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    Hybrid nano-adsorbent supported carbon dots for removal of chromium from aqueous solution

    , Article Desalination and Water Treatment ; Volume 103 , 2018 , Pages 221-231 ; 19443994 (ISSN) Eslami, A ; Borghei, S. M ; Rashidi, A ; Takdastan, A ; Sharif University of Technology
    Desalination Publications  2018
    In this study, hybrid nano adsorbent supported carbon dots was prepared and used for removing Cr(VI) from aqueous solution. Carbon dots were synthesized from sugarcane molasses under microwave irradiation. Hybrid nano adsorbent was prepared by impregnating carbon dot with H3PO4 in a ratio of 2:1 and introducing 0.01 M FeCl3 into the slurry. The carbon dot hybrid was activated via a conventional thermal method under N2 flow. The physico-chemical properties of the synthesized material were investigated using X–ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption/desorption, and field emission scanning electron microscopy (FESEM). Chromium adsorption was studied... 

    Wide color-varying visualization of sulfide with a dual emissive ratiometric fluorescence assay using carbon dots and gold nanoclusters

    , Article Microchemical Journal ; Volume 157 , September , 2020 Farahmand Nejad, M. A ; Bigdeli, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier Inc  2020
    Development of visual detection methods regarding water pollutants can effectively facilitate water resource monitoring programs. A wide color-varying ratiometric approach has been developed for sensitive determination of sulfide by mixing orange emissive glutathione stabilized gold nanoclusters (AuNCs) and blue emissive urea stabilized carbon dots (CDs) in an appropriate ratio. Under a single excitation wavelength of 365 nm, the ratiometric fluorescence (RF) probe exhibited two distinct emission bands at 452 and 607 nm corresponding to CDs and AuNCs, respectively. Owing to the high affinity of sulfide ions to AuNCs in alkaline medium, the fluorescence (FL) of AuNCs was turned-off while the... 

    Controlling Amyloid Formation Using Novel Carbon Based Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Yahyazadeh, Amin (Author) ; Kalhor, Hamid Reza (Supervisor)
    Proteins carry out most important roles in the organisms and they have a number of functions including structural, catalytically, regulatory and transportal, However for protein to have functional role they must be able to possess tridimensional structure. Several proteins due to various genetic and physico-chemical conditions have shown to alter their tridimensional structure leading to insoluble fibrilar structure. One of the properties of these insoluble fibrils is conformational change, converting to β-sheet rich structures; the entire process of converting soluble to proteins insoluble fibrils known as amyloid formation. The proteins amyloidosis have been seen as causative role in a... 

    Synthesis of S- and N-doped Carbon Quantum Dots

    , M.Sc. Thesis Sharif University of Technology Minagar, Ava (Author) ; Madah Hosseini, Hamid Reza (Supervisor)
    In recent years, adjustable optical properties, simple and inexpensive synthesis, and excellent biocompatibility of carbon dots have attracted much attention. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission or excitation in the red or near-infrared region. Studies have shown that doping in carbon dots can affect the displacement and increase the light intensity. This study aims to use the engineering methods of optical properties of carbon points by doping heteroatoms and adjusting the surface state to synthesize biocompatible carbon dots with luminescence at long wavelengths with strong... 

    Investigating Process Factors on Red-shift of Photoluminescence of Carbon Dots

    , M.Sc. Thesis Sharif University of Technology Feghhi, Fazeleh (Author) ; Madah Hosseini, Hamid Reza (Supervisor)
    In recent years, studies in luminescent carbon dots are overgrowing, the prominent features of carbon quantum dots include cheap and straightforward synthesis, excellent biocompatibility, and adjustable optical properties. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region.. However, the widespread use of carbon dots in biomedical diagnostics, photoluminescence, and photocatalysis has been limited due to a lack of emission and excitation in the red or near-infrared region. This research tried to produce carbon dots with redshift in emission... 

    Synthesis of Modified Nanocomposite Based on Metal Organic Frameworks for Kinetic Study of Environmental Pollutant Elimination

    , M.Sc. Thesis Sharif University of Technology Shahsavari, Shayan (Author) ; Gholami, Mohammad Reza (Supervisor)
    An environmentally friendly heterogeneous ternary carbon dots (CDs)/MIL-88B (Fe)/Bi2S3 nanocomposite was synthesized by a multistep method. In this study, we have studied low-temperature calcination with relatively inexpensive reactants. Fabricated nanocomposite structures were characterized by FT-IR, XRD, EIS, SEM, BET, and TGA techniques, demonstrating the decoration of the Bi2S3 on the CDs/MIL-88B (Fe) nanocomposite surface. MOF templating has been chosen as a systemic method for limited size CD formation inside MIL-88B (Fe) pores. The CD arrays also revealed an excellent efficacy for catalytic and photocatalytic applications. According to the experimental results, CDs/MIL-88B (Fe)/Bi2S3... 

    Smartphone-based portable device for rapid and sensitive pH detection by fluorescent carbon dots

    , Article Sensors and Actuators A: Physical ; Volume 332 , 2021 ; 09244247 (ISSN) Ehtesabi, H ; Asadollahi, A ; Hallaji, Z ; Goudarzi, M ; Rezaei, A ; Sharif University of Technology
    Elsevier B.V  2021
    In the past few years, most studies have focused on smart substances that can respond to changes in the environment, as they can be appropriately applied in different fields, including biosensing, biotechnology, and drug delivery. Here, new fluorescent carbon dots (CDs) are synthesized by Terebinth by designing a simple and single-stage hydrothermal path, which facilitates the manufacture of CDs with no need for boring artificial methods, or using poisonous/costly solvents and starting substances. The method is used to concurrently form CDs and passivate their surface, which results in inherently emitted fluorescence. The study of the structure and optical features of the resulting CDs... 

    Developments of Fluorescence Sensor Arrays Using Nanostructured Sensor Elments and Nanocellulose Substrate for Identification and Discrimination of Biomolecules and Environmental pollutants

    , Ph.D. Dissertation Sharif University of Technology Abbasi-Moayed, Samira (Author) ; Hormozi-Nezhad, Mohammad Reza (Supervisor) ; Golmohammadi Ghaneh, Hamed (Co-Supervisor)
    In the first part of this research, a ratiometric fluorescent sensor array has been developed on nanocellulose platform towards chemical discrimination applications. Bacterial nanocellulose (BC) was utilized for the first time as a novel, flexible and transparent substrate in optical sensor arrays for developing portable and high performance sensor array.. To fabricate this platform, the hydrophobic walls on BC nanopaper substrates were successfully created using laser printing technology. In addition, we have used the properties of immobilized ratiometric fluorescence sensor elements (Carbon Dots- Rhodamine B (CDs-RhB) nanohybrids) on nanopaper platform to improve the visual... 

    Development of Ratiometric Sensors Based on Fluorescent Nanostructures for Naked Eye Detection

    , Ph.D. Dissertation Sharif University of Technology Farahmand Nejad, Mohammad Amin (Author) ; Hormozi-Nezhad, Mohammad Reza (Supervisor)
    In the first part of this research, we have developed a simple and effective ratiometric fluorescence sensor for selective detection of dopamine (DA) in alkaline media by simply mixing thioglycolic acid (TGA) functionalized orange fluorescent cadmium telluride (CdTe) quantum dots (QDs) with amino-functionalized blue fluorescent carbon nanodots (CDs). Under a single excitation wavelength of 365 nm, the sensor exhibits dual-emissions centered at 445 and 603 nm. The fluorescence of CdTe QDs is selectively quenched by DA, whereas the fluorescence of CDs is insensitive to the analyte. In the presence of different amounts of DA, the variations in the dual emission intensity ratios exhibit a... 

    Fabrication of Magnetic Halloysite-Supported Catalyst for Reduction of Organic Dyes in Water

    , M.Sc. Thesis Sharif University of Technology Latifipour, Mostafa (Author) ; Kazemeini, Mohammad (Supervisor) ; Sadjadi, Samaheh (Supervisor)
    A new magnetic catalytic nanocomposite of Hal-MT-Cys-Ag/MNCD was fabricated and utilized for catalyzing reductive de-colorization of methyl orange and rhodamin B in aqueous media at room temperature. To prepare this material, Cl-functionalized halloysite nanoclay was successively reacted with melamine and 2,4,6-trichloro-1,3,5-triazine to furnish multi-nitrogen containing ligand on halloysite surface. Then, magnetic carbon dots were crafted through a facile method and decorated with Ag nanoparticles and cysteine to furnish Cys-Ag/MNCD species. The final nanocomposite was obtained via incorporation of this latter species onto functionalized halloysite. This was characterized through the XRD,... 

    Designing a Ratiometric Probe for Naked Eye Detection of Hydrogen Peroxide

    , M.Sc. Thesis Sharif University of Technology Mohammadpour, Fatemeh (Author) ; Hormozinezhad, Mohammad Reza (Supervisor)
    Hydrogen peroxide (H2O2) is of great importance in numerous fields such as pharmaceuticals, mining, textile, environmental and food industry. Therefore, the development of low cost, on-site, and uncomplicated H2O2 sensors are of high interest. To date, colloidal quantum dots (QDs) have been used to detect H2O2 based on the quenching of fluorescence intensity in a single wavelength. However, intensity of fluorescent signal could be easily disturbed by various factors. To overcome these undesirable effects, here, a ratiometric sensor has been developed by adding a second fluorophore (as reference) to QDs. For this purpose TGA-capped CdTe QDs were prepared. To detect H2O2, the ratiometric... 

    Turn-off chelation-enhanced fluorescence sensing of carbon dot-metallic deep eutectic solvent by imidazole-based small molecules

    , Article Sensors and Actuators B: Chemical ; Volume 344 , 2021 ; 09254005 (ISSN) Manshaei, F ; Bagheri, H ; Es-haghi, A ; Sharif University of Technology
    Elsevier B.V  2021
    Low accuracy, requirement of expensive instruments, derivatization and multi-step sample preparation, inconsistencies during the fabrication process, time-consuming procedures and utilization of eco-unfriendly chemicals are some limitations of various developed methods for detection of 4-methylimidazol (4-MeI). Herein, a rapid and miniaturized fluorescent probe based on the ultrasound‒assisted formation of carbon dots (CDs) in a metallic deep eutectic solvent (MDES) was developed and conveniently implemented to detect 4-MeI in commercial dark soft drinks. In-situ synthesis of CDs-chelated metals in the presence of the target analyte facilitates a kinetically fluorescence emission with no... 

    Preparation of activated carbon dots from sugarcane bagasse for naphthalene removal from aqueous solutions

    , Article Separation Science and Technology (Philadelphia) ; Volume 53, Issue 16 , 2018 , Pages 2536-2549 ; 01496395 (ISSN) Eslami, A ; Borghei, S. M ; Rashidi, A ; Takdastan, A ; Sharif University of Technology
    Taylor and Francis Inc  2018
    The synthesis of cheap and environmental friendly adsorbent from residual sugarcane bagasse was done for the removal of naphthalene from aqueous solution. The activated carbon dot was obtained by KOH chemical activation of carbon dots. The characteristics of carbon dots and activated carbon dots were determined using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetric analysis. A series of experiments were conducted in a batch system to assess the effect of the system variables, i.e., initial pH, initial naphthalene concentration, adsorbent dosage, and contact time. The kinetic data showed better fit to the... 

    A new strategy to design colorful ratiometric probes and its application to fluorescent detection of Hg(II)

    , Article Sensors and Actuators, B: Chemical ; Volume 259 , 2018 , Pages 894-899 ; 09254005 (ISSN) Ghasemi, F ; Hormozi Nezhad, M. R ; Mahmoudi, M ; Sharif University of Technology
    Elsevier B.V  2018
    A new strategy has been proposed to expand color-tunability of ratiometric fluorescent probes. It was shown that the combination of blue emissive color (as an internal standard) and yellow emissive color (as a probe) is an efficient way to create an extensive color range in ratiometric probes. However, due to the nature of the interaction between the analyte and the probe in terms of fluorescence quenching, occurance of the redshift in the emission is the major provision of such a probe. Our developed ratiometric fluorescence probe consists of blue emissive carbon dots (BCDs) and thioglycolic acid (TGA)-capped yellow emissive cadmium telluride (CdTe) quantum dots (YQDs). The ratiometric... 

    Determination and identification of nitroaromatic explosives by a double-emitter sensor array

    , Article Talanta ; Volume 201 , 2019 , Pages 230-236 ; 00399140 (ISSN) Ghasemi, F ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier B.V  2019
    Detection of nitroaromatic explosives is of strong concern because of human health, public safety, environment, and military issues. In this study, we present a ratiometric sensor array for detection and discrimination of widely-used nitroaromatics (i.e., 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol (TNP), and 2,4-dinitrotoluene (DNT)). In the design of sensor elements (SE) we employ blue emissive carbon dots (BCDs) in combination with yellow (SE-A) and red (SE-B) emissive cadmium telluride quantum dots (CdTe QDs). The fluorescence intensity of BCDs, YQDs, and RQDs is quenched by TNT, DNT, and TNP in various degrees. Both TNT and TNP cause the quenching and spectral shift of BCDs (TNT...