Chitosan-based smart hybrid materials: a physico-chemical perspective

2021 ◽  
Author(s):  
Giuseppe Cavallaro ◽  
Samantha Micciulla ◽  
Leonardo Chiappisi ◽  
Giuseppe Lazzara
Keyword(s):  
Hybrid Materials ◽  
Polyelectrolyte Complexes ◽  
Physico Chemical ◽  
Smart Coatings

An overview of the properties of chitosan-based materials: polyelectrolyte complexes, gels, chitosan-surfactant complexes, smart coatings, organic–inorganic hybrids.

scholarly journals Textile Wastewater Purification Using an Elaborated Biosorbent Hybrid Material (Luffa–Cylindrica–Zinc Oxide) Assisted by Alternating Current

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1326 ◽  
Author(s):  
Amina Othmani ◽  
Aida Kesraoui ◽  
Roberto Boada ◽  
Mongi Seffen ◽  
Manuel Valiente
Keyword(s):  
Hybrid Materials ◽  
Photoelectron Spectroscopy ◽  
Textile Wastewater ◽  
Alternating Current ◽  
Luffa Cylindrica ◽  
Wastewater Purification ◽  
Physico Chemical ◽  
Basic Functions ◽  
Method Point ◽  
Structural Characterizations

This paper aims to synthesize hybrid materials with high pollutant-uptake capacity and low costbased based on Luffa cylindrica (L.C) and different percentage of Zn2+ in the presence and absence of alternating current (AC). Physico-chemical, morphological and structural characterizations of the hybrid materials were performed by Boehm method, point zero charge (pHpzc), infrared characterizations (IR), scanning electron microscopy (SEM), energy–dispersive spectroscopyand and X-ray photoelectron spectroscopy. The efficiency of the designed hybrid materials was optimized based on their performance in water depollution. Methylene blue (MB) and industrial textile wastewater were the investigated pollutants models. IR characterizations confirmed the fixation of Zn2+ onto the L.C by the creation of Zn-OH, Zn-O and Zn-O-C bonds. Boehm titration showed that the fixation of Zn2+ onto L.C is accompanied by an increase of the basic functions of its surface and subsequently an increase in the pHpzc. SEM results confirmed the fixation of Zn2+ onto the L.C coupling AC with biosorption showed an increase in the adsorbed amount of MB and speed when adding the 4% of Zn2+ compared to the pure L.C the Qm shifted from 3.22 to 9.84 and 8.81 mg/g, respectively, for hybrid materials synthesized under AC, in absence of AC and pure L.C.

scholarly journals Preparation and Characterization of Montmorillonite/PEDOT-PSS and Diatomite/PEDOT-PSS Hybrid Materials. Study of Electrochemical Properties in Acid Medium

2020 ◽  
Vol 4 (2) ◽  
pp. 51 ◽  
Author(s):  
Mohamed Kiari ◽  
Raúl Berenguer ◽  
Francisco Montilla ◽  
Emilia Morallón
Keyword(s):  
Electron Transfer ◽  
Electrochemical Properties ◽  
Hybrid Materials ◽  
Environmental Remediation ◽  
Electroactive Material ◽  
Physico Chemical ◽  
Emerging Pollutant ◽  
Transfer Capability ◽  
Potential Applications ◽  
Concentration Sensitivity

The hybridization of clay minerals with conducting polymers receives great interest for different potential applications, including environmental remediation. This work studies and compares the electrochemical properties of two different clays, montmorillonite (Mont) and diatomite (Diat), and their respective clay/PEDOT-PSS hybrid materials in H2SO4 medium. The hybrid materials were prepared by electropolymerization of EDOT in the presence of PSS. The physico-chemical and electrochemical properties of both clays were analyzed by different techniques, and the influence of the clay properties on electropolymerization and the electroactivity of the resulting clay/PEDOT-PSS hybrids was investigated. Specifically, the Fe2+/Fe3+ redox probe and the oxidation of diclofenac, as a model pharmaceutical emerging pollutant, were used to test the electron transfer capability and oxidative response, respectively, of the clay/PEDOT-PSS hybrids. The results demonstrate that, despite its low electrical conductivity, the Mont is an electroactive material itself with good electron-transfer capability. Conversely, the Diat shows no electroactivity. The hybridization with PEDOT generally enhances the electroactivity of the clays, but the clay properties affect the electropolymerization efficiency and hybrids electroactivity, so the Mont/PEDOT displays improved electrochemical properties. It is demonstrated that clay/PEDOT-PSS hybrids exhibit diclofenac oxidation capability and diclofenac concentration sensitivity.

scholarly journals Titania-Based Hybrid Materials with ZnO, ZrO2 and MoS2: A Review

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2295 ◽  
Author(s):  
Adam Kubiak ◽  
Katarzyna Siwińska-Ciesielczyk ◽  
Teofil Jesionowski
Keyword(s):  
Hybrid Systems ◽  
Hybrid Materials ◽  
Binary Systems ◽  
Sol Gel ◽  
Morphological Properties ◽  
Oxide Systems ◽  
Practical Applications ◽  
Current State ◽  
Physico Chemical ◽  
Electrospinning Method

Titania has properties that enable it to be used in a variety of applications, including self-cleaning surfaces, air and water purification systems, hydrogen evolution, and photoelectrochemical conversion. In order to improve the properties of titanium dioxide, modifications are made to obtain oxide/hybrid systems that are intended to have the properties of both components. In particular, zinc oxide, zirconia and molybdenum disulfide have been proposed as the second component of binary systems due to their antibacterial, electrochemical and photocatalytic properties. This paper presents a review of the current state of knowledge on the synthesis and practical utility of TiO2-ZnO and TiO2-ZrO2 oxide systems and TiO2-MoS2 hybrid materials. The first part focuses on the hydrothermal method; then a review is made of the literature on the synthesis of the aforementioned materials using the sol-gel method. In the last section, the literature on the electrospinning method of synthesis is reviewed. The most significant physico-chemical, structural and dispersive-morphological properties of binary hybrid systems based on TiO2 are described. A key aim of this review is to indicate the properties of TiO2-ZnO, TiO2-ZrO2 and TiO2-MoS2 hybrid systems that have the greatest importance for practical applications. The variety of utilities of titania-based hybrid materials is emphasized.

Functional Coatings

2016 ◽  
pp. 1-25
Author(s):  
Ana Zuzuarregui ◽  
Maria Carmen Morant-Miñana
Keyword(s):  
Optical Properties ◽  
Hybrid Materials ◽  
Solder Joints ◽  
Chemical Properties ◽  
Environmental Problems ◽  
Functional Coatings ◽  
Huge Amount ◽  
Physical Damage ◽  
Material Layer ◽  
Physico Chemical

Traditionally a coating is defined as a material layer applied onto a surface for protection or decoration. Usually it protects the surface from a variety of environmental problems such as corrosion of solder joints, moisture and mildew, fuels and process solvents, service temperatures and dust, dirt and physical damage from handling. Since 2010, the rapid advancement of the micro and nanotechnology has collided with the coatings field resulting in new coatings with novel properties and functions that differ from the traditional ones. Functional coatings consists of organic, inorganic or hybrid materials and can be prepared using a huge amount of techniques depending on the properties of the materials, the substrate and the final application of the coating. Therefore it is possible to find coatings with optical properties, thermal capabilities, structural and mechanical features, physico-chemical properties, magnetic and electric characteristics and biological purposes that cannot be found in the starting materials.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

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