Synthesis of a PEBAX-1074/ZnO nanocomposite membrane with improved CO_2 separation performance

In this investigation, polymeric nanocomposite membranes（PNMs） were prepared via incorporating zinc oxide（ZnO） into poly（ether-block-amide）(PEBAX-1074) polymer matrix with different loadings. The neat membrane and nanocomposite membranes were prepared via solution casting and solution blending methods, respectively. The fabricated membranes were characterized by field emission scanning electron microscopy（FESEM） to survey cross-sectional morphologies and thermal gravimetric analysis（TGA）to study thermal stability. Fourier transform infrared（FT-IR） and X-ray diffraction（XRD） analyses were also employed to identify variations of the chemical bonds and crystal structure of the membranes, respectively. Permeation of pure gases, CO, CHand Nthrough the prepared neat and nanocomposite membranes was studied at pressures of 3–18 bar and temperature of 25 °C. The obtained results showed that the fabricated nanocomposite membranes exhibit better separation performance compared to the neat PEBAX membrane in terms of both permeability and selectivity. As an example, at temperature of 25 °C and pressure of 3 bar, COpermeability, ideal CO/CHand CO/Nselectivity values for the neat PEBAX membrane are 110.67 Barrer, 11.09 and 50.08, respectively, while those values are 152.27 Barrer,13.52 and 62.15 for PEBAX/ZnO nanocomposite membrane containing 8 wt% ZnO.

Enhanced Photocatalytic Activity of ZnO/CuO Nanocomposites Synthesized by Hydrothermal Method

In this paper, we have demonstrated a facile and low-cost synthesis of the ZnO/CuO nanocomposites by two-step hydrothermal methods. The photocatalytic properties of the as-synthesized ZnO/CuO nanocomposites have been evaluated by the photodegradation of methylene blue(MB) and methyleneorange(MO) under UV irradiation. Experimental results show that MB and MO can be degraded completely within 15 and 25 min by the ZnO/CuO nanocomposites and its photodegradation rate is 6 times faster than that of pure ZnO. This enhanced photocatalytic activity can be ascribed to the low recombination probability of photo-induced carriers due to the efficient charge transfer in the nanocomposites. The as-synthesized ZnO/CuO nanocomposite may be a promising candidate for dye photodegradation of wastewaters.

Photoluminescence behavior and visible light photocatalytic activity of ZnO,ZnO/ZnS and ZnO/ZnS/α-Fe_2O_3 nanocomposites

In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange（MeO）, ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic route in the aqueous medium. Phase, crystallinity, surface structure and surface behavior of the synthesized materials were determined by X-ray diffraction（XRD） and Brunauer-Emmett-Teller analysis（BET） techniques. XRD study established formation of good crystalline ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanomaterials. By using intensity of constituent peaks in the XRD pattern, the compositions of nanocomposites were determined. From the BET analysis, the prepared materials show mesoporous behavior, type Ⅳ curves along with H4 hysteresis. The ZnO/ZnS/α-Fe2O3 composite shows the largest surface area among three materials. From the UV-visible spectra, the band gap energy of the materials was determined. Photoluminescence spectra（PL） were used to determine the emission behavior and surface defects in the materials. In PL spectra, the intensity of UV peak of ZnO/ZnS is lowered than that of ZnO while in case of ZnO/ZnS/α-Fe2O3, the intensity further decreased. The visible emission spectra of ZnO/ZnS increased compared with ZnO while in ZnO/ZnS/α-Fe2O3 it is further increased compared with ZnO/ZnS. The as-synthesized materials were used as photocatalysts for the degradation of dye MeO. The photo-degradation data revealed that the ZnO/ZnS/α-Fe2O3 is the best photocatalyst among three specimens for the degradation of dye MeO. The decrease of intensity of UV emission peak and the increase of intensity of visible emission cause the decrease of recombination of electrons and holes which are ultimately responsible for the highest photocatalytic activity of ZnO/ZnS/α-Fe2O3.

Synthesis and Characterization of Sol-Gel Derived MgO/CNTs Nanocomposite

In this research, synthesis of magnesium oxide-multi walled carbon nanotube （MgO/MWCNTs） nanocomposite is reported using sol-gel method in which magnesium nitrate is added to aqueous solution. The structure of MWCNTs and MgO/MWCNTs composite has been characterized by analyzing the X-ray diffraction pattern （XRD）, Fourier Transform Infrared （FT-IR） spectra and Scanning Electron Microscopy （SEM） images. Experimental results indicate that the surface of purified MWCNTs sample is covered homogenously by a layered of MgO nanoparticles.

Synthesis, characterization and antimicrobial activity of alkaline ion-exchanged ZnO/bentonite nanocomposites

Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by placing bentonite in a melting bath of ZnSO4 for 10, 20, 40, 60 and 90 rain. The complexes were characterized by XRD, SEM and DRS. XRD analyses and SEM observations confirmed the diffusion of zinc to the clay surfaces. Antibacterial activity tests against Escherichia coli showed that bentonite did not present any antibacterial properties, but after alkaline ion exchange treatment, inhibition was noted. The highest antibacterial activity was observed with ZnO/bentonite composite alkaline ion exchange for 60 and 90 rain. Interestingly, the leaching test indicated that ZnO/bentonite did not present any risk for drinking water treatment.

Bio-capped and green synthesis of ZnO/g-C_(3)N_(4) nanocomposites and its improved antibiotic and photocatalytic activities: An exceptional approach towards environmental remediation

In this research study, we have synthesized the bio-capped ZnO/g-C_(3)N_(4) nanocomposites by employing lemon juice(Citrus limon) as a stabilizer and mediator. Fruitfully, lemon juice which contains various acidic functional groups and citric acid has the capability to block the surface of g-C_(3)N_(4) from chemical reactivity and activated the surface of g-C_(3)N_(4) for various reactions. Consequently, the agglomeration behavior and controlled shape of g-C_(3)N_(4) has also been achieved. Our experimental results i.e. XRD,TEM, HRTEM, PL, FS, XPS, and PEC have confirmed that the lemon juice mediated and green g-C_(3)N_(4)(L-CN) have good performances and remarkable visible light photocatalytic activities as compared to the chemically synthesized g-C_(3)N_(4)(CN). Furthermore, the small surface area and low charge separation of g-C_(3)N_(4) is upgraded by coupling with Zn O nanoparticles. It is proved that the coupling of Zn O worked as a facilitator and photoelectron modulator to enhance the charge separation of g-C_(3)N_(4). Compared to pristine lemon-mediated green g-C_(3)N_(4)(L-CN), the most active sample 5Zn O/L-CN showed ~ 5-fold improvement in activities for ciprofloxacin(CIP) and methylene blue(MB) degradation. More specifically,the mineralization process and degradation pathways, and the mineralization process of ciprofloxacin(CIP) and methylene blue(MB) are suggested. Finally, our present novel research work will provide new access to synthesize the eco-friendly and bio-caped green g-C_(3)N_(4)nanomaterials and their employment for pollutants degradation and environmental purification.

Preparation of Polysulfonamide/ZnO Nanocomposite by In-Situ Polymerization

Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylacetamide(DMAc). Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA and mechanical property was characterized by DXLL-1000 electromechanical material testing machine. The results showed that the breaking strength of the film containing 0.5% ZnO was great enhanced. The average size of ZnO particles was below 100 nm. The introduction of ZnO as nano filler in PSA react as UV shield effect and make the composite mechanical property improved.

Synthesis of Multi-Walled Carbon Nanotubes/ZnO Nanocomposites Using Absorbent Cotton

This letter focuses on the synthesis of multi-walled carbon nanotubes(MWNTs) and MWNTs/ZnO nanocomposites using absorbent cotton.The MWNTs have been synthesized by a rapid heating of absorbent cotton at different temperature(400,550,600).The MWNTs/ZnO nanocomposites have been synthesized by heating mixtures of Zn(OH)_2/H_2O/absorbent cotton at different temperature(at about 550 and600).The X-ray diffraction(XRD) pattern and energy dispersive spectrum(EDS) clearly show that the pure MWNTs and ZnO nanocomposites(with a mean size of 35.9 nm) were synthesized.The scanning electron microscopy(SEM) images demonstrate that the structure of synthesized MWNTs was middle-hollow,with inner and outer diameter of around 10 and 80 nm.The ZnO nanocomposites that had grown on the walls of MWNTs were nonuniform and agglomerated,with an outer diameter of around 110 nm.The selected area diffraction(SAD) patterns and Raman spectrum indicate that the MWNTs were well-crystallised,and there are a few defects in the walls.Infrared absorption spectroscopy(IR) spectra suggest that the surface of MWNTs has been covered by ZnO.

Zn ^(2+) Release Performance in Simulated Uterine Solution and Surface Characteristics of ZnO/LDPE Nanocomposites

Zinc oxide/low-density polyethylene （LDPE） nanocomposites were prepared for intrauterine devices. The change of Zn^2＋ release rates of nanocomposites （ doped with various mass fractions of zinc oxide nanoparticles between 5wt% and 65 wt% ） for 264 days in a simulated uterine solution were investigated. The resuits show that initial burst phases are followed by near zero-order release phases. SEM technique was employed to observe the surface morphology of the 45wt% ZnO/ LDPE composite. Elements and phases on the surface of the nanocomposite after incubation were also analyzed by EDX and XRD respectively. The experimental results show that incrustation formation does not occur after incubation.

Silica encapsulated ZnO quantum dot-phosphor nanocomposites:Sol-gel preparation and white light-emitting device application

ZnO quantum dots （QDs） as an eco-friendly and low-cost material has bright fluorescence, which makes it promising material for healthy lighting and displaying. However, the low fluorescence efficiency and poor stability of ZnO QDs impede their applications in lighting application. In this work, silica encapsulated ZnO QD-phosphors nanocomposites （ZSPN） have been prepared through a sol-gel synthesis process, where yellow-emitting ZnO QDs and blue-emitting BaMgAl10O17：Eu2＋ are employed as the luminescence cores and silica as link between two luminescence materials. Tunable photoluminescence of ZSPN and the white light emission have been achieved through changing mass ratio of both of ZnO QDs and commercial phosphors. The PLQY of the ZSPN can reach 63.7% and they can maintain high luminous in- tensity even the ambient temperature up to 110 ℃ and after 35 h of UV irradiation. In addition, they can keep stable for 40 days. By coating the ZSPN phosphors onto a ultraviolet chip, WLEDs with luminous efficiency of 73.6 lm/W and the color coordinate, correlated color temperature, and color rendering index can reach （0.32, 0.34）, 5580 K, and 87, respectively, indicating the bright prospect of the ZSPN phosphors used in healthy lighting.

Highly stable Ga-doped ZnO/polystyrene nanocomposite film with narrow-band cyan emission

In the present study,a simple method for the preparation of a luminescent flexible gallium doped zinc oxide(GZO)/polystyrene nanocomposite film was developed.The prepared GZO powder was characterized through different optical and structural techniques.The XRD study revealed the existence of a wurtzite structure with no extra oxide peaks.Elemental-mapping,EDX,FTIR and XPS analyses were used to confirm the presence of elements and the several groups present in the structure.Under excitations of UV,the prepared hybrid nanocomposite showed a strong cyan emission with narrow full width at half the maximum value(20 nm)that has not been reported before.X-ray and laser-induced luminescence results of the hy-brid film revealed novel blue-green emission at room temperature.The prepared composite film showed a strong scintillation re-sponse to ionizing radiation.The strong emissions,very weak deep-level emissions,and low FWHM of composite indicate the de-sirable optical properties with low-density structural defects in the GZO composite structure.Therefore,the prepared hybrid film can be considered to be a suitable candidate for the fabrication of optoelectronic devices.

Fabrication and electrochemical performance of graphene-ZnO nanocomposites

Graphene-ZnO nanocomposites were synthesized successfully through a one-step solvothermal approach. The mor-phology, structure, and composition of the prepared nanocomposites were investigated by scanning electron microscopy （SEM）, transmission electron microscope （TEM）, laser micro Raman spectroscopy, and Fourier transform infra-red spec-troscopy （FT-IR）. The outcomes confirmed that this approach is comparatively steady, practicable, and operable compared with other reported methods. The electrochemical performance of the graphene-ZnO electrodes was analyzed through cyclic voltammetry, altering-current （AC） impedance, and chronopotentiometry tests. The graphene-ZnO electrodes exhib-ited an improved electrode performance with higher specific capacitance （115 F·g^-1 ）, higher electrochemical stability, and higher energy density than the graphene electrodes and most reported graphene-ZnO electrodes. Graphene-ZnO nanocom-posites have a steady reversible charge/discharge behavior, which makes them promising candidates for electrochemical capacitors （ECs）.

Selective Removal of Photocatalytically Active Anatase TiO_(2)Phase from Mixed-Phase TiO_(2)-ZnO Nanocomposites:Impact on Physicochemical Properties and Photocatalytic Activity

TiO_(2)-ZnO nanocomposites were synthesized by varying Ti:Zn molar ratio from 1:0.1(TZ-1:0.1)to 1:1(TZ-1:1).With increase in Zn content,from TZ-1:0.1 to TZ-1:0.2,anatase transformed to rutile phase.TZ-1:0.3,which contained a blend of phases,including rutile and anatase TiO_(2),ZnO,and zinc titanates,exhibited the narrowest bandgap(2.5±0.1 e V),and showed the highest photocatalytic activity.TZ-1:1 was predominated by zinc titanates.All the nanocomposites exhibited narrower bandgaps compared to pure TiO_(2)nanoparticles,facilitating visible light activity.This study was designed to explore whether a method targeting the removal of a specific crystalline phase(anatase)influenced the properties and photocatalytic activity of the nanocomposite.Selective dissolution not only removed anatase phase,but also led to significant loss of crystallinity,widened the bandgap,and adversely affected photocatalytic performance,in nanocomposites that contained>80%anatase phase(TZ-1:0.1 and TZ-1:0.2).However,in nanocomposites that contained less of anatase phase(TZ-1:0.3and TZ-1:1),the morphology,bandgap,crystallinity,and the extent of photocatalytic activity at the end of 240 min remained largely unaffected.Photocatalytic activity in TZ-1:0.3 and TZ-1:1 originated from a blend of phases comprising of less photocatalytically active phases,such as rutile TiO_(2),Zn TiO3,and Zn2TiO4,rather than from the anatase phase.The Ti:Zn molar ratio controlled the phases present in TiO_(2)-ZnO nanocomposites,which,in turn,controlled the physicochemical properties and visible light activity.Thus,in nanocomposites that contained a mix of several phases,the properties and photocatalytic activity were not dependent on anatase phase.

MgO/ZnO对锂铝硅系微晶玻璃性能的影响

采用MgO和ZnO作为复合助熔剂,结合高温粘度、SEM、XRD等测试手段,研究MgO和ZnO引入比例对锂铝硅系(LAS)微晶玻璃熔制和性能的影响。w(MgO)/w(ZnO)的升高,促进了微晶玻璃析晶,增大热膨胀系数,降低可见光透过率。结果表明:MgO和ZnO最佳引入比为3∶1,此时微晶玻璃具有较高的强度(98 MPa)、非常低的热膨胀系数(0.769×10-7/K)和较理想的透过率(可见光内70%)。

纳米CeO_2/ZnO/MgO的制备及其光催化性能研究

通过共沉淀法制备了纳米氧化铈/氧化锌/氧化镁(CeO_2/ZnO/MgO)复合光催化剂。采用X射线粉末衍射(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱法(FT-IR)以及紫外-可见吸收光谱法(UV-Vis)对制得的纳米CeO_2/ZnO/MgO进行表征,并对染料亚甲基蓝(MB)进行光催化降解。结果表明,采用共沉淀法合成的纳米CeO_2/ZnO/MgO具有良好的光催化性能,在MB的初始浓度为20mg/L,CeO_2/ZnO/MgO浓度为0.2g/L,紫外光照射40min条件下,对MB的降解率达到98%,紫外光照射60min条件下MB完全降解,优于相同方法合成的CeO_2/ZnO。

在蓝宝石、MgO衬底上ZnO波导膜的制备

以ZnO烧结陶瓷为靶材,应用射频磁控溅射技术在(001)蓝宝石、(100)MgO衬底上制备ZnO波导薄膜。利用棱镜耦合、X射线衍射、RBS背散射分析等技术研究了所沉积薄膜的光波导及内部结构信息。结果表明:在两种衬底上所沉积的ZnO薄膜可以形成优良的平面光波导结构;薄膜结晶状况为存在少量其他晶向的c轴择优取向;薄膜含有的Zn及O组分原子数比例为近化学计量比;薄膜的沉积速率受衬底材料表面能作用轻微影响;薄膜的有效折射率较ZnO体材料小且受衬底材料影响。生长在蓝宝石衬底上ZnO薄膜的平均晶粒尺寸较在MgO衬底上的小,且其随膜厚的增加无明显变化,但在MgO衬底上晶粒尺寸则随膜厚的增加有增大趋势。

ZnO-CaO-MgO-SiO_2助烧剂对氧化铝陶瓷性能的影响

研究了ZnO-CaO-MgO-SiO2助烧剂对氧化铝陶瓷烧结性、相组成和力学性能的影响。XRD和SEM分析结果表明:由于氧化锌含量和烧结温度的变化,导致析出尖晶石相、钙长石和莫来石相含量的不同,影响着材料的性能。

微波辅助制备纳米MgO·ZnO复合粉体

用乙二醇为溶剂,以ZnSO_4·7H_2O、MgCl_2·6H_2O与Na_2CO_3为原料,采用微波加热直接沉淀法合成了锌与镁的复合碱式碳酸盐前驱体。将此前驱体在700℃煅烧,制得了纳米MgO·ZnO的复合粉体。分别对样品进行XRD、TG、TEM、IR、UV表征,结果表明:加热分解制备出的纳米MgO-ZnO复合粉体结晶性能良好,晶体形貌为球形,粒径大小为30～80nm,且具有纳米MgO和ZnO的双重特性。

MgO对ZnO压敏电阻电性能的影响

研究了ＭｇＯ掺杂对ＺｎＯ压敏电阻电性能的影响。结果表明，ＭｇＯ含量增加，压敏场强Ｅ１ｍａ＝Ｖ１ｍＡ／ｄ上升，通流能力增强，非线性指数α和漏电流ＩＬ变化不大。文中还对上述结果进行了理论分析。

加入ZnO对含Al低碳MgO-C耐火材料抗氧化性的影响

以质量分数为70%的粒度≤3 mm和24%的粒度<0.074 mm的电熔镁砂,3%的粒度<0.15 mm的鳞片石墨,3%的粒度<0.045 mm的金属铝粉为原料,外加4%的酚醛树脂制备了含Al低碳MgO-C耐火材料。加入1%(w)的<0.045 mm的ZnO替代电熔镁砂粉,研究了加入ZnO对含Al低碳MgO-C材料抗氧化性的影响。通过对比这两种材料的显气孔率、常温耐压强度,试样基质的物相变化来探讨原位尖晶石的生成与基质中加入ZnO之间的关系,并通过对比试样中脱碳层与原始层之间出现的致密MgO层来讨论两种低碳MgO-C材料抗氧化性的差异。研究表明:加入ZnO能够在MgO-C材料基质中形成ZnAl2O4,并加速尖晶石的原位生成,使得材料中能够更快更多地形成致密的MgO层,最终提高低碳MgO-C耐火材料的抗氧化性。