The Experts below are selected from a list of 9990 Experts worldwide ranked by ideXlab platform
Meiping Tong - One of the best experts on this subject based on the ideXlab platform.
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Efficient bacteria capture and inactivation by Cetyltrimethylammonium Bromide modified magnetic nanoparticles
Colloids and Surfaces B: Biointerfaces, 2015Co-Authors: Yinjia Jin, Jialiang Liang, Chao Shan, Jun Deng, Meiping TongAbstract:Functionalized magnetic nanoparticles have shown great application potentials in water treatment processes especially for bacterial removal. Antibacterial agent, Cetyltrimethylammonium Bromide (CTAB), was employed to modify Fe3O4nanoparticles to fabricate bactericidal paramagnetic nanoparticles (Fe3O4@CTAB). The as-prepared Fe3O4@CTAB could effectively capture both Gram-negative Escherichia coli and Gram-positive Bacillus subtilis from water. For both cell types, more than 99% of bacteria with initial concentration of 1.5×107CFU/mL could be inactivated by Fe3O4@CTAB (0.5g/L) within 60min. Fe3O4@CTAB could remove more than 99% of cells over a wide pH (from 3 to 10) and solution ionic strength range (from 0 to 1000mM). The copresence of sulfate and nitrate did not affect the bacterial capture efficiencies, whereas, phosphate and silicate slightly decreased the bacterial removal rates. However, more than 91% and 81% of cells could be captured at 10mM of phosphate and silicate, respectively. Over 80% of cells could be removed even in the presence of 10mg/L of humic acid. Moreover, Fe3O4@CTAB exhibited good reusability, and greater than 83% of cells could be captured even in the fifth regeneration cycle. Fe3O4@CTAB prepared in this study have great application potentials for water disinfection.
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removal of arsenate by Cetyltrimethylammonium Bromide modified magnetic nanoparticles
Journal of Hazardous Materials, 2012Co-Authors: Meiping TongAbstract:Abstract Cetyltrimethylammonium Bromide (CTAB) modified magnetic nanoparticles (Fe 3 O 4 @CTAB) were synthesized and used to remove arsenate from water. Fe 3 O 4 @CTAB was prepared by a modified simple co-precipitation process with cheap and environmental friendly iron salts and cationic surfactant CTAB. Powder X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infra-red spectroscopy were utilized to characterize the prepared adsorbent (Fe 3 O 4 @CTAB). Transmission electron microscopy (TEM) image showed that Fe 3 O 4 @CTAB particles were approximately spherical with the core size of 10 nm. With a saturation magnetization of 67.2 emu g −1 , the Fe 3 O 4 @CTAB nanoparticles could be easily separated from solutions with a simple magnetic process in very short time (within 5 min). Adsorption of arsenate on Fe 3 O 4 @CTAB reached equilibrium within 2 min at pH 6. Arsenate adsorption agreed well with pseudo-second order kinetic model and two-site Langmuir isotherm model with the arsenate adsorption capacity of 23.07 mg g −l , which was twice greater than that of pure Fe 3 O 4 . Arsenate removal rate was over 90% at a wide pH range from 3 to 9 and the removal of arsenate was not obviously affected by the presence of dissolved natural organic matter (up to 10 mg L −1 as TOC) and competitive anions (sulfate, bicarbonate, and silicate up to 20 mg L −1 , and phosphate up to 5 mg L −1 ) in solutions. Fe 3 O 4 @CTAB could be regenerated in alkali solutions and more than 85% As(V) was removed even in fifth regeneration/reuse cycle.
Abdullah Y Obaid - One of the best experts on this subject based on the ideXlab platform.
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shape directing role of Cetyltrimethylammonium Bromide in the preparation of silver nanoparticles
Journal of Colloid and Interface Science, 2012Co-Authors: Zaheer Khan, Shaeel A Althabaiti, Abdullah Y Obaid, Ziya Ahmad Khan, Abdulrahman O AlyoubiAbstract:Abstract We report a simple chemical reduction method for the synthesis of different colored silver nanoparticles, AgNP, using tyrosine as a reducing agent. Effects of Cetyltrimethylammonium Bromide, CTAB, and tyrosine concentrations are analyzed by UV–visible measurements and scanning electron microscopy (SEM) to evaluate the mode of AgNP aggregation. The position and shape of the surface resonance plasmon absorption bands strongly depend on the reaction conditions, i.e., [CTAB], [tyrosine], and reaction time. Sub-, post-, and dilution-micellar effects are accountable for the fast and slow nucleation and growth processes. Spectrophotometric measurement also shows that the average size and the polydispersity of AgNP increase with [CTAB] in the solution. CTAB acted as a shape-directing agent.
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effect of macromolecule poly vinyl alcohol on the growth of Cetyltrimethylammonium Bromide stabilized ag nanoparticles
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009Co-Authors: Zaheer Khan, Shaeel Ahmad Altnabaiti, E H Elmossalamy, Abdullah Y ObaidAbstract:Abstract The kinetics of Cetyltrimethylammonium Bromide stabilized silver nanoparticles was studied spectrophotometrically in the absence and presence of poly(vinyl alcohol) (PVA). Silver nanoparticles were prepared in aqueous solution using silver nitrate and cysteine as oxidant and reductant, respectively. Size and the distribution of the particles were determined by transmission electron microscopy. Silver nanoparticles were spherical, aggregated, cross-linking and of uniform particle size (the average particle size was about 30 and 7 nm in absence and presence of PVA, respectively). At higher concentration of PVA, the formation of silver sol was not observed for a certain reaction time, i.e., 200 min. Silver sol formation follows zero-order kinetics with respect to [Ag + ]. Viscosity of the CTAB-PVA mixture was also determined. A mechanism that involves simultaneous formation of cysteine–Ag complex has been proposed.
Erkang Wang - One of the best experts on this subject based on the ideXlab platform.
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synthesis and self assembly of Cetyltrimethylammonium Bromide capped gold nanoparticles
Langmuir, 2003Co-Authors: Wenlong Cheng, Shaojun Dong, Erkang WangAbstract:In this article, Cetyltrimethylammonium Bromide (CTAB)-capped gold nanoparticles were synthesized successfully by using CTAB as a phase-transfer catalyst and stabilizer simultaneously in a two-phase toluene/water system. The as-prepared gold nanoparticles were characterized and analyzed by virtue of X-ray photoelectron spectroscopy, UV−visible absorbance spectroscopy, and infrared spectroscopy. The particle size information and collective self-assembling properties of the CTAB-capped gold nanoparticles on carbon-coated copper grid and mica were evaluated by transmission electron microscopy and atomic force microscopy, respectively. As a result, it is demonstrated that the 3-D CTAB monolayers on a gold cluster are in the disordered liquid state. The interparticle spacing can be controlled either physically by the inherent particle-to-particle interactions or chemically by molecular linker. The assembly of both nanoparticles and linker-bridged nanonetworks on mica follows a hydrophobic interaction mechanism.
Zaheer Khan - One of the best experts on this subject based on the ideXlab platform.
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shape directing role of Cetyltrimethylammonium Bromide in the preparation of silver nanoparticles
Journal of Colloid and Interface Science, 2012Co-Authors: Zaheer Khan, Shaeel A Althabaiti, Abdullah Y Obaid, Ziya Ahmad Khan, Abdulrahman O AlyoubiAbstract:Abstract We report a simple chemical reduction method for the synthesis of different colored silver nanoparticles, AgNP, using tyrosine as a reducing agent. Effects of Cetyltrimethylammonium Bromide, CTAB, and tyrosine concentrations are analyzed by UV–visible measurements and scanning electron microscopy (SEM) to evaluate the mode of AgNP aggregation. The position and shape of the surface resonance plasmon absorption bands strongly depend on the reaction conditions, i.e., [CTAB], [tyrosine], and reaction time. Sub-, post-, and dilution-micellar effects are accountable for the fast and slow nucleation and growth processes. Spectrophotometric measurement also shows that the average size and the polydispersity of AgNP increase with [CTAB] in the solution. CTAB acted as a shape-directing agent.
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effect of macromolecule poly vinyl alcohol on the growth of Cetyltrimethylammonium Bromide stabilized ag nanoparticles
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009Co-Authors: Zaheer Khan, Shaeel Ahmad Altnabaiti, E H Elmossalamy, Abdullah Y ObaidAbstract:Abstract The kinetics of Cetyltrimethylammonium Bromide stabilized silver nanoparticles was studied spectrophotometrically in the absence and presence of poly(vinyl alcohol) (PVA). Silver nanoparticles were prepared in aqueous solution using silver nitrate and cysteine as oxidant and reductant, respectively. Size and the distribution of the particles were determined by transmission electron microscopy. Silver nanoparticles were spherical, aggregated, cross-linking and of uniform particle size (the average particle size was about 30 and 7 nm in absence and presence of PVA, respectively). At higher concentration of PVA, the formation of silver sol was not observed for a certain reaction time, i.e., 200 min. Silver sol formation follows zero-order kinetics with respect to [Ag + ]. Viscosity of the CTAB-PVA mixture was also determined. A mechanism that involves simultaneous formation of cysteine–Ag complex has been proposed.
Wenlong Cheng - One of the best experts on this subject based on the ideXlab platform.
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synthesis and self assembly of Cetyltrimethylammonium Bromide capped gold nanoparticles
Langmuir, 2003Co-Authors: Wenlong Cheng, Shaojun Dong, Erkang WangAbstract:In this article, Cetyltrimethylammonium Bromide (CTAB)-capped gold nanoparticles were synthesized successfully by using CTAB as a phase-transfer catalyst and stabilizer simultaneously in a two-phase toluene/water system. The as-prepared gold nanoparticles were characterized and analyzed by virtue of X-ray photoelectron spectroscopy, UV−visible absorbance spectroscopy, and infrared spectroscopy. The particle size information and collective self-assembling properties of the CTAB-capped gold nanoparticles on carbon-coated copper grid and mica were evaluated by transmission electron microscopy and atomic force microscopy, respectively. As a result, it is demonstrated that the 3-D CTAB monolayers on a gold cluster are in the disordered liquid state. The interparticle spacing can be controlled either physically by the inherent particle-to-particle interactions or chemically by molecular linker. The assembly of both nanoparticles and linker-bridged nanonetworks on mica follows a hydrophobic interaction mechanism.