A Review Featuring Fabrication,Properties, and Application of Polymeric Mixed Matrix Membrane Reinforced with Different Fillers

Mixed matrix membrane is composed of polymer matrix reinforced with organic or inorganic particles to improve its performance. This review presents comprehensive study on fabrication, properties, and application of polymeric composite-based mixed matrix membrane. Inorganic fillers (silica, alumina, and zeolite) are extensively used in mixed matrix membrane due to low cost, abundance, and simplistic surface treatment. Organic fillers (graphene and carbon nanotube) are also preferred due to low specific gravity, and high thermal, flame, and chemical resistance. Reinforcement of these nanofiller during membrane provides flux enhancement and low fouling. Various applications of mixed matrix membrane such as in tissue engineering, catalysis, and electrochemistry have also been discussed.     

Progression from Polyimide to Polyimide Composite in Proton-Exchange Membrane Fuel Cell: A Review

This review is designed as a comprehensive source of research on polyimide and polyimide composite-based fuel cell membranes. Polyimide and modified polyimide-based nanocomposite fuel cell membranes have gained research attention due to high operation temperature of ～150°C. To increase the lifetime of polyimide-based fuel cell, water stability and dimensional stability of hydrated membrane have been studied. Nanofillers such as silica, titania, graphene, carbon nanotube, and polyhedral oligomeric silsesquioxane have been reinforced in polyimide to improve proton conductivity (at low humidity/high temperature) and water stability. Design of new polyimide composite membranes must be focused in future for high water, chemical, and mechanical stability.     

State-of-the-Art Overview on Polymer/POSS Nanocomposite

Research into polymer containing polyhedral oligomeric silsesquioxane has been expanded during the past years, enlightening new categories of polymer/polyhedral oligomeric silsesquioxane nanocomposite and unanticipated applications. These hybrids own superior structural and functional properties (strength, thermal stability, optical features, low toxicity, biocompatibility) due to nanometer size of polyhedral oligomeric silsesquioxane. The state of polyhedral oligomeric silsesquioxane-reinforced polymeric [poly(methyl methacrylate, poly(vinyl chloride), polyurethane, polyamide, epoxy, and poly(ethylene glycol)] systems are reviewed in this article. Physical blending, covalent bonding, and chemical cross-linking have been used to provide excellent reinforcement. A comprehensive coverage of various appliances of polymer/polyhedral oligomeric silsesquioxane nanocomposite has been given particularly aerospace, semiconducting material, biomedical, and textile industry.     

Emerging Research Trends in Polyurethane/Graphene Nanocomposite: A Review

Polyurethane is a versatile engineering material, which is usually synthesized by polyaddition of polyol, isocyanate, and chain extender. Graphene is a monolayer of carbon atoms packed into honeycomb structure with fascinating thermal, electrical, and mechanical properties. Among the rapidly expanding families of nanocomposite, polyurethane/graphene materials have attracted considerable attention in academia and industry. This article reviews essential aspects of graphene-reinforced polyurethane nanocomposite. Various strategies for fabricating polyurethane/graphene nanocomposite have been conversed. Recent developments in the field of polyurethane/graphene nanocomposite (as shape memory, adsorbent, electromagnetic interference shielding, and gas barrier materials), associated challenges, and future potential have been reviewed.     

Equilibrium modeling and kinetic studies on the adsorption of basic dye by a low-cost adsorbent: coconut (Cocos nucifera) bunch waste

In this paper, the ability of coconut bunch waste (CBW), an agricultural waste available in large quantity in Malaysia, to remove basic dye (methylene blue) from aqueous solution by adsorption was studied. Batch mode experiments were conducted at 30 degrees C to study the effects of pH and initial concentration of methylene blue (MB). Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to Langmuir isotherm and the monolayer adsorption capacity was found to be 70.92 mg/g at 30 degrees C. The kinetic data obtained at different concentrations have been analyzed using a pseudo-first-order, pseudo-second-order equation and intraparticle diffusion equation. The experimental data fitted very well the pseudo-second-order kinetic model.     

Adsorption of basic dye on high-surface-area activated carbon prepared from coconut husk: equilibrium, kinetic and thermodynamic studies

Adsorption isotherm and kinetics of methylene blue on activated carbon prepared from coconut husk were determined from batch tests. The effects of contact time (1-30 h), initial dye concentration (50-500 mg/l) and solution temperature (30-50 degrees C) were investigated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The equilibrium data were best represented by Langmuir isotherm model, showing maximum monolayer adsorption capacity of 434.78 mg/g. The kinetic data were fitted to pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and was found to follow closely the pseudo-second-order kinetic model. Thermodynamic parameters such as standard enthalpy (DeltaH degrees), standard entropy (DeltaS degrees) and standard free energy (DeltaG degrees) were evaluated. The adsorption interaction was found to be exothermic in nature. Coconut husk-based activated carbon was shown to be a promising adsorbent for removal of methylene blue from aqueous solutions.     

Batch removal of malachite green from aqueous solutions by adsorption on oil palm trunk fibre: equilibrium isotherms and kinetic studies

Oil palm trunk fibre (OPTF)--an agricultural solid waste--was used as low-cost adsorbent to remove malachite green (MG) from aqueous solutions. The operating variables studied were contact time, initial dye concentration, and solution pH. Equilibrium adsorption data were analyzed by three isotherms, namely the Freundlich isotherm, the Langmuir isotherm, and the multilayer adsorption isotherm. The best fit to the data was obtained with the multilayer adsorption. The monolayer adsorption capacity of OPTF was found to be 149.35 mg/g at 30 degrees C. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho's pseudo-second-order and Elovich models. It was found that the Lagergren's model could be used for the prediction of the system's kinetics. The overall rate of dye uptake was found to be controlled by external mass transfer at the beginning of adsorption, then for initial MG concentrations of 25, 50, 100, 150, and 300 mg/L the rate-control changed to intraparticle diffusion at a later stage, but for initial MG concentrations 200 and 250 mg/L no evidence was found of intraparticle diffusion at any period of adsorption. It was found that with increasing the initial concentration of MG, the pore-diffusion coefficient increased while the film-diffusion coefficient decreased.     

Kinetics and equilibrium studies of malachite green adsorption on rice straw-derived char

In this work, the potential feasibility of rice straw-derived char (RSC) for removal of C.I. Basic Green 4 (malachite green (MG)), a cationic dye from aqueous solution was investigated. The isotherm parameters were estimated by non-linear regression analysis. The equilibrium process was described well by the Langmuir isotherm model. The maximum RSC sorption capacity was found to be 148.74 mg/L at 30 degrees C. The kinetics of MG sorption on RSC followed the Lagergren's pseudo-first-order model and the overall rate of dye uptake was found to be controlled by external mass transfer at the beginning of adsorption, while intraparticle diffusion controlled the overall rate of adsorption at a later stage. The results indicated that RSC was an attractive adsorbent for removing basic dye from aqueous solutions.