Search for: synthesis-conditions
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    Influence of polyaniline synthesis conditions on its capability for removal and recovery of chromium from aqueous solution

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 30, Issue 3 , 2011 , Pages 97-100 ; 10219986 (ISSN) Riahi Samani, M ; Borghei, S. M ; Olad, A ; Chaichi, M. J ; Sharif University of Technology
    Absorptive characteristics of polyaniline synthesized in different solvents were studied. Water and mixture of water with other solvents were implemented for polyaniline synthesis. Synthesized polyanilines in powder shape is used as an adsorbent to remove toxic hexavalent chromium from aqueous solutions. Experiments were conducted in batch mode. Removal mechanism involving polyaniline is the combination of surface adsorption and reduction. The kind of solvent used at synthesizing stage can affect the capacity of produced polyanilines for removal of heavy metals including chromium. Synthesized polyaniline in water had the maximum chromium removal efficiency. The morphology study of... 

    The control of morphological and size properties of carbamazepine-imprinted microspheres and nanospheres under different synthesis conditions

    , Article Journal of Materials Research ; 2013 ; 08842914 (ISSN) Esfandyari Manesh, M ; Javanbakht, M ; Shahmoradi, E ; Dinarvand, R ; Atyabi, F ; Sharif University of Technology
    Potential applications of the molecularly imprinted polymers (MIPs) demand physical configurations in different size ranges. Nowadays, research on MIPs is focused on the development of new or improved morphologies, which involves control and modification of the different parameters during the synthesis. In this study, the effect of different synthesis conditions on the particle size and morphology is investigated. Carbamazepine-imprinted polymers were prepared using precipitation polymerization under various conditions such as: the amounts of cross-linker and functional monomers, initiator, porogen, temperature and time of polymerization. We studied the polymerization conditions to obtain... 

    Speech synthesis based on gaussian conditional random fields

    , Article Communications in Computer and Information Science ; Vol. 427, issue , 2014 , p. 183-193 Khorram, S ; Bahmaninezhad, F ; Sameti, H ; Sharif University of Technology
    Hidden Markov Model (HMM)-based synthesis (HTS) has recently been confirmed to be the most effective method in generating natural speech. However, it lacks adequate context generalization when the training data is limited. As a solution, current study provides a new context-dependent speech modeling framework based on the Gaussian Conditional Random Field (GCRF) theory. By applying this model, an innovative speech synthesis system has been developed which can be viewed as an extension of Context-Dependent Hidden Semi Markov Model (CD-HSMM). A novel Viterbi decoder along with a stochastic gradient ascent algorithm was applied to train model parameters. Also, a fast and efficient parameter... 

    Controlled growth of hollow polyaniline structures: From nanotubes to microspheres

    , Article Polymer (United Kingdom) ; Volume 54, Issue 21 , 2013 , Pages 5586-5594 ; 00323861 (ISSN) Pirhady Tavandashti, N ; Ghorbani, M ; Shojaei, A ; Sharif University of Technology
    Homogeneous and fairly monosized microspherical structures of polyaniline has been synthesized using a simple soft template method with β-naphthalene sulfonic acid (β-NSA) as both the surfactant and dopant, and ammonium persulfate (APS) as the oxidant at 2-5 C. The morphology of PANI-NSA was successfully controlled from nanotubes to microsphere, by changing the synthesis conditions (i.e. pH, the concentration of surfactant and monomer, and temperature). Some mechanistic aspects of the formation of nanotubes and hollow spheres have been discussed precisely based on SEM, TEM, DLS, FTIR and UV-visible results. Moreover, synthesis was performed under acidic environment to obtain further... 

    Synthesis and characterization of polyamide membrane for the separation of acetic acid from water using RO process

    , Article Membrane Water Treatment ; Volume 8, Issue 4 , 2017 , Pages 323-336 ; 20058624 (ISSN) Mirfarah, H ; Mousavi, S. A ; Mortazavi, S. S ; Sadeghi, M ; Bastani, D ; Sharif University of Technology
    Techno Press  2017
    The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute... 

    Effect of synthesis conditions on performance of a hydrogen selective nano-composite ceramic membrane

    , Article International Journal of Hydrogen Energy ; Volume 37, Issue 20 , October , 2012 , Pages 15359-15366 ; 03603199 (ISSN) Amanipour, M ; Safekordi, A ; Ganji Babakhani, E ; Zamaniyan, A ; Heidari, M ; Sharif University of Technology
    Elsevier  2012
    A hydrogen-selective nano-composite ceramic membrane was prepared by depositing a dense layer composed of SiO2 and Al2O 3 on top of a graded multilayer substrate using co-current chemical vapor deposition (CVD) method. The multilayer substrate was made by dip-coating a macroporous α-alumina tubular support by a series of boehmite solutions to get a graded structure. Using DLS analysis, it was concluded that decreasing hydrolysis time and increasing acid concentration lead to smaller particle size of boehmite sols. XRD analysis was carried out to investigate the structure of intermediate layer and an optimized calcination temperature of 973 K was obtained. SEM images indicated the formation... 

    Key parameters in hydrothermal synthesis and characterization of low silicon content SAPO-34 molecular sieve

    , Article Microporous and Mesoporous Materials ; Volume 126, Issue 1-2 , 2009 , Pages 1-7 ; 13871811 (ISSN) Izadbakhsh, A ; Farhadi, F ; Khorasheh, F ; Sahebdelfar, S ; Asadi, M ; Yan, Z. F ; Sharif University of Technology
    Low silicon content SAPO-34 was successfully synthesized using the conventional hydrothermal crystallization in the static condition. Effects of different synthesis conditions including crystallization temperature and the silicon source were investigated through X-ray diffraction patterns. It was concluded that the silicon source had a significant effect on silicon incorporation into the alumino-phosphate building blocks in the course of crystallization. Using precipitated silica instead of silica sol resulted in the formation of impurities of alumino-phosphates phases whose crystalline structures collapse at the high temperature of calcination. For the low silicon SAPO-34 synthesis, the... 

    Synthesis and swelling behavior of a new superabsorbent hydrogel network based on polyacrylamide grafted onto salep

    , Article Journal of Applied Polymer Science ; Volume 112, Issue 5 , 2009 , Pages 2625-2633 ; 00218995 (ISSN) Pourjavadi, A ; Rezanejade Bardajee, G ; Soleyman, R ; Sharif University of Technology
    Synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with Polyacrylamide is described. The new superabsorbent hydrogel biopolymer was synthesized via radical crosslink-ing and graft copolymerization of acrylamide monomer onto salep backbones. Regarding to the water absorption of hydrogel, the best synthesis condition is reported. FTIR spectroscopy and thermogravimetric analysis were used to confirm the structure of the final product and a mechanism for superabsorbent hydrogel formation was also suggested. After preparing the desired hydrogels based on optimum condition, several factors affecting the swelling behavior of hydrogel including pH of...