Sharif Digital Repository

Degradation of Clindamycin phosphate (CMP) was studied in aqueous solutions by an anodic oxidation process under galvanostatic conditions. The electrolysis cell consisted of a Ti/SnO2-Sb anode, prepared by dip-coating technique, and a 316 stainless steel cathode, both of which had a surface area of 6 cm2. The effects of critical factors, including CMP concentration, current density, initial pH, and the supporting electrolyte were evaluated. The electrochemical oxidation of CMP was controlled by mass transport within the studied range. The kinetic analysis indicated that the degradation reactions followed pseudo-first-order equation. The rate of CMP decay, as well as that of COD removal,... 

In the present study, the ACF-TiO2 catalyst was synthesised and used as a catalyst for the destruction of toxic cyanide in both synthetic and real industrial wastewaters. The ACF-TiO2 catalyst was found to be micro-porous with the BET surface area of 163 m2/g. The effect of different operational parameters such as catalyst concentration, cyanide concentration, operation time, and ozone concentration were target parameters in the present study. The findings show that 500 mg/L of catalyst is the optimum value for the photocatalytical process to completely oxidise 25 mg/L of cyanide within 10 min. While it was found that 300 mg/L of catalyst in the presence of 200 mg/h ozone is enough to remove... 

In the present study, the ACF-TiO2 catalyst was synthesised and used as a catalyst for the destruction of toxic cyanide in both synthetic and real industrial wastewaters. The ACF-TiO2 catalyst was found to be micro-porous with the BET surface area of 163 m2/g. The effect of different operational parameters such as catalyst concentration, cyanide concentration, operation time, and ozone concentration were target parameters in the present study. The findings show that 500 mg/L of catalyst is the optimum value for the photocatalytical process to completely oxidise 25 mg/L of cyanide within 10 min. While it was found that 300 mg/L of catalyst in the presence of 200 mg/h ozone is enough to remove... 

A novel ɑ-NiMoO4/ɑ-MoO3 binary nanocomposite was fabricated by using facile method. The fabricated nanocomposite was characterized by various techniques, and the photocatalytic activity was evaluated in degradation of Acid blue 92 dye. Among of as-made photocatalysts with various weight ratios of ɑ-MoO3, ɑ-NiMoO4/ɑ-MoO3 (1:5%w/w) exhibited the best photocatalytic performance, and selected as optimum photocatalyst. Under optimum reaction conditions ([dye] = 10 mg L−1, [catalyst] = 200 mg L−1, and pH = 7.0), complete removal efficiency was obtained within 100 min. Also, the first-order rate constant value of reaction in the presence of ɑ-NiMoO4/ɑ-MoO3 was calculated to be 0.032 min−1 that was... 

The simultaneous oxidation performance of benzene, toluene, ethylbenzene, and xylene (BTEX) by nanoscale calcium peroxide particles (nCaO2) activated with ferric ions (Fe(III)) and the mechanism of the enhancement of BTEX degradation by L-cysteine (L-cys) were investigated. The batch experimental results showed that the nCaO2/Fe(III)/L-cys process was effective in the destruction of BTEX in both ultrapure water and actual groundwater. A proper amount of L-cys could enhance BTEX degradation due to the promotion of Fe(II)/Fe(III) redox cycles by the participation of L-cys, but an excessive presence of L-cys would cause inhibition. Adding 1.0 mM L-cys to the nCaO2/Fe(III) system, the... 

The effect of oxygenate modifiers on the performance of PtSnγAl 2O3 catalyst in dehydrogenation of propane was studied. Dehydrogenation reaction was carried out in a fixed-bed quartz reactor in the temperature range of 575620 °C. Two types of oxygenate modifiers, namely water and methanol, were added to the feed. The optimum amounts of water for reaction temperatures of 575, 600 and 620 °C were 84, 120 and 140 ppm, respectively. The optimum amounts of methanol for the same reaction temperatures were 9.9, 25 and 50 ppm, respectively. Any further addition of water or methanol beyond these optimum levels resulted in a loss in activity. The addition of water or methanol led to the formation of... 

Herein, a novel quaternary Ag3PO4/BiPO4@MIL-88B(Fe)@g-C3N4 (AB@MIL-88B(Fe)@g-CN) nanocomposite with a core@shell structure is successfully fabricated in two simple steps. The prepared samples are characterized via various techniques. The photocatalytic activity of the prepared samples is evaluated by the degradation of navy Acid Blue 92 (AB92) dye as an organic pollutant under visible light irradiation. Highly enhanced photocatalytic efficiency is observed for the quaternary AB@MIL-88B(Fe)@g-CN nanocomposite compared to that for the other samples. The experimental results indicate that the photocatalytic activity enhancement is mainly attributed to the strong visible light absorption and... 

According to current researches, graphene oxide (GO) membranes show promising desalination properties due to ease of synthesis, low production cost, and high efficiency. There are several experimental works to study ionic sieving properties of GO membranes. However, it is difficult to characterize atomistic mechanism of water permeation and ion rejection by experimental approaches. On the other hand, there exist a few reports in which the atomistic picture of water permeation across GO membranes is investigated by means of molecular dynamics (MD) simulation. In the present work, in addition to water desalination, the atomic scale mechanism of ion rejection is studied using large scale MD... 

This research aimed to prepare a recoverable sonophotocatalyst, in which microfibrillated carboxymethyl cellulose (MFC) acted as the Zn-Cu-Mg-mixed metal hydroxide/graphitic carbon nitride (MMH/g-C3N4) carrier. The characteristics of bare and composite sonophotocatalysts were analyzed by the XRD, FT-IR, BET, DRS, PL and FE-SEM equipped with the EDX mapping. The performance of prepared composites (MMH/g-C3N4@MFC) with various weight ratios of the MMH/g-C3N4 was studied for the sonophotocatalytic degradation of sulfadiazine (SDZ) as the model emerging contaminant. 93% of SDZ was degraded using the most effective catalyst (MMH/g-C3N4@MFC3) with 15% weight ratio of the MMH/g-C3N4 under the... 

Purpose: This paper aims to study peroxymonosulfate (PMS) activation in the ultraviolet (UV)/ozone process for toxic cyanide degradation from aqueous solution by a novel and simple method. Design/methodology/approach: Photocatalytic degradation of cyanide (CN-) was carried out using a bench-scale photoreactor. Optimization of the UV/ozone process for the highest removal of cyanide was obtained. The effect of parameters such as ozone concentration, PMS concentration, temperature, cations (Cu2+, Co2+ and Fe2+), cyanide concentration, anions (bicarbonate, carbonate, chloride, nitrite, nitrate and sulfate [SO42−]) and scavengers (ethanol [EtOH], humic acid, TBA and NaN3) was investigated for CN-... 

We present the first density functional theory study on α-ketoglutarate dependent halogenase and focus on the mechanism starting from the iron(IV)-oxo species. The studies show that the high-valent iron(IV)-oxo species reacts with substrates via an initial and rate determining hydrogen abstraction that is characterized by a large kinetic isotope effect (KIE) of 26.7 leading to a radical intermediate. This KIE value is in good agreement with experimental data. The reaction proceeds via two-state reactivity patterns on competing quintet and septet spin state surfaces with close lying hydrogen abstraction barriers. However the septet spin radical intermediate gives very high barriers for... 

A conic body packed bed reactor, internally irradiated with a UV-C lamp and equipped with circulating upflow stream was employed to investigate the decomposition of a widely used azo dye, direct red 16, in water. The synthesized nanostructure TiO 2 photocatalyst particles were immobilized on the surface of transparent Raschig ring packings. Solutions with initial concentration of 30 mg L -1 of dye, within the range of typical concentration in textile waste waters, were treated under the mild operating conditions of natural pH of 6.75 and temperature of 25 °C. Investigations on the active species showed that hydroxyl radicals play the major role in the process, providing a perfect degradation... 

Mn-doped ZnO nanoparticles, Zn1−xMnxO, were synthesised by a polyethylene glycol (PEG) sol–gel method and the physicochemical properties of compounds were characterised by atomic absorption spectroscopy (AAS), energy-dispersive X-ray analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The catalytic degradation of an organic dye, methylene blue (MB), in the presence of Zn1−xMnxO as the catalyst and hydrogen peroxide (H2O2) as the oxidant at room temperature in water has been studied. Effects of oxidant, catalyst amount, catalyst composition, pH value of the solution and an OH-radical... 

In the present study, a novel α-MnO2/AgI photocatalyst was successfully fabricated by using hydrothermal/precipitation methods, and its photocatalytic performance was evaluated from the degradation of Acid blue 92 (AB92) dye under visible light irradiation. The surface and crystalline structure, morphology, and electro-chemical properties of the as-made photocatalyst were investigated by BET, XRD, XPS, SEM-EDS, TEM, DRS, PL, PC, and Raman analysis. The optimized nanocomposite (α-MnO2/AgI) with a weight ratio of 1:15 showed the best photocatalytic activity in the decomposition of AB92 with a removal efficiency of 100% in 40 min which was better than that of pure α-MnO2 (48%) and AgI (61%),... 

Mass transfer efficiency and catalytic reactivity are the two major hurdles for heterogeneous catalytic wet peroxide oxidation (CWPO) technologies. To address these issues, nanocomposite CuFeO2/Al2O3 was synthesized and assessed as a novel catalyst for enhanced adsorption and oxidation of anionic pollutants (catechol and reactive red 195 (RR195)) in waters. With a positive charge on the nanocomposite by introducing Al2O3, the adsorption of anionic pollutants was promoted. The surface complexation reaction on CuFeO2/Al2O3, which fits well to the Langmuir isotherm, has engined the mass transfer of pollutants to the nanocatalyst that demonstrated 96.46% and 99.75% removal of catechol and RR195... 

This study demonstrated the prolonged benefits of polyvinyl-coated calcium peroxide (PVA@CP) in Fe(II)/nFeS mediated Fenton-like reaction. PVA@CP was prepared by a coating of PVA on calcium peroxide (CP) and synthesized nano-sized iron sulfide (nFeS) was characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopy (EDS) elemental mapping, X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier transmission infrared (FTIR) techniques. Trichloroethylene (TCE) degradation in various oxic environments (H2O2, CP, or... 

This study demonstrated the prolonged benefits of polyvinyl-coated calcium peroxide (PVA@CP) in Fe(II)/nFeS mediated Fenton-like reaction. PVA@CP was prepared by a coating of PVA on calcium peroxide (CP) and synthesized nano-sized iron sulfide (nFeS) was characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopy (EDS) elemental mapping, X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier transmission infrared (FTIR) techniques. Trichloroethylene (TCE) degradation in various oxic environments (H2O2, CP, or... 

Carbonaceous materials (CMs) have been applied extensively for enhancing the catalytic performance of environmental catalysts, however, the self-catalytic mechanism of CMs for groundwater remediation is rarely investigated. Herein, we unveiled the catalytic ability of various CMs via Fe(III) reduction through polyvinyl alcohol-coated calcium peroxide nanoparticles (PVA@nCP) for trichloroethylene (TCE) removal. Among selected CMs (graphite (G), biochar (BC) and activated carbon (AC)), BC and AC showed enhancement of TCE removal of 89% and 98% via both adsorption and catalytic degradation. BET and SEM analyses showed a higher adsorption capacity of AC (27.8%) than others. The generation of... 

Carbonaceous materials (CMs) have been applied extensively for enhancing the catalytic performance of environmental catalysts, however, the self-catalytic mechanism of CMs for groundwater remediation is rarely investigated. Herein, we unveiled the catalytic ability of various CMs via Fe(III) reduction through polyvinyl alcohol-coated calcium peroxide nanoparticles (PVA@nCP) for trichloroethylene (TCE) removal. Among selected CMs (graphite (G), biochar (BC) and activated carbon (AC)), BC and AC showed enhancement of TCE removal of 89% and 98% via both adsorption and catalytic degradation. BET and SEM analyses showed a higher adsorption capacity of AC (27.8%) than others. The generation of...