Journal of Nanoanalysis
Volume:4 Issue: 3, Sep 2017

Mercury (Hg) causes hazardous cumulative effects in humans; like central nervous system disorders,hypertension and chromosomal aberrations. Therefore, due to high toxicity and bioaccumulationfactor, mercury determination and speciation in human blood is very important. A sensitive,accurate, precise and inexpensive method was demonstrated for preconcentration and speciationof ultra-trace mercury in human blood samples. The amine-functionalized mesoporous silicananoparticles (NH2-MSNPs) as solid phase sorbent was prepared and investigated in a new andsimple dispersive-ionic liquid-micro-solid phase extraction (D-IL-μ-SPE) procedure for rapidspeciation and determination of trace inorganic and organic mercury [Hg+2 , (CH3Hg)+ and (C2H5Hg)+]in human blood samples. Under the optimal conditions, the linear range, limit of detection andpreconcentration factor were obtained 0.05-9.8 μg L−1, 15 ng L−1 and 9.6 for human blood samples,respectively (Peak Area, RSD<5%). The reusability and batch adsorption capacity of the MSNPsand NH2-MSNPs were also obtained 25 and 159 mg g-1, respectively. The developed method wassuccessfully applied for validation of methodology by standard reference materials (SRM).

The methodology involves preparing polyvinyl sulfuric acid as a solid acid by simple mixing ofpolyvinyl alcohol with chlorosulfonic acid in CH2Cl2 at room temperature. The catalytic ability ofthe solid acid was investigated for the facile conversion of benzylic alcohols to the unsymmetricalethers with aliphatic alcohols in the presence of the solid acid. Results show that the solid acid isan appropriate catalytic agent for these condensation reactions. The silica was also extracted fromlow-cost rice husk and the amorphous silica gel nanoparticles were prepared with sol- gel method.The polyvinyl sulfuric acid was supported on nano rice husk silica. Then the catalytic effect of thissystem was investigated for synthesis of unsymmetrical ethers which consisted of a combination ofhigh acidic power for this solid acid and high- surface area of nanoparticles. Results show that totallycatalytic effect of polyvinyl sulfuric acid supported on nano silica is more suitable than polyvinylsulfuric acid. The reason for this is in its ability to produce the end products in shorter reaction timeswhile having high isolated yields.

Enzymes Immobilization onto different types of the substrate could be helpful in various applicationsof biomedical devices and biosensors. Enzyme activity and stability could be affected by support andmethod of immobilization. In this study, the silver metal foam was successfully synthesized by thesoft-shell method and then was coated with silica. Then, glucose oxidase (GOx) immobilized on noncoated,and silica-coated silver metal foam and removal of malachite green was investigated. FourierTransform Infrared Spectroscopy (FT-IR) and scanning electron microscopy (SEM) results confirmedthat the enzyme was attached to support surface. The maximum immobilized enzyme activity wasabout 118.980 U/grSupport at 40°C. The removal of malachite green showed the indirect relationwith dye concentration confirmed by decolorization assay. The high activity, thermal stability, andreusability of immobilized glucose oxidase onto the silver metal foam in comparison to free enzymeintroduce the capability of the biological system for removal of malachite green in the industry.

Using DC-Plasma Enhanced Chemical Vapour Deposition (PECVD) system, the impact of pure Co onthe growth of diamond-like carbon (DLC) nano-structures were investigated. In this study, Acetylene(C2H2) was diluted in H2 and used as the reaction gas and Cobalt (Co) nano-particles were used asthe catalyst. The effect of preparing Co catalyst at temperatures of 240°C and 350°C and growthconditions was studied. The results showed that the Co catalyst sputtering at 350°C temperature hasa significant impact on purity, morphology, and synthesized diamond-like carbon nano-structures.This research was conducted to investigate the effect of catalyst preparation and growth conditions.Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were used tocharacterize the diamond-like carbon nano-structures produced under different conditions.

Phenol-formaldehyde/silica hybrid gel with hydrophobic character, high porosity, and thesmall pore size mean was prepared via sol-gel polymerization under solvent saturated vaporatmosphere and was dried by ambient drying method. The silica sols were prepared based onTetraethoxysilane (TEOS) and Methyltrimethoxysilane (MTES) as hydrophilic and hydrophobicprecursors, respectively. Phenol-formaldehyde resin was used as organic phase to achievesuitable physical properties. The contact angle of this aerogel was about 147˚ and it is a resultof formation of CH3 groups on the pore walls. The results of FESEM and nitrogen adsorptionindicated that the structure of this aerogel is highly porous, uniform, and colloid like network.The Phenol-formaldehyde/silica hybrid aerogel was used for removal of phenol from aqueoussolution. The study was carried out as functions of contact time, pH and initial phenolconcentration. The experiments demonstrated that maximum phenol removal was obtainedat neutral pH in unbuffered condition and it takes 40 min to attain equilibrium. Langmuir,Freundlich and Temkin isotherm models were applied to fit adsorption equilibrium data. Thebest-fitted data was obtained with the Langmuir model and the adsorption capacity was 97.09mg g−1. Kinetic studies indicated that the adsorption process was described better by pseudosecond-order model.

Nanoparticles bio production, considering their performance in medicine and biologicalscience, is increasing; also, raising awareness of green chemistry and bioprocesses hasencouraged the use of environmentally friendly methods for the production of non-toxicnanomaterials.. Also uses of plant extracts are found to be more advantageous over chemical,physical and microbial (bacterial, fungal, algal) methods for silver nanoparticles (AgNPs)synthesis. The objectives of this study were the production of silver nanoparticles using aqueous andhydroalcoholic extracts of Avena sativa L. an investigation of the effect of extracts on thesynthesis of nanoparticles. The morphology and size of the nanoparticles were determinedusing Scanning Electron Microscope (SEM) and UV-Vis spectroscopy. SEM images showed thatthe synthesized nanoparticles were mainly spherical and round shaped. The results indicatedthat synthesized nanoparticles using an aqueous extract were better than the synthesizednanoparticles using hydro-alcoholic extract in shape and size.Synthesize silver nanoparticles using Avena sativa L. Extract provides environmentally friendlyoption as compared to currently available chemical/ physical methods.

In this research, a simple and efficient cathodic electrochemical deposition (CED) route wasdeveloped for the preparation of magnetite nanoparticles (NPs) in an aqueous media. Thesurface of magnetite NPs was also coated for the first time via an in situ procedure during theCED process. In this method, initially, the Fe3O4 NPs (with size ~10 nm) were prepared from theFe2+/Fe3+ chloride bath through CED process. Then, dextran as the coating agent was coatedon the surface of Fe3O4 NPs during the CED process. The prepared NPs were characterizedby different techniques such as XRD, FE-SEM, TEM, IR, TGA, DLS and VSM. The XRD resultsproved the pure magnetite i.e. Fe3O4 crystal phase of the prepared samples. Morphologicalobservations through FE-SEM and TEM revealed particle morphology with nano-sizes of 8nm and 12 nm for the naked and dextran coated NPs, respectively. The dextran coat on thesurfaces of NPs was confirmed by FT-IR and DSC-TGA analyses. The average hydrodynamicdiameters of 17 nm and 54 nm were measured from DLS analysis for the naked and dextrancoated NPs, respectively. The magnetic analysis by VSM revealed that prepared NPs havesuperparamagnetic behavior, i.e. Ms=82.3 emu g–1, magnetization Mr=0.71 emug–1 and Ce=2.3Oe for the naked NPs, and Ms=43.1 emu g–1, Mr=0.47 emu g–1 and Ce=0.81Oe for the dextrancoated NPs. These results implied that this electrochemical strategy can be recognized as aneffective preparation method of polymer coated Fe3O4 NPs.

In the present work CuBi2O4 nano-spinel has been synthesized via mild hydrothermal methodat 180°C for 10 h. The synthesized nanomaterials were characterized by several techniquesto emphasis the structure and properties of produced materials. The crystal structure wasinvestigated by X-ray powder diffraction method and the values of the refined unit cell volumeand the structure properties were studied by using the Rietveld analysis is done using Fullprofprogram. The results shew the formation of tetrahedral structure with space group P4/ncc for this sample. Also, the morphologies of the synthesized materials were figured outby field emission scanning electron microscope (FE-SEM). According to the FESEM images,several nano cubic form of particles grew on micro spherical particles. As well, the catalyticperformance of obtained CuBi2O4 was studied in Biginelli reaction. The reaction conditions ofthis study optimized by experimental design method. This experiment stablished high catalyticperformance of copper bismuth oxide in compare with some other metal oxide catalysts. Also,the results shew this product is reusable homogenous catalyst.

Ceramic membranes are considered as alternatives for their polymeric counterparts due to highmechanical strength and thermal resistance; thus long lifetime. Usually, asymmetric ceramicmembranes are synthesized including several layers with different pore size distributionswith the top-layer playing the main separation role. Titania has several properties such asphotocatalytic activity and chemical stability making it sutitable as an option for the top-layer.This study is devoted to the preparation and characterization of a ceramic membrane, dipcoatingof mesoporous interlayers and preparation of a microporous anatase top-layer viasol-gel technique. Moreover, the performance of the membrane modified by nano-copperisinvestigated for salt rejection enhancement. Membranes were characterized by FE-SEM andX-ray diffraction. The sol particle size was determined using DLS. Cross-flow filtration setupwas used for membrane permeability and salt retention experiments. Membrane top-layershowed crystal structures including rutile and anatase phases. By increasing salt concentration,chloride rejection is decreased and retention is increased by increasing the pressure. In case ofmodified membranes using nano-copper, higher retentions are observed, with 35% rejectionfor NaCl and 73% for Na2SO4.

The rapidly growing field of biotechnology has created a critical need for simple, fast andhigh-throughput processes for the separation and purification of biomolecules from biologicalmatrices. In recent years, several bioseparation techniques have been proposed as advancedalternatives to the classical separation methods. These modern processes emphasize ultrahighselective and sensitive analysis to determine promising chemical and biological entities.The current paper discusses the recent developments in the field of biotechnology usingmagnetic separation techniques based on oligonucleotides as the chemically synthesized andcost-effective biological ligands. In particular, they are very stable and not subject to thermaland chemical degradation. This allows the researchers to use labeled aptamers as highlysensitive and specific olgonucleotide probes in solution, membrane or magnetic nanoparticlesbasedassay systems. Since aptamers bind their targets with high affinity and specificity, theyare promising alternative ligands in the purification of proteins. The purpose of this reviewpaper is to show the critical role of oligonucleotides ligands for separation or purification ofbiological compounds and ions in complex matrices. Using the suitable aptamers in separationand preconcentration processes is an excellent alternative to the classical ligands. Somepractical examples of DNA-based magnetic separation processes are also discussed to showthe efficiency of magnetic bioseparation.