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A novel core-shell sulfonated tin-loaded diatomite catalyst, namely SO 4 2−/CX-DMSn, was synthesized by hybridizing sulfuric carbon layer on DM-Sn intermedium. Lewis and Brønsted acid sites displayed on the surface of DM core and on the coated carbon layer of the SO 4 2−/CX-DMSn, respectively. The catalyst exhibited excellent catalytic ability, high water tolerance and good stability. The existence of acid sites and carbon layer on the diatomite were characterized by SEM, EDS, XRD, XPS, NH 3 -TPD and Py-IR. The unique core-shell structure of the carbonized diatomite catalyst significantly improved furfural production from xylose and lignocellulosic matrix even in organic solvent-free process. Results showed 66.24% of furfural yield and 79.92% of selectivity were obtained from xylose, whilst 65.74% of furfural yield and 66.83% of selectivity from corn cob, implying the side reactions for furfural production were well-eliminated. This strategy shows a promising application for novel SO 4 2−/CX-DMSn material toward effective and green catalytic production of furfural from biomass materials. Image 1 • SO 4 2−/CX-DMSn was prepared by hybridizing sulfuric carbon layer on tin-loaded diatomite. • High furfural yield and selectivity can be obtained when using water as solvent. • 65.74% of furfural yield and 66.83% of selectivity were obtained from corn cob. • The hydrophobicity and hierarchical active cites of catalyst affected the catalysis performances. [ABSTRACT FROM AUTHOR]

The treatment of high chemical oxygen demand (COD) organic wastewater is one of the major technical bottlenecks for the industrialization of second-generation biobutanol production. An effective strategy to decrease the wastewater discharge in biobutanol fermentation process is broth recycling (BR). Nevertheless, the conventional BR process suffered from server organic-acid by-products inhibition, causing low butanol yield. In this study, to solve the barrier, active carbon (AC) adsorption system was hybrid with the acetone-butanol-ethanol (ABE) fermentation and ex - situ product separation (ESPR) units. After fermentation and pervaporation, organic acids that remaining in the ABE-separated broth were partially adsorbed onto AC so that improve the continuity and efficiency of the BR process. The physicochemical characterizations of different types of commercial ACs and the organic acids adsorption efficiency was evaluated by analyzing the static and dynamic adsorptions kinetics. When adopting the DD-type AC (code C299105), the better adsorbent for organic acids removal, 87.50% of fermentative wastewater can be saved whilst the ABE concentrations were also kept constantly at 15.22 ± 0.45 g L−1 in the following cycles of fermentation, and the ABE productivity was almost no changed (0.21 ± 0.01 g L−1 h−1) after 3 cycles of operation. Therefore, the AC assisted ESPR process is an attractive method for ABE production with low wastewater discharge. [Display omitted] • Active carbon (AC) adsorption was hybrid with ex - situ ABE separation for broth recycling. • The commercial DD-type AC exhibited the high absorbability for acids specific loadings. • The static and dynamic adsorptions kinetics of DD-type AC for organic acids were evaluated. • 87.50% of fermentative wastewater can be saved after recycling the broth for 3 times. [ABSTRACT FROM AUTHOR]

Large amounts of effluent discharge and a costly wastewater treatment hinder the scale-up of the lignocellulosic acetone-butanol-ethanol (ABE) fermentation process. By recycling the broth after solvents removal and using it in the subsequent cycles of biomass hydrolysis and fermentation, the overall amount of effluent can be reduced. However, the ABE production is severely inhibited by the accumulated acids and other toxic by-products when reusing the cycled streams. In this study, a pervaporation assisted sequential fermentation was performed. The ABE liquor recovered after batch fermentation and ex situ pervaporation was used as the buffer for corn stover pulp hydrolysis and the following microbial lipids fermentation. In microbial lipids fermentation stage, toxic acid by-products remained in the liquor can be co-utilized as a substrate. The acids eliminated post-harvested broth was further cycled as the buffer for pulp hydrolysis and ABE fermentation. As a result, ABE yield of 0.349 g/g and concentration of 14.40 g/L were achieved after 3 cycles of operation, which show only 3.86% and 14.98% reduction compared to those of the initial cycle. Remarkably, the effluent discharge was reduced by 92.20% after applying the hybrid two-stage sequential fermentation. Meanwhile, 8.20 g/L of microbial lipids can be co-generated. The novel process offers an environmentally friendly strategy for the co-production of ABE and microbial lipids from lignocelluloses under the concept of biorefinery. Image 1 • ABE fermentation was hybrid with ex situ pervaporation and microbial lipids fermentation. • The effluent wastewater in the hybrid process was reused by a recycled loop. • Acids by-product in the ABE fermentation broth can be used as carbon source for lipids production. • Total 3 cycles of was conducted with 92.20% of ABE wastewater saving rate. • ABE and lipids production were not obvious decreased within 3 cycles of operation. [ABSTRACT FROM AUTHOR]