桉树遗态结构HAP/C复合材料制备及表征

以桉树为植物模板,循环浸渍在磷酸氢二铵和氢氧化钠溶液中,得到一种新型的桉树遗态结构羟基磷灰石/碳(HAP/C)复合材料。通过X射线衍射仪、红外光谱和扫描电镜等手段对所制备的复合材料进行表征。结果表明:桉树遗态钙羟基磷灰石/碳复合材料(PBGC-HAP/C-E)主要由HAP和C组成,复合材料很好保留了桉树天然多孔分级的遗态特征,比表面积为159.8m~2/g。考察了所制备复合材料对典型重金属离子的吸附能力,研究发现其吸附能力优于市售活性炭,为水环境重金属污染处理提供了一种新材料。     

生物炭-膨润土共改性及其铅离子吸附与稳定化研究

重金属污染具有高毒性、持久存留和生物积累等特性, 严重危害人体健康和生态安全。本研究通过氯化钙对玉米芯残渣和膨润土混合物进行碱改性, 在无氧条件下高温煅烧制备了一种碱改性生物炭-膨润土复合物(CaO-Bent-CB)。该复合物的比表面积高, 达到441.1 m²/g, 明显高于直接煅烧制备的生物碳(132.7 m²/g)和碱改性生物炭(177.2 m²/g)。进一步评价了该复合物对水中铅离子吸附性能, 结果表明在水中铅离子浓度为120 mg/L, 膨润土与玉米芯残渣质量比为1:5, 用量为1 g/L条件下, 吸附6 h后铅离子去除率达98%, 吸附量为109.6 mg/g, 均高于生物炭(13.4 mg/g)、膨润土(72.9 mg/g)和碱改性生物炭(86.9 mg/g)。此外, 采用CaO-Bent-CB对铅离子污染土壤进行稳定化处理, 当土壤中铅离子浓度为2200 mg/kg, CaO-Bent-CB用量为土壤干重的8%时, 在pH=3.2的硫酸-硝酸浸提液中浸出12 h, 酸浸出铅离子浓度低至4.5 mg/L, 低于危险废物鉴别标准值(5 mg/L)。上述研究结果表明这种生物炭-膨润土共改性复合物在重金属污染水体和土壤修复中具有很好的应用前景。     

模板整理对SnO2/C遗态材料显微结构及性能的影响

以不同整理工艺处理的苎麻纤维为生物模板,酚醛树脂为黏接剂,经800℃炭化后获得三种苎麻炭模板,再经Sn(OH)4溶胶浸渗和560℃真空原位炭热还原反应制备得三种SnO2/C遗态材料试样.采用XRD和SEM技术分析了苎麻模板整理工艺对SnO2/C遗态材料物相组成和微观形貌的影响,利用自制磨耗仪对比测试了三种遗态材料试样的磨损率.结果表明:三种SnO2/C遗态材料试样在显微结构以及耐磨性能等方面存在明显差异,通过生物模板整理工艺可有效调控遗态材料的微观结构和性能.     

氧化锌空心球的制备及光致发光特征

采用水热和硬模板辅助技术,成功制备得到ZnO空心球结构.以葡萄糖和锌盐为原料,首先通过催化葡萄糖聚合-原位离子吸附一步进行(一步法)或葡萄糖聚合成球-离子吸附分步进行(二步法)制备锌/炭复合微球,然后经空气低温氧化制得ZnO空心球.用XRD、SEM、TEM研究产物的组成和结构及形貌,用光致发光光谱(PL)测试产物的室温光致发光性能.研究发现,两种方法得到的空心球壳均属多孔结构,由ZnO纳米粒子构成;与聚合-吸附分步法相比,聚合-原位离子吸附一步法更加简单快捷;制得的ZnO空心球结构材料具有良好的近紫外发光性能.对ZnO空心球结构的形成过程和可能的机制进行了分析和讨论.     

PEI功能化多孔生物炭对水中V(Ⅴ)的吸附研究

针对水体钒污染现象,以经磷酸浸渍的马缨丹为原料制备多孔生物炭后负载聚乙烯亚胺(PEI),得到PEI功能化多孔生物炭(PBC)。采用BET、扫描电镜(SEM)、EDS能谱和红外光谱(FT-IR)进行表征,并探究其对水中钒离子[V(Ⅴ)]的吸附。结果表明：PBC具有丰富的孔隙结构及表面官能团,比表面积和孔容分别为原始炭(LBC)的5.87倍和12.33倍;PBC和LBC对V(Ⅴ)的饱和吸附量分别为147.47mg/g和4.98mg/g; PBC对V(Ⅴ)的吸附行为符合Langmuir模型和拟二级动力学模型,可选择性高效吸附水中V(Ⅴ)并循环再生利用。PBC对V(Ⅴ)的吸附机理以静电作用、多孔吸附、络合及还原作用为主。     

木材结构分级多孔ZnO的同步辐射XAFS研究

利用同步辐射XAFS (X-ray AbsorptionFine Structure)实验及FEFF计算进行数据拟合,研究遗态转化工艺制备的ZnO产物的微观晶体结构参数.研究结果表明,遗态转化工艺得到了ZnO产物,木材结构分级多孔ZnO产物的第一壳层Zn-O距离为0.1986nm,第二壳层Zn-Zn距离为0.3240n...     

五种作物秸秆生物炭对重金属Pb^(2+)的吸附性的比较北大核心CSCD

为探讨小麦、玉米、水稻、花生壳和稻壳制备生物炭的差异,本文对这些植物纤维在不同预成型压力下制备的生物质炭的结构和性能进行了测定和分析,并研究了其对铅离子(Pb^(2+))的吸附性。结果表明:玉米、小麦和水稻三种秸秆生物质炭对溶液中Pb^(2+)的吸附性能较好,且在不同初始浓度下对Pb^(2+)的吸附符合Langmuir等温吸附模型,吸附量分别为141.310、121.226和122.753mg·g^(-1)。而花生壳和稻壳生物炭对Pb^(2+)的吸附性能较差,吸附量分别为62.914和51.037mg·g^(-1)。玉米秸秆生物质炭的-OH、-C-H、C=C等表面官能团较多,可通过表面官能团的络合作用吸附溶液中的Pb^(2+)。小麦和水稻秸秆制备生物炭由于含有较高的碳酸盐、磷酸等无机矿物形成化学沉淀。不同初始压力下制备生物质炭对溶液中Pb^(2+)的吸附影响较小。     

Z壳聚糖交联印迹材料对稀土中Cu(Ⅱ)的选择吸附性能

以羧甲基壳聚糖(CMC)为原料,Cu(Ⅱ)为模板离子,环氧氯丙烷(ECH)为交联剂,制得交联印迹材料Cu-ECMC。研究了该材料对模板离子的结合性能与识别选择性。探讨了溶液的pH值、吸附时间等因素对该材料吸附性能的影响。结果表明,材料Cu-ECMC对Cu(Ⅱ)可产生吸附作用,最大吸附量达到44.3mg·g~(-1);pH=3.0时,相对于La(Ⅲ),对Cu(Ⅱ)的选择性系数可达到15.57。印迹材料对铜离子的吸附符合准二级动力学模型。     

仿生FeS复合材料的制备及其对Cr(Ⅵ)的吸附性能

纳米FeS比表面积大且还原性强,对Cr(Ⅵ)吸附性能优异,但不稳定、易团聚,为解决这一问题,本文以油菜花粉为生物模板,通过共沉淀-焙烧法制得仿生FeS复合材料(bioFeS)。通过SEM、XRD及XPS等方法对bioFeS复合材料的表面微观形态和结构进行了表征。以Cr(Ⅵ)为目标污染物,分别考察了吸附剂用量、反应时间、反应温度、初始Cr(Ⅵ)浓度和pH对bioFeS复合材料吸附Cr(Ⅵ)性能的影响,探究了反应机制。结果表明：油菜花粉生物模板成功分散了FeS,制得的bioFeS复合材料比表面积大,在反应时间为120 min、pH值为1、吸附剂投加量为0.2 g·L^-1、反应温度为25℃的条件下,bioFeS复合材料对Cr(Ⅵ)的吸附量可达88.95 mg·g^-1;该吸附过程符合准二级动力学和Langmuir等温吸附模型;共存离子NO₃^-和SO₄^2-会抑制Cr(Ⅵ)的去除。结合吸附动力学、热力学及XPS表面元素分析可知bioFeS复合材料除铬机制主要是吸附及化...     

模板改性对SnO_2遗态陶瓷孔结构及气敏性的影响

以整理改性的苎麻纤维为模板,制备获得独具苎麻形态的SnO2遗态陶瓷材料。研究了试样的物相构成、显微结构,以及比表面积和孔径分布特点,测试了试样对多种气(液)体的气敏性能。结果表明,通过纺织纤维整理改性技术,可有效调控遗态材料微观结构和性能。模板的整理改性对SnO2遗态陶瓷的晶粒尺寸影响不大,但对SnO2遗态陶瓷的比表面积、孔容及孔径分布等孔结构参数影响显著。模板经碱液改性后所制备的试样,具有更优的比表面积和吸附特性,因此表现出对HCHO、C2H5OH和Petrol等气(液)体更优的气敏性优势。     

Pb(Zr0.95Ti0.05)O3 powders prepared by aqueous Pechini method using one-step pyrolysis process: characterization and porous ceramics

Zr-riched lead zirconate titanate, Pb(Zr_0.95Ti_0.05)O₃ (PZT 95/5) powders were prepared using lead acetate, zirconium oxynitrate, and titanium sulfate by aqueous Pechini method. The chelation behaviors of metallic ions and citric acid were investigated and the development of the phase formation of perovskite structure was detected. PZT 95/5 powders were obtained directly from the as-synthesized gels by one-step pyrolysis process at 450 °C for 10 h. Perovskite phase was formed at about 450 °C and no distinct intermediates were obtained. There were some carbonates as impurities but they did not affect the formation of the complete perovskite phase of PZT 95/5 ceramics after sintering at 1,100–1,150 °C for 2 h. The decomposition of few organic residues among the one-step pyrolyzed powders could form uniform porous structure and the formation mechanism of porous ceramics was also presented.     

线形结构的ZnO生长与光致发光特性研究

采用模板生长法在Si衬底上制备了具有线形结构的ZnO。样品的晶体结构、形貌及光致发光性使用XRD、AFM、SEM及PL谱进行表征。结果表明所制备的线形ZnO为六方纤锌矿型晶体结构，线宽度大约为1μm，长度约10-30μm，具有良好的发光特性。我们对这种线形结构的形成作了推测。     

Growth and characterization of ZnO nanoflakes by hydrothermal method: effect of hexamine concentration

Flake-like ZnO nanostructures, which have potential applications in fields of photo catalysts, biosensors, solar cells, et al., were fabricated on indium doped tin oxide substrates through hydrothermal method at 90 °C. Zinc chloride hydrate and hexamine (HMT) were used as zinc source and the alkali source, respectively, no other surfactants were involved. The morphology evolution of ZnO from nanoflakes to the occurrence of nanorods can be attributed to the competition between the absorption effect of chloride ions and HMT. With the adsorption of chloride ions onto the polar faces instead of growth units, ZnO nanoflakes were formed by restraining the crystal growth along <0001> direction. Controllable growth of different ZnO nanostructures was achieved by tuning the corresponding stoichiometric ratios of reactants. ZnO nanoflakes were formed with equivalent concentrations of zinc chloride hydrate and HMT. Increase in the concentration of HMT resulted in the fabrication of the rod-on-flake structure, or even multilevel ZnO nanoflakes. Scanning electron microscopy results revealed that all these ZnO nanoflakes are with typical wurtzite hexagonal phase. The crystal and optical properties of the as-synthesized samples were characterized by X-ray diffraction spectrum and room temperature photoluminescence spectrometer, which showed close relationship with structure variations.     

Preparation of porous nano-calcium titanate microspheres and its adsorption behavior for heavy metal ion in water

Using D311 resin as a template, porous nano-calcium titanate microspheres (PCTOM) were prepared by a citric acid complex sol-gel method and characterized by X-ray diffraction (XRD), SEM and FTIR. The method's adsorption capabilities for heavy metal ions such as lead, cadmium and zinc were studied and adsorption and elution conditions were investigated. Moreover, taking the cadmium ion as an example, the thermodynamics and kinetics of the adsorption were studied. The results show that the microspheres were porous and were made of perovskite nano-calcium titanate. The lead, cadmium and zinc ions studied could be quantitatively retained at a pH value range of 5-8. The adsorption capacities of PCTOM for lead, cadmium and zinc were found to be 141.8 mg g(-1), 18.0 mg g(-1) and 24.4 mg g(-1) respectively. The adsorption behavior followed a Langmuir adsorption isotherm and a pseudo-second-order kinetic model, where adsorption was an endothermic and spontaneous physical process. The adsorbed metal ions could be completely eluted using 2 mol L(-1) HNO(3) with preconcentration factors over 100 for all studied heavy metal ions. The method has also been applied to the preconcentration and FAAS determination of trace lead, cadmium and zinc ion in water samples with satisfactory results.     

热蒸发法制备四角Co3O4／ZnO异质结及其性能研究

采用热蒸发法,在四角ZnO（T-ZnO）表面包覆了一层Co3O4,制备出一种新型的异质结构,利用X射线衍射仪、场发射扫描电镜、能谱分析仪、振动样品磁强计对T—ZnO的结构、形貌等进行了表征,结果表明,该异质结的形貌强烈依赖于前躯体的碱度、热蒸发的温度和时间,当温度为150℃,反应3h时,产物能保持四角结构,异质结构拥有较好的室温铁磁性能。另外,讨论了其晶体生长和磁性能理论机制。     

超声辅助SILAR法生长纳米晶ZnO多孔薄膜及其光学性能研究

将超声辐照技术引入连续离子层吸附与反应(SILAR)法,提出超声辅助连续离子层吸附与反应(UA-SILAR)液相成膜技术.以锌氨络离子([Zn(NH₃)₄]²⁺)溶液为前驱体,在90℃下沉积得到ZnO薄膜,对其晶体结构,微观形貌、透过光谱和光致发光性能进行表征, 并考察了超声辐照和沉积循环次数对薄膜形貌、结构和光学特性的影响.结果表明,所得薄膜由彼此交联、尺寸均匀的ZnO晶粒组成,呈现典型的多孔特征,同时具有高结晶性和强c轴取向性.由于多孔结构对入射光的散射作用,薄膜在可见光区具有低透射率(约20%);在紫外光激发下,薄膜具有较强的近带边发射和很弱的蓝带发射,体现出薄膜较高的光学质量;薄膜生长过程中超声辐照的引入可对薄膜的结晶性能和微观结构产生显著的影响.     

Utilization of ZnO nanocones for the photocatalytic degradation of acridine orange

A facile aqueous solution process was used to synthesize well-crystalline ZnO nanocones at 60 degrees C by using zinc nitrate hexahydrate and sodium hydroxide. The morphological, structural and optical properties of the synthesized ZnO nanocones were investigated by using field emission scanning electron microscopy (FESEM) attached with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) equipped with high-resolution (HRTEM), X-ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) spectroscopy and UV-Vis. spectroscopy measurements. The structural and optical properties of the as-synthesized nanocones confirmed a pure and well crystalline product possessing wurtzite hexagonal phase. The as-synthesized ZnO nanocones were used as photocatalyst for the efficient photocatalytic degradation of acridine orange. The acridine orange was almost completely degraded within 105 minutes. This research demonstrates that the simply synthesized ZnO nanostructures could be efficient photocatalyst for the photocatalytic degradation of various organic dyes and chemicals.     

Synthesis of ZnO nanoparticles and their ink-jetting behavior

Zinc oxide (ZnO) nanoparticles were synthesized by ultrasonically-assisted solution process without using any surfactants. The as-synthesized spherical ZnO nanoparticles with diameter of 20 +/- 5 nm possessed crystalline nature with wurtzite hexagonal phase and showed a blue-shifted near band-edge ultra-violet absorption at -340 nm due to quantum confinement effect of ZnO nanoparticles. The as-synthesized ZnO nanoparticles were further formulated as an ink for ink-jet printing application. Jetting and writing of various line patterns on Si and ITO substrates were demonstrated using the as-formulated ZnO ink. UV-treated substrates showed an improvement in the fixation of ink on substrate due to decreased contact angle with controlled surface wettability.     

Synthesis of biomorphic ZnO interwoven microfibers using eggshell membrane as the biotemplate

A simple and green technique has been developed to prepare hierarchical biomorphic ZnO, using eggshell membrane (ESM) as the template. ESM was infiltrated with zinc nitrate solution and subsequently sintered at high temperatures to produce the final ZnO interwoven nanofibers. Different from traditional immersion technics, the whole synthesis process depends more on the restriction or direction functions of the ESM biomacromolecules. The precision replication of natural biostructures can be achieved by the assembly of ZnO nanocrystallites about 5 nm. Consequently, the interwoven meshwork at three dimensions is formed due to the direction of biotemplate. The action mechanism is summarily discussed here. It may bring the biomorphic ZnO semiconductors with hierarchical interwoven structures to more applications, such as catalysts, photoelectrochemical devices, etc.     

Taguchi optimization approach for Pb(II) and Hg(II) removal from aqueous solutions using modified mesoporous carbon

Using the Taguchi method, this study presents a systematic optimization approach for removal of lead (Pb) and mercury (Hg) by a nanostructure, zinc oxide-modified mesoporous carbon CMK-3 denoted as Zn-OCMK-3. CMK-3 was synthesized by using SBA-15 and then oxidized by nitric acid. The zinc oxide was loaded to the modified CMK-3 by the equilibrium adsorption of Zn(II) ions from aqueous solution followed by calcination to convert zinc nitrate to zinc oxide. The CMK-3 had porous structure and high specific surface area which can accommodate zinc oxide in a spreading manner, the zinc oxide connects to the carbon surface via oxygen atoms. The controllable factors such as agitation time, initial concentration, temperature, dose and pH of solution have been optimized. Under optimum conditions, the pollutant removal efficiency (PRE) was 97.25% for Pb(II) and 99% for Hg(II). The percentage contribution of each controllable factor was also determined. The initial concentration of pollutant is the most influential factor, and its value of percentage contribution is up to 31% and 43% for Pb and Hg, respectively. Our results show that the Zn-OCMK-3 is an effective nanoadsorbent for lead and mercury pollution remediation. Langmuir and Freundlich adsorption isotherms were used to model the equilibrium adsorption data for Pb(II) and Hg(II).