Zakaria Man

Dissolution and Delignification of Bamboo Biomass Using Amino Acid-Based Ionic Liquid

In the present work, the dissolution of bamboo biomass was tested using a number of ionic liquids synthesized in laboratory. It was observed that one of the synthesized amino acid-based ionic liquids, namely 1-ethyl-3-methylimidazolium glycinate, was capable of dissolving the biomass completely. The dissolved biomass was then regenerated using a reconstitute solvent (acetone/water) and was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results were compared to preconditioned bamboo biomass. The regenerated biomass was found to have a more homogenous macrostructure, which indicates that the crystalline form and structure of its cellulose has changed from type Ι to type ΙΙ during the dissolution and regeneration process.

Ionic liquid—a future solvent for the enhanced uses of wood biomass

Biomass refers to biological materials that can be used as fuel or for the production of chemicals. Globally, ever growing demand of energy and concerns for the environment have prompted researchers to develop convenient and efficient ways for converting wood biomass into valuable chemicals, bio-fuels and useful biomaterials. In this context, ionic liquid has the potential to play a major role. Ionic liquids, considered as green solvents, have been found capable of dissolving wood biomass, and the dissolution process can be enhanced in a number of ways, like heating, microwave treatment, addition of acids etc. The anionic part of ionic liquid plays an important role in this process coupled with hydrogen bond basicity (β) property of ionic liquid, which has a significant effect on wood biomass dissolution. This paper reviews the applications of ionic liquids for the dissolution, fractionation and regeneration of wood biomass. It is also related to the processing of cellulose and wood biomass, preparation of cellulose and wood biomass derivatives and composites.ZusammenfassungAls Biomasse werden biologische Stoffe bezeichnet, die für die Energieerzeugung oder die Herstellung von Chemikalien verwendet werden. Der weltweit stetig zunehmende Energiebedarf und steigendes Umweltbewusstsein haben bewirkt, dass Wissenschaftler praktische und effiziente Verfahren zur Umwandlung von Biomasse in wertvolle Chemikalien, Biotreibstoffe und brauchbare Biomaterialien entwickeln. In diesem Zusammenhang könnten ionische Flüssigkeiten eine große Rolle spielen. Ionische Flüssigkeiten gelten als umweltfreundliche Lösungsmittel und sind in der Lage, Holzbiomasse aufzulösen. Dieser Auflösungsprozess kann auf verschiedene Art und Weise, wie zum Beispiel durch Erhitzung, Mikrowellenbehandlung, Zugabe von Säuren etc., verbessert werden. Der anionische Anteil der ionischen Flüssigkeit spielt dabei in Verbindung mit der Wasserstoffbrückenbasizität (β) der ionischen Flüssigkeit, die einen signifikanten Einfluss auf die Auflösung der Holzbiomasse hat, eine große Rolle. Diese Studie gibt einen Überblick über die Verwendung der ionischen Flüssigkeit zur Auflösung, Fraktionierung und Gewinnung von Holzbiomasse. Daneben wird auch auf die Verarbeitung von Zellulose und Holzbiomasse sowie die Herstellung von Zellulose und anderen Holzbiomasseprodukten sowie Verbundwerkstoffen eingegangen.

Latest Development on Membrane Fabrication for Natural Gas Purification: A Review

In the last few decades, membrane technology has been a great attention for gas separation technology especially for natural gas sweetening. The intrinsic character of membranes makes them fit for process escalation, and this versatility could be the significant factor to induce membrane technology in most gas separation areas. Membranes were synthesized with various materials which depended on the applications. The fabrication of polymeric membrane was one of the fastest growing fields of membrane technology. However, polymeric membranes could not meet the separation performances required especially in high operating pressure due to deficiencies problem. The chemistry and structure of support materials like inorganic membranes were also one of the focus areas when inorganic membranes showed some positive results towards gas separation. However, the materials are somewhat lacking to meet the separation performance requirement. Mixed matrix membrane (MMM) which is comprising polymeric and inorganic membranes presents an interesting approach for enhancing the separation performance. Nevertheless, MMM is yet to be commercialized as the material combinations are still in the research stage. This paper highlights the potential promising areas of research in gas separation by taking into account the material selections and the addition of a third component for conventional MMM.

A comprehensive review on biodegradable polymers and their blends used in controlled-release fertilizer processes

Abstract Biodegradable polymer-coated controlled-release fertilizers (PC-CRFs) are essential means to reduce cost, improve marketability, conserve land fertility, achieve high crop yields and combat climate challenges. It is known that about 15–30% of any fertilizer packed in a PC-CRF does not get released due to the concentration gradient difference across the polymer coatings. To release the trapped fertilizer(s), it is desired that polymer-based coatings should biodegrade after the fertilizer is completely released into the soil. This review has aimed to provide a comprehensive account for various biodegradable polymers/blends derived either from natural or synthetic sources which are cited in the literature for PC-CRFs. In addition, this review covers the discussion on their classification criteria, trends in the processes of fertilizer coatings, methodological issues for their biodegradation assessment, coating attributes that affect the biodegradability and an outlook into their biodegradation kinetic models that involve enzymes and microbial processes. It also concludes that experimental as well as modeling data are insufficient to assess the biodegradation contribution of the overall nutrient release in PC-CRFs.

Review and selection criteria of classical thermodynamic models for acid gas absorption in aqueous alkanolamines

Abstract The knowledge of vapour-liquid equilibrium (VLE) and thermodynamic properties plays a pivotal role in the process development of absorption systems for acid gas capture in precombustion and postcombustion streams. A large number of thermodynamic modelling approaches for acid gas absorption in aqueous alkanolamine solutions are published in the literature. However, the reviews of these modelling techniques are limited and scattered. Moreover, poor guidelines exist for the selection of an appropriate modelling approach for the VLE prediction of the aforementioned system. Therefore, the current study presents a concise classification and review of classical thermodynamic models for acid gas absorption in aqueous alkanolamine solutions since their inception. The article systematically details the chronological development and highlights the major capabilities and limitations of classical thermodynamic approaches, namely, semiempirical models, activity coefficient models, and equation of state (and equation of state/excess Gibbs energy) models. A graphical comparison of VLE prediction by each classical approach is presented to form a general guideline in the selection of a suitable approach for process development studies. The review precisely discusses the issues, challenges, and future prospects of each classical thermodynamic approach in the context of application, complexity, and development.

Effect of fixed carbon molecular sieve (CMS) loading and various di-ethanolamine (DEA) concentrations on the performance of a mixed matrix membrane for CO2/CH4 separation

Polyethersulfone (PES) as a polymer along with carbon molecular sieves (CMS) as an inorganic filler and di-ethanolamine (DEA) as the third component were used to fabricate amine mixed matrix membranes (A3Ms). The CMS and the developed membranes were characterized by variable pressure field emission scanning electron microscopy (VPFESEM) and thermal gravimetric analysis (TGA). FESEM micrographs showed that with the addition of DEA, uniform distribution of CMS particles in the PES matrix was achieved with good polymer-filler contact. The combined effect of DEA concentration (5–15 wt%), feed pressure (2–10 bar) and CMS loading on the CO2/CH4 transport properties of the PES–CMS–DEA membranes were studied. The results revealed that the PES–CMS–DEA (15 wt% DEA) membrane showed a CO2 permeance of 123.49 GPU at 2 bar, which is more than a threefold increment with respect to the native PES membrane. The corresponding CO2/CH4 ideal selectivity was increased from 5.40 for PES to 51.39 for PES–CMS–DEA (15 wt% DEA). The CO2 permeance of the PES–CMS–DEA (A3Ms) membranes was higher than PES membranes over the operating pressure range.

Improvement of Hydrophobicity of Urea Modified Tapioca Starch Film with Lignin for Slow Release Fertilizer

Tapioca starch was chemically modified with urea in the presence of borate as crosslinker and catalyst. Fourier transform infrared (FTIR) and viscosity were performed to measure qualitatively the reactivity of the mixture. To improve the hydrophobicity, 10% of lignin (10%L) was then added into the starch-urea-borate (SUB) system. The incorporation of lignin leads to lower water uptake film. It was found that lignin retards the urea release and the SUB10%L film is stable and stayed intact for one month after immersing in water which shows high potential as a biopolymer for slow release fertilizer.

Synthesis, characterization and the effect of temperature on different physicochemical properties of protic ionic liquids

In this work, eleven protic ionic liquids (PILs) containing different cations and anions were prepared and their physicochemical properties were measured. The structures of all the PILs were confirmed using NMR, and elemental analysis (CHNS) was carried out. The physicochemical properties such as density, surface tension, viscosity and thermal degradation behaviour were measured, and the effect of the cations/anions was investigated. The density and viscosity were measured within the temperature range of 293.15–373.15 K at atmospheric pressure. The thermal expansion coefficient values were calculated from the density data. Surface tension was measured in the temperature range of 293.15 to 353.15 K and the values were used to estimate the surface entropy and enthalpy of the ionic liquids at 303.15 K. The boiling and critical temperature are also estimated according to the Eotvos and Rebelo methods. The refractive indices were measured within the temperature range of 293.15 to 323.15 K. The thermal gravimetric analysis was performed in the temperature range of 373.15–773.15 K.

Effective removal of methylene blue from water using phosphoric acid based geopolymers: synthesis, characterizations and adsorption studies

Phosphoric acid based geopolymers (PAGPs) are a class of geopolymers that are produced by phosphoric acid activation of metakaolin. In this work, two different PAGPs have been synthesized using phosphoric acid to alumina molar ratios of 1 : 1 and 1.2 : 1. The surface profile, chemical composition, micromorphology, and texture properties of the geopolymers were instrumentally determined. Both geopolymers have shown a mesoporous profile with the avg. pore size of 8.6 and 19.4 nm by GP-1M (P : Al = 1 : 1) and GP-2M (P : Al = 1.2 : 1), respectively. Thermogravimetric analysis revealed that these geopolymers were thermally stable up to 800 °C, although the formation of quartz, cristobalite and tridymite was observed in XRD analysis of the samples treated at 800 °C for two hours. The synthesized geopolymers were utilized for the adsorption of methylene blue (MB) by investigating the effect of the amount of adsorbent, pH of the solution and shaking period. The batch kinetics study fitted best into the pseudo second order (PSO) reaction kinetic model. In isotherm modelling studies, the Langmuir isotherm model was best fitted and was used to describe the mechanism of the adsorption. Experimental adsorption capacities (qe) of 2.84 and 3.01 mg g−1 were recorded for GP-1M and GP-2M, respectively. Used adsorbents were successfully regenerated by furnace treatment at 400 °C for two hours, and the regenerated adsorbents presented enhanced adsorption capacities in the range of 4.9–5.07 mg g−1 for five repeat cycles, elucidating that the material is suitable for multiple time use.

Surface modification in inorganic filler of mixed matrix membrane for enhancing the gas separation performance

Abstract The development of mixed matrix membrane (MMM) in gas separation process has drawn great attention due to its promising properties. MMM consists of a polymer as the matrix phase, whereas the inorganic filler serves as the dispersed phase. However, poor contact between these two phases often results in unselective gas flow and becomes one of the major issues in the MMM development. Currently, various modification techniques of the inorganic filler to improve the compatibility between the polymers and the particles have been reported. Because of this modification, the CO2 separation from natural gas is expected to enhance. This review provides a better understanding about the modification of inorganic filler. Mechanisms and factors affecting the modification of filler such as the effect of solvent polarity, the effect of water content in solvent, and the effect of drying condition are discussed. The details of the current progress in the MMM involving the silane-modified fillers are also summarized.