Porous and fractal analysis on the permeability of nanofiltration membranes for the removal of metal ions

Porous and fractal analysis on the permeability of nanofiltration membranes was investigated for the removal of metal ions. The permeability of a porous membranes used in wastewater treatment is strongly depended on its local geometry and connectivity, the size distribution of the pores available for flow. Fouling studies with two different membranes at three different pHs were carried out with manganese and magnesium. It was shown that the tighter membrane was less rougher and less fouled compared with the rougher membrane. NF90-2450 showed the highest degree of fouling. The X-ray diffraction showed that NF90-2540 consist of a pronounced diamond at the angle of 45 �C which was responsible for porosity. The threshold images were obtained from the scanning electron microscopy images with the use of Image J software confirmed that NF90-2540 has higher percentage porosity when compared with the percentage porosity of NF1540-3. An evaluation of the relationships between porosity and permeability for the fractal analysis by a box counting was done. The evaluation also confirmed that the lower fractal dimension corresponds to a lower value of porosity. The higher the pH, the lower the fractal dimension of the used membranes due to the blockage of pores. A higher value of fractal dimension of the used membrane at a lower pH corresponds to a lower rejection of the metal ions

Preparation of a high surface area zirconium oxide for fuel cell application

Abstract Stable and high surface area zirconium oxide nanoparticles have been synthesised by means of the hydrothermal method. The Brunauer–Emmett–Teller results show that a high surface area of 543 m2/g was obtained in the hydrothermal process, having a high porosity in nanometre range. The hydrothermal method was applied at 120 °C by using an autoclave with a Teflon liner at an ambient pressure for 48 h. High-resolution scanning electron microscopy shows the different morphologies of zirconia nanoparticles, which could be categorised as one-dimensional and zero-dimensional, as they had a high crystallite orientation, which was also confirmed by the X-ray diffraction (XRD). The mixture of two types of cubic phases in one sample was obtained from XRD and confirmed by the zirconia nanostructure, showing the stable phase of fluorite, which has full cubic symmetry (Im-3m), and also an Arkelite zirconia nanostructure, showing the stable phase of fluorite, which has full cubic symmetry (Fm-3m). The XRD results also show the different structure orientations of face-centred cubic and body-centred cubic in one sample

Fractionation and Crystallization of Isotactic Polypropylenes Prepared Using Homogenous Metallocene Catalyst

A series of polypropylenes were prepared using rac-ethylene-bis(4,5,6,7-tetrahydro-1-indenyl) zirconium dichloride (Et(H4Ind)2ZrCl2 (EI(4H)) as a homogeneous metallocene catalyst. The molecular weight of the polypropylene polymers was controlled using molecular hydrogen which was used as a transfer agent. To obtain materials with differing molecular weight and tacticities, polymers were fractionated with prep-TREF. Polypropylene polymers and fractions were fully characterized using various analytical techniques: differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), 13C nuclear magnetic resonance spectroscopy (13C-NMR) and high temperature gel permeation chromatography (HT-GPC). It was found that the addition of molecular hydrogen to propylene polymerizations catalyzed using EI(4H) catalyst system resulted in a reduction in polymer molecular weight and isotacticity. Furthermore, the molecular weight, the isotacticity and the degree of crystallinity of the TREF fractions increased significantly with increasing elution temperature for all samples. Also, only the crystal form existed in all TREF fractions of different samples.Civil and Chemical Engineerin

Characterization of Two Nanofiltration Membranes for the Separation of Ions from Acid Mine Water

We evaluated nanofiltration for separation of ions from acid mine drainage (AMD), using two composite nanofiltration membranes (Nano-Pro-3012 and NF90) as examples of the polyamide class of acid-stable membranes. The structure of the NF membranes was characterized by scanning electron and atomic force microscopy. The NF90 displayed a higher permeate flux than Nano-Pro-3012, with higher relative roughness at both pH values. Both membranes suitably rejected most of the metals found in the AMD, but the Nano-Pro-3012 membrane proved unsuitable for sulphate remova

Effect of Treatment Methods on Used Lubricating Oil for Recycling Purposes

The need to treat used lubricating oil for possible reuse has arisen due to concern for the environment, scarcity, price stability, and increasing dependence on this product for many industrial applications. Various methods, such as distillation/clay, acid/clay, acid, and activated charcoal/clay treatment methods, were employed in this study for the treatment of used Mobil and Total lubricating oil samples with the aim of improving their qualities for reuse. The characteristics of the fresh, used, and treated oil are tested for water content, specific gravity, kinematic viscosity, viscosity index, flash point, pour point, sulphur content, and concentrations of heavy metals (aluminum, iron, and lead). The results obtained showed that the usage of the lubricant oil affects the qualities of oil, for instance the sulphur of both brands of the oil samples was below the detectable limit, while the sulphur contents of the used oil are 0.80 and 0.69% for the used Mobil and Total oil samples, respectively. The results also revealed that treatments employed in this work were able to improve the characteristics of the used oil samples after treatment. The analyses of the results showed that the acid/clay method was the most effective method of treatment that brings the characteristics of the treated oil close to the fresh oil sample, while the distillation/clay and activated/charcoal methods were the best in terms of recovery of the oil after treatment. These two methods also recovered about 80% of the used lube oil samples compared to acid and acid/clay treatment methods, where the oil recovered was about 50% of the charge used oil sample

Synthesis of zirconia-based solid acid nanoparticles for fuel cell application

Zirconia nanoparticles were prepared by the precipitation and ageing methods. The precipitation method was performed by adding ammonium solution to the aqueous solution of zirconium chloride at room temperature. The ageing method was performed by leaving the precipitate formed in the mother liquor in the glass beaker for 48 hours at ambient temperatures. The nanoparticles from both methods were further sulphated and phosphated to increase their acid sites. The materials prepared were characterised by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), Brunauer-EmmettTeller (BET), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The XRD results showed that the nanoparticles prepared by the precipitation method contained mixed phases of tetragonal and monoclinic phases, whereas the nanoparticles prepared by ageing method had only tetragonal phase. The TEM results showed that phosphated and sulphated zirconia nanoparticles obtained from the ageing method had a smaller particle size (10–12 nm) than the nanoparticles of approximately 25–30 nm prepared by precipitation only. The BET results showed that the ZrO2 nanoparticles surface area increased from 32 to 72 m2/g when aged

Hydrogels and its Nanocomposites from Renewable Resources: Biotechnological and Biomedical Applications

Eco-friendly hydrogel and its nanocomposite (NC) hydrogels prepared from renewable resources have drawn significant attention from industrial and academic sectors. The ecofriendly polymeric hydrogels contain polymers or their composites, which are either biodegradable or biobased (from renewable resources). Their carbon-neutral lifecycle may reduce the emission of carbon dioxide and the dependence on petroleum-based materials and then reduce the human footprint on the environment. In this concern, the technologies are required in order to develop novel soft materials beside to get the new information, and fundamental understanding results in important advancement in the field of hydrogels and its NC hydrogels. A wide diversity of complex hydrogel structures have been found with distinct physical, chemical, and biological properties at the nanometer level. The possibility in order to develop self-assembled and supramolecular morphologies makes natural polymers and inorganic nanoparticles desirable building blocks for the design of water-based gels. In this book chapter, we partially covered the accomplishments and trends in the field of NC polymer hydrogels with a focus on creative approaches to generating structures, properties, and function within mostly biotechnological and biomedical application