Journal of Water and Environmental Nanotechnology
Year:2019 | Volume:4 | Issue:1|Papers Count:9

In this study, membranes were prepared by pristine and polyethylene glycol (PEG)-grafted nanodiamond (ND) embedded in cellulose acetate (CA) as matrix polymer via non-solvent induced phase separation method. The antifouling properties of the membranes were studied during filtration of bovine serum albumin (BSA) solutions and the governing fouling mechanisms of the membranes were also investigated using the Hermia model. Fourier Transform Infrared Spectroscopy (FTIR) and Thermal gravimetric analysis (TGA) confirmed that ND was successfully functionalized by PEG. CA/ ND-PEG nanocomposite membranes have higher hydrophilicity, porosity, water uptake, mechanical strength and a lower amount of adsorbed protein than pure CA and CA/ND membranes. Besides, the antifouling performance of the CA/ND-PEG (0. 5 wt. %) nanocomposite membrane also witnessed considerable improvement, in comparison with that of pure CA and CA/ND (0. 5 wt. %) membranes. The obtained results showed that the best fit to experimental data for all membranes (pure and nanocomposite membranes) corresponds to the cake layer formation model.

Photocatalytic treatment of wastewater from azo dyes with semiconductors promises efficient method to refine water. Cobalt ferrite is synthesized and utilized for dye removal as a semiconducting composite. To compare the photocatalytic performance of its individual oxides, Co3 O4 and FeO were synthesized by the same route and applied to water treatment. In this work, cobalt ferrite, Co3 O4, and FeO nanoparticles were synthesized as photocatalysts by employing wet chemical method with chloride precursors respectively (CoCl2. 6H2 O & FeCl3. 6H2 O, CoCl2. 6H2 O, FeCl3. 6H2 O). The synthesized photocatalysts were characterized by powder X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and field emission scanning electron microscopy (FESEM). The obtained photocatalysts were coated on the glass by Dr. Blade method. The degradation of Acid Black 1 (AB1) and Reactive Red 4 (RR4) by cobalt ferrite, Co3 O4 and FeO were carried out under UV light irradiation to investigate their photocatalytic activities. FeO nanoparticles were found as the best photocatalyst to achieve maximum degradation of Azo dyes. The high degradation performance of FeO can be attributed to the photo-Fenton phenomena-like furthermore photocatalytic process. The Degradation rate of AB1 by photocatalysts decreases in the order of FeO > Co3 O4 > CoFe2 O4. The photocatalytic degradation kinetics of AB1 using photocatalyst nanoparticles was found to be the first order kinetic rate. For RR4, CoFe2 O4 followed first order, FeO and Co3 O4 followed a second order kinetic rate. Presence of iron oxide in cobalt ferrite improved the photocatalytic performance.

In this paper, Ag-TiO2-Graphene (Ag-TiO2-G) photocatalyst is synthesized via an economic and green rout. Pranus Cerasus is applied as a green reducing agent due to the presence of anthocyanin pigment. The anthocyanin molecules are responsible for the red color of the prunus cerasus seeds. The nanocomposites were characterized by XRD, EDS mapping, DRS and TEM. In order to explore the presence of Ag, different mass ratio of Ag to in Ag-TiO2-G composite (5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, and 50wt%) were synthesized and their performance on the Acid Orange 7 (AO7) photodegradation were compared with bare graphene. In addition, for investigation of the presence of graphene, the AgTiO2 was synthesized and compared with the Ag-TiO2-G composite from the photocatalytic performance point of view. Ag nanoparticles and graphene are two crucial factors in AO7 photodegradation. Finally, we showed that photodegradation of AO7 with photocatalyst depends on photogenerated holes.

The remaining dye in the wastewater is not desirable as it damages the ecosystem and nature, and also is very toxic. The Crystal Violet (CV) dye is toxic and potentially carcinogenic. In addition, it reduces light in water and prevents the process of photosynthesis of aquatic plants. Therefore, nanozeolite-X (NX) was utilized as an adsorbent to remove the Crystal Violet (CV); effects of pH, catalyst mass, sonication time, and concentration of dye were also investigated. Effects of variables on the removal efficiency were studied via the Central Composite Design (CCD) to determine the dye removal percentage. The quadratic model was selected to predict the removal efficiency using the software. Optimal conditions for CV removal from aqueous solution were: pH= 8, sonication time= 6 min, concentration of dye= 13 mg L-1, and catalyst mass= 0. 26 g. In these circumstances, the recovery efficiency was 97. 60%. The research results indicated that NX could be applied potentially for CV removal.

In this study, the impact of doping graphene with silicon and germanium on the adsorption of Ag + was evaluated by density functional theory for the first time. At the outset, the structures of silver, adsorbents and their derived products at ten different configurations were optimized geometrically. Then, IR and frontier molecular orbital calculations were implemented on them and some important parameters such as adsorption energy, Gibbs free energy changes, enthalpy variations, the thermodynamic equilibrium constant, specific heat capacity, chemical hardness, energy gap, and electrophilicity were obtained and inspected. The achieved results indicate that by doping graphene with silicon and germanium the adsorption process has become more spontaneous, exothermic and experimentally feasible. The influence of temperature on the adsorption procedure was also checked out and the results indicate that 298. 15 K is the optimum temperature for the desired process at all of the evaluated configurations. The HOMO-LUMO related parameters reveal that the pure and also doped nano-adsorbents are not appropriate sensing material in the construction of conductometric sensors but they can act as an eminent neutral ion carrier in the development of a potentiometric ion selective electrode for determination of silver (I) cations.

In this study, the impact of doping graphene with silicon and germanium on the adsorption of Ag + was evaluated by density functional theory for the first time. At the outset, the structures of silver, adsorbents and their derived products at ten different configurations were optimized geometrically. Then, IR and frontier molecular orbital calculations were implemented on them and some important parameters such as adsorption energy, Gibbs free energy changes, enthalpy variations, the thermodynamic equilibrium constant, specific heat capacity, chemical hardness, energy gap, and electrophilicity were obtained and inspected. The achieved results indicate that by doping graphene with silicon and germanium the adsorption process has become more spontaneous, exothermic and experimentally feasible. The influence of temperature on the adsorption procedure was also checked out and the results indicate that 298. 15 K is the optimum temperature for the desired process at all of the evaluated configurations. The HOMO-LUMO related parameters reveal that the pure and also doped nano-adsorbents are not appropriate sensing material in the construction of conductometric sensors but they can act as an eminent neutral ion carrier in the development of a potentiometric ion selective electrode for determination of silver (I) cations.

The aim of the present study is to synthesize and characterize Fe-doped TiO2 nanoparticles prepared by a molten salt method using a solid mixture of TiO2 powder and FeCl3 precursor. As far as this study is concerned, this is the simplest method that has been reported so far for the synthesis of Fe-doped TiO2 nanoparticles. Pure TiO2 nanoparticles and 0. 5, 1 and 3 wt% Fe-doped TiO2 samples were prepared. The prepared nanoparticles were characterized by UV-Vis diffusion reflection spectroscopy (DRS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDX). SEM and XRD analysis of the samples indicated the presence of anatase spherical-shaped TiO2 particles. The results of EDX study confirmed the presence of Fe in all samples. According to DRS results, the band gap energy of Fe doped TiO2 nanoparticles decreased with increasing Fe concentration from 3. 1 eV for pure TiO2 to 3. 0-2. 80 eV for Fe-doped TiO2. The photocatalytic activity was also checked. It was found that, the photocatalytic activity of Fe-doped nanoparticles was higher than that of the pure TiO2. The maximum degradation activity of 69% was obtained at the Fe doping content of 0. 5 wt%.

Template-assist method is one of the most important techniques for synthesize nanostructures, because of more parameters that can be change to fabricate different nanostructures with desired nano-scale features. self-ordered anodic alumina is one of the most important honeycomb structure that can be used as a template. by using self-ordered nanoporous as a template and hydrothemal process as a deposition technique, different structures like nanowire, nanotube and nanoparticle was fabricated. The effect of surfactant and temperature on the formation of various nano-structures were investigated by SEM (scanning electron microscopy) and EDX (Energy dispersive x-ray) analysis. Electrical properties and I(Current)-Voltage (V)-Gate-source behavior of the samples was measured by four-probe (4-probes) method. Tin oxide nanoparticle array on the surface of alumina membrane used as chemical sensor in case of detecting hydrazine. The obtained results indicate that Alumina doped with tin oxide nanoparticle is suitable for detection of toxic chemicals in water such as hydrazine.

The use of nanotechnology in replacing cement with nanomaterials due to environmental aspects and reduction of pollutants is presently an important issue in the world. In this regard, the effect of various weight percentages of functionalized carbon nanotubes together with montmorillonite nanoparticles and with titanium oxide nanoparticles were studied as replacements for the cement to improve the mechanical and microstructural properties of hardened cement paste composites. In the present study, carbon nanotubes, TiO2, and montmorillonite nanoparticles were synthesized as additions into cement matrix, and their nano-structural characterizations were studied using the TEM, XRD, X-Powder, DSC-TGA, FTIR, and GPS132A techniques. The obtained results indicate that the addition of nanomaterials to cement-based composites improves mechanical, electrical and nano-structural properties and the quality as well as emission factors of samples with optimization portion of nano-particles found by RSM method.