氧化铝微纳结构材料的研究进展

氧化铝微纳结构材料由于具有特殊的形貌、高比表面积、高介电常数、高的热和化学稳定性等特性,以及可以作为构筑单元,采用自下而上的方法合成各种超级结构材料,从而使其在吸收剂、催化剂裁体、陶瓷材料、耐磨材料和新结构材料合成等诸多领域得到重要应用,已成为当前纳米材料科学领域的前沿和热点.结合近年来国内外的最新研究进展对氧化铝微纳结构材料的制备方法、表征和物性研究等进行了综述,并对其发展趋势和前景进行了展望.     

新型重金属离子吸附剂的研究进展

重金属离子废水严重威胁人类的生命安全,现有多种处理方法都存在一定问题。吸附法具有简单、方便、高效、快捷、选择性强等优势,引起了人们的日益关注。在综述了腐植酸类吸附剂、碳类吸附剂、矿物吸附剂、高分子吸附剂、生物材料吸附剂以及介孔SiO_2材料等多种现有工业应用吸附剂的基础上,着重介绍了新型特定功能组分SiO_2气凝胶的制备及其在重金属废水处理的研究现状,并就今后SiO_2气凝胶材料在水处理过程中的应用进行了展望。     

微纳结构超疏水材料制备技术的研究进展

综述了超疏水材料制备技术的研究进展,总结了聚合物和金属基两类主要超疏水材料的制备工艺以及国内外研究现状,指出制备具有各种特殊功能性的超疏水材料如定向疏水材料、超双疏材料等将是今后重要的研究万向.     

生物医学诊疗用磁性微纳材料

磁性微气泡是由包膜微气泡和磁性纳米粒子组成的微纳复合结构,由于其具有超声对比剂和核磁共振对比剂的双重特性,已被应用于双模造影领域。声致穿孔现象（Sonoporation）使得磁性微气泡能介导多种生物学效应,使其在药物输运和基因转染等方面有潜在的应用价值,而磁性微气泡与各种生物分子（抗体、肿瘤标记物等）的偶联,又扩展了磁性微气泡的应用领域,可用于分子影像诊断和靶向治疗肿瘤等方面,可以说磁性微气泡是新一代的生物医学诊疗用磁性微纳材料。总结了磁性微气泡的制备方法,磁性纳米颗粒与微气泡的结合方式,磁性微气泡的功能扩展,以及磁性微气泡在生物医学诊疗领域的实验研究,最后对磁性微气泡在未来的发展方向提出了一些构想,展望了磁性微气泡在诊疗学上广阔的应用前景。     

抗污染海藻酸钙水凝胶纳滤膜对水中重金属离子的去除性能

以海藻酸钠为单体,尿素为致孔剂,采用钙离子交联的方法制备海藻酸钙水凝胶纳滤膜,并研究该纳滤膜的表面形貌、亲水性、抗污染性以及对水中重金属离子的去除。结果表明,海藻酸钙纳滤膜具有优良的抗污染性能,水接触角在2s几乎降为0。牛血清白蛋白(BSA)的通量为纯水通量的97.7%,交替过滤纯水和BSA溶液3次后,通量恢复率仍能达到91.3%。0.1 MPa压力下运行120 min,海藻酸钙纳滤膜对20 mg/L Cd~(2+)溶液的通量为15.5 L/(m~2·h),Cd~(2+)去除率达到99.5%以上。纳滤膜对混合重金属离子的去除率从高到低依次为Pb~(2+)Cu~(2+)Cd~(2+)。重金属离子的去除主要依靠吸附效应和离子交换来实现。     

静电纺纳米纤维膜用于重金属离子吸附的研究进展

静电纺丝制备的纳米纤维膜具有较高的比表面积和孔隙率,在重金属离子吸附领域有着广阔的应用前景。在简要阐述纳米纤维膜吸附重金属离子机理的基础上,主要从有机纳米纤维膜、有机-无机复合纳米纤维膜及无机纳米纤维膜等3个方面,介绍了近年来静电纺纳米纤维膜对重金属离子的吸附性能及其相关的研究进展,并针对目前纳米纤维膜吸附重金属离子应用研究中存在的一些问题给出了建议,为纳米纤维膜吸附重金属离子的后续研究提供参考。     

高产量制备石墨烯及其优异的重金属离子检测性能

以氧化石墨的高温膨胀为基础,研发了一种简便经济的高产量制备石墨烯的工艺,考察了制备得到的石墨烯对痕量重金属离子的检测性能,检测离子包括Cu2+、Pb2+和Cd2+.所制薄层石墨烯存在部分结构缺陷和残余羟基官能团,电化学检测结果表明,这种结构的石墨烯在检测液相中重金属离子的过程中表现出了很好的性质,尤其是对铅离子的检测限...     

基于时域相移技术的结构光三维微纳形貌检测方法

针对微纳器件三维形貌快速检测及重构中的高精度和高速度难以兼得的技术难题,本文提出一种基于时域相移技术的结构光检测方法,通过空间光调制器对测量光进行调制,结合时域相移技术实现微纳器件三维形貌检测和重构.相比传统的结构光检测方法,本技术在样片轴向扫描的同时,利用空间光调制器进行相移测量,保证测量精度的同时提高测量的效率.通...     

高温隔热用微纳陶瓷纤维研究进展

陶瓷纤维具有密度低、强度高、耐高温、抗氧化和耐机械震动性能好等优点,是空天飞行器、核能发电和化工冶金等热防护领域所需的关键高温隔热材料.传统陶瓷纤维直径粗(?>5μm)、脆性大、热导率高,在实际隔热领域应用中受到了极大限制.减小纤维直径,制备微纳陶瓷纤维,不仅有利于提高纤维力学性能,还有望改善其高温隔热性能,近年来引起...     

污水重金属离子选择性吸附的研究进展

重金属离子因具有生物不可降解性,对水环境系统和生态体系的污染严重威胁人类及其他动物的生命安全,已受到广泛关注。吸附法是一种操作简单、方便有效的方法,在污水重金属离子去除领域得到广泛研究,但多数工作主要关注吸附性能和去除效果。近年来,人们开始重视对污水中金属离子的回收再利用,因为这不仅能够缓解或解决环境污染,还可以实现废物的资源化利用,而吸附剂的选择性对目标金属离子的回收利用效果具有决定性作用。本文从软硬酸碱理论(HSAB)、离子印迹技术以及其他影响因素三个方面论述了污水中重金属离子选择性吸附的研究进展,详细总结了改善吸附剂选择性的方法并分析了当前存在的问题,最后对金属离子选择性吸附研究的发展方向进行了展望。     

An inelastic micro/macro theory for hybrid smart/metal composites

Motivated by the emerging concept of including metal phases within piezoelectric and other smart structures and materials, this paper presents a micro/macro theory for determining the coupled thermo-electro-magneto-elasto-plastic behavior of arbitrary composite laminates. The approach involves two models capable of analyzing geometries that include inelastic materials. The first is the electro-magnetic generalized method of cells (EMGMC) (Micromechanical Prediction of the Effective Behavior of Fully Coupled Electro-Magneto-Thermo-Elastic Multiphase Composites, 2000. [1]) micromechanics model. EMGMC has been reformulated to improve its computational efficiency and has been extended to admit arbitrary anisotropic local material behavior (in terms of the thermal response, mechanical response, electric response, magnetic response, as well as the coupling behavior) and inelasticity. The second model is classical lamination theory, which has also been extended for arbitrary anisotropic material behavior and electro-magnetic and inelastic effects. The end result is a coupled theory that employs EMGMC to provide the homogenized behavior of the composite plies that constitute the thermo-electro-magneto-elasto-plastic laminate. Sample results, which address the inelastic response of a hybrid smart/metal matrix composite laminate, are presented.     

Removal of heavy metal ions from water by using calcined phosphate as a new adsorbent

Calcined phosphate (CP) has been employed in our laboratories as a heterogeneous catalyst in a variety of reactions. In this study, CP was evaluated as a new product for removal of heavy metals from aqueous solution. Removal of Pb2+, Cu2+, and Zn2+ on the CP was investigated in batch experiments. The kinetic of lead on CP adsorption efficiency and adsorption process were evaluated and analysed using the theories of Langmuir and Freundlich. The influence of pH was studied. The adsorption capacity obtained at pH 5 were 85.6, 29.8, and 20.6 mg g(-1) for Pb2+, Cu2+ and Zn2+, respectively. We hypothesize at pH 2 and 3, the dissolution of CP and precipitation of a fluoropyromorphite for lead and the formation of solid-solution type fluorapatite for copper. The results obtained show that CP is a good adsorbent for these toxic heavy metals. The abundance of natural phosphate, its low price and non-aggressive nature towards the environment are advantage for its utilisation in point of view of wastewater and wastes clean up.     

磁性炭包铁纳米粒子对重金属离子的吸附性能

采用氩电弧等离子体法制备炭包铁纳米粒子,并用体积分数30%的H2O2氧化其外层非晶态类石墨碳层,研究炭包铁纳米粒子对水溶液中Cr、Ni、Cd、Pb、Co和Mn等金属离子的吸附和分离特性。结果表明,炭包铁非晶炭层的特殊结构可通过双氧水氧化处理使其表面产生羧基和羟基。在强碱性介质下,羟基和羧基强化了纳米颗粒表面的静电作用,提高了炭包铁对金属离子的吸附性能。当pH值为8.0～10.0时,炭包铁纳米粒子对Cr、Ni、Cd、Pb、Co和Mn的吸附率均超过90%,对重金属离子的吸附能力明显高于活性炭。     

Removal of heavy metal ions from aqueous solutions using various low-cost adsorbents

The removal of single heavy metals Co and Zn from aqueous solutions using various low-cost adsorbents (Fe(2)O(3), Fe(3)O(4), FeS, steel wool, Mg pellets, Cu pellets, Zn pellets, Al pellets, Fe pellets, coal, and GAC) was investigated. Experiments were performed at different solution pH values (1.5-9) and metal concentrations (0.67-333 mg/l). The effect of solution pH on metal adsorption using Fe(2)O(3) and Fe(3)O(4) was significant, but was negligibly small using steel wool, Mg pellets, Fe pellets, and Al pellets over the entire pH range. Steel wool and Mg pellets were the most excellent adsorbents; for example, the removal of Zn and Co from dilute solutions (<35 mg/l) was greater than 94% at an adsorbent dose of 1.7 g/l. A mass transfer model, which involves two parameters tau (50% breakthrough time) and k (proportionality constant), was proposed to describe breakthrough data of Co in the fixed beds packed with steel wool and Mg pellets. The calculated breakthrough curves agreed well with the measured data (standard deviation < 6%). The value of tau decreased with increasing the flow rate. The effects of flow rates on the value of k and adsorption capacity are discussed.     

Adsorption of divalent heavy metal ions from water using carbon nanotube sheets

Removal of some divalent heavy metal ions (Cu(2+), Zn(2+), Pb(2+), Cd(2+), Co(2+)) from aqueous solutions using carbon nanotube (CNT) sheets was performed. CNT sheets were synthesized by chemical vapor deposition of cyclohexanol and ferrocene in nitrogen atmosphere at 750°C, and oxidized with concentrated nitric acid at room temperature and then employed as adsorbent for water treatment. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of heavy metal ions by oxidized CNT sheets. The obtained results demonstrated that the oxidized CNT sheets can be used as an effective adsorbent for heavy metal ions removal from water. It was found out that kinetics of adsorption varies with initial concentration of heavy metal ions. Preference of adsorption onto the oxidized CNT sheets can be ordered as Pb(2+)>Cd(2+)>Co(2+)>Zn(2+)>Cu(2+). Using the oxidized CNT sheets, waste water treatment without CNT leakage into water is economically feasible. Therefore, CNT sheets have good potential application in environmental protection.     

Theoretical study of stable dropwise condensation on an inclined micro/nano-structured tube

In this paper, a numerical model for dropwise condensation on a micro/nano-structured inclined tube is developed based on previous theoretical and experimental studies for flat plates. Thermal resistances consisting of conduction through a droplet, vapor–liquid interfacial resistance, droplet curvature, promoter layer, and micro/nano-pillars are included into the model and incorporated in calculating the heat transfer rate across an individual droplet. Droplet morphologies (Wenzel, Cassie, and partially wetting) are considered in the model. Effects of various parameters are investigated on single droplets behaviors and total heat transfer. Results show that average droplets radii on a horizontal tube are higher than on a vertical tube; consequently, vertical tubes have better heat transfer rate. For example, vertical tubes have five times higher overall heat flux than horizontal tubes in some cases. In addition, partially wetting droplets have higher heat transfer rates in comparison with Wenzel or Cassie state in all configurations.     

改性纳米SiO_2/PVA复合纤维的制备及重金属离子吸附性能

通过静电纺丝技术制备酰肟化功能改性的纳米SiO_2/聚乙烯醇(SiO_2/PVA)复合纤维膜。采用SEM、FTIR、DSC和TGA进行表征分析;考察了在水溶液中随pH值和接触时间的变化纤维膜对金属离子吸附效果的影响。研究表明,在pH=6的条件下,纳米纤维对金属离子的吸附最佳,对Cu2+、Ni 2+金属离子的最大吸附量分别为143.7mg/g和125.1mg/g,平衡吸附时间为240min。在纤维膜吸附的前50min内,SiO_2/PVA纤维膜对Cu2+和Ni 2+金属离子的吸附量为126.8mg/g和109.8mg/g,吸附率分别为90.18%和89.92%。通过吸附等温线和吸附方程考察SiO_2/PVA纤维对Cu2+和Ni 2+金属离子的吸附行为。结果显示,复合纤维对两种金属离子的吸附满足拟二级动力学方程,热力学分析表明,吸附过程符合Langmuir单层吸附。使用酸处理纤维膜进行再生吸附试验,发现循环4次试验后,吸附效率达到53%,结果说明复合纤维膜可作为可再生金属离子吸附材料。     

Removal of heavy metal ions by iron oxide coated sewage sludge

The municipal sewage sludge was modified with iron oxide employed in metal ions removal. The surface modification method was proposed and the effect of parameters in the preparation was studied. The iron oxide coated sludge had higher surface area, pore volume and iron content, compared to uncoated sludge. The suitable conditions for removal of Cu(II), Cd(II), Ni(II) and Pb(II) ions from solutions were investigated using batch method. The suitable pH value in the extraction was 7 for adsorption of Cd(II) and Ni(II), 6 for Cu(II) and 5 for Pb(II) ions. The presence of NaNO(3), Ca(NO(3))(2) and Na(2)SO(4) in metal solution in the concentration of 0.01 M and 0.50 M could reduce the removal efficiency. The adsorption isotherms for the adsorption of the metal ions were defined by Langmuir relation. The maximum adsorption capacity of the iron oxide coated sludge for Cu(II), Cd(II), Ni(II) and Pb(II) was 17.3, 14.7, 7.8 and 42.4 mg g(-1), respectively. The adsorption kinetics for every metal ions followed pseudo-second order model. The metal removal from wastewater by iron oxide coated sludge was also demonstrated.     

Biosorption of heavy metal ions from aqueous solution by red macroalgae

Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment.     

Influence of hierarchical hybrid micro/nano-structured surface on biological performance of titanium coating

In this article, hierarchical hybrid micro/nano-structured titanium surface was obtained by alkali treating the vacuum plasma sprayed titanium coating following hot water immersing for 24 h. The influences of the surface microstructure on the in vitro and in vivo biologic performance of titanium coating were studied. Human bone marrow-derived stromal cells (hBMSCs) were used for in vitro cytocompatibility evaluation. Compared with the rough titanium coating surface, cell behaviors, such as spread and proliferation were apparently enhanced by mimicking the hierarchical hybrid structure of bone tissue, while ALP expression was lower at days 4 and 7. With the expanding of induction time, the ALP activity rapidly increased on the hierarchical surface. After 10 days induction, it became much higher than that on the rough titanium surface. A canine model was applied for an in vivo evaluation of the bone bonding ability. Histologic examination demonstrated that new bone was formed more rapidly on the hierarchical surface implants than that on the rough titanium surface. All these results indicate that the hierarchical surface is favorable for the response of hBMSCs and early bone bonding.