纳米磁性壳聚糖对腐殖酸和重金属离子混合吸附研究

研究了纳米磁性壳聚糖吸附剂对腐殖酸的吸附性能和重复使用性能,分析了腐殖酸存在的条件下对Cu2+、Pb2+、Cd2+三种重金属离子吸附的影响及机理.实验结果表明:该吸附剂对腐殖酸吸附的最佳pH值为11,饱和吸附量为292mg/g;吸附速度快,15min可达吸附平衡;经5次吸附后,保留了初次吸附量的60%,具有一定的可再生性和重复使用性.同时,该吸附剂吸附腐殖酸后仍可对Cu2+、Pb2+、Cd2+产生吸附作用,较单独吸附时Cu2+、Pb2+的吸附量有所降低,而Cd2+的吸附量则有大幅提高.     

PPY掺杂离子对电催化脱氯Pd/PPY/Ni电极的影响

为制备高效稳定的用于电催化去除氯代有机物的电极,采用扫描电子显微镜和电催化脱氯实验考察不同聚吡咯掺杂离子对Pd/PPY/Ni复合电极的形貌和电催化加氢脱氯性能的影响.将制备的电极在强吸附性阴离子存在情况下,考察其电催化性能的变化.结果表明,掺杂离子对复合电极的形貌和电催化性能有显著的影响,对甲苯磺酸掺杂的聚吡咯对应的Pd/PPY(PTS)/Ni电极有最高的电催化加氢脱氯效率(高达91.1％),高氯酸钠掺杂的聚吡咯对应的电极电催化性能最差.电催化体系中强吸附离子(ClO4-,Cl-)的存在对电极性能有微弱影响,表明电极具有良好的稳定性,可高效去除水中的氯酚类氯代有机物.     

基于聚苯胺的电吸附法处理含铅离子废水的研究

采用化学氧化聚合法合成聚苯胺（PANI）,并对其进行了红外光谱和扫描电镜表征.以PANI为电极材料,通过电吸附技术去除模拟废水中的Pb2＋;同时PANI链上富含的亚氨基还可以与pb2＋发生络合,从而提高了PANI电吸附去除pb2＋的效率.研究了吸附电位、吸附时间、初始浓度等因素对pb2＋去除效果的影响,并且分别从动力学与热力学的角度研究了PANI对pb2＋的电吸附.结果表明,PANI电极对pb2＋的电吸附过程符合Lagergren准一级动力学方程和Freundlich吸附等温式.最后,对吸附了pb2＋的PANI电极的脱附再生进行了研究,经过多次电吸附-脱附循环后,PANI电极对pb2＋的去除率并无明显降低.因此通过电吸附技术,用PANI电极去除实际废水中的pb2＋具有可行性.     

胶原纤维负载金属离子对氟的吸附性能研究

以胶原纤维为基质,利用Zr(Ⅳ)、Al(Ⅲ)和Fe(Ⅲ)能与其形成配合物的特性制备吸附材料,并研究了该吸附材料对水溶液中氟离子的吸附特性。结果表明,在pH 4～9范围内,胶原纤维负载Zr( ZrCF)、Al( AlCF)和Fe( FeCF)对氟离子具有较强的吸附能力,吸附容量大小顺序为：ZrCF>AlCF> FeCF。在303 K时,３种吸附材料对F-的平衡吸附容量分别为57.94 mg/g、31.84 mg/g和15.24 mg/g,对氟离子的吸附等温线均符合Langmuir方程。ZrCF对氟离子的吸附动力学可以用拟二级速度方程来描述,计算得到的平衡吸附量与实测平衡吸附量非常吻合。用0.05 mol/L氢氧化钠溶液进行解吸时,其解吸率达97％。     

Adsorption behaviors and mechanism of heavy metals onto attapulgite functionalized by polyamine silane

Pollution from heavy-metal ions has become a major challenge to the global fight against environmental pollution. Given the availability of various low-cost and environmentally friendly adsorbents, adsorption has become the most efficient technology for the removal of heavy metals from water. In this study, attapulgite (ATP) was directly functionalized by coupling with an aminosilane agent. Analysis showed this maneuver provided a suitable adsorbent for the removal of lead ion (Pb²⁺) from an aqueous solution. The effects of several parameters including solution pH, contacting time, adsorbent dosage, and initial Pb²⁺ ion concentration were investigated. Batch sorption results showed that the adsorption process was rapid and over 98% of Pb²⁺ was removed within 30 min at the optimal pH 4.0. The maximum adsorption capacity at 25°C, calculated by the Langmuir isotherm, was 82.17, 78.80, 61.13, and 28.56 mg/g for γ-divinyltriaminepropyl-methyldimethoxylsilane-grafted attapulgite (KH-103-ATP), γ-aminopropyl-methyldiethoxysilane-grafted attapulgite (KH-912-ATP), N-(β-aminoethyl-γ-aminopropyl)-methyl-dimethoxysilane-grafted attapulgite (KH-602-ATP), and ATP, respectively. Moreover, molecular dynamics simulations of adsorption behaviors of heavy-metal ions at attapulgite surfaces (010) modified by aminosilane agents were carried out. Both the PMF value and diffusion coefficient of metal ions suggest that KH-103-ATP owns the highest rate constant and capacity compared with the other two. And the analysis of free energy and results of XPS characterization revealed that Pb²⁺ formed covalent bonds with the nitrogen atom of aminosilane agents.     

VB/CHCl3液膜体系中银离子的传输分离

采用内耦合大块液膜分离技术, 通过考察料液相pH值、料液相NaCN浓度、载体浓度以及解析相NaOH浓度对Ag(Ⅰ)传输的影响, 研究了以维多利亚蓝(VB)为流动载体的液膜中银的传输规律, 并建立了渗透系数与pH值、 NaCN浓度以及载体浓度等之间的关系方程.结果表明, Ag(Ⅰ)以VB+*Ag(CN)2-离子缔合物形式在液膜中传输, 最佳传输条件为 料液相中NaCN浓度为5.0×10-3 mol*L-1(pH=5.5), 解析相为0.05 mol*L-1 NaOH, 载体VB浓度为4.00×10-4 mol*L-1.Ni(Ⅱ), Co(Ⅱ), Zn(Ⅱ), Cu(Ⅱ), Pb(Ⅱ)及Cd(Ⅱ)离子对Ag(Ⅰ)传输无影响.     

掺Yb3+闪烁晶体的研究进展

掺Yb3+闪烁晶体是新近发展起来的一类闪烁体,有可能用于探测太阳中微子.本文简要介绍了掺Yb3+闪烁晶体的电荷迁移发光的机理以及基质晶体对温度猝灭与浓度猝灭的影响.综述了具有石榴石结构和钙钛矿结构的两类掺Yb3+闪烁晶体的研究进展,特别是YbYAG和YbYAP晶体的生长、闪烁性能以及应用前景.最后,对掺Yb3+闪烁晶体的未来研究方向做了展望.     

X-ray yields from high-energy heavy ions channeled through a crystal: their crystal thickness and projectile dependences

X-rays emitted from Ar¹⁷⁺, Fe²⁴⁺ and Kr³⁵⁺ ions of about 400 MeV/u transmitting through a thin Si crystal of about 20 μm thickness have been measured in a planar channeling condition and compared with those in a random incident condition. We have found that the X-ray yield from Ar¹⁷⁺ ions is larger for the channeling condition than for the random incidence, while those from Fe²⁴⁺ and Kr³⁵⁺ ions are rather smaller. Such tendencies are explained by considering the projectile dependences of excitation and ionization probabilities together with X-ray emission rates. A crude simulation has qualitatively reproduced these experimental results. When the crystal thickness is small, the X-ray yield is smaller in the channeling condition than in the random incident condition, because excitation is depressed. However, for thicker crystals, the X-ray yield is larger, since the survived population of projectile-bound electrons is larger due to small ionization probabilities under the channeling condition. This inversion occurs at a specific crystal thickness depending on projectile species. Whether the thickness of the used crystal is smaller or larger than the inversion thickness determines enhancement or depression of the X-ray yield in the channeling condition.     

掺铒碲钨酸盐玻璃及其平面波导

研制了一种用于宽带波导放大器的掺铒碲钨酸盐激光玻璃材料,对玻璃热稳定性、光谱性质进行了表征,并在其上采用离子交换法制作了平面光波导.掺铒碲钨酸盐玻璃的转变温度Tg和析晶开始温度Tx分别为377.1和488.5℃;荧光半高宽为52nm;应用McCumber理论,计算得出Er3+离子4I13/2→4I15/2跃迁在峰值波长1532nm的受激发射截面为0.91×10-20cm2. 不同条件下制作了在632.8nm处多模的平面光波导,通过拟合得到Ag+离子在300℃的有效扩散系数De为2.82×10-16μm2,活化能Q为149.7kJ/mol.研究结果表明掺铒碲钨酸盐玻璃具有较好的热稳定性、优良的光谱性能和离子交换性能,有望成为宽带放大的集成光学材料.     

利用膨润土和铝土矿制备4A分子筛的研究

以精制膨润土与铝土矿为原料，采用硫酸酸化法制备4A分子筛，其影响因素主要是：（1）酸浓；（2）液固比；（3）酸化温度；（4）酸化时间。通过正交实验对影响其制备的各个因素进行分析，得出了制备最佳工艺条件为酸浓50％，液固比3．0，酸化温度90℃，酸化时间为6h；制备的优等4A分子筛的钙离子交换容量为311mg／g，符合4A分子筛国家标准优等品要求。进一步对酸化白土进行碱处理的对照实验，得出进行碱处理是制备4A分子筛的关键。通过对4A分子筛制备的晶化时间、晶化温度实验，得出最佳的晶化时间为5h，最佳的晶化温度为90℃。对产品作X射线衍射分析，其衍射数据和标准的4A分子筛衍射数据相吻合，证明所得产品为4A分子筛。亦可以看出存在杂峰，说明制备的4A分子筛不纯，含有杂质。但所得产品主要性能指标优越，对生产廉价的4A分子筛产品具有指导意义。