金属离子掺杂对纳米TiO2光催化活性的影响及其机理研究进展

介绍了金属离子掺杂纳米TiO2的制备方法，阐述了金属离子掺杂对纳米TiO2光催化性能的影响及其机理。     

A系列树脂对金属离子的吸附性能及吸附机理

对前文合成的Ａ系列氮杂聚合物冠醚树脂（多胺交联乙二醇双缩水甘油醚）进行了元素分析、差热分析及红外光谱表征。研究了该系列树脂对Ｃｕ２＋、Ｎｉ２＋、Ｃｏ２＋的静态吸附动力学、等温吸附过程,并根据元素分析,ｐＨ值对吸附性能的影响及吸附前后红外光谱分析结果对其吸附机理作了初步探讨。实验结果表明,Ａ系列树脂具有热稳定性高、吸附速率快、吸附容量大等特点。可广泛应用于脱除污水中的过渡金属离子并可根据其对不同离子的吸附性能差异对金属离子进行有效分离。     

二溴新戊二醇在膨胀型阻燃乙烯-醋酸乙烯酯共聚物中的作用机理

以季戊四醇(PER)/二溴新戊二醇(DBNPG)混和磷酸酯三聚氰胺甲醛树脂(MFR)微胶囊化聚磷酸铵(APP)合成膨胀型阻燃剂(IFR)。研究了DBNPG的含量在膨胀型阻燃乙烯-醋酸乙烯酯共聚物(EVA)中的影响。流变行为、热分析、扫描电镜、阻燃性能与膨胀度测试结果表明:DBNPG可以通过改善炭层的膨胀度、致密度和封闭性来提高隔热性能。适当的DBNPG可改善IFR与EVA的相容性,增大熔体的黏度,形成封闭的炭层,提高炭层的隔热性能,降低燃烧体系放热,有利于阻燃性能的提高。但DBNPG含量过高,会降低流体的黏度,恶化炭层的隔热性能,放热量增大,阻燃性能降低。当IFR中DBNPG/PER的质量比为38.5/90.0,EVA/IFR的质量比为70/30时,复合材料具有最佳的阻燃性能和良好的力学性能。     

石墨烯复合材料对水中金属离子的吸附研究进展

石墨烯是一种新型的纳米材料,具有一些独特的物理和化学性质,如高机械强度、良好的导电导热性、比表面积、化学稳定性好等。关于石墨烯的应用涉及到电子、信息、能源、材料、催化和生物医药等多个领域。概述了近年来石墨烯复合材料在水处理过程中对重金属离子的吸附研究,内容有石墨烯复合材料的制备及它们的吸附效果、吸附机理、吸附动力学、热力学,并就今后石墨烯复合材料在水处理过程中的应用进行了展望。     

表面负载不同金属离子的活性炭吸附二苯并噻吩

主要研究活性炭表面负载不同金属离子以提高其对二苯并噻吩吸附性能.通过浸渍法制备5种负载过渡金属离子活性炭Ag(Ⅰ)/AC、Cu(Ⅱ)/AC、Ni(Ⅱ)/AC、Zn(Ⅱ)/AC和Fe(Ⅲ)/AC.用静态吸附法测定了二苯并噻吩在不同活性炭上的吸附平衡等温线,并应用软硬酸碱理论分析和讨论活性炭表面负载不同金属离子对二苯并噻吩吸附性能的影响.结果表明活性炭表面负载Ag ,Ni2 、Cu2 或Zn2 离子,可提高其对二苯并噻吩的吸附,而活性炭表面负载Fe3 ,反而降低了其对二苯并噻吩的吸附能力.由于Ag 价格昂贵,而Ni2 、Cu2 和Zn2 价廉易得,而且Zn(Ⅱ)/AC、Cu(Ⅱ)/AC和Ni(Ⅱ)/AC对二苯并噻吩又具有良好的吸附能力,故表面负载Ni2 、Cu2 和Zn2 可改善活性炭吸附脱除油品中有机硫化物的能力.     

PAN纳米纤维的改性及其应用于吸附金属离子

用盐酸羟胺溶液对静电纺聚丙烯腈(PAN)纳米纤维进行化学改性,制得偕胺肟PAN(AOPAN)纳米纤维,并用作吸附金属离子的基材。用SEM、FT-IR对化学改性前后PAN纳米纤维的表面形貌及分子结构进行表征。采用原子吸收分光光度计(AAS)测试溶液中金属离子的浓度,以此研究AOPAN纳米纤维对铜和铁金属离子的吸附性能。结果表明,AOPAN纳米纤维对Fe3+、Cu2+的饱和吸附量分别为206.36mg/g和118.38mg/g,且其吸附过程非常符合Langmuir吸附等温模型。此外,在1mol/L的硝酸溶液中反应60min后,Fe3+、Cu2+的洗脱率分别达到了90.6%和86%。     

改性壳聚糖对重金属离子的吸附研究和应用进展

壳聚糖是一种来源广泛、无毒、易降解的天然高分子材料,其分子中的羟基和氨基等功能团能形成活泼的界面,可以与重金属离子进行螯合,发生吸附作用;通过对壳聚糖进行适当的改性,可以提高壳聚糖的物理稳定性,选择吸附性.综述了采用交联、交联模板、羧甲基化、Schiff碱化、含氮、硫、磷等杂原子等方法对壳聚糖进行改性及其对重金属离子吸附的研究和应用进展.     

利用碳纳米管吸附溶液中金属离子的研究进展

碳纳米管具有中空层状结构,大的比表面积和长径比,高的化学稳定性和热稳定性以及端帽、内腔、管壁容易被修饰等特点,是一种较为理想的吸附材料。综述了碳纳米管与吸附相关的结构和性质,分析了经硝酸氧化处理过的碳纳米管对溶液中金属离子的吸附作用原理,以及pH值、离子浓度对吸附作用的影响。讨论了将碳纳米管对金属离子的吸附作用与分离富集技术相联系,应用于元素分析测定,能够提高方法灵敏度,降低了元素检出限。在仪器分析方面将有巨大潜力。     

介孔-枝状化合物复合体系对重金属离子吸附研究

在高含量硅羟基的SBA-15介孔孔道中用3-氨丙基三乙氧基硅烷(APTES)表面改性后, 在介孔孔道内合成了1代和2代的PAMAM (Poly(amide amine)) 枝状化合物. 利用该复合体系进行了重金属离子吸附实验, 并与只用APTES(3-氨丙基三乙氧基硅烷) 改性的SBA-15进行对比, 得到了各代样品对Pb²⁺和Cu²⁺的饱和吸附容量, 并且用TG-MS分析方法证实了PAMAM改性后的SBA-15对金属离子的络合强度要比仅用APTES改性的要强. 在模拟废水溶液吸附实验中, 该复合体系对Pb²⁺、Zn²⁺离子具有选择吸附, 处理后溶液中Pb²⁺、Zn²⁺离子浓度为0.003mg/L和0.037mg/L, 均低于国家饮用水标准.     

基于机器学习训练金属离子吸附能预测模型的研究

本研究通过密度泛函理论对氧化石墨烯和金属离子的吸附行为进行理论模拟。基于机器学习方法训练预测模型的过程中,缺失值采用推荐系统中广泛使用的奇异值分解方法处理,并用梯度提升机解释了影响吸附能的重要因素。结果发现吸附体系中存在九种特征可为吸附能提供90%的累积重要性,分别为离子半径、零点振动能量、密立根电荷、沸点、偶极矩、原子量、摩尔定容热容、自旋多重度和键长。定量评估了六种回归方法的预测精度,包括支持向量回归、岭回归、随机森林、极端随机森林、极端梯度提升和轻梯度提升机。结果表明,机器学习方法可提供足够的吸附能预测准确性,其中极端随机森林方法表现出最优的预测性能,均方误差仅为0.075。该模型用于香兰素吸附金属离子的测试,验证了基于机器学习训练金属离子吸附能预测模型的可行性,但仍需进一步提高其泛化能力。本研究基于机器学习预测吸附能,简化预测过程、节省计算时间,可为吸附去除金属离子的理论和实验研究提供参考。     

乙烯槽车绝热结构的设计与试验

简要介绍了乙烯公路槽车的绝热结构、设计要求与方法、绝热材料的选择和有关物性参数的试验结果。通过槽车的试制和使用情况证明，所选择的绝热结构和工艺方法完全能满足设计要求。     

H2C2O4稳定剂对SOl-Gel法制备LiNbO3薄膜的影响

研究了分别以H2C2O，HNO3，HCOOH和CH3COOH作稳定剂的LiNbO3薄膜先驱液的稳定性，发现H2C2O4作稳定剂的先驱液的稳定性最好，用sol-gel法在Si(110)基板上制备了以H2C2O4作稳定剂的LiNbO3薄膜，并对LiNbO3薄膜进行了IR，XRD和SEM表征，结果表明，生成的LiNbO3为多晶，与HNO3相比，以H2C2O4作稳定剂制备的LiNbO3薄膜形貌较差。     

In Situ Fabrication of Hierarchically Branched TiO2 Nanostructures: Enhanced Performance in Photocatalytic H2 Evolution and Li–Ion Batteries

1D branched TiO₂ nanomaterials play a significant role in efficient photocatalysis and high‐performance lithium ion batteries. In contrast to the typical methods which generally have to employ epitaxial growth, the direct in situ growth of hierarchically branched TiO₂ nanofibers by a combination of the electrospinning technique and the alkali‐hydrothermal process is presented in this work. Such the branched nanofibers exhibit improvement in terms of photocatalytic hydrogen evolution (0.41 mmol g⁻¹ h⁻¹), in comparison to the conventional TiO₂ nanofibers (0.11 mmol g⁻¹ h⁻¹) and P25 (0.082 mmol g⁻¹ h⁻¹). Furthermore, these nanofibers also deliver higher lithium specific capacity at different current densities, and the specific capacity at the rate of 2 C is as high as 201. 0 mAh g⁻¹, roughly two times higher than that of the pristine TiO₂ nanofibers.     

尖晶石型LiMn2O4酸洗提锂机理研究

以高温固相法合成的尖晶石型LiMn2O4前驱体为研究对象,通过对离子筛和离子筛吸附产物的化学分析、X射线衍射图谱分析、热重分析、红外分析和滤液中锂交换量与锰损失量分析,提出并验证了离子筛和吸附产物化学组成式可由LixMn2O4(0≤x≤1)表达,其结构依然保持尖晶石结构,阐明了以盐酸为洗脱剂离子筛提锂过程的氧化还原反应机理,给出了完善的洗脱过程与吸附过程反应式。实验结果表明,洗脱和吸附过程不彻底是导致离子筛吸附量与饱和吸附量相差较大的原因,离子筛中Mn3+歧化是离子筛发生溶损的主因;提出了关于尖晶石型离子筛提锂深入研究关键问题的建议。     

锂离子电池正极材料LiMn_2O_4制备新工艺

采用球磨湿混和旋转合成相结合的新工艺来制备锂离子电池正极材料ＬｉＭｎ２Ｏ４,并对制备的材料进行了粒度、化学成分以及电化学性能测试．制备的ＬｉＭｎ２Ｏ４为正尖晶石结构,而且物质纯净．同一批次制备的材料化学成分均匀,粉末粒度分布范围窄,中粒径为１０．６７μｍ,首次充电容量为１２４ｍＡｈ／ｇ,放电容量为１１５ｍＡｈ／ｇ．循环次数达３０次时,放电容量还大于１００ｍＡｈ／ｇ,循环稳定性良好．球磨湿混工艺能将原料混合均匀,并能有效地使原料粒度细化而且粒度均匀．旋转合成工艺能使反应物和反应产物的温度均匀、粒度均匀、晶型结构与成分均匀．球磨湿混和旋转合成相结合的固相合成新工艺能制备出电化学性能性能良好的ＬｉＭｎ２Ｏ４     

Hierarchically Porous Fe2CoSe4 Binary‐Metal Selenide for Extraordinary Rate Performance and Durable Anode of Sodium‐Ion Batteries

Owing to high energy capacities, transition metal chalcogenides have drawn significant research attention as the promising electrode materials for sodium‐ion batteries (SIBs). However, limited cycle life and inferior rate capabilities still hinder their practical application. Improvement of the intrinsic conductivity by smart choice of elemental combination along with carbon coupling of the nanostructures may result in excellence of rate capability and prolonged cycling stability. Herein, a hierarchically porous binary transition metal selenide (Fe₂CoSe₄, termed as FCSe) nanomaterial with improved intrinsic conductivity was prepared through an exclusive methodology. The hierarchically porous structure, intimate nanoparticle–carbon matrix contact, and better intrinsic conductivity result in extraordinary electrochemical performance through their synergistic effect. The synthesized FCSe exhibits excellent rate capability (816.3 mA h g^?1 at 0.5 A g^?1 and 400.2 mA h g^?1 at 32 A g^?1), extended cycle life (350 mA h g^?1 even after 5000 cycles at 4 A g^?1), and adequately high energy capacity (614.5 mA h g^?1 at 1 A g^?1 after 100 cycles) as anode material for SIBs. When further combined with lab‐made Na₃V₂(PO₄)₃/C cathode in Na‐ion full cells, FCSe presents reasonably high and stable specific capacity.     

A study of corrosion performance of tinplate with different tin coating thickness in H2SO4 solution

The corrosion performance of tinplate with different coating mass in H₂SO₄ solution has been investigated by electrochemical measurements and scanning electron microscope observation. The results indicate that the tinplate with a higher tin coating mass exhibits better corrosion resistance than the sample with a lower tin coating mass due to that a lower tin coating mass may not uniformly cover the base steel surface with roughness or other defects. Besides, the amount of coating mass on tinplate can greatly affect its corrosion evolution behavior, and in practical applications the coating mass selection should be selected based on its surrounding corrosive environment. Moreover, the cyclic corrosion process of tinplate in H₂SO₄ solution can re-generate H₂SO₄, and it again accelerates the tinplate dissolution process.     

A Brown Mesoporous TiO2‐x/MCF Composite with an Extremely High Quantum Yield of Solar Energy Photocatalysis for H2 Evolution

A brown mesoporous TiO_2‐x/MCF composite with a high fluorine dopant concentration (8.01 at%) is synthesized by a vacuum activation method. It exhibits an excellent solar absorption and a record‐breaking quantum yield (Φ = 46%) and a high photon–hydrogen energy conversion efficiency (η = 34%,) for solar photocatalytic H₂ production, which are all higher than that of the black hydrogen‐doped TiO₂ (Φ = 35%, η = 24%). The MCFs serve to improve the adsorption of F atoms onto the TiO₂/MCF composite surface, which after the formation of oxygen vacancies by vacuum activation, facilitate the abundant substitution of these vacancies with F atoms. The decrease of recombination sites induced by high‐concentration F doping and the synergistic effect between lattice Ti³⁺–F and surface Ti³⁺–F are responsible for the enhanced lifetime of electrons, the observed excellent absorption of solar light, and the photocatalytic production of H₂ for these catalysts. The as‐prepared F‐doped composite is an ideal solar light‐driven photocatalyst with great potential for applications ranging from the remediation of environmental pollution to the harnessing of solar energy for H₂ production.     

Microstructure and Mechanical Properties of B4C/6061Al Nanocomposites Fabricated by Advanced Powder Metallurgy

In this study, B₄C/6061Al nanocomposites reinforced with various volume fractions of nano‐sized B₄C particles (B₄C/6061Al NCs) are successfully fabricated by a powder metallurgy route consisting of spark plasma sintering (SPS) and hot extrusion and rolling (HER). The microstructure evolution, phase composition, and mechanical properties of B₄C/6061Al NCs are experimentally investigate. The results show that nearly fully dense (maximum ≈99.21%) as‐SPSed NCs can be fabricated, and this can be attributed to joule heating at the particle contacts and tip spark plasma at the gaps. Nanosized B₄C particles mainly distributed in the 6061Al particles boundaries and formed inhomogeneous network materials in as‐SPSed NCs, while B₄C particles distributed relatively homogeneously in the 6061Al matrix after HER. No new phases are found in the B₄C/6061Al NCs over three deformation stages. The pin effect of the nanosized B₄C can suppress dynamic recovery and improve the driving force for dynamic recrystallization. The mechanical properties are further improved after HER, and the maximum ultimate tensile strength and yield strength for as‐rolled NCs are 305 and 168 MPa. The strengthening mechanisms mainly included load transfer strengthening, dislocation strengthening, Orowan strengthening, and fine‐grain strengthening.

     

铸态Mg-4Al-2Si合金的显微组织与力学性能

采用重力铸造法制备Mg-4Al-2Si(AS42)镁合金,研究了铸态合金的显微组织和室温力学性能。结果表明:铸态AS42合金主要由α-Mg基体、β-Mg17Al12相及Mg2Si相组成;β-Mg17Al12相呈网状和棒状分布于晶界上,粗大的汉字状Mg2Si相沿晶界或穿晶分布,多边形块状Mg2Si相随机分布于基体组织中。铸态合金的硬度为64.5 HV,室温抗拉强度为113.5 MPa,屈服强度为86 MPa,伸长率为4.1%;拉伸断裂形式为准解理脆性断裂。