Sharif Digital Repository

The increasing utilization of silver nanoparticles (Ag-NPs) in industrial and consumer products has raised concern to wastewater treatment utilities, due to its antimicrobial activity. In this research, recovery of silver nanoparticles from wastewater via using activated carbon and convert it into usable nanoparticles is presented. real waste of silver nanoparticles have been used and activated carbon as adsorbent has a high absorption recovery for silver. Under the optimized experimental parameters e.g. pH, temperature, time of process, and amount of activated carbon, an absorption maximum was achieved and over than 99% of silver nanoparticles can be removed from wastewater. After the... 

Aspect ratio dependant optical properties of silver and gold nanorods is responsible for great attention toward controlling the aspect ratio of this class of the nanostructure for their application in variety of area, such as medical diagnosis, drug delivery, biosensing and treatment. In this research, gold and silver nanorods have been synthesized using chemical reducation and growth based on seed mediated method, which is the newest and one of the best methods with less difficulty for producing silver and gold nanorods. Absorption of the visible light by gold and silver nanorods results in appearing the longitudinal and transverse Plasmon bands in their absorption spectra which is related... 

Due to the high cost of the conventional silicon-based circuits, printed electronic introduced as an ultra-low-cost saving techniques which are widely used in RFID tags, displays, sensors and thin film transistors and so on. Unlike the silicon-based devices, Organic materials are used in printed electronic devices, owing to this these devices can be used on large and flexible substrates like glass and plastic. Also in the printing method, there is no demand for expensive and time-consuming processes such as lithography or sputtering. Only by an ink-jet printer or graved cylinders the different layers of a device can be deposited. Besides these advantages of printed electronics to... 

Silver and gold are precious, expensive metals and are used in various applications, such as jewellery and ornamentals, electronics and optics. In the present study, soda-lime glass surfaces firstly were activated with acidic stannous chloride solution. Then, silver and gold were coated on these surfaces via simultaneous spraying of two solution: A silver- or gold-complex bearing solution and a reducing agent (Dextrose for Ag and H2O2 for Au) bearing solution. For silver coating, the effect of various parameters such as time, reducing agent concentration, number of passes, presence and concentration of Urotrpin and Decamethylcyclopentasiloxane (DMCPS) as microstructural modifiers and... 

Burns are one of the most important accidents related to human health. Due to the intense physical and mental complications and high fatality rate associated with them, receiving proper treatment is of paramount importance. The control of infection in wounds would cure and eliminates the effect of wounds and treatment of skin lesions with engineered scaffolds can be an effective method. The purpose of this project is proposing a hydrogel scaffold based on natural polymers of oxidized alginate and gelatin loaded with an herbal drug to control infection and treat burn wounds. For this purpose, the Iranian Oak extract that it's main content is Tanin and PolyPhenolinc materials, was prepared and... 

Pesticides are broadly applied in croplands, glasshouses, and orchards in order to increase agricultural products and their quality. Among the variety of pesticides, organophosphorus pesticides (OPs), possessing high insecticidal activity, acute toxicity and relatively short environmental persistence, have been widely used for pest control in agriculture. However, this effect might lead to adverse health impacts or death for mammals and humans. Thus, even at trace levels, it is of great importance to develop a simple, sensitive, inexpensive and real-time detection method for monitoring the levels of pesticides in the environment, foodstuffs and biological samples. The integration of metallic... 

In this work two shapes of silver nanostructures including silver nanowires and silver nanocubeswere synthesized by polyol method. Silver nanostructures were characterized by SEM, XRD and UV-Vis spectroscopy. Afterwards the morphology-dependent electrocatalyticperformance of these nanocrystals on the differential pulse behavior of naltrexone (NAL) was investigated. To this aim the differential pulse voltammetric behavior of NAL on a glassy carbon electrode modified with electrochemical deposited gold nanoparticles conjugated with different shapes of silver nanostructures and nafion was investigated. It was proved that silver nanowires show more effective electrocatalytic activity toward... 

Acceleration of healing process for crucial wounds has been remained a challenging issue and it is critical to improve treatments against infection during wound healing period. Among various antimicrobial agents, silver components has been extensively since they are resistant against a wide range of bacteria. In this study, we developed electrospun mats composed of Polycaprolactone (PCL) and Polyvinyl alcohol (PVA) loaded with major silver components using co-electrospinnig method. Chitosan- Ag nanoparticles was synthesized using chitosan via heating prior to electrospinning. Various amounts of Silver components including Ag+, Silversulfadiazine (SSD) and Chitosan- Ag NPs were added to PVA... 

The exitance of a certain amount of halide ions including Chloride (Cl-), Bromide (Br-) and Iodide (I-) in human body is crucial for ensuring health. However, exposure to high levels of these ions can cause diseases, such as goiter and neurological disfunction. As a result, the development of a simple and efficient analytical method for determining the aforesaid halide ions is so important. Triangular silver nanoparticles (TSNPs) display wide color variations due to their tunable plasmonic properties dependent on the aspect ratio of the nanoparticles. Hence, designing a colorimetric sensor array using the optical properties of TSNPs for determination and discrimination of halide ions is of... 

Biopotential sensors are used in a wide range of biomedical applications. For example, measuring electric potentials on the surface of living tissues in electroencephalography (EEG), electromyography (EMG), and electrocardiography (ECG) systems in which the brain, muscle, and heart activities respectively are measured over time. Moreover, these electrodes are used in measuring the pH of different materials and also in receiving and recording the electric field changes of the environment. The major purpose of biopotential electrodes is to act as a transducer between the ionic transport of the tissue and the electron flow in the electrode. Such a transduction takes place due to an oxidation or... 

Electric field sensors are one of the common types of sensors that are widely used today to record changes in the electric field in underwater environments, also record pH changes in different materials. This type of sensor is inspired by the shark mucous membrane. In this study, silver / silver chloride silver (Ag / AgCl) was used for three methods of silver filtration directly in electrolyte containing chloride ion, Electrophoretic electrode method and electrode making method using silver oxide adhesive. Part of the electrodes manufacturing method involves converting part of silver into silver chloride. The made electrode has a length of 7 cm and a diameter of 0.5 mm, with its core made of... 

Due to the widespread use of pesticides and their harmful effects on humans and wildlife, monitoring their residual amounts in crops is critically essential but still challenging regarding the development of high-throughput approaches. Herein, a colorimetric sensor array has been proposed for discrimination and identification of triazole fungicides using monometallic and bimetallic silver and gold nanoparticles. Aggregation-induced behavior of AgNPs, AuNPs and Au-AgNPs in the presence of four triazole fungicides produced a fingerprint response pattern for each analyte. Pattern recognition methods, including linear discriminant analysis (LDA) and hierarchical cluster analysis, have been... 

Development of simple and rapid approaches for identification of pesticides has been known as a critical demand, due to the broad usage of pesticides and their harmful effects on mammals. Herein, we have introduced a silver nanoparticle (AgNP) based colorimetric sensor array for simultaneous identification of Azinphosmethyl (AM) and Phosalone (PS). In the presence of the target pesticides, unmodified AgNPs at various pHs (4.5, 5.5 and 9.5) showed different aggregation behaviours. As a result of aggregation, the color and UV-Vis spectra of AgNPs changed which led to distinct patterns for AM and PS. The aggregation induced spectral changes of AgNPs were used to identify AM and PS with the help... 

Silver(I) complex of [Ag2(μ-dppm)2(μ-phth)(phth)](BF4)2 (1) (dppm = bis(diphenylphosphino)methane and phth = phthalazine) has been prepared from the reaction of [Ag(CH3CN)4]BF4 with phthalazine and dppm in a 1:1 molar ratio. The structure of 1 was determined using X-ray crystallography in solid state and by multinuclear NMR spectroscopy in solution. Complex 1 shows a dynamic process including rotation of phthalazine ligand around the [Ag2(μ-dppm)2] unit wich was investigated by 1H NMR, 31P NMR and 13C NMR spectroscopy. Also, the complex 1 shows the aggregation induced emission (AIE) probably by restriction of internal motions (RIM). The trimethyl platinum(IV) complex [PtMe3(phth)3]+X- (2)... 

In this research binuclear platinum(IV) complexes with coinage metals have been synthesized and characterized. the trimethyl platinum(IV) complex [PtMe3(phthalazine)3]+X- has been prepared by the reaction of [PtMe3(THF)]4 with 3 equiv. phthalazine and used as initial material. The first complex, [PtMe3(µ-(phthalazine)2Cl)PtMe3], synthesized via reaction of 2 equiv. [Pt(Me)3(Phthalazine)3] with 1 equiv. [AuClSMe2]. The second complex, [PtMe3(µ-phthalazine)3Ag][BF4], synthesized by reaction of one equiv. of each compound [Ag(CH3CN)4]BF4 and [Pt(Me)3(Phthalazine)3] And the third complex, [PtMe3(µ-phthalazine)3Cu][PF6], synthesized like second one via reaction of [Cu(CH3CN)4]PF6 and... 

In this project, the catalytic properties of CuO and ZnO were investigated in reduction reactions.MOFs were used as a precursor to preparation of these metal oxides. Gold and silver nanoparticles were used to improve the catalytic properties of the prepared metal oxides. Structural characteristics of nanocatalysts were stydied by SEM, TEM, XRD and FT-IR techniques. The prepared nanocomposites were applied in the catalytic reduction of paranitrophenol in the presence of sodium borohydride and the kinetics and mechanism were investigated according to the structure of the prepared catalysts  

The aim of this project is the synthesis and study of the photocatalytic activity of biphasic titanium dioxide loaded with Au@Ag@Au core double shell bimetallic nanoparticles. The creation of nanostructure, utilization of hierarchical biphasic morphology, loading of light-sensitive particles, and stabilization of photocatalytic particles have enhanced the titanium dioxide photocatalytic activity via approaches of (1) sensitization to visible light, (2) separation of charge carriers produced by light irradiation and minimization of their recombination, and (3) advancing reaction and absorption of reactants by increasing quantity and quality of surface active sites. Hierarchical TiO2... 

Developing an efficient visible-light-driven photocatalyst is believed to be a practical solution for clean energy and environmental remediation. The present study aimed to broaden current knowledge of the graphitic carbon nitride (g-C3N4)-based plasmonic photocatalysts by decorating polydopamine-grafted g-C3N4 (PDA/g-C3N4) with silver nanoparticles (AgNPs). The ternary nanocomposite was prepared using a facile synthesis method, while XPS and electron microscopy measurements confirmed the homogenous dispersion of AgNPs on PDA/g-C3N4. It was revealed that AgNPs successfully reduced the recombination rate of photoinduced electron-hole charge carriers. The calculated bandgap energy was... 

This study was performed to synthesize Ag-doped TiO2 nanotubes and investigate the antibacterial property of the nanostructure. In the first step, self-organized TiO2 nanotubes were fabricated through anodizing in an electrolyte containing 0٫3 Wt% NH4F, 0٫2٪V DI water and ethylene glycol. Anodizing was performed in 30 and 60V for 2hrs in order to have different nanotube diameters. In the second step, photoreduction process was done on the way to dope Ag nanoparticles on the nanotubes. Herein, AgNO3 solution concentration, time period of TiO2 nanotubes soaking in the solution, time period of UV irradiation and ethanol solution concentration were taken as factors to achieve Ag nanoparticles in... 

In this study, silver nanoparticles (Ag NPs) with different morphologies were synthesize by physical and chemical methods. Spherical silver nanoparticles were synthesized by electro magnetic levitation melting approach, while silver nanoplates and nanorods were prepared by chemical reduction route. Ag NPs were then coated with thin porous silica shell. The dissolution behavior of synthesized Ag@SiO2 was investigated in PBS at 25, 37 and 55 °C. Spherical and triangular Ag@SiO2 were conjugated by Penicillin G molecules. The silver and penicillin contents of the synthesized nano-antibiotics were determined by ICP-OES and TGA analyses. The nanoparticles were characterized by X-ray diffraction...