Sharif Digital Repository

Photocatalytic membrane reactors (PMRs), coupling photocatalysts and membranes in a single system, have shown a considerable potential to reduce membrane fouling, which is one of the major drawbacks of using membranes to treat water and wastewater. In this study, the visible light-activated photocatalysts were incorporated into the polyacrylonitrile (PAN) casting solution to synthesize the photocatalytic composite membranes. The physicochemical properties and the morphology of the membranes and photocatalysts were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction analysis (XRD), ultraviolet–visible diffuse reflectance... 

Conventional wastewater treatment processes are not completely effective in removing vancomycin. In this study, affecting parameters on vancomycin degradation, such as pH, catalyst, initial vancomycin concentration, temperature, and reaction time were investigated simultaneously during a removal process based on titanium dioxide with ultraviolet irradiation in an aqueous solution. Titanium dioxide was synthesized and characterized using X-ray diffraction and scanning electron microscopy. The average size of the synthesized crystals was 4.7 (± 0.2) nm. Design of experiments was done by a central composite design based on the response surface methodology and multiple linear regression was... 

The COVID-19 outbreak has triggered a massive research, but still urgent detection and treatment of this virus seems a public concern. The spread of viruses in aqueous environments underlined efficient virus treatment processes as a hot challenge. This review critically and comprehensively enables identifying and classifying advanced biochemical, membrane-based and disinfection processes for effective treatment of virus-contaminated water and wastewater. Understanding the functions of individual and combined/multi-stage processes in terms of manufacturing and economical parameters makes this contribution a different story from available review papers. Moreover, this review discusses... 

The treatment of water contaminated by bacteria is becoming a necessity. The nanomaterials possessing both intrinsic antibacterial properties and photocatalytic activity are excellent candidates for water disinfection. The powdered form of nanomaterials can be aggregated while embedding the nanomaterials into the NFs can overcome the limitation and enhance the photocatalytic activity and transition from UV-light to visiblelight. Here, graphene oxide (GO) was synthesized, grafted to chitosan, and decorated with silver nanoparticles (Ag NPs) to produce Ag-decorated reduced GO-graft-Chitosan (AGC) NPs. The blends of polyacrylonitrile (PAN) and AGC NPs were prepared in various concentrations of... 

The selection of a suitable duty factor (DF) remains a major challenge in respiratory-gated treatments. Therefore, this study aims at presenting a new methodology for fast optimizing the gating window width (duty factor (DF)) in respiratory-gated proton partial breast irradiation (PBI). To do so, GATE Monte Carlo simulations were performed for various target sizes and locations in supine and prone positions. Three different duty factors of 20, 25, and 33% were considered. Sparing factors (SF) for four organs-at-risk (OARs) were then assessed. The weighted-sum method was employed to search for an optimal DF. The results indicate that an SF higher than unity was obtained for all plans. The SF... 

Over the past few decades, biological hazards and organic pollution have become major environmental concerns. Photocatalysis has been found to be effective in minimizing the negative impacts of these issues in air and water. Lozenge shape Ag/AgCl/ZnTiO3 photocatalysts were fabricated by a facile two-step synthesis method, including hydrothermal and coprecipitation. The physicochemical characteristics and morphological properties of the structures were comprehensively described taking advantage of a multi-technique approach. The prepared photocatalysts offered excellent nitrophenol mineralization (>90%) after 90 min of visible light irradiation. Based on the spin-trapping ESR technique, •O2̅–... 

Photocatalytic wastewater treatment and concurrent energy production or metal ions conversion to less harmful products have great potential to address both environmental and energy challenging issues, two of the most significant problems facing humankind. Many efforts have been devoted for achieving enhanced photocatalytic activity as well as optimizing reaction conditions and materials design. In this context, various strategies were applied to develop efficient dual-functional photocatalysts for environmental purification and simultaneous energy production. Concurrent photocatalytic degradation of organic pollutants and Cr(VI) reduction to less toxic Cr(III) improved the rate of both... 

In this study, we perform numerical simulations to investigate the thermal and flow characteristics of a parabolic trough solar collector equipped with a porous receiver tube and internal longitudinal fins. The heat transfer medium is a synthetic oil-Cu-Al2O3 hybrid nanofluid. We examine the thermal characteristics of the nanofluid in response to variations in several system parameters. We find that at Reynolds numbers between 5 × 103 and 5 × 105, increasing the volume fraction of Cu nanoparticles can increase the temperature gain at the exit of the receiver tube by 6.4%. Furthermore, the temperature gradient in the cross-section of the collector increases as the direct normal solar... 

The coupling of photocatalysis with membrane technology, which is known as photocatalytic membrane reactors (PMRs), has received great consideration in recent years and become a promising approach with the high potential to improve the fouling of membranes. In this paper, the photocatalyst of g-C3N4 treated with H2O2 was incorporated with a polysulfone membrane to enhance the anti-fouling properties of the membrane. AFM, FE-SEM images, porosity, and contact angle analysis indicated that the membrane properties like hydrophilicity, porosity, and surface roughness were improved. Also, UV–visible DRS, PL spectra, EIS analysis confirmed that the treated g-C3N4 (H2O2-g-C3N4) had high light... 

The rapid and effective separation of high-viscosity heavy crude oil from seawater is a worldwide challenge. Herein, an ultralow density, photothermal, superhydrophobic, and thermally conductive polyurethane/polyaniline/hexagonal boron nitride@Fe3O4/polyacrylic-oleic acid resin sponge (PU/PANI/h-BN@Fe3O4/AR) was fabricated with a water contact angle (WCA) of 158°, thermal conductivity of 0.76 W m-1 K-1, density of 0.038 g cm-3, limited oxygen index (LOI) of 28.82%, and porosity of 97.97% and used for solar-assisted separation of high-viscosity crude oil from water. Photothermal components were composed of PANI and Fe3O4, while h-BN particles were used as thermally conductive and flame... 

Herein, MIL-101(Fe), CoFe2O4, novel binary (MIL-101(Fe)/CoFe2O4, MIL-101(Fe)/GO and CoFe2O4/GO), and ternary (MIL-101(Fe)/CoFe2O4/(3%)GO and MIL-101(Fe)/CoFe2O4/(7%)GO) magnetic composites based upon the MIL-101(Fe) were synthesized. The XRD, FESEM, TEM, EDX, BET-BJH, FTIR, VSM, DRS, PL, EIS and other electrochemical analyses were applied to characterize samples. The MIL/CoFe2O4/(3%)GO demonstrated the best performance compared to other samples for visible light photocatalytic and photo-Fenton-like degradation of Direct Red 23 (DtR-23), Reactive Red 198 (ReR-198) dyes as well as Tetracycline Hydrochloride (TC-H) antibiotic. Degradation of dyes using the ternary composite after 70 min of... 

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. The sufficient CD arrays were generated by loading the glucose molecules into the pores of an as-obtained metal-organic framework (MOF), i.e. MIL-88B (Fe)), by heating to 200 °C. Fabricated nanocomposite structures were characterized by FT-IR, XRD, EIS, SEM, TEM, 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... 

AgNPs@Chitosan and Co3O4-NPs@Chitosan were fabricated with Salvia hispanica. Results showed MZI values of 5 and 30 mm for Co3O4-NPs- and AgNPs@Chitosan against S. aureus, and 15 and 21 mm for Co3O4-NPs- and AgNPs@Chitosan against E. coli (24 h, 20 μg/mL), respectively. MTT assays showed up to 80% and 90%, 71% and 75%, and 91% and 94% mammalian cell viability for the green synthesized, chemically synthesized AgNPs and green synthesized AgNPs@Chitosan for HEK-293 and PC12 cells, respectively, and 70% and 71%, 59% and 62%, and 88% and 73% for the related Co3O4-NPs (24 h, 20 μg/mL). The photocatalytic activities showed dye degradation after 135 and 105 min for AgNPs@Chitosan and... 

The current study develops a 3D constitutive model for photo-thermal sensitive hydrogels based on free energy decomposition. The hydrogel under study is PNIPAM network with copper chlorophyllin nanoparticle agents attached to the network. The effect of light intensity is considered as a rise in temperature since chlorophyllin nanoparticle agents absorb light irradiation and convert it to heat. Moreover, it is necessary to consider the effect of dissociation of these agents on the hydrogel’s free energy function; therefore, a term is added to the free energy function. After introducing the model, some problems, including the free swelling and uniaxial loading problems, are studied, and the... 

Herein, a novel Pt-APA composite (APA = pyridinium bromide salt) based on magnetic graphene oxide was synthesized and used as an effective catalyst. In this way, Fe3O4 nanoparticles are grown on graphene oxide (GO) nanosheets by a simple and practical method which creates a unique nanostructure (Fe3O4/GO) through dispersing uniformly among graphene nanosheets. The resulted Pt-APA composite was obtained via adding PtCl2 to an ethanol solution of Fe3O4/GO and α-keto stabilized pyridinium ylide in related conditions. The synthesized nanocomposite structure was identified using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive... 

Introduction: Porous 3D scaffolds synthesized using biocompatible and biodegradable materials could provide suitable microenvironment and mechanical support for optimal cell growth and function. The effect of the scaffold porosity on the mechanical properties, as well as the TiO2 nanoparticles addition on the bioactivity, antimicrobial, photocatalytic, and cytotoxicity properties of scaffolds were investigated. Methods: In the present study, porous scaffolds consisting poly (lactide-co-glycolide) (PLGA) containing TiO2 nanoparticles were fabricated via air-liquid foaming technique, which is a novel method and has more advantages due to not using additives for nucleation compared to former... 

Gamma irradiation systems are used extensively in the industry in order to sterilize medical devices, disinfect hygienic products and increase the shelf life of agricultural products. The method of gamma irradiation is superior to the older methods of heat or chemical treatment because it is by far a simpler operation. In this method, only one parameter, the exposure time is controlled, whereas in the other mentioned methods five or six different parameters need to be controlled. The design of irradiation systems generally includes the size and the location of products, and the arrangement of source rack pencils. In order to optimize the design of the gamma irradiation systems, it is needed... 

Separating produced water is a key part of production processing for most crude oils. It is required for quality reasons, and to avoid unnecessary transportation costs and prevent pipework corrosion rates caused by soluble salts present in the water. A complicating factor is that water is often present in crude oil in the form of emulsions. Experiments were performed to evaluate the performance of ultrasonic fields in demulsifying crude oil emulsions using novel pipe-form equipment. A horn-type piezoelectric ultrasonic transducer with a frequency of 20 kHz and power ranging from 80 W to 1000 W was used for experimental purposes. The influences of the intensity of ultrasonic fields,... 

In recent years, a range of studies have been conducted with the aim to design and characterize delivery systems that are able to release multiple therapeutic agents in controlled and programmed temporal sequences, or with spatial resolution inside the body. This sequential release occurs in response to different stimuli, including changes in pH, redox potential, enzyme activity, temperature gradients, light irradiation, and by applying external magnetic and electrical fields. Sequential release (SR)-based delivery systems, are often based on a range of different micro- or nanocarriers and may offer a silver bullet in the battle against various diseases, such as cancer. Their distinctive... 

The purpose of this research is to explain the surface modification of fabricated polyamide reverse osmosis (RO) membranes using UV-initiated graft polymerization at different irradiation times (15, 30, 60, and 90 s) and various acrylamide concentrations (10, 20, and 30 g L−1). Also, coating of membranes surface with various concentrations of TiO2 nanoparticles (10, 20, 30, and 50 ppm) followed by the same UV irradiation times was investigated. After that, the membranes modification was done by grafting of acrylamide blended with TiO2 nanoparticles via UV irradiation. The characterization of membranes surface properties and their performance were systematically carried out. The results...