Ionic liquids as a sustainable platform for Nanocellulose processing from Bioresources: overview and current status

The two-fold threats of the crisis of petrochemical industry-based plastics and serious environmental pollution have triggered the valorization of naturally occurring biopolymers to produce nanocellulose (NC). Nanocellulose has been used extensively in a variety of demanding applications due to its excellent features including biocompatibility, light weight, tunable surface properties, and improved environmental footprint. However, the sustainable production of NC is still confronted with bottlenecks to realize commercial feasibility due to poor solubility and hard processability of biopolymers using conventional hazardous solvents and reagents including concentrated sulfuric acid. The key might rest on the use of ionic liquids (ILs) that have induced a great deal of interest in recent years as powerful “green” solvents for biopolymer processing. ILs can be used as a catalyst and/or reaction medium and/or swelling agent for NC production with an eminent yield of high-quality NC under mild operating conditions coupled with proficient recoverability and recyclability. This review presents the recent technological developments of ILs-assisted proper valorization strategies of numerous bioresources for NC isolation and modification. The impact of IL cation/anion on structural changes of NC is also covered. The major advances in exploring ILs for NC surface modification reactions such as esterification, silylation, and surface plasticization as well as the microscopic insights of NC interaction with ILs are also reviewed. In view of the dominance of green chemistry principles for high purity of the recovered nanocellulose, close R&D endeavors for cheap and biodegradable ILs conjoined with emerging recycling techniques might boost sustainable commercialization

Influence of different compositions of fly ash as fluxing agent in porcelain

Fly ash is alumina-silica waste products from the combustion of palm fiber and shells in the boiler which are collected at the multi-cyclone collectors where almost 3 million tonnes per annum being produced in palm oil industry in Malaysia. The aim of this paper is to investigate the replacement of feldspar by fly ash as potential fluxing agent in triaxial porcelain. Clay, feldspar, quartz and fly ash were mixed for 12 hours, pressed into pellets and sintered at 1250 ºC. The samples were measured according to the physical and mechanical properties. Microstructure study was done through SEM analysis. The optimum composition of fly ash was observed at 5 wt.% where the maximum compressive strength was achieved at 105.04 MPa and shows the decreasing results in volume shrinkage. SEM study shows intense interlocking between the primary and secondary mullite needles in glassy matrix which contribute in improving the strength of the porcelain at this composition. Therefore the substitution of fly ash is suitable as a fluxing agent in porcelain that improved its physical and mechanical properties

Fast-charging of Lithium-ion batteries with ohmic-drop compensation method

L'objectif de cette thèse est l’étude de la charge rapide de batteries lithium-ion basée sur la méthode de la compensation chute ohmique. Cette méthode permet théoriquement de réduire le temps total de charge des batteries. Dans cette thèse, cette méthode a été mise en œuvre sur trois types différents de cellules de format 18650 : C/ FP, C/NMC et LTO/LFP. Cette méthode montre de bons résultats pour les batteries C/LFP et LTO/LFP avec une réduction du temps de charge total d'environ 70% par rapport à la méthode classique. Néanmoins, cette méthode présente des inconvénients comme notamment l’élévation de la température interne de la batterie pendant la charge rapide. De plus, cette méthode implique un courant élevé et conduit à des potentiels élevés qui peuvent engendrer également des dégradations. En particulier, nous avons démontré que la batterie C / LFP subissait des dégradations internes notamment une déformation mécanique de l’enroulement et une dégradation de la composition d’électrolyte.The aim of this thesis is to study fast-charging of lithium-ion, battery using the ohmic-drop compensation method. The latter method theoretically will reduce the total charging of the batteries considered. In this thesis, the ODC method was implemented on three different types of 18650 battery cells. These batteries are C/LFP, C/NMC and LTO/LFP. This method show a good result for C/LFP and LTO/LFP batteries with a reduction of total charging time of about 70% in comparison with the classical method. Nevertheless, there are some issues regarding this method; the temperature elevation of the battery is high during fast-charging. Indeed, almost all fast-charging procedure experiences the same problem concerning that matter. Moreover, with ODC fast-charging method, high current rate and high voltage will worsen the situation. These complications of the ODC fast-charging method are key points for both performance and durability of the batteries. Particularly, we have demonstrated that C/LFP battery underwent internal degradation as a mechanical deformation of the active materials and degradation of electrolyte

Charge rapide de batteries lithium-ion basée sur la compensation de chute-ohmique

The aim of this thesis is to study fast-charging of lithium-ion, battery using the ohmic-drop compensation method. The latter method theoretically will reduce the total charging of the batteries considered. In this thesis, the ODC method was implemented on three different types of 18650 battery cells. These batteries are C/LFP, C/NMC and LTO/LFP. This method show a good result for C/LFP and LTO/LFP batteries with a reduction of total charging time of about 70% in comparison with the classical method. Nevertheless, there are some issues regarding this method; the temperature elevation of the battery is high during fast-charging. Indeed, almost all fast-charging procedure experiences the same problem concerning that matter. Moreover, with ODC fast-charging method, high current rate and high voltage will worsen the situation. These complications of the ODC fast-charging method are key points for both performance and durability of the batteries. Particularly, we have demonstrated that C/LFP battery underwent internal degradation as a mechanical deformation of the active materials and degradation of electrolyte.L'objectif de cette thèse est l’étude de la charge rapide de batteries lithium-ion basée sur la méthode de la compensation chute ohmique. Cette méthode permet théoriquement de réduire le temps total de charge des batteries. Dans cette thèse, cette méthode a été mise en œuvre sur trois types différents de cellules de format 18650 : C/ FP, C/NMC et LTO/LFP. Cette méthode montre de bons résultats pour les batteries C/LFP et LTO/LFP avec une réduction du temps de charge total d'environ 70% par rapport à la méthode classique. Néanmoins, cette méthode présente des inconvénients comme notamment l’élévation de la température interne de la batterie pendant la charge rapide. De plus, cette méthode implique un courant élevé et conduit à des potentiels élevés qui peuvent engendrer également des dégradations. En particulier, nous avons démontré que la batterie C / LFP subissait des dégradations internes notamment une déformation mécanique de l’enroulement et une dégradation de la composition d’électrolyte

Insight into the molecular mechanism that controls the solubility of CH4 in ionic liquids

The solubility of methane (CH4) in ionic liquids (ILs) is required in order to develop processes involving CH4, such as methane conversion and CO2/CH4 separation from natural gas or biogas processes. Nevertheless, the solubility of CH4 in ILs is still very rarely achieved and, consequently, fundamental knowledge about the factors that govern the solubility are still poorly understood. Therefore, this work aims to extend the solubility data of CH4 in various ILs and to gain some insights into the factors at a molecular level that play a role in the solubility process through experimental and computational modelling using Conductor-like Screening Model for Real Solvent (COSMO-RS). The solubility of CH4 in 17 commercial ILs was measured experimentally at four different temperatures (298.15 to 343.15 K) and pressures up to 8 MPa. The large number of ILs studied allows the study of the impact of the cation and anion head group and the alkyl chain length on the solubility of CH4. From the experimental solubility data collected, Henry’s law constant (KH) values were calculated. The results show that the solubility of CH4 increases with decreasing temperature and increasing pressure. The solubility of CH4 can also be enhanced by increasing the alkyl chain length of the IL cation or anion. Despite the inability of COSMORS to make quantitative predictions, the model is able to predict accurately the impact of the IL cation head group, anion, and alkyl chain length on the solubility of CH4. Good correlation between the electrostatic – misfit energy, HE,MF, of CH4 and the experimentally calculated KH values was obtained (R2 = 0.932). This correlation indicates, for the first time, that the electrostatic – misfit energy arising from the repulsive interaction of CH4 plays a dominant role in determining its solubility in ILs. In addition, it is shown that the IL size and van der Waals forces only have marginal influences on the solubility of CH4. The experimental and computational modelling results in this work could pave the way to designing ILs as a medium for gas absorption and separation involving CH4

Ionic Liquids as a Sustainable Platform for Nanocellulose Processing from Bioresources: Overview and Current Status

The two-fold threats of the crisis of petrochemical industry-based plastics and serious environmental pollution have triggered the valorization of naturally occurring biopolymers to produce nanocellulose (NC). Nanocellulose has been used extensively in a variety of demanding applications due to its excellent features including biocompatibility, light weight, tunable surface properties, and improved environmental footprint. However, the sustainable production of NC is still confronted with bottlenecks to realize commercial feasibility due to poor solubility and hard processability of biopolymers using conventional hazardous solvents and reagents including concentrated sulfuric acid. The key might rest on the use of ionic liquids (ILs) that have induced a great deal of interest in recent years as powerful “green” solvents for biopolymer processing. ILs can be used as a catalyst and/or reaction medium and/or swelling agent for NC production with an eminent yield of high-quality NC under mild operating conditions coupled with proficient recoverability and recyclability. This review presents the recent technological developments of ILs-assisted proper valorization strategies of numerous bioresources for NC isolation and modification. The impact of IL cation/anion on structural changes of NC is also covered. The major advances in exploring ILs for NC surface modification reactions such as esterification, silylation, and surface plasticization as well as the microscopic insights of NC interaction with ILs are also reviewed. In view of the dominance of green chemistry principles for high purity of the recovered nanocellulose, close R&D endeavors for cheap and biodegradable ILs conjoined with emerging recycling techniques might boost sustainable commercialization

Influence on the phase formation and strength of porcelain by partial substitution of fly ash compositions

This paper presents the study of the influence on the phase formation and strength of the porcelain by the partial substitution of fly ash. The fly ash was calcined at the temperature of 800 °C and partially substituted into feldspar. Each mixture were mixed and pressed into green pellets sintered at different sintering temperature (1100 – 1300 °C) at the interval of 50 °C for 120 min. The compressive strength, crystalline phase and the microstructure of the porcelain were investigated. The optimum physical and mechanical properties were obtained at 5 wt % of fly ash porcelain sintered at 1250 °C. The apparent porosity reaches a minimum value with 0.22 % which is nearly to zero and obtained the highest compressive strength of 105.40 MPa. The XRD results reveal that the highest percentage of mullite was obtained at the substitution of 5 wt % of fly ash with 49.0 %. The glassy phase shows an increasing trend with dissolution of mullite content which affects the strength and microstructure of the porcelain