Search results for " Adsorption"

Halloysite nanotubes sandwiched between chitosan layers: novel bionanocomposites with multilayer structures

2018

This work is a contribution to the design of multilayer biocomposites based on halloysite nanotubes (HNTs) and chitosan. Both the polymer and nanotubular inorganic additive have been selected among easily available green materials. An innovative preparation procedure based on the sequential casting of chitosan and HNTs has been proposed in order to obtain multilayer composite biofilms. A physico-chemical investigation (contact angle measurements, differential scanning calorimetry, thermogravimetry) has been conducted to characterize the bionanocomposites. As evidenced by scanning electron microscopy, the nanocomposites possess an intermediate halloysite layer between the chitosan ones. The …

Equilibrium coverage fluctuations: a new approach to quantify reversible adsorption of proteins.

2005

Extraction and trace enrichment of genotoxicants from environmental samples by solid-phase adsorption on blue pearls

1988

Voltammetric Investigation on Uranyl Sorption by Alginate Based Material. Influence of Hydrolysis and pH Dependence

2015

The removal of U(VI) as uranyl (UO22+) from aqueous solutions was investigated by sorption onto alginate based material. The hydrolysis of uranyl ion was always taken into account in the calculations of free (22UO) ion in aqueous solution, in the experimental pH range considered, as well as the acid-base properties of alginate polymer. The sorption process follows a pseudo-second order kinetic model and the sorption rate decreases when the pH value increases. In addition to the classical Langmuir and Freundlich models, the equilibrium data were fitted by using a modified multi-component equilibrium model, never tested before. Differential Pulse Voltammetry (DPV) and Inductively Coupled Plas…

Protein aggregates for water purification

Water pollution is the contamination of water bodies including lakes, rivers, oceans and it is a leading global risk factor for illness and death for people, plants and living organisms. A principal source of water pollution is industry, from which increasing amounts of toxic pollutants are released including heavy metals such as cobalt, lead and copper. Today various technologies for purifying contaminated water can be applied, a lot of them being typically expensive, ion specific and characterised by low efficiency. For these reason, the search of new biocompatible materials with increased capabilities is strongly needed.Protein aggregates have already revealed their potential as environm…

Influence of bentonite fining on protein composition in wine

2017

Abstract Bentonite is the only fining agent which can stabilize wine and prevent protein haze formation after bottling. Currently many approaches are used to find an alternative because of bentonite's negative influence on color and aroma compounds. Nevertheless, the interaction of bentonite with wine proteins is not fully understood. Therefore, we analyzed the influence of a NaCa-combined bentonite on the protein content and composition of different wines showing a partial selectivity on protein adsorption. For example, glycosylated proteins were not removed by bentonite in notable amounts. Performing mass spectrometry we were able to demonstrate that 96% of class IV chitinase was adsorbed…

Applications of mathematical modelling to the simulation of binary perfusion chromatography

1993

Abstract A mathematical model of binary (competitive adsorption involving two components) perfusion chromatography is used to simulate and study the behavior of a binary adsorption system. The dynamic behavior of column systems (frontal analysis) is examined for different particles sizes, column fluid superficial velocities, Vf, and intraparticle fluid velocities, νp. Column systems with perfusive (νp > 0) and purely diffusive (νp = 0) adsorbent particles are studied. The results obtained from the binary system studied in this work suggest that the times at which breakthrough begins for components 1 and 2, and the dynamic (unsteady state) relative separation between components 1 and 2 obtai…

2D slab models of TiO2 nanotubes for simulation of water adsorption: Validation over a diameter range

2020

Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2019/2 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, project CAMART 2 .

Zeolites for the nutrient recovery from wastewater

2023

To meet the growing food demand of the world population, excessive use of chemical fertilizers is occurring to improve soil fertility and crop production. The excessive use of chemical fertilizers is not economically and environmentally sustainable. Indeed, from one hand, due to the increasing demand of fertilizers is rising their costs whereas, on the other hand, the accumulation of fertilizers in wastewaters is altering the homeostasis of the ecosystems thus causing serious damages to human health [1,2]. The recovery of nutrients, such as nitrogen (N) and phosphorus (P), from wastewaters is a good option to counteract both economic and environmental issues raised by the excessive use of f…

Syntheses of TiO2 anatase nanocrystals with controlled size distribution. Influence of the crystallites size on the Raman spectrum and investigation …

2006

The determination of the size and the size distribution of anatase TiO2 nanopowders using Raman spectroscopy is presented. Several synthesis methods (soft chemistry, water-in-oil microemulsion, continuous hydrothermal synthesis) are used in order to control the size (from 3 to 20 nm), shape, phase and size distribution. The shift and width of the anatase Eg peak are often used to obtain the nanoparticles size. Homever, this peak is also sensitive to nonstoichiometry and others parameters. Low-frequency Raman scattering does not suffer from this problem. Size distibutions obtained by Raman spectroscopy and MET micrographs are compared. Finally, in situ Raman spectroscopy is used to study the…