Preparation And Characterization Of Cross Linked Chitosan Filled Chitosan Composites

The interfacial bonds, homogeneity and rigidity of filler are the two main criteria that significantly influenced the mechanical, thermal and hydrophilicity of the chitosan (Cs) based bio-composites. Therefore, the aim of this study was to investigate the role of cross linked chitosan (XCs) as filler in the Cs matrix towards the interfacial, homogeneity and rigidity of the produced Cs bio composites. XCs was synthesized using three different cross linking agents named as 1,2,4,5-benzentetr carboxylic (BT), 4,4’-oxydiphtalic anhydride (ODA) and 3,3’,4,4’-diphthalic anhydride (DPA) which consequently produced three different types of XCs filler; 1,2,4,5-benzentetra carboxylic-chitosan (BTC), 4,4’-oxydiphtalic anhydride-chitosan (ODAC) and 3,3’,4,4’- diphthalic anhydride-chitosan (DPAC)

Bio-nanocomposites from natural fibre derivatives: manufacturing and properties

Bionano-materials are playing an important role in a number of applications due to their inherent eco-friendly advantages since the last few decades. These materials are being explored as the potential alternatives to traditional synthetic materials for diverse applications with particular emphasis as green reinforcement and offer a number of advantages including considerable toughness, flexibility, easy processing, and recyclability. Indeed, nano-sized materials often display an out-standing equilibrium between toughness and strength and frequently enhanced characteristics of their individual components. The effect of different manufacturing conditions and different surface modification techniques for the bionano- materials as well as their polymer composites is discussed in details. Indeed, bionano-material-reinforced polymer composites are emerging very rapidly as the potential substitute to the metal- or ceramic-based materials in applications including automotive, aerospace, marine, sporting goods, and electronic industries

Multi-functionalized carbon nanotubes polymer composites: properties and applications

Carbon nanotubes (CNTs) is a rigid rod-like nanoscale material produced from carbon in powder, liquid, or gel form via acid or chemical hydrolysis. Due to its unique and exceptional renewability, biodegradability, mechanical, physicochemical properties, and abundance, the incorporation associated with a small quantity of CNTs to polymeric matrices enhance the mechanical and thermal resistance, and also stability of the latter by several orders of magnitude. Moreover, NCC-derived carbon materials are of no serious threat to the environment, providing further impetus for the development and applications of this green and renewable biomaterial for lightweight and degradable composites. Surface functionalization of CNTs remains the focus of CNTs research in tailoring its properties for dispersion in hydrophilic and hydrophobic media. Through functionalization, the attachment of appropriate chemical functionalities between conjugated sp² of CNTs and polymeric matrix is established. It is thus of utmost importance that the tools and protocols for imaging CNTs in a complex matrix and quantify its reinforcement, antimicrobial, stability, hydrophilicity, and biodegradability are be developed

Supramolecular assembly and spectroscopic characterization of indolenine–barbituric acid zwitterions

A series of indolenine and barbituric acid zwitterion scaffolds were synthesized with a maximum yield of 98% via the formation of C–C single bond. The structures were unambiguously elucidated by various spectroscopic techniques such as 1H, 13C NMR (1D, 2D), FT-IR and high-resolution mass spectrometry (HRMS). Single crystal X-ray crystallography analysis on 22, as the 22.DMF 1:1 solvate, confirms the presence of wellseparated iminium and enolate centres, and also confirms that the BA ring is highly twisted with respect to the indolenine ring due to steric hindrance. The presence of N–H∙∙∙O and N–H∙∙∙O- groups favour a 1D-supramolecular assembly in the solid-state. The orange or yellow solutions of the zwitterion exhibit an intense molar absorption coefficient, ε ranging between 0.21 × 104 and 2.93 × 104 M-1 cm-1 in the UV-vis region. Furthermore, the Intramolecular Charge Transfer (ICT) peak of zwitterion displays a hypsochromic shift in absorption behavior when the polarity of the solvent increases. Moreover, treatment of small amount of trifluoroacetic acid (TFA) to the DMF solution of 19 resulted in the protonation of an enolate of BA ring. This fundamental work provides valuable structural design and information for the construction of supramolecular chemistry and synthetic dyes based on indolenine substituted BA derivatives

Response surface approach for visible light assisted photocatalytic degradation of ortho nitrophenol by magnetically separable TiO2/CS nanocomposite

Visible light induces photocatalytic degradation technology has gained increasing interest in the treatment of organic pollutants for the wastewater system. In this study, magnetically separable nanocomposite (M-TiO 2 /CS) was successfully synthesized with a narrow band gap (2.85 eV) than pure TiO 2 . A central composited design (CCD) coupled with response surface methodology (RSM) was effectively utilized to inquire about the photocatalytic degradation of ONP degradation by using M-TiO 2 /CS. Three independent factors including the M-TiO 2 /CS loading, initial ONP concentration, and pH of the solution were examined in details. Based on the results obtained from RSM analyses, an efficient pathway leading to the high degradation rate (92%) was achieved by applying 0.02 g of M-TiO 2 /CS dosage with 30 mg/L of a concentration of ONP at pH 6 for 180 min. The experimental results fit well with the derived response model (R 2 = 0.9789). The current study proposed a cost-effective and highly efficient approach to wastewater pollution issues. © 201

Functionalized Activated Carbon Derived from Biomass for Photocatalysis Applications Perspective

This review highlighted the developments of safe, effective, economic, and environmental friendly catalytic technologies to transform lignocellulosic biomass into the activated carbon (AC). In the photocatalysis applications, this AC can further be used as a support material. The limits of AC productions raised by energy assumption and product selectivity have been uplifted to develop sustainable carbon of the synthesis process, where catalytic conversion is accounted. The catalytic treatment corresponding to mild condition provided a bulk, mesoporous, and nanostructure AC materials. These characteristics of AC materials are necessary for the low energy and efficient photocatalytic system. Due to the excellent oxidizing characteristics, cheapness, and long-term stability, semiconductor materials have been used immensely in photocatalytic reactors. However, in practical, such conductors lead to problems with the separation steps and loss of photocatalytic activity. Therefore, proper attention has been given to develop supported semiconductor catalysts and certain matrixes of carbon materials such as carbon nanotubes, carbon microspheres, carbon nanofibers, carbon black, and activated carbons have been recently considered and reported. AC has been reported as a potential support in photocatalytic systems because it improves the transfer rate of the interface charge and lowers the recombination rate of holes and electrons

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications

Recent Advances in Heterogeneous Photocatalytic Decolorization of Synthetic Dyes

During the process and operation of the dyes, the wastes produced were commonly found to contain organic and inorganic impurities leading to risks in the ecosystem and biodiversity with the resultant impact on the environment. Improper effluent disposal in aqueous ecosystems leads to reduction of sunlight penetration which in turn diminishes photosynthetic activity, resulting in acute toxic effects on the aquatic flora/fauna and dissolved oxygen concentration. Recently, photodegradation of various synthetic dyes has been studied in terms of their absorbance and the reduction of oxygen content by changes in the concentration of the dye. The advantages that make photocatalytic techniques superior to traditional methods are the ability to remove contaminates in the range of ppb, no generation of polycyclic compounds, higher speed, and lower cost. Semiconductor metal oxides, typically TiO2, ZnO, SnO, NiO, Cu2O, Fe3O4, and also CdS have been utilized as photocatalyst for their nontoxic nature, high photosensitivity, wide band gap and high stability. Various process parameters like photocatalyst dose, pH and initial dye concentrations have been varied and highlighted. Research focused on surface modification of semiconductors and mixed oxide semiconductors by doping them with noble metals (Pt, Pd, Au, and Ag) and organic matter (C, N, Cl, and F) showed enhanced dye degradation compared to corresponding native semiconductors. This paper reviews recent advances in heterogeneous photocatalytic decolorization for the removal of synthetic dyes from water and wastewater. Thus, the main core highlighted in this paper is the critical selection of semiconductors for photocatalysis based on the chemical, physical, and selective nature of the poisoning dyes

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications