Synthesis and characterization of fluorescent N-CDs/ZnONPs nanocomposite for latent fingerprint detection by using powder brushing method

This study reports the first new approach of using nitrogen functionalized carbon dots coated on zinc oxide nanoparticles (N-CDs/ZnONPs) as a novel nanocomposite for latent fingerprint detection using the powder brushing method. N-CDs/ZnONPs nanocomposite was prepared using melamine, potato peel waste and zinc acetate dehydrate as precursors. This nanocomposite was characterized by Fourier-transform infrared spectroscopy, UV–Visible spectroscopy, Fluorescence spectroscopy, X-ray diffraction, Raman spectroscopy, Zeta nanosizer, Scanning Electron Microscope, Energy-Dispersive X-ray Spectrometry and Transmission Electron Microscopy. The size of N-CDs was around at 50–20 nm and ZnONPs was around at 40–50 nm. The quantum yield of N-CDs increased the fluorescence intensity of the fluorophore by 5.54%. The N-CDs were coated on surface of ZnONPs to increase the quantum yield and increase the blue emission after formation of N-CDs/ZnONPs by 5.12%.The N-CDs/ZnONPs nanocomposite demonstrated extraordinary sensitivity and selectivity for Latent Fingerprint (LPF) detection on the distinctive non-porous substrates which included aluminum foil, aluminum sheets, an aluminum rod, an iron disc, a compact disc, a black mat, white marble and magazine paper. This nanocomposite acts as a labeling agent and it helped to detect LFP with clear readability ridges and high contrast fingerprint images under UV light irradiation. N-CDs/ZnONPs nanocomposite additionally demonstrated superior ability to reveal readability ridges and clarity and high contrast LFP images with 415 nm and 450 nm light sources and a yellow filter by using a Living Image Microscope. This nanocomposite exhibited advantages such as improved efficiency, a non-toxic nature, good optical properties and good results in the LFP detection of the freshly applied fingerprints. N-CDs/ZnONPs nanocomposite is, therefore, a good alternative material for detection of latent fingerprints in crime investigations.     

Synthesis and characterization of fluorescent Europium (III) complex based on D-dextrose composite for latent fingerprint detection

A europium salt-Na[Eu(5,5′-DMBP)(phen)₃]·Cl₃ (Eu(III)-CPLx) was prepared by using various precursors such as 5,5′-Dimethyl-2,2′-bipyridyl (5,5′-DMBP), 1,10-phenanthroline (phen) and europium chloride hexahydrate (EuCl₃·6H₂O) by a complexation method. The red emission fluorescent Na[Eu(5,5′-DMBP)(phen)₃]·Cl₃/D-Dextrose (Eu(III)-CPLx/D-Dex) composite was synthesized by using an adsorption method with Eu(III)-CPLx and D-Dextrose (D-Dex). The Eu(III)-CPLx and fluorescent (Eu(III)-CPLx/D-Dex) composites were characterized by numerous techniques. The fluorescent (Eu(III)-CPLx/D-Dex) composite demonstrated a strong red emission and controlled fluorescence quenching in the solid state and was consequently used in latent fingerprint (LFP) detection. The LFPs were developed by using a powder dusting method (PDM) with Eu(III)-CPLx and fluorescent Eu(III)-CPLx/D-Dex composites on different substrates under daylight and UV-light irradiation at 365 nm. The fluorescent Eu(III)-CPLx/D-Dex composite was effectively explored for developing LFP images on various substrates and also acts as a better labeling agent for LFP detection in forensic science crime scene investigations.     

Synthesis and Crystal Structure of Pb3O2(SeO3)

Single crystals of Pb₃O₂(SeO₃) have been prepared hydrothermally at 230 °C. The structure (orthorhombic, Cmc2₁, a = 10.529(2), b = 10.722(2), c = 5.7527(12)Å, V = 649.5(2)ų) has been solved by direct methods and refined to R₁ = 0.059 on the basis of 615 unique observed reflections (|F_o| = 4σ_F). The structure is based upon double [O₂Pb₃]²⁺ chains of edge‐sharing [OPb₄]⁶⁺ tetrahedra. These [O₂Pb₃]²⁺ chains run parallel to [001], and their planes are parallel to (010). The pyramidal (SeO₃)^2— anions are located between the chains; their triangular oxygen atom bases lie parallel to (001) and all (SeO₃)^2— groups are pointing in the same direction. A short compilation of [O₂M₃] chains of oxocentred M₄ tetrahedra in minerals and inorganic compounds is provided.     

Chromenone-rhodamine conjugate for naked eye detection of Al3+ and Hg2+ ions in semi aqueous medium

Chromenone-rhodamine conjugate 1 has been synthesized and its metal ion binding properties have been studied in CH₃CN/water (3:1, v/v; 10 mM HEPES buffer; pH = 6.85). Compound 1 senses multiple metal ions such as Al³⁺ and Hg²⁺ by exhibiting turn on fluorescence and color change (colorless to pink). Al³⁺ and Hg²⁺ ions have been distinguished with the aid of tetrabutylammonium iodide (TBAI). While in the presence of I^? the pink color of the 1.Hg²⁺ complex was completely discharged; under identical conditions the pink color of 1.Al³⁺ complex was retained.     

结构强健的Al2O3-SiO2气凝胶的 制备及可重复使用性能

通过纳米晶组装技术, 构筑了Al₂O₃-SiO₂复合气凝胶; 利用不同组分耐温性的差异, 经过热处理过程得到了骨架强健的Al₂O₃-SiO₂气凝胶. 研究了不同配比及热处理温度对材料微观结构和组分的影响, 确定了最佳制备条件, 得到了比表面积为123.9 m ²/g, 密度为 0.25 g/cm ³, 导热系数为0.029 W·m ^-1·K ^-1的气凝胶材料. 在泡水和冰冻等极端环境下, 气凝胶材料未发生结构的破坏, 模拟10次重复隔热应用(800 ℃, 30 min)后导热系数保持不变. 该隔热性气凝胶的开发有望解决未来飞行器隔热材料需重复使用的技术瓶颈, 为开发新型气凝胶隔热材料提供了新思路.     

氨基化锰铁氧体纳米粒子的制备及吸附pb2+和Cd2+性能研究

利用一步水热法合成了氨基化锰铁氧体纳米粒子吸附材料,并研究了对Pb₂₊和Cd₂₊的吸附特性和去除效果;通过SEM、XRD、 FT-IR和XPS等方法进行了表征分析和吸附机理研究。结果表明：温度为25 ℃,氨基化锰铁氧体纳米粒子吸附Pb₂₊和Cd₂₊在60 min内即可达到吸附平衡,最大饱和吸附量分别为255.57 mg?g_-1和129.72 mg?g_-1;吸附过程符合准二级动力学方程和Langmuir等温吸附方程,对Pb₂₊和Cd₂₊的吸附过程主要是单分子层化学吸附。氨基化锰铁氧体纳米粒子吸附-再生重复利用5次后,对Pb₂₊和Cd₂₊的吸附量分别仍为初始吸附量的87%以上,表现了良好的再生吸附性能。     

Synthesis and characterization of Al2O3/Cr2O3-based ceramic pigments

The synthesis and the characterization of Al₂O₃-based nanocrystalline inorganic pigments are reported. The pigments were synthesized by the polymeric precursor (Pechini method) using Cr₂O₃ as chromophore. XRD results only evidenced the corundum phase. The average particle size was about 34 nm. The samples were also characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG), and CIE-L*a*b* calorimetry. The pigments obtained in this work presented different colors, ranging from green to rose. This revised version was published online in August 2006 with corrections to the Cover Date.     

双模板铅离子印迹吸附剂的制备及其应用于环境水及沉积物样品中铅的选择性吸附

利用溶胶-凝胶法制备了一种双模板介孔Pb2+印迹吸附剂(Pb-CTMAB-imp).通过平衡吸附实验,研究了Pb-CTMAB-imp的吸附性能和对Pb2+的选择识别性能.结果表明,Cd2+存在时,Pb-CTMAB-imp对Pb2+的选择系数可以达到91,远高于只用十六烷基三甲基溴化铵(CTMAB)作为模板的印迹吸附剂(...     

H2-induced CO adsorption and dissociation over Co/Al2O3 catalyst

The activation of adsorbed CO is an important step in CO hydrogenation. The results from TPSR of pre-adsorbed CO with H2 and syngas suggested that the presence of H2 increased the amount of CO adsorption and accelerated CO dissocia-tion. The H2 was adsorbed first, and activated to form H* over metal sites, then reacted with carbonaceous species. The oxygen species for CO2 formation in the presence of hydrogen was mostly OH*, which reacted with adsorbed CO subsequently via CO*+OH* → CO2*+H*; however, the direct CO dissociation was not excluded in CO hydrogenation. The dissociation of C-O bond in the presence of H2 proceeded by a concerted mechanism, which assisted the Boudourd reaction of adsorbed CO onthe surface via CO*+2H* → CH*+OH*. The formation of the surface species (CH) from adsorbed CO proceeded as indicated with the participation of surface hydrogen, was favored in the initial step of the Fischer-Tropsch synthesis.     

Synthesis of anionic gemini surfactant-templated mesoporous silica nanoparticles and its adsorption application for Pb2+

Abstract

Amino-functionalized mesoporous silica nanoparticles (AFMSN) were prepared based on the self-assembly process of the pre-fabricated template of anionic gemini surfactant. The perfect mass ration of the reactants for the synthesis of the AFMSN with high surface area and amino loading was optimized by orthogonal experiments. Adsorption capability of the optimized product for lead ion (Pb²⁺) was investigated in detail. Specially, the effects of the amino content, solution pH, adsorbent dosage, temperature, and interference of other metal ions on the removal efficiency of Pb²⁺ were studied. It is found that these factors can greatly affect the removal efficiency of Pb²⁺ and the prepared adsorbent exhibits the high adsorption selectivity for Pb²⁺. At an optimal condition, the AFMSN adsorbent presents an excellent adsorption capacity for Pb²⁺ up to 211.42?mg/g. The adsorption kinetics study revealed that the pseudo-second-order model could well describe the Pb²⁺ adsorption process, and the adsorption isotherm was fitted well with the Langmuir model. More importantly, the AFMSN adsorbent could be recycled 8 times and a high adsorption efficiency of Pb²⁺ could still be maintained. Therefore, the prepared AFMSN adsorbent may find practical application in removing Pb²⁺ from the polluted water.     

Evaluation of PANI-Averraoha bilimbi leaves activated carbon nanocomposite for Cd2+ and Pb2+ removal from wastewater

In current investigation, we synthesized new Polyaniline-Averraoha Bilimbi Leaves Activated Carbon (PANI-ABLC) nanocomposites and utilized as cost effectual for the elimination of Cd²⁺ and Pb²⁺ ions from the wastewater. The synthesized nanocomposite was confirmed by Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDX), Fourier Transform-Infrared (FT-IR) spectroscopy and X-Ray Diffraction (X-RD) techniques. A batch adsorption study carried in wastewater containing different concentrations of Cd²⁺ and Pb²⁺ ions in the temperature range of 303–343 K. The results show that, around 80% of Cd²⁺ and Pb²⁺ ions from the wastewater was successfully isolated by using PANI-ABLC nanocomposite. Attempts were made to fit adsorption to different isotherm models. The PANI-ABLC nanocomposite complied Langmuir adsorption model (R² = 0.999) and pseudo-second order kinetics. Further, maximum adsorption efficiency observed at 0.5 g of Polyaniline-Averraoha bilimbi leaves activated carbon nanocomposites. AC- Impedance Spectroscopy (IS) technique shows that, Polyaniline-Averraoha Bilimbi Leaves Activated Carbon (PANI-ABLC) nanocomposite is suitable for removal of Cd²⁺ and Pb²⁺ ions from the wastewater. AC impedance spectroscopy technique study shows that, the process of adsorption was controlled by charge transfer process.     

H2-induced CO adsorption and dissociation over Co/Al2O3 catalyst

The activation of adsorbed CO is an important step in CO hydrogenation. The results from TPSR of pre-adsorbed CO with H2 and syngas suggested that the presence of H2 increased the amount of CO adsorption and accelerated CO dissociation. The H2 was adsorbed first, and activated to form H＊ over metal sites, then reacted with carbonaceous species. The oxygen species for CO2 formation in the presence of hydrogen was mostly OH^＊, which reacted with adsorbed CO subsequently via CO^＊＋OH^＊ → CO2^＊＋H^＊; however, the direct CO dissociation was not excluded in CO hydrogenation. The dissociation of C-O bond in the presence of H2 proceeded by a concerted mechanism, which assisted the Boudourd reaction of adsorbed CO on the surface via CO^＊＋2H^＊ → CH^＊＋OH^＊. The formation of the surface species （CH） from adsorbed CO proceeded as indicated with the participation of surface hydrogen, was favored in the initial step of the Fischer-Tropsch synthesis.     

[Pb6(H2O)2(cit)4]·3H2O和Pb(tar)(H2O)2两种柔性酸和铅的配位聚合物的水热合成与表征

在水热条件下, 合成了2个含柔性配体柠檬酸和酒石酸的二价铅配位聚合物[Pb6(H2O)2(cit)4]·3H2O(1)(H3cit=citric acid)及Pb(tar)(H2O)2(2)(tar=tartaric acid). 用红外光谱、差热-热重、元素分析、粉末X射线衍射及单晶X射线衍射等手段对化合物进行了表征. 化合物1属三斜晶系, P1空间群, a=0.97053(19) nm, b=0.9764(2) nm, c=1.0955(2) nm, α=109.016(3)°, β=98.380(3)°, γ=92.136(3)°, V=0.9671(3) nm3, Z=2, R1=0.0420, wR2=0.1049, GOF=1.064. 在化合物1的不对称结构单元中, 有3个铅离子以及2个柠檬酸阴离子和2个游离的水分子. 铅离子分别以4, 5, 7配位与柠檬酸配合形成了中性的三维骨架结构. 化合物2属于正交晶系, Pbca空间群, a=1.39739(6) nm, b=0.64922(2) nm, c=1.80354(10) nm, V=1.63620(13) nm3, Z=8, R1=0.0283, wR2=0.0649, GOF=1.014. 在化合物2的不对称结构单元中, 有1个铅离子、1个酒石酸分子和1个水分子, 六配位的铅和酒石酸形成了一维外消旋的无限长链, 链与链之间通过氢键连接成一个三维超分子结构. 在化合物1和2中, 两种配体均出现了α羟基和α羧基螯合的配位模式, 铅的6s孤电子对均显示了立体化学活性, 使配位键分布于半球区域.     

Catalytic Performance and IR Characterization of Co-Mo/Al2O3 and Ru-Co-Mo/Al2O3 Catalysts in Hydrodesulfurization

Recently, owing to high costs and increasing demands for better catalysts, it is worthwhile to improve its activity and selectivity, and reduce its costs. Adding secondary promoters such as phosphorus, boron, magnesium, titanium, zinc and ruthenium to Co-Mo/Al_2O_3 catalyst has been proved to be one of the ways to attain this result. The addition of those metals or metal oxides changes the surface states of molybdenumstructure.     

EXAFS characterization of Ti/Al2O3 supports and Co/Ti/Al2O3 catalysts

The structure of Ti/Al₂O₃ supports (0–14 wt% Ti) and Co/Ti/Al₂O₃ catalysts (3 wt% Co) was examined by EXAFS. The results indicated that the Ti was present primarily as a highly dispersed surface phase. The Ti EXAFS results indicated that the Ti species were octahedrally coordinated. Evidence of Ti—Ti interactions was found for all loadings (2–14 wt% Ti) suggesting that the Ti surface species are present as small clusters of TiO₂.The Co EXAFS results showed evidence for several structurally different Co surface phases as a function of Ti loading. Evidence of a Co species interacting with the Ti surface phase was observed for the 3% Co/2% Ti-3%Co/6%Ti catalysts. At the highest loadings studied, 3%Co/8%Ti and 3%Co/14%Ti, evidence was found for a CoTiO₃-like phase.     

Synthesis of a MnO2/multiwalled carbon nanotube nanocomposite and its application as a sorbent for removing Cu2+ ions from aqueous media

In this research, a manganese dioxide/multiwalled carbon nanotube (MnO₂/MWCNT) was firstly synthesized and characterized and then was applied as an effective sorbent for removing Cu²⁺ ions from aqueous solution. The effects of initial concentration, temperature, contact time, pH solution, and sorbent dosage were investigated and the optimum value of each was determined. The Langmuir isotherm model, Freundlich model, and Temkin model were used to fit our experimental results. Ultimately, using the Van't Hoff approach, the thermodynamic functions of the intended adsorption phenomenon such as ΔH°_ad, ΔS°_ad, and ΔG°_ad were estimated.     

Preparation and fabrication of porous-Fe2O3/carbon black nanocomposite: a portable electrochemical sensor for psychotropic drug detection in environmental samples

Herein, we reported the fabrication of porous iron oxide/carbon black (P–Fe₂O₃/CB) composite through a two-step engineering method. At first, Prussian blue microcubes were used as a precursor and further calcined to form P–Fe₂O₃ microcubes. The intercalation of CB nanoparticles with P–Fe₂O₃ nanocubes was processed through the ultrasonication method. The obtained P–Fe₂O₃/CB were successfully scrutinized through various physiochemical characterization methods. The proposed P–Fe₂O₃/CB-modified glassy carbon electrode sensor was successfully implemented in the electrochemical sensing of chlorpromazine hydrochloride due to its very low charge transfer resistance (R_ct) compared to the other electrode modifiers. The sensitive detection of CPMH through differential pulse voltammetry exemplifies an excellent electroanalytical performance such as a wide linear range of 0.5–1472 μM, a lower detection limit (0.001 μM), and an appraisable sensitivity of 1.99 μA/μM cm^?2 due to its availability of a high number of active sites and its large surface area, respectively. It also expresses excellent selectivity, repeatability, reproducibility, and stability results. Moreover, the practical feasibility of the as-fabricated P–Fe₂O₃/CB/glassy carbon electrode sensor shows exquisite recovery (98.1–100.8%) results with an appraisable current response in various biological, pharmaceutical, and environmental samples.     

Mixed phase Fe2O3/Mn3O4 magnetic nanocomposite for enhanced adsorption of methyl orange dye: Neural network modeling and response surface methodology optimization

In this research, a novel magnetic mesoporous adsorbent with mixed phase of Fe₂O₃/Mn₃O₄ nanocomposite was prepared by a facile precipitating method and characterized extensively. The prepared nanocomposite was used as adsorbent for toxic methyl orange (MO) dye removal from aqua matrix considering its high surface area (178.27 m²/g) with high saturation magnetization (23.07 emu/g). Maximum dye adsorption occurs at solution pH 2.0 and the electrostatic attraction between anionic form of MO dye molecules and the positively charged nanocomposite surface is the main driving force behind this adsorption. Response surface methodology (RSM) was used for optimizing the process variables and maximum MO removal of 97.67% is obtained at optimum experimental condition with contact time, adsorbent dose and initial MO dye concentration of 45 min, 0.87 g/l and 116 mg/l, respectively. Artificial neural network (ANN) model with optimum topology of 3–5–1 was developed for predicting the MO removal (%), which has shown higher predictive ability than RSM model. Maximum adsorption capacity of this nanocomposite was found to be 322.58 mg/g from Langmuir isotherm model. Kinetic studies reveal the applicability of second‐order kinetic model with contribution of intra‐particle diffusion in this process.     

Synthesis,characterization, dielectric and rectification properties of PANI/Nd2O3:Al2O3 nanocomposites

Polyaniline–Nd₂O₃:Al₂O₃ nanocomposites were prepared by in situ oxidative polymerization method using different weight percentages of oxide powders. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy and X‐ray diffraction for molecular and crystal structures. Scanning electron microscopy and transmission electron microscopy images show the tubular structure of polyaniline nanocomposite with embedded metal oxides. The electrical conductivity of the nanocomposites increases with increase in temperature as well as with concentration of Nd₂O₃:Al₂O₃ particles in polyaniline. This is because of the hopping of charge polarons and extended chain length of the nanocomposites as evidenced by the negative thermal coefficient (NTC) characteristic. A high NTC value of 2.67 was found in nanocomposites with 15 wt% of oxide particles. These nanocomposites show low dielectric constant and dielectric loss; the electrical conductivity is higher than 0.3 S/cm as confirmed by Cole–Cole plot that indicates a decrease in both grain resistance and bulk resistance of the nanocomposites. The current–voltage and capacitance–voltage measurements were also carried out. The carrier mobility μ values of pure polyaniline and nanocomposites were found to be 4.27 × 10^?3 and 1.45 × 10^–2 H.M^?1, respectively. A significant enhancement in carrier mobility was observed in comparison with the literature. Copyright © 2016 John Wiley & Sons, Ltd.