ABSTRACT
5-hydroxymethylfurfural (5-HMF) is a promising high value-added platform chemical, which can be produced from glucose, fructose, or lignocellulosic biomass via catalysis technology. However, the effective separation of 5-HMF from aqueous solution and actual biomass hydrolysate is still challenging because 5-HMF can be further rehydrated into levulinic acid (LA) and formic acid (FA) under acidic conditions. Herein, the adsorption behavior of glucose and 5-HMF and its follow-up products (LA and FA) from aqueous solutions onto polymeric adsorbents modified with various functional groups (XAD-4, XAD7HP, and XAD761 resins) was systematically investigated. The results showed that XAD761 resin exhibited the highest adsorption selectivity (α5-HMF/glucose = 42.42 ± 5.84, α5-HMF/FA = 18.41 ± 0.50, and α5-HMF/LA = 3.01 ± 0.10) and capacity for 5-HMF (106 mg g-1 wet resin). The adsorption equilibrium was better fitted by the Freundlich isotherm model at the studied range of 5-HMF concentrations. The thermodynamic study and activation energy also revealed that the adsorption process of XAD761 resin for 5-HMF was spontaneous, exothermic, and physical. The kinetic regression results revealed that the kinetic data of 5-HMF was accurately followed by the pseudo-second-order kinetic model. In conclusion, the present study revealed that the potential of phenol formaldehyde resin with hydroxyl groups could be used as an adsorbent for aldehyde organic compounds.
ABSTRACT
In these studies, a low-cost and energy efficiency production of cellulosic ethanol from sugarcane bagasse (SCB) using one-pot without solid-liquid separation, water washing, and detoxification was performed. Firstly, SCB was pretreated using liquid hot water as the only reagent at 210 °C for a short time (0 min), and the solid liquid ratio (SLR) was 1:20 (w/v). Then, the whole slurry of pretreated SCB was enzymatically hydrolyzed and fermented for cellulosic ethanol in one-pot. The results indicated that the one-pot preparation for ethanol achieved a high total fermentable sugar conversion of 84.52 ± 1.24%, containing 88.61 ± 1.57% of glucose and 78.01 ± 1.63% of xylose. Moreover, the ethanol yield reached 257 ± 5.51 mg/g SCB, which was 77.56 ± 1.64% of the theoretical ethanol conversion from SCB. Importantly, there was no wastewater discharge in the whole process. Overall, the present work provides an economically feasible method for ethanol production.
Subject(s)
Saccharum , Cellulose , Ethanol , Fermentation , Hydrolysis , WaterABSTRACT
To enhance our understanding of the influence of quaternary ammonium salts on CH4 hydrate formation, the chosen anti-agglomerant lauroylamide propylbetaine (LPB) was tested in an oil-water system in this work and analyzed by Raman spectroscopy, PXRD, and SEM. The results showed that LPB promoted CH4 hydrate formation by reducing the induction time and increasing the CH4 consumption rate for hydrate growth. The promotion effect on the CH4 hydrate growth was the best when the LPB concentration reached 0.18 wt%. Raman and PXRD analyses of the hydrate samples showed that the ratio of the CH4 molecules in large and small cages was below 3 and the (222) plane of the CH4 hydrate formed from an LPB solution was obviously lower compared to that for a typical CH4 hydrate. It was suggested that the positions of the water molecules in the host water lattice changed. The LPB molecules were thought to modify the surface structure of the hydrate phase, where the methyl head groups of LPB were allowed to penetrate both the 51262 and 512 cages of the CH4 hydrate. The modifications on the hydrate surface were further revealed by SEM images. The porous surface of the formed solids turned into curved sheets when LPB was added. Therefore, the mechanical properties of the bulk solid phase were assumed to be weakened.
