In recent years there has been growing interest in the use of dimethyl ether (DME) as an alternative fuel. In this study, the adsorption of DME on molecular sieves 4 Å (Mol4A) and 5 Å (Mol5A) has been experimentally investigated using the volumetric adsorption method. Data on the adsorption isotherms, heats of adsorption, and adsorption kinetic have been obtained and used to draw conclusions and compare the performance of the two adsorpents. Within the conditions considered, the adsorption capacity of Mol5A was found to be around eight times higher than the capacity of Mol4A. Low temperature adsorption and thermal pre-treatment of the adsorbents in vacuum were observed to be favourable for increased adsorption capacity. The adsorption isotherms for both adsoprbent were fitted to the Freundlich model and the corresponding model parameters are proposed.The adsoprtion kinetic analysis suggest that the DME adsorption on Mol5A is controlled by intracrystalline diffusion resistance, while on Mol4A it is mainly controlled by surface layering resistance with the diffusion only taking place at the start of adsorption and for a very limited short time. The heats of adsorption were calculated by a calorimetric method based on direct temperature measurements inside the adsorption cell. Isosteric heats, calculated by the thermodynamic approach (Clasius-Clapeyron equation), have consistently shown lower values. The maximum heat of adsorption was found to be 25.9 kJ mol -1 and 20.1 kJ mol -1 on Mol4A and Mol5A, respectively; thus indicating a physisorption type of interactions.

Highlights For oligosaccharides production, SE and [C 2 mim][OAc] pretreatment is advised. 90% (w/w) of initial biomass xylan dissolved to XOS via [C 2 mim][OAc] pretreatment. Up to 50% glucan to GOS conversion using commercial endo -1,4-β-D-glucanases. 33% extra profit for SE + [TEA][HSO 4 ] compared to [TEA][HSO 4 ] pretreatment. XOS could contribute to economic viability of an integrated biorefining process.

Two anhydrosugar model compounds (cellobiose and levoglucosan), and a mixture of anhydrosugars from the fast-pyrolysis of birch wood were subjected to acid hydrolysis using sulfuric acid as catalyst. The anhydrosugars mixture or bio-oil aqueous fraction was found to contain mainly levoglucosan with a concentration of 30 g L-1. Hydrolysis temperature, reaction time, and catalyst to substrate molar ratios (c/s), were varied to identify their influence for glucose production. At 120 °C, 60 minutes, and 0.9 c/s ratio; glucose yields of 98.55% and 96.56%, and substrate conversions of 100% and ~92%, were achieved when hydrolysing cellobiose and levoglucosan respectively. An increase in the temperature to 135 °C, resulted in a decrease in both glucose yield and selectivity; whereas substrate conversions around 90% were maintained for both anhydrosugars. During the hydrolysis of the bio-oil fraction, a range of conditions to achieve glucose yields above 90%, was depicted. It was found that c/s ratios between 0.17 and 0.90, and temperatures between 118 °C and 126 °C were suitable to achieve glucose yields around 100% (30 g L-1). Furthermore glucose concentrations ~117% (35 g L-1) and levoglucosan conversions above 90%, were attained at 135 °C, 20 minutes and 0.2 estimated c/s ratio.

Background: Platform chemicals are essential to industrial processes. Used as starting materials for the manufacture of diverse products, their cheap availability and efficient sourcing are an industrial requirement. Increasing concerns about the depletion of natural resources and growing environmental consciousness have led to a focus on the economics and ecological viability of bio-based platform chemical production. Contemporary approaches include the use of immobilized enzymes that can be harnessed to produce high-value chemicals from waste. Results: In this study, an engineered glucose dehydrogenase (GDH) was optimized for gluconic acid (GA) production. Sulfolobus solfataricus GDH was expressed in Escherichia coli. The K m and V max values for recombinant GDH were calculated as 0.87 mM and 5.91 U/mg, respectively. Recombinant GDH was immobilized on a hierarchically porous silica support (MM-SBA-15) and its activity was compared with GDH immobilized on three commercially available supports. MM-SBA-15 showed significantly higher immobilization efficiency (> 98%) than the commercial supports. After 5 cycles, GDH activity was at least 14% greater than the remaining activity on commercial supports. Glucose in bread waste hydrolysate was converted to GA by free-state and immobilized GDH. After the 10th reuse cycle on MM-SBA-15, a 22% conversion yield was observed, generating 25 gGA/gGDH. The highest GA production efficiency was 47 gGA/gGDH using free-state GDH. Conclusions: This study demonstrates the feasibility of enzymatically converting BWH to GA: immobilizing GDH on MM-SBA-15 renders the enzyme more stable and permits its multiple reuse.

Adsorption of methyl chloride (CH3Cl or MeCl) on five different types of adsorbents was investigated experimentally at increasing pressures and room temperature. Prior to adsorption, all adsorbents were analyzed to assess their physical and chemical characteristics. The experimental data was then used to determine the adsorption isotherms, heats of adsorption, adsorption rates, and their respective theoretical models. The MeCl adsorption capacity was found to reasonably correlate with the adsorbent's surface area. The MeCl adsorption isotherm and adsorption rates were fitted for the first time to a Freundlich isotherm model and pseudo first‐/second‐order kinetic models, respectively. The range of heat of adsorption indicated a physisorption type of bonding; hence, the investigated adsorbents can potentially be regenerated for cyclic adsorption.