Journal of Water and Environmental Nanotechnology

Number 1, 2016

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Foreword

Authors: Mohsen Jahanshahi

Abstract

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Richard Feynman was the first scientist to suggest that devices and materials could someday be fabricated to atomic specifications. Later the term nanotechnology was coined. Today nanotechnology is reshaping technology. Nanotechnology is not only a part of future, but is all of it. Mankind history has always experienced waves of growth and development which affect societies, chances developed by mankind and employed to enhance the life quality and create wealth. Nanotechnology is one of these waves emerged to make a superior future. Nanotechnology is a group of emerging technologies in which the structure of matter is controlled at the nanometer scale, the scale of small numbers of atoms, to produce novel materials and devices that have useful and unique properties. Some of these technologies impose only limited control of structure at the nanometer scale, but they are already in use, producing useful products. They are also being further developed to produce even more sophisticated products in which the structure of matter is more precisely controlled. The nanotechnology community thus focuses on applying these developing technologies to solving important world problems.

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Effective removal of hexavalent mercury from aqueous solution by modified polymeric nanoadsorbent

Authors: Lida Rahmanzadeh1 ; Mohsen Ghorbani 2 ; Mohsen Jahanshahi2

Abstract

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Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury adsorbent. The kinetics of adsorption depends on the adsorbent concentration, and the physical and chemical characteristics of adsorbent. In this study we were used a novel adsorbent, magnetite-polyrhodanine core- shell nanoparticles, for removing Hg(II) from aqueous solution. The effect of pH, initial Hg(II) concentration, initial adsorbent concentration and contact time on the efficiency of Hg(II) removal were investigated systematically by batch experiments. The maximum adsorption capacity was obtained 29.14 mg g-1 at PH=6.5 and 25°C with 10 g L-1 nano adsorbent. The kinetic data of adsorption of Hg(II) ion on the synthesized adsorbent were best described by a pseudo- second- order equation, indicating their chemical adsorption. The Freundlich, Langmuir and Temkin isotherms were used to modeling of mercury adsorption on Hg(II) in aqueous medium which modeled best by the Freundlich isotherm is whole concentration rage.

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Predictions of the adsorption equilibrium of CO2/O2 mixture on multi-walled carbon nanotube using Ideal Adsorbed Solution Theory

Authors: Soodabeh Khalili 1 ; Ali Asghar Ghoreyshi2 ; Mohsen Jahanshahi2 ; Behnam khoshandam1

Abstract

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Number of views: 516

Multiwalled carbon nanotubes (MWCNT) were found to be an effective separation media for purifing CO2 from O2. Significant uptakes of CO2 and O2 were measured at 288 K, 298K and 308 K over the pressure range of 1 to 40 bar using volumetric method in dual sorption vessels. The same shape of isotherms introduced a common mechanism of adsorption but the amount of CO2 adsorbed on MWCNT is 2 times higher than O2 adsorption. The mass uptake of CO2 and O2 by MWCNT was found to increase with increasing pressure and decreasing temperature. The experimental data was well fitted by the Langmuir and Freundlich model isotherms considering the values of regression correlation coefficients. Following a simple acidic treatment procedure, CO2 and O2 adsorption was increased over range of pressure. The adsorbents was characterized by N2 adsorption isotherm at 77 K, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effect of temperature and pressure on selectivity obtained from IAST demonstrated that maximum selectivity over the pressure and temperature ranges p = 0.5-5 bar and T = 298–308 K was achieved at 308 K and 5 bar.

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Selective removal of dicamba from aqueous samples using molecularly imprinted polymer nanospheres

Authors: Tooraj Beyki; Mohammad Javad Asadollahzadeh

Abstract

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Number of views: 602

For the first time, uniform molecularly imprinted polymer (MIP) nanoparticles were prepared using dicamba as a template. The MIP nanoparticles were successfully synthesized by precipitation polymerization using methacrylic acid (MAA) as functional monomer, trimethylolpropane trimethacrylate (TRIM) as cross-linker and acetonitrile as porogen. The produced polymers were characterized by differential scanning calorimetry (DSC) and their morphology was precisely examined by scanning electron microscopy (SEM). The MIP nanospheres were obtained with the average diameter of 234 nm. Batch-wise guest binding experiments were carried out to determine the removal efficiency of the produced MIP nanoparticles towards the template molecule in aqueous solutions. The MIP showed outstanding affinity toward dicamba in aqueous solution with maximum removal efficiency of 87.5% at 300 mg.L-1 of dicamba solution. The MIP exhibited higher adsorption efficiency compared with the corresponding non-imprinted polymer (NIP) as well as outstanding selectivity towards dicamba relative to the template analog in an aqueous solution. Moreover, effects of pH on removal efficiency and selectivity of MIP were evaluated in detail.

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Photo-Catalytic Degradation of Methylene Blue by ZnO/SnO2 Nanocomposite

Authors: Samad Sabbaghi 1 ; Fateme Doraghi2

Abstract

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Number of views: 512

In this study, considering the importance of protecting the environment and preventing the pollution caused by industrial plants, a nanocomposite each component thereof is capable of removing the desired combination to solve this problem has been produced. To achieve this goal, ZnO/SnO2nanocomposite was synthesized using the co-precipitation method. The characterization of this nanocomposite was conducted by DLS, XRD, FTIR and SEM. The nanocomposite size was about 15nm. Several parameters such as the initial concentration of the wastewater, as well as the amount of catalyst and time were investigated. The reduction of the particle size due to an increase in the surface area of the nanocomposite increased the amount of decolorization. For all the performed experiments, the dye removal rate was 100% and the difference was to do with the time of the complete removal of methylene blue. A decrease in the concentration of methylene blue in the range of the tested concentrations reduced the decolorization, and by increasing the amount of nanocomposite in the range of the tested values, a decline in decolorization was observed.

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Synthesis, characterization and application of Lanthanide metal-ion-doped TiO2/bentonite nanocomposite for removal of Lead (II) and Cadmium (II) from aquatic media

Authors: Susan Samadi ; Rokhsareh Motallebi; Maryam Nasiri Nasrabadi

Abstract

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Number of views: 649

The efficient application of the photocatalytic activity and superficial adsorption on removing heavy metals from water, two types of sorbents, Nd-TiO2/bentonite and Ce-TiO2/bentonite nanocomposites, were synthesized by sol-gel method. The crystalline nanocomposites were obtained after heat treatment at 500 °C for 3 hours. The results of scanning electron microscopy (SEM) indicates that Nd-TiO2/bentonite and Ce-TiO2/bentonite were produced on a nanoscale. The phase change of both nanocomposite from amorphous to anatase has been investigated by X- ray diffraction. Removal of lead (II) and cadmium (II) were studied through adsorption on these nanocomposites by letting them float in the bulk of sample for a definite time in presence and absence of light. The effective parameters in removal process were studied and optimized. The optimum pH, removal time and sorbent dosage in the absence and presence of light for Pb2+ ion were 7, 0.3 g, 15 min and for Cd2+ ion were 7, 0.4 g, 20 min, respectively. Subsequently, the effect of interfering ions in removal process was investigated at optimum conditions and no evidence of interference was observed. The study showed that reproducibility of method (n=9) is good and suitable. The results further indicated that the removal efficiency of Pb2+ ion with Nd-TiO2/bentonite in the presence of light was more than that in the absence of light. Finally, the equilibrium adsorption data fitted Freundlich and Langmuir adsorption models.

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Comparison of Kaolin and chemical source for preparation of Nano pore NaA Zeolite membranes

Authors: Mansoor Kazemimoghadam

Abstract

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Number of views: 585

Zeolite membranes have uniform and nano-sized pores, and they separate molecules based on differences in the molecules size and diffusion properties. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports. Our approach to membrane synthesis was based on hydrothermally converting films of layered aluminosilicates into zeolite films. In this research, synthesis of nano NaA zeolite membrane from kaolin was investigated. In the first step, kaolin has been calcined at 700 °C to the metakaolinite phase. As a second step, the zeolitisation experiments have been carried out under hydrothermal conditions. The metakaolinite obtained has been reacted with NaOH solutions in autoclaves at 100°C. X-ray diffraction (XRD) patterns of the membranes exhibited peaks corresponding to the support and the zeolite. The morphology of the support and membrane subjected to crystallization was characterized by Scanning electron microscopy (SEM). Separation performance of the NaA membranes was evaluated using pervaporation of water–Ethanol mixtures. The membranes showed high water selectivity in the water–Ethanol mixtures.

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TiO2/Gold nanocomposite as an extremely sensitive molecule sensor for NO2 detection: A DFT study

Authors: Amirali Abbasi; Jaber Jahanbin Sardroodi ; Alireza Rastkar Ebrahimzadeh

Abstract

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Number of views: 593

First-principles calculations within density functional theory (DFT) have been performed to investigate the interactions of NO2 molecules with TiO2/Gold nanocomposites in order to completely exploit the adsorption properties of these nanostructures. Given the need to further comprehend the behavior of the NO2 molecules positioned between the TiO2 nanoparticle and Au monolayer, we have geometrically optimized the complex systems consisting of the NO2 molecule oriented at appropriate positions between the nanoparticle and Au monolayer. The structural properties such as bond lengths, bond angles, adsorption energies and Mulliken population analysis and the electronic properties including the density of states and molecular orbitals have been also analyzed in detail. The results indicate that the interaction between NO2 and undoped TiO2-N/Gold nanocomposites is stronger than that between gas molecules and N-doped TiO2/Gold nanocomposites, which reveals that the pristine nanocomposite can react with NO2 molecule more efficiently. Therefore, the obtained results also suggest a theoretical basis for the potential applications of TiO2/Gold nanocomposites in gas sensing, which could help in the developing of novel TiO2 based advanced sensor devices.

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Green synthesis of silver nanoparticles by Escherichia coli : Analysis of antibacterial activity

Authors: Koilparambil Divya; Liya C. Kurian; Smitha Vijayan; Jisha Manakulam Shaikmoideen

Abstract

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Number of views: 534

The emerging infectious diseases and the development of drug resistance in the pathogenic microorganism is a matter of serious concern. Despite the increased knowledge of microbial pathogenesis and application of modern therapeutics, the morbidity and mortality associated with the microbial infections still remains high. Therefore, there is a pressing demand to discover novel strategies and identify new antimicrobial agents to develop the next generation of drugs or agents to control microbial infections. The use of nanoparticles is gaining impetus in the present century as they possess defined chemical, optical and mechanical properties. In the present study green synthesis of silver nanoparticles by Escherichia coli has been done. Various parameters such as mixing ratio of culture supernatant and silver nitrate, media, temperature and pH for production of silver nanoparticles were optimised. The nanoparticles synthesised was characterized using SEM, FTIR and XRD. The antibacterial activity of silver nanoparticles synthesised using both pellet and supernatant against human pathogens Salmonella typhi, Vibrio cholerae, Bacillus subtilis and Klebsiella pneumoniae was analysed and MIC was calculated as 20µg and 50µg respectively.