C2H3＋NO2反应速率常数的研究

利用激光光解C2H3Br产生C2H3自由基,在气相298 K, 总压2.66×103 Pa的条件下,研究C2H3与NO2的反应,用激光光解-激光诱导荧光（LP-LIF）检测中间产物OH自由基的相对浓度随着反应时间的变化关系,报导了双分子反应C2H3＋NO2的速率常数k(C2H3＋NO2)=(1.8±0.05)×10－11cm3•molec.－1•s－1,同时也得到OH＋NO2反应的速率常数k(OH＋NO2)=(2.1±0.15)×10－12 cm3•molec.－1•s－1.     

甲烷在飞秒强激光场中的解离

用波长为800 nm，脉宽为160 fs，强度范围为7.6×1013～1.4×1014 W•cm－2的强激光使甲烷分子解离，并用质谱仪检测产生的离子.母体离子在较低的激光强度（7.6×1013 W•cm－2）下出现;当激光强度增加到8.0×1013 W•cm－2时，开始出现；CH2＋、CH＋和C＋离子出现的阈值分别为1.0×1014 W•cm－2、1.4×1014 W•cm－2和1.4×1014 W•cm－2.这些现象表明甲烷的解离是一个顺序过程.质谱图中没有多电荷离子，因此排除了发生库仑爆炸的可能.以线偏振激光作用于甲烷，只有H＋离子有各向异性的角度分布，暗示分子中的化学键是被激光外场拉断的，且初级产物离子H＋是沿着激光电场的方向飞出.提出的准双原子分子模型较好地解释了实验结果.     

纳米CdS与明胶蛋白质的相互作用

利用荧光光谱和紫外-可见吸收光谱研究了pH＝12.0及不同温度下, CdS纳米晶与明胶结合反应的光谱行为, 实验发现在明胶溶液中CdS的生成对明胶的内源荧光有较强的猝灭作用. 用Lineweave-Burk方程处理实验数据, 发现CdS与明胶发生反应生成了配合物, 结合红外和紫外-可见吸收光谱结果, 属于静态荧光猝灭; 计算了不同温度下反应的结合常数K (285 K: 1.07×104 L•mol－1; 292 K: 9.69×103 L•mol－1; 299 K: 8.06×103 L•mol－1)及对应温度下结合反应的热力学参数(ΔrHm＝－14.18 kJ•mol－1; ΔrGm＝－21.98/－22.28/－22.36 kJ•mol－1; ΔrSm＝27.36/27.74/27.36 J•K－1•mol－1), 证明二者主要靠静电作用力结合. 根据Förster的偶极-偶极非辐射能量转移原理计算出结合位置距离色氨酸残基4.09 nm, 发生分子内的非辐射能量转移. 为探讨纳米颗粒与此类生物大分子之间相互作用的化学机制提供了重要的信息.     

Pt(111)单晶电极上乙二醇解离吸附反应动力学

运用电化学循环伏安和程序电位阶跃方法研究了乙二醇在Pt(111)单晶电极上的解离吸附过程.动力学研究的定量结果指出,乙二醇解离吸附反应的平均速率随电极电位变化呈火山型分布,其最大值在0.10 V(vs SCE)附近.测得在含2×10－3 mol•L－1乙二醇的溶液中,最大初始解离速率vi为4.35×10－12 mol•cm-－2•s－1.     

二安替比林-(2-甲氧基)-苯基甲烷光度法测定铬

合成了新试剂二安替比林－（2－甲氧基）－苯基甲烷（DAoMM）；研究了在Mn（Ⅱ）存在下，DAoMM与Cr（Ⅵ）生成橙黄色化合物。该化合物最大吸收位于480nm；表观摩尔吸收系数为ε=1．58×105L·mol－1·cm－1和ε2=9．85×104L·mol－1·cm－1化合物至少稳定20h。服从比尔定律范围0～1．6×102μg／LCr（Ⅵ）和2×102～8×102μg／LCr（Ⅵ）。用于含铬废水和电镀废液中铬的测定，结果满意。     

硫氰酸钨(Ⅴ)络合物稳定常数的测定

测定了水溶液中硫氰酸钨(Ⅴ)络合物的吸收光谱,最大吸收波长为405 nm.在盐酸浓度为3.56 mol/L、离子强度为0.088 mol/L的溶液中,硫氰酸钾溶液浓度在0.018～0.088 mol/L范围内,与硫氰酸钨(Ⅴ)络合物的平均摩尔吸光系数△-ε呈函数关系.测得络合物的络合比为14.计算出络合物的各级累积稳定常数和摩尔吸光系数分别为β1=40.73,β2=1.10×103,β3=2.40×104,β4=4.16×105,Δε1=9.33×103,Δε2=9.64×103,Δε3=9.93×103,Δε4=1.10×104(t=17.7℃).     

铂电极上醋酸-醋酐溶液中Mn(III)/Mn(II)电对研究

平衡电极电势实验确定了25 ℃, 1.5 mol•L－1醋酸钾＋醋酸-醋酐(3:1体积比)溶液中Mn(III)/Mn(II)的条件电极电势为0.719 V（vs SCE）;采用电势扫描和旋转圆盘电极技术研究了醋酸-醋酐溶液中铂电极上Mn(III)/Mn(II)电对的阳极氧化动力学. 结果表明:Mn(II)阳极氧化成Mn(III)的电极反应控制步骤属电荷传递过程, 阳极传递系数β=0.347,交换电流密度i0=5.84×10－6 A•cm－2,阳极标准反应速率常数ka=1.35×10－8 m•s－1, Mn(II)和OAc－的反应级数均为一级.     

NCO自由基与SO2、CS2反应的速率常数

利用波长为266 nm的激光光解CHBr3产生CH自由基,其与NO反应作为NCO自由基的来源.在298 K,总压2660 Pa的条件下,采用激光诱导荧光的方法,研究了NCO自由基与SO2、CS2的反应.得到了NCO自由基与SO2、CS2双分子反应速率常数分别为（1.8±0.3）×10－11和（3.1±0.4）×10－12 cm3•molecule－1•s－1.对这两个反应在B3LYP/6-31＋G(d)的水平上进行理论研究的结果表明,NCO自由基与SO2、CS2的反应是加成反应,其机理是NCO自由基中的N原子攻击反应物的中心原子,得到加成产物.     

阿西美辛的吸附伏安特性

在乙酸 -乙酸钠 ( p H 4.2 0 )底液中 ,阿西美辛 ( ACE)在汞电极上有一线性扫描还原峰 ,峰电位 Epc=- 1 .1 8V( vs.Ag/Ag Cl) ,该峰具有明显的吸附性。吸附粒子为 ACE中性分子 ,测得 ACE在汞电极上的饱和吸附量为 1 .1 9× 1 0 - 10 mol/cm2 ,每个 ACE分子所占电极面积为 1 .43nm2 ,ACE在悬汞电极上的吸附符合 Frumkin等温式。测得吸附系数β =1 .2 9× 1 0 6 ,吸引因素γ =1 .0 4 ,电子转移数 n为 2 ,不可逆吸附的电子转移系数α为 0 .86,表面电极反应速率常数 ks=0 .32 /s。建立了吸附伏安法测定 ACE的最佳条件 ,检出限为 1 .0× 1 0 - 9mol/L     

铟(Ⅲ)-茜素红体系的吸附伏安法

本文对铟（Ⅲ）与茜素红络合物在悬汞电极上的吸附伏安法作了研究，确定了电极过程．在HAc－NaAc（PH4．92）缓冲溶液中有菌素红存在下，用1．5阶微分吸附伏安法测定铟，其线性范围是1×10－10～8×10－8mol／L，检测限5×10－11mol／L，用此法测定了化探样中痕量铟，结果良好。     

探针体耐尔蓝(NB)与DNA结合反应研究

应用微相吸附-光谱修正(MPASC)新技术研究DNA与耐尔蓝(NB)探针分子间的相互作用,分析生物大分子内静电场的形成与Langmuir吸附的关联性,测定了结合产物结合比、平衡常数等.通过在pH=10.38介质中对DNA-NB反应的光谱分析,结果表明产物结合比NB∶ DNA-P=3∶ 1、平衡常数K=3.33×105,摩尔吸收系数ε660 nm=4.81×103 L/mol cm.样品分析表明DNA回收率95.6%～108%,相对标准偏差RSD=2.8%.     

Adsorption of nucleic acids on collodion films

Adsorption of nucleic acids on collodion films from solutions of different ionic strengths was studied, and the adsorption equilibrium constants were determined. The primary adsorption of DNA samples on collodion films was examined depending on various factors. A comparative analysis of different techniques (vacuum drying, UV irradiation) employed for immobilization of DNA samples on collodion films was carried out.     

Biosorption of Ni(II) from aqueous solutions by living and non-living ureolytic mixed culture

The present study explores the ability and the comparison of living and non-living ureolytic mixed culture (UMC) to remove Ni(II) from aqueous solution. Time dependency experiments for the Ni(II) uptake showed that adsorption equilibrium was reached almost 110 and 60 min after addition Ni(II) of 100mg/L. The kinetic data were analyzed in term of pseudo-first-order and pseudo-second-order expressions. Ni(II) sorption of living UMC was appropriate with pseudo-first-order kinetic (k(1)=2.15 h(-1), R(2)=0.93) while non-living UMC sorbed Ni(II) with respect to second-order kinetics (k(2)=1.64 g/mgh, R(2)=0.98). Also, comparison between the biosorption capacity of untreated living and non-living biomass was conducted for removal of Ni(II). The biosorption process was investigated in equilibrium batch tests for Langmuir, Freundlich and Temkin isotherm models. The data pertaining to the sorption dependence upon Ni(II) ion concentration ranged from 5 to 320 mg/L could be fitted to a Freundlich isotherm model. The capacity constants K of Freundlich model for living and non-living UMC were 1.55 and 0.38 mg/g, respectively; the affinity constants 1/n were 0.47 and 0.75, respectively. Based on the results, the UMC appear to be a potential biosorbent for removal of Ni(II) from wastewater.     

羧甲基化壳聚糖- Fe3O4纳米粒子的制备及对Zn2+的吸附行为

以共沉淀法制备纳米Fe3O4, 通过在颗粒表面接枝羧甲基化壳聚糖(CMC), 制备一种新型磁性纳米吸附剂, 用透射电镜(TEM)、X射线衍射分析(XRD)等对其进行了表征, 并考察了吸附剂对Zn2+的吸附性能. 结果表明, 制备的磁性纳米吸附剂平均粒径18 nm, 粒子中CMC的含量约5%. 该吸附剂对Zn2+吸附速率很快, 在2 min内基本达到平衡, 能有效去除Zn2+. 等温吸附数据符合Langmuir模型, 饱和吸附容量为20.4 mg•g−1, 吸附常数为0.0314 L•mg−1. 热力学计算表明吸附为放热过程, 焓变为−5.68 kJ•mol−1.     

过氧硝酸乙酰酯分解反应的速率常数

在G3MP2B3结构优化和能量计算的基础上, 采用RRKM理论和疏松过渡态模型重新估算了过氧硝酸乙酰酯(PAN)的热分解反应PAN→CH₃C(O)OO+NO₂(R1)的反应速率常数, 得到与实验值吻合的结果.用同样的模型计算了PAN→CH₃C(O)O+NO₃(R2)的反应速率常数. 结果表明, 在相同的反应条件下, R1是主要的分解通道, R2是次要通道, R2的反应速率常数比R1的小两个数量级.     

两个多胺铜配合物的合成，晶体结构以及DNA切割活性

本文以配体N,N′-二(3-氨丙基)-4-甲氧基苄胺(amba)与4,4′-联吡啶,铜盐反应合成了两种多胺Cu(Ⅱ)配合物[Cu(amba)Cl2](1)和[Cu(4,4′-bipy)(amba)(ClO4)]ClO4(2),通过红外光谱、质谱和X-射线单晶衍射对其结构进行了表征。利用紫外吸收光谱、分子荧光,电化学以及粘度试验研究了配合物与小牛胸腺DNA(CT-DNA)的相互作用方式。通过紫外吸收光谱得到配合物1和2与DNA的结合常数Kb分别为1.3×104 mol-1.L和1.7×104 mol-1.L,荧光光谱得到配合物1和2的荧光淬灭常数分别为1.04×103mol-1.L和1.81×103 mol-1.L,表明了配合物1和2与CT-DNA结合方式均为静电模式。凝胶电泳实验的结果表明配合物对pBR322 DNA的切割均为水解切割。     

Adsorption of cationic copolymer nanoparticles onto bamboo fiber surfaces measured by conductometric titration

Monosized nanoparticles of 57.3 nm were prepared by cationic emulsion polymerization using a polymerizable emulsifier DMHB. The adsorption of nanoparticles onto bamboo fibers was measured by conductometric titration. The results indicated that the adsorption capacity increased with increasing contact time until 120 min. The equilibrium data for nanoparticles adsorption onto bamboo fibers were well fitted to the Langmuir equation. Moreover, the monolayer adsorption capacity of nanoparticles in the concentration range (from 0.03 g/L to 0.6 g/L) studied, as calculated from Langmuir isotherm model at 25℃, was found to be 38.61 mg/g of fibers. The SEM images showed that the nanoparticles form a uniform monolayer on bamboo fiber surfaces.     

Removal of Cu(II) and Zn(II) from industrial wastewater by acid-activated montmorillonite-illite type of clay

An acid-activated montmorillonite-illite type of clay collected from the Gulbarga region of Karnataka, India was examined for removing copper and zinc ions from industrial wastewater containing Cu(II), Zn(II) and minor amounts of Pb(II). Langmuir, Freundlich, Brunauer-Emmett-Teller (BET), and competitive Langmuir (two competing ions) isotherms were fitted to experimental data and the goodness of their fit for adsorption was compared. The shapes of isotherms obtained indicated multilayer adsorption of Cu(II) and monolayer adsorption of Zn(II) on the acid-activated clay. Competitive adsorption was found to be significant due to the presence of Cu(II) in the wastewater.     

2-chlorophenol sorption from aqueous solution using granular activated carbon and polymeric adsorbents

Adsorption equilibrium and kinetics of 2-chlorophenol (2-CP) one of the chlorophenols (CPs) onto bituminous coal based Filtrasorb-400 grade granular activated carbon and three different types of polymeric adsorbents were studied in aqueous solution in a batch system. Langmuir isotherm models were applied to experimental equilibrium data of 2-CP adsorption. Equilibrium data fitted very well to the Langmuir equilibrium models of 2-CP. Adsorbent monolayer capacity Q Langmuir constant b and adsorption rate constants k _a were evaluated. 2-CP adsorption using GAC is very rapid in the first hour of contact where 70–80% of the adsorbate is removed by GAC followed by a slow approach to equilibrium. Whereas in case of polymeric adsorbents 60–65% of the adsorbate is removed in the first 30 min which is then followed by a slow approach to equilibrium. The order of adsorption of 2-CP on different adsorbents used in the study is found to be in following order: F-400 > XAD-1180 > XAD-4 > XAD-7HP.     

Biosorption of lead from aqueous solution by seed powder of Strychnos potatorum L.

In the present study, Pb(II) removal efficiency of Strychnos potatorum seed powder (SPSP) from aqueous solution has been investigated. Batch mode adsorption experiments have been conducted by varying pH, contact time, adsorbent dose and Pb(II) concentration. Pb(II) removal was pH dependent and found to be maximum at pH 5.0. The maximum removal of Pb(II) was achieved within 360 min. The Lagergren first-order model was less applicable than pseudo-second-order reaction model. The equilibrium adsorption data was fitted to Langmuir and Freundlich adsorption isotherm models to evaluate the model parameters. Both models represented the experimental data satisfactorily. The monolayer adsorption capacities of SPSP as obtained from Langmuir isotherm was found to be 16.420 mg/g. The FTIR study revealed the presence of various functional groups which are responsible for the adsorption process.