Porous ZSM-5 zeolite catalyst modified with sulfonic acid functional groups for hydrolysis of biomass

Sulfonated P-W modified nitrogen-containing carbon-based solid acid catalysts for one-pot conversion of cellulose to ethyl levulinate under water-ethanol medium

Converting cellulose (Cel) into ethyl levulinate (EL) is one of the promising strategies for supplying liquid fuels. In this paper, the prepared sulfonated P-W-modified N-containing carbon-based solid acid catalyst (PWNCS), in which the Polyaniline (PANI) was employed as N and C precursors, successfully converted Cel into EL under the water-ethanol medium. The characterization results demonstrated that a tiny addition of P increased the Brønsted acid sites (BAS) content and defective WO3 provided the Lewis acid sites (LAS), meanwhile, the sulfonation process did not change the fundamental structure but introduced the sulfonic groups to dramatically increase the acidic content. Therefore, under optimized reaction conditions, PWNCS realized about 100% Cel conversion and 71.61% of EL yield, furthermore, the selectivity of EL reached 89.14%. In addition, the effect of water on the reaction pathway of Cel to EL over PWNCS was proposed. The addition of water generally resulted in the hydration of defective WO3 to reduce the LAS and increase BAS, which significantly inhibited the side reactions of retro-aldol condensation (RAC) and subsequent etherification reactions during Cel conversion and then improved the selectivity of EL.

Amphiphilic HZSM-5 for Cyclopentene Hydration at the Liquid-Liquid Interface in Pickering Emulsion

Zeolite is considered an ideal catalyst for olefin hydration due to its high specific surface area and abundant acid sites. However, the immiscibility of the water-oil two phases in olefin hydration limits mass transfer, and the side reaction of etherification occurs acutely, resulting in a low yield of alcohol. Thus, water-oil amphiphilic HZSM-5 was prepared by sulfonating silanized zeolite. The successful introduction of organic and sulfonic acid groups is demonstrated by FT-IR, TG, and water contact angles. Amphiphilic HZSM-5 can stabilize the Pickering emulsion and catalyze cyclopentene hydration at the phase interface. In addition, NH3-TPD and Py-IR show that the amount of strong Bro̷nsted acid sites of zeolites increases significantly after sulfonation. This facilitates the rate-determining step of cyclopentene activation by H+ to form carbocation. Moreover, the nucleophilic side reactions are inhibited by a high concentration of H+. Finally, under the optimized reaction condition, the conversion of cyclopentene can achieve 5.066% with a selectivity of 85.37% to cyclopentanol, which almost reaches the reaction equilibrium.

Preparation of Metal-Loaded ZSM-5 Zeolite Catalyst and Its Catalytic Effect on HMF Production from Biomass

This research work presented the preparation of metal-loading ZSM-5 zeolite catalyst by loading Cu and Cr ions into the ZSM-5 zeolite particles using ion exchange method. Technical conditions of ion exchange processes were investigated to find suitable process for preparation of modified zeolite. The as-obtained zeolite catalyst was then applied for the transformation reaction of biomass-derived glucose into 5-hydroxymethyl furfural (HMF). Glucose hydrolysate that achieved from enzymatic hydrolysis of rice straw was used as feedstock for transformation reaction using Cu-Cr/ZSM-5 catalyst. This metal-loading zeolite exhibited good catalytic activity for lignocellulosic conversion to HMF, a valuable renewable green chemical. The content of loading metals in the zeolite catalyst affected significantly on the HMF yield. Moreover, the influence of transformation conditions such as solvent, temperature, catalyst dosage, and reaction time was investigated. According to the results, the optimum condition leading to the highest yield of HMF of 49.5 ± 0.5% was established. The as-prepared Cu-Cr/ZSM-5 zeolite catalyst showed impressive performance and can be considered a promising catalyst for the transformation of biomass-derived glucose to HMF.

Strategic development and performance evaluation of functionalized tea waste ash-clay composite as low-cost, high-performance separator in microbial fuel cell

The separator is an important component of the microbial fuel cells (MFCs), which separates anode and cathode entities and facilitates ion transfer between both. Despite the high research in separators in recent years, the need for cost-effective, waste-driven selective separators in MFCs persists. Present study discloses the strategic fabrication of functionalized-tea-waste-ash-clay (FTWA-C) composite separator by integrating functionalized tea waste ash (FTWA) with potter's clay. Clay was used as a base, while FTWA was used as cation exchanger. FTWA and clay were separately mixed in four different ratios, 00:100 (C1); 05:95 (C2); 10:90 (C3); 15:85 (C4). Mixtures were then crafted manually as consecutive four layers. C1-side faced anode while separator-cathode-assembly was developed at C4. The separator was characterized by evaluating proton and oxygen transfer coefficient, and water-uptake analysis. The separator was also analysed for elemental composition, microstructure, particle size, and surface area and porous structure. SEM analysis of FTWA showed the presence of 15-100 nm pores. EDS analysis of the FTWA-C showed the presence of hygroscopic oxides, mainly SO₄^2- and SiO₂. A slight peak observed at P/P_o∼1, confirmed the presence of macropores. The FTWA-C separator showed proton transfer coefficient as high as 18.7 × 10^-5cm/s, and oxygen mass transfer coefficient of 2.1 × 10^-4cm/s. The FTWA-C displayed the highest operating voltage of 612.4.2 mV, the power density of 1.81 W/m³, and COD removal efficiency of 87.52%. The fabrication cost of this separator was estimated to be $9.8/m². FTWA-C could be an affordable and high-efficiency alternative for expensive ion-exchange membranes in MFCs.

Production of 5-hydroxymethylfurfural (HMF) from rice-straw biomass using a HSO3–ZSM-5 zeolite catalyst under assistance of sonication

This work studied the application of sulfonated ZSM-5 zeolite, a bi-functional catalyst for conversion of biomass-derived glucose to HMF. Glucose hydrolysate was obtained by enzymatic hydrolysis of rice straw, that was pretreated by sodium hydroxide. Glucose hydrolysate was then subjected to a transformation reaction to achieve HMF using HSO₃–ZSM-5 zeolite under the assistance of sonication. The reaction conditions including solvent, temperature, catalyst dosage and reaction time were studied. Suitable conditions, which gave the highest yield of HMF of 54.1% have been found. The HSO₃–ZSM-5 zeolite presented a high catalytic efficiency for conversion of glucose to HMF, an important and useful intermediate in the chemical industry.

A porous HSO₃–ZSM-5 zeolite was successfully synthesized and applied for conversion of biomass-derived glucose to HMF.