Search results for " Adsorption"
showing 10 items of 222 documents
Engineering Proteins at Interfaces: From Complementary Characterization to Material Surfaces with Designed Functions
2018
Abstract Once materials come into contact with a biological fluid containing proteins, proteins are generally—whether desired or not—attracted by the material's surface and adsorb onto it. The aim of this Review is to give an overview of the most commonly used characterization methods employed to gain a better understanding of the adsorption processes on either planar or curved surfaces. We continue to illustrate the benefit of combining different methods to different surface geometries of the material. The thus obtained insight ideally paves the way for engineering functional materials that interact with proteins in a predetermined manner.
Method of Discrimination of Surface Fractality
1993
Abstract A simple method for the discrimination of surface fractality is proposed. This method is based on the comparison of the nitrogen adsorption isotherm on a given sample with the "standard" isotherm on a smooth surface. The proposed comparative method makes it possible to determine the lower limit of the scale range of surface fractality. A thermodynamic method is recommended as a complement to fractal analysis in the scale range of about 10-1000 A. The results of the investigation of surface roughness are presented with examples of typical samples of silica gels, porous glasses, apatite, and coal.
Effect of H Adsorption on the Magnetic Properties of an Fe Island on a W(110) Surface
2019
<p>Low-dimensional materials, such as ultrathin films, nanoislands and wires, are actively being researched due to their interesting magnetic properties and possible technological applications for example in high density data storage. Results of calculations of an Fe nanoisland on a W(110) support are presented here with particular focus on the effect of hydrogen adsorption on its magnetic properties. This is an important consideration since hydrogen is present even under ultra-high vacuum conditions. The calculations are based on density functional theory within the generalized gradient approximation. The adsorption of H atoms is found to strongly decrease the magnetic moment of the …
α-d-Glucopyranose Adsorption on a Pd30 Cluster Supported on Boron Nitride Nanotube
2016
Boron nitride nanotube (BNNT) as an innovative support for carbohydrate transformation processes was evaluated, using density functional theory. The α-d-glucopyranose adsorption on a Pd30 cluster, supported on BNNT, was used to check both the local activity of topologically different metallic sites and the effects of the proximity of the BNNT surface to the same metallic sites. Detailed geometrical and electronic analyses performed on Pd30/BNNT and α-d-glucopyranose/Pd30/BNNT systems were discussed. It was observed that the deposition of the Pd30 cluster onto the BNNT support gives rise to an electronic rearrangement, determining a charge transfer from the support to the adsorbed metal clus…
CHARACTERIZATION OF CHEMICAL AND PHYSICAL PROPERTIES OF BIOCHAR FOR ENERGY PURPOSES AND ENVIRONMENTAL RESTORATION
2014
Biochar production processes as well as its various applications provide numerous benefits to both environment and economy (Lehmann et al., 2006; Basu, 2010). However, understanding the physicochemical structure of this valuable product has to be improved in order to be able to obtain the aforementioned benefits and to avoid environmental costs. In this study, chicken or poultry manure (PM) was chosen as feedstock for biochar preparation. This biomass is traditionally used by farmers as an effective organic fertilizer (Chan et al., 2008). Indeed, it is considered a valuable source for readily available plant nutrients, such as N, P, K and other micronutrients (Huang et al., 2011). Notwithst…
Ni/Zn Layered Double Hydroxide (LDH) Micro/Nanosystems and Their Azorubine Adsorption Performance
2021
A membranous shaped Ni/Zn layered double hydroxide based nanohybrid was obtained using a low-cost template-free hydrothermal process at optimized growth conditions of 180 °C for 6 h. The synthesized nanohybrid was structurally, texturally and morphologically characterized using different techniques such as X-ray diffraction, FTIR, XPS spectroscopy, BET analysis and FESEM microscopy. The adsorption performance of our product was estimated through the Azorubine dye removal from synthetic wastewater. We therefore studied the synergic effects of Ni/Zn adsorbent dosage, contact time, pH, adsorbate concentration, stirring speed and temperature on the Azorubine adsorption efficiency. In this inves…
Chitosan Functionalized with Carboxyl Groups as a Recyclable Biomaterial for the Adsorption of Cu (II) and Zn (II) Ions in Aqueous Media
2022
The modification of chitosan represents a challenging task in obtaining biopolymeric materials with enhanced removal capacity for heavy metals. In the present work, the adsorption characteristics of chitosan modified with carboxyl groups (CTS-CAA) towards copper (II) and zinc (II) ions have been tested. The efficacy of the synthesis of CTS-CAA has been evaluated by studying various properties of the modified chitosan. Specifically, the functionalized chitosan has been characterized by using several techniques, including thermal analyses (differential scanning calorimetry and thermogravimetry), spectroscopies (FT-IR, XRD), elemental analysis, and scanning electron microscopy. The kinetics an…
Adsorption isotherms and thermal behavior of hybrids based on quercetin and inorganic fillers
2019
We investigated the adsorption process of quercetin onto several inorganic fillers, such as kaolinite, calcium carbonate and alumina. Firstly, we performed equilibrium adsorption studies in order to determine the quercetin/filler adsorption isotherms, which were successfully fitted through the Langmuir model. Based on the adsorption data analysis, we estimated the maximum adsorption capacity of each filler as well as the Langmuir constant, which is related to the affinity between quercetin and the surfaces of the inorganic particles. Then, we prepared hybrids formed by fillers saturated with quercetin. The obtained composites were characterized by thermogravimetric analysis with the aim of …
Preparation and characterization of a novel chitosan/Al2O3/magnetite nanoparticles composite adsorbent for kinetic, thermodynamic and isotherm studie…
2015
Abstract In this study we developed a novel chitosan/Al 2 O 3 /magnetic iron oxide nanoparticle composite acting as an adsorbent for removing Methyl Orange (MO), a model anionic dye, from aqueous solution. The new adsorbent was characterized by Scanning Electron Microscope (SEM), Thermo Gravimetric Analysis (TGA), Brunauer–Emmett–Teller (BET) specific surface area, Energy Dispersive spectrometer (EDAX), powder X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) methods. The MO removal by the developed adsorbent was investigated using batch adsorption technique and all parameters influencing the removal efficiency such as: dose of adsorbent, pH and initial MO concentr…
Silica aerogel–metal composites produced by supercritical adsorption
2010
Abstract Silica aerogel has been loaded with ruthenium acetyl acetonate (Ru(acac) 3 ) by adsorption from supercritical carbon dioxide. Adsorption isotherms and kinetics were measured at different pressures and temperatures. The properties of impregnated aerogel were obtained by optical and electron microscopy (SEM), X-ray microanalysis (EDX) and thermogravimetric analysis (TGA). Results showed that Ru(acac) 3 can be uniformly dispersed into the aerogel up to 5 wt%. Moreover, precursor loading is controllable by properly changing operating conditions. The adsorbed metallorganic compound has been reduced to elemental ruthenium by heat treatment without inducing degradation and morphological c…