in the solution studied here is attributable to the formation of a head-to-tail linear dimer of ACN, whereas the antiparallel dimer is energetically more favorable in the gas phase.     

Estimation of molecular diffusivity in aqueous solution of acetonitrile by the Wilke-Chang equation

It was tried to estimate the molecular diffusivity (D(m)) of solutes in the mixtures of acetonitrile (ACN) and water by the Wilke-Chang equation. Although the information about association coefficient (α) is necessary for the calculation, it has never been proposed for ACN. The value of α was estimated as 1.37 from D(m) of benzene in ACN at 303 K experimentally measured by the peak parking method. The values of α, i.e. 2.6, 1.9, 1.5, and 1.0, which have respectively been proposed for four solvents, i.e. water, methanol, ethanol, and benzene, were correlated with two physico-chemical parameters of the solvents, i.e. solubility parameter and E(T) value. The α value for ACN was plotted around the two correlations, indicating its appropriateness. The values of D(m) calculated by the Wilke-Chang equation using the α value for ACN were compared with those measured by the peak parking method and the Aris-Taylor method in aqueous solutions of ACN. The mean square deviation of the estimation of D(m) was calculated as 8.8 and 14%. It was demonstrated that the Wilke-Chang equation can be used for estimating D(m) with a reasonable accuracy in the mixtures consisting of ACN and water.     

Incorporation of carbon nanotubes in a silica HPLC column to enhance the chromatographic separation of peptides: theoretical and practical aspects

The retention mechanism of a series of peptides on a single-wall carbon nanotube (SWCNT) stationary phase inside an HPLC column was investigated over a wide range of mobile phase compositions. While the similar size C18 column exhibited an efficiency of 11.5 μm, the SWCNT column increased the efficiency, i.e. 7.10 μm at a flow rate of 0.8 mL/min, and significantly affected the separation quality of the peptides. The values of enthalpy (ΔH) and entropy (ΔS(*)) of transfer of the peptides from the mobile to the SWCNT stationary phase were determined. The method studied each factor, i.e. ACN fraction x in the ACN/water mixture and column temperature. The changes in retention factor, ΔH and ΔS(*) as a function of the ACN fraction in the mobile phase were examined. These variations are explained using the organization of ACN in clusters in the ACN/water mixture and on the steric and electronic forces implied in the retention process. The information obtained in this work makes this SWCNT stationary phase useful for peptide research and demonstrated the role of ACN to improve the separation quality.     

Acetonitrile as Adsorbate or Solvent to Probe the Crystal Face Specificity of Metal–Water Interaction at Silver Electrode/Solution Interfaces

The crystal face specificity of metal–water interaction at Ag electrode/solution interfaces is investigated by using acetonitrile (ACN) as a probe molecule of the water interfacial structure or as a solvent in which water is a solute. Capacitance and voltammetric curves suggest that ACN is weakly adsorbed from aqueous solution on Ag in the order (111) > (100) > (110). Apparent inconsistencies of adsorption parameters are explained by the occurrence of two ACN adsorption modes: (i) directly on the metal surface and (ii) on the water layer adsorbed on the metal surface. Ag surface oxidation in ACN in the presence of variable amounts of water suggests that water has an inhibiting effect on Ag oxidation, the diminution of the water content in ACN leading to free anodic dissolution of the metal surface.     

Tracking the Micro-Heterogeneity and Hydrogen-Bonding Interactions in Hydroxyl-Functionalized Ionic Liquid Solutions: A Combined Experimental and Computational Study

Ionic liquids (ILs) are an important class of media that are usually used in combination with polar solvents to reduce costs and tune their physicochemical properties. In this regard, it is essential to understand the influence of adding solvents on the properties of ILs. In this work, the micro-heterogeneity and H-bonding interactions between a hydroxyl-functionalized IL, [HOEmim][TFSI], and acetonitrile (ACN) were investigated by attenuated total reflection Fourier transform infrared spectroscopy and molecular simulations. All studied IL-ACN mixtures were found to deviate from the ideal mixtures. The degree of deviations reaches the maximum at about x(ACN)=0.7 with the presence of both homogeneous clusters of pure IL/ACN and heterogeneous clusters of IL-ACN. With the addition of ACN to IL, the mixtures undergo the transformation from “ACN solvated in [HOEmim][TFSI]” to “[HOEmim][TFSI] solvated in ACN”. It is found that the newly formed H-bonding interactions between the IL and ACN is the main factor that contributes to the red shifts of O−H, C₂−H, C_4,5−H, and C_alkyl−H of [HOEmim]⁺ cation, and the blue shifts of C−D, C≡N of ACN, and C−F, S=O of [TFSI]⁻ anion. These in-depth studies on the mixtures of hydroxyl-functionalized IL and acetonitrile would help to understand the micro-heterogeneity and H-bonding interactions of miscible solutions and shed light on exploring their applications.     

Comprehensive study on critical micellar concentrations of SDS in acetonitrile–water solvents

The CMC is one of the fundamental characteristics of surfactants and its determination is crucial for detail understanding of micelles formation. In this study the CMC of SDS in presence of ACN was determined by two independent experimental techniques, capillary electrophoresis and fluorescence correlation spectroscopy (FCS). Yet, studies of SDS micellization in solutions containing ACN as organic modifier are sparse and inconsistent in literature. The measurements were performed for various ACN contents in the range of 0–50% v/v. At ACN contents of up to 10% v/v the CMC is lower when compared to the aqueous solution, while increasing ACN content causes a significant increase of the CMC. Formation of micelles was observed up to ACN concentrations of 35% v/v, which is in contrast to most of the reports in literature. Based on the results of the FCS experiments, we were able to confirm that presence of ACN causes a gradual increase of the size of the micelles with increasing concentration of SDS. Simultaneously, we proved that the classical conductivity approach for the determination of the CMC does not yield reliable results in the presence of higher content of an organic modifier such as ACN.     

Reaction of Acenaphthylene with the Benzoyloxy Radical

Acenaphthylene (ACN) has been polymerized at 60° C using benzoyl peroxide labeled with carbon-14 and tritium as the Lnitiator. End-group analyses show a very high proportion of benzoate groups among the incorporated initiator fragments. It is deduced that ACN is much more reactive than most other monomers toward the benzoyloxy radical. There is evidence that transfer to benzoyl peroxide is significant during the polymerization of ACN.     

SO4●－自由基氧化酪氨酸反应中的溶剂效应

研究了水-乙腈混合溶液中SO4●－自由基氧化酪氨酸的反应.实验结果表明，SO4●－自由基氧化酪氨酸的反应机制不因乙腈的加入而改变，但所产生的瞬态粒子的动力学行为受到较大影响.随介质中乙腈体积分数的增加，SO4●－的衰变速率减慢而酪氨酸中性自由基（TyrO●）的衰变速率加快.我们认为这两种自由基所呈现出来的相反的溶剂效应是由于其所带电荷的不同.随介质中乙腈体积分数的增加，SO4●－氧化酪氨酸的反应速率减慢.这一实验结果意味着，在有机溶剂存在的情况下TyrO●/ TyrOH的氧化还原电势可能发生了变化，从而旁证了关于TyrO●/ TyrOH的氧化还原电势因酪氨酸从游离状态变到肽或蛋白质中而发生变化的推测.     

SO·4-自由基氧化酪氨酸反应中的溶剂效应

研究了水-乙腈混合溶液中SO·4-自由基氧化酪氨酸的反应.实验结果表明,SO·4-自由基氧化酪氨酸的反应机制不因乙腈的加入而改变,但所产生的瞬态粒子的动力学行为受到较大影响.随介质中乙腈体积分数的增加,SO·4-的衰变速率减慢而酪氨酸中性自由基(TyrO·)的衰变速率加快.我们认为这两种自由基所呈现出来的相反的溶剂效应是由于其所带电荷的不同.随介质中乙腈体积分数的增加,SO·4-氧化酪氨酸的反应速率减慢.这一实验结果意味着,在有机溶剂存在的情况下TyrO·/TyrOH的氧化还原电势可能发生了变化,从而旁证了关于TyrO·/TyrOH的氧化还原电势因酪氨酸从游离状态变到肽或蛋白质中而发生变化的推测.