Sulfonation Treatment Research Articles

Rapid surface modification of PEEK by ambient temperature sulfonation for high shelf-life biomedical applications

The aim of this study is to develop a rapid, simple, and economical surface treatment process for Poly (ether-ether-ketone) (PEEK) using concentrated sulfuric acid. PEEK is a biocompatible material, with a bonelike elastic modulus and is mechanically superior to other implant materials like titanium, stainless steel etc. This property brings PEEK to limelight as a promising alternative for bone implants. However, a strong challenge is observed of osseointegration mainly due to its inert surface behavior and poor hydrophilicity. Chemical surface modification is considered as one of the best ways to bioactivate the PEEK surface. In this work, two different sulfonation treatment methodologies have been designed and the effect of reaction time is systematically studied over its changing surface properties and favorable cellular growth. In one treatment, only rapid sulfonation is implemented while in other treatment processes, scaffolds are treated with NaOH solution to terminate the sulfonation process. The modified PEEK surface is next evaluated using Fourier transform infra-red spectroscopy (FTIR), contact angle, optical profilometer and scanning electron microscopy to ascertain its behavior. The modified surface is observed to possess higher hydrophilicity, higher surface roughness and high porosity. No significant difference in hydrophilicity is observed for over a month once treated, showing permanency in modification. A 90 second treatment is observed to have the highest hydrophilicity and thus selected for cellular integration studies. No sign of cell toxicity was observed in the modified surfaces, which also showed improved protein adsorption, cell viability, cell adhesion, and proliferation compared to untreated PEEK.The proposed chemical modifications are promising techniques for a rapid, easy, and economical bioactivation of PEEK polymer for improved cellular activity.

The Incorporation of Sulfonated PAF Enhances the Proton Conductivity of Nafion Membranes at High Temperatures.

Nafion membranes are widely used as proton exchange membranes, but their proton conductivity deteriorates in high-temperature environments due to the loss of water molecules. To address this challenge, we propose the utilization of porous aromatic frameworks (PAFs) as a potential solution. PAFs exhibit remarkable characteristics, such as a high specific surface area and porosity, and their porous channels can be post-synthesized. Here, a novel approach was employed to synthesize a PAF material, designated as PAF-45D, which exhibits a specific surface area of 1571.9 m2·g-1 and possesses the added benefits of facile synthesis and a low cost. Subsequently, sulfonation treatment was applied to PAF-45D in order to introduce sulfonic acid groups into its pores, resulting in the formation of PAF-45DS. The successful incorporation of sulfonic groups was confirmed through TG, IR, and EDS analyses. Furthermore, a novel Nafion composite membrane was prepared by incorporating PAF-45DS. The Nyquist plot of the composite membranes demonstrates that the sulfonated PAF-45DS material can enhance the proton conductivity of Nafion membranes at high temperatures. Specifically, under identical film formation conditions, doping with a 4% mass fraction of PAF-45DS, the conductivity of the Nafion composite membrane increased remarkably from 2.25 × 10-3 S·cm-1 to 5.67 × 10-3 S·cm-1, nearly 2.5 times higher. Such promising and cost-effective materials could be envisioned for application in the field of Nafion composite membranes.

A solid acid derived from fishbone catalyzes the hydrolysis of cellulose into nanocellulose

The necessity to look into waste biomass resource regeneration has increased due to growing environmental and energy-related problems. This study successfully developed an innovative fishbone-derived carbon-based solid acid catalyst using the carbonation-sulfonation method, which was subsequently applied to catalyze the hydrolysis of cellulose to produce nanocellulose. The data analysis reveals that the sulfonation treatment affects the microstructure of the catalyst, resulting in a decline in its specific surface area (134.48 m2/g decreased to 9.66 m2/g). However, this treatment doesn't hinder the introduction of acidic functional groups. In particular, the solid acid catalyst derived from fishbone exhibited a total acid content of 3.76 mmol/g, with a concentration of -SO3H groups at 0.48 mmol/g. Furthermore, the solid acids originating from fishbones manifested remarkable thermal stability, exhibiting a mass loss of <15 % at temperatures up to 600 °C. Moreover, the catalyst displayed exceptional catalytic performance during the cellulose hydrolysis reaction, achieving an optimum nanocellulose yield of 45.7 % at an optimized reaction condition. An additional noteworthy feature is the solid acid catalyst's impressive recyclability, maintaining a nanocellulose yield of 44.87 % even after undergoing five consecutive usage cycles. This research outcome underscores an innovative approach to for the sustainable utilization of waste biomass resources.

Enhancing osteointegration and antibacterial properties of PEEK implants via AMP/HA dual-layer coatings

Polyetheretherketone (PEEK) is a widely used engineering plastic in orthopedic and dental implants, but its bioinertness leads to poor bone integration. To overcome this, a sulfonation treatment was applied to PEEK first to create a rough, microporous surface enhancing cellular adherence and integration. Subsequently, amorphous magnesium phosphate (AMP) nanosheets were produced through microwave-assisted synthesis, and hydroxyapatite (HA) was generated using a bionic solution hydrothermal method. A dual-layer coating system composed of an interlayer AMP and a top layer HA on the surface of PEEK was developed to enhance osteointegration. Surface analysis confirms the creation of increased surface area, improved hydrophilicity with introduced hydrophilic groups, and enhanced protein attraction. In vitro assessments on mouse embryonic osteoblasts (MC3T3-E1) demonstrate the non-toxicity of these coatings and their efficacy in promoting cell proliferation. Moreover, antimicrobial evaluations against E. coli and S. aureus highlight the potential of these composite coatings in preventing implant-related infections. The AMP/HA dual-layer coating on sulfonated PEEK emerges as a potent method for enhancing osteointegration and antibacterial properties, offering a promising approach to improve bone repair efficiency in clinical applications.

Adjustable n→π* electronic transition by sulfonated benzene functionalized g-C3N4 for enhanced photocatalytic H2 generation

The photocatalytic efficiency of graphitic carbon nitride (g-C3N4) in hydrogen production is primarily hindered by its poor absorption of visible light, rapid recombination of electron-hole pairs, and the absence of hydroxyl radical formation. Herein, a novel g-C3N4 nanosheets functionalized with sulfonic acid groups were effectively produced through thermal polymerization of melamine and 2, 4-diamino-6-phenyl-1, 3, 5-triazine (DPT), followed by sulfonation treatment. The introduction of the phenyl group brings about alterations to the initial symmetrical arrangement of g-C3N4, leading to the disruption of certain hydrogen bonds. This, in turn, facilitates the movement of electrons from the n to π* orbitals, resulting in enhanced light absorption and improved efficiency in charge separation. Moreover, it induces modifications to the band structure and amplifies the production of hydroxyl radicals. Additionally, the introduction of sulfonic acid enhances the water affinity and the ability of dispersing graphitic carbon nitride in water. The optimized sulfonated benzene-substituted g-C3N4 (1000-BCN-SO3H) with a melamine to DPT ratio of 4:1 exhibits a maximum hydrogen production rate of 6.52 mmol·h−1·g−1 under simulated sunlight irradiation with good cycling stability, which is 3.93 times higher than that of g-C3N4 nanosheets. This research offers a promising opportunity for a novel approach in advancing carbon nitride materials for effective photocatalytic processes.

Sulfonated cellulose nanocrystal modified with ammonium salt as reinforcement in poly(lactic acid) composite films

Poly(lactic acid) (PLA) composites reinforced with cellulose nanocrystals (CNCs) are promising biodegradable materials. However, the poor compatibility and dispersion of CNCs in the PLA matrix remain a significant obstacle to improving the properties of composites. In this study, the modified CNC (CNC-D) was prepared through sulfonation treatment, followed by modification with didecyl dimethyl ammonium chloride (DDAC). Then, CNC-D was mixed with PLA to prepare composite films (PLA-CNC-D). The results revealed that the PLA-CNC-D had higher tensile strength and elongation at break than PLA-CNC at 3 wt% nanofiller content, increasing by 41.53 and 22.18 %, respectively. SEM and DSC analysis indicated that surface modification improved the compatibility and dispersion of CNC-D in the PLA matrix. The sulfonation process increased the anion content on the surface of CNC-D, enabling the CNC-D surface to adsorb more cationic DDAC, consequently sharply reducing the hydrophilicity of CNC-D. Moreover, the PLA-CNC-D exhibited excellent antibacterial activity against S. aureus and E. coli. In summary, this study provides a novel CNC modification approach to enhance the physical properties and antibacterial activity of PLA composite films, enlarging the application of degradable PLA composites.

Rapid Batch Surface Modification of 3D-Printed High-Strength Polymer Scaffolds for Enhanced Bone Regeneration In Vitro and In Vivo

In the emergency treatment of acute injuries in orthopedics, 3D-printing technology shows great promise due to its ability to rapidly and mass production of implants with complex structures. However, further surface modification on 3D-printed implants can often be complicated and time-consuming, leading to a prolonged timeframe from manufacturing to implantation. Therefore, there is an urgent need for rapid batch surface modification technology that can be effectively integrated with 3D-printing technology within the field of orthopedics. In this study, air-plasma treatment was used to rapidly modify 3D-printed polyetherimide (PEI) porous scaffolds and compared it with sulfonation treatment. Both methods achieved rapid surface modification of complex porous scaffolds in seconds to minutes (10 minutes), helping establish a cell-friendly surface morphology that encourages osteogenesis. Some new functional groups such as -OH and -SO3H were also introduced to promote osteogenesis. Interestingly, the air-plasma treated group enhanced cell adhesion, as indicated by a 1.6-fold increase in the number of cells compared to the control group. While sulfonation treatment accelerated the osteogenesis process, evidenced by a 1.7-fold increase in the number of calcium nodules in the sulfonation treated group compared to the control group in 7 days. To combine the advantages of air-plasma treatment and sulfonation treatment, the biological properties of their combined application were studied in vitro and in vivo for the first time. It was surprising to find that the combined application actually decreased the biological property of the material, which was associated with the generation of new free radicals. The results of this study will hopefully be applied to the rapid batch surface modification in 3D-printed porous implants to enhance their biological activity and improve the efficiency from manufacturing to implantation.

Trash to treasure: Sulfonation-assisted transformation of waste masks into high-performance carbon anode for sodium-ion batteries

The global pandemic of COVID-19 poses significant challenge to the recycling of disposable polypropylene (PP)-based waste masks. Herein, a simple but effective sulfonation route has been proposed to transform PP-based waste masks into value-added hard carbon (CM) anode materials for advanced sodium-ion batteries. The sulfonation treatment improves the thermal stability of the PP molecule, preventing their complete decomposition and the release of massive gas molecules during the carbonization process. Meanwhile, the oxygen functional groups introduced during sulfonation effectively facilitates the cross-linking between the PP chains, hindering the rearrangement of carbon microcrystalline structures and enhancing its structural disorder. As a result, the prepared hard carbon anode (CM-180) with a high disorder degree and minimal surface defects realizes a high sodium storage capacity of 327.4 mAh g−1 with excellent cycle and rate capability. In addition, when coupled with O3–NaNi1/3Fe1/3Mn1/3O2 cathode, the fabricated sodium-ion full cell delivers a high energy density of 238 Wh kg−1 and achieves an outstanding rate capability with a retained capacity of 75 mAh g−1 even at an ultrahigh current rate of 50 C. This work offers a novel insight into transforming the waste masks to value-added hard carbons with promising prospects for sodium-ion batteries.

Effect of Surface Modification of PEEK Artificial Phalanx by 3D Printing on its Biological Activity

Objective: Polyetheretherketone (PEEK) is widely used as an orthopedic implant material owing to its good biocompatibility and mechanical strength; however, PEEK implants are biologically inert, resulting in suboptimal cellular responses after implantation. The aim of this study was to enhance the biological activity of PEEK through sulfonation treatment. Methods: In this study, distal phalangeal implants of PEEK were customized by fused deposition modeling (FDM) printing technology and soaked in concentrated sulfuric acid at different times to obtain sulfonated PEEK (SPEEK). The groups were divided into five groups according to the sulfonation time as follows: 0 min (control group), 1 min (group SPEEK1), 2 min (group SPEEK2), 4 min (group SPEEK4), and 8 min (group SPEEK8). Then the physicochemical characteristics of implants were determined by SEM, XRD, EDS, etc. The implants were co-cultured with stem cells from human exfoliated deciduous teeth (SHED), and then the cell proliferation, adhesion, alkaline phosphatase (ALP) activity, and alizarin red staining were performed to detect the biological activity, biocompatibility, and osteogenic activity of the SPEEK implants. Results: The sulfonation time range of 1 to 8 min could promote the formation of micropores on the surface of PEEK implants, while slightly affecting the composition and compression performance of the implants. Compared with the control group, the hydrophilicity of PEEK materials was not improved after sulfonation treatment. Tests for adhesion and proliferation of SHED indicated that SPEEK2 showed superior biocompatibility. Furthermore, ALP activity and semi-quantitative analysis of Alizarin red staining showed that the osteogenic activity of SPEEK2 phalanges exhibited significantly stronger osteogenic activity than the other groups. Conclusions: The method presented here provides a promising approach to improve the surface bioactivity of PEEK implants prepared by FDM, providing a shred of primary evidence to support the application of SPEEK in orthopedics.

46 Sulfonation-Based Decontamination Alters Biotransformation and Excretion of Deoxynivalenol in Nursery Pigs

Abstract Deoxynivalenol (DON) is a primary mycotoxin in cereal feed ingredients that negatively affects feed intake and immune function of pigs. Formation of DON sulfonate (DONS) with sulfites in feed has become an effective approach to mitigate the DON toxicities in practice, but the metabolic fate of DON under sulfonation-based decontamination was not well defined. In this study, 48 nursery pigs (35 d of age, 10.8 ± 1.3 kg) were stratified by weight and sex and grouped following a 2 x2 factorial design on the DON content in corn-soybean meal diets (1.2 vs. 4.1 ppm) and the inclusion of NoTox Ultimate D, a sulfite-based mitigant (0 vs. 0.25%). Four experimental diets, including low-DON feed with no mitigant treatment (LD-NT); low-DON feed with sulfonation treatment (LD-ST): high-DON feed with no mitigant treatment (HD-NT); high-DON feed with sulfonation treatment (HD-ST), were fed for 21 d for urine collection on day 0, 10, and 21 and fecal collection on day 21. Urine and fecal samples were analyzed by both targeted metabolite analysis and untargeted metabolomic modeling. DON itself was absent in all fecal and urine samples, indicating a complete biotransformation. As expected, sulfonation led to the formation of DONS in feces in correlation with the DON content in feed and the decrease of two DON glucuronides in urine (HD-ST &amp;lt; HD-NT). Interestingly, sulfonation did not decrease the concentrations of two deepoxy-deoxynivalenol (DOM) glucuronides in urine. Instead, it significantly increased DOM in feces (HD-ST &amp;gt; HD-NT). The results indicate that the formation of DONS by sulfite treatment alters the biotransformation and excretion of DON by decreasing the availability of free DON for absorption and simultaneously increasing its availability for microbial metabolism to form DOM, an inactivated metabolite, for fecal and urine excretion.

Strategies to improve bioactive and antibacterial properties of polyetheretherketone (PEEK) for use as orthopedic implants.

Polyetheretherketone (PEEK) has gradually become the mainstream material for preparing orthopedic implants due to its similar elastic modulus to human bone, high strength, excellent wear resistance, radiolucency, and biocompatibility. Since the 1990s, PEEK has increasingly been used in orthopedics. Yet, the widespread application of PEEK is limited by its bio-inertness, hydrophobicity, and susceptibility to microbial infections. Further enhancing the osteogenic properties of PEEK-based implants remains a difficult task. This article reviews some modification methods of PEEK in the last five years, including surface modification of PEEK or incorporating materials into the PEEK matrix. For surface modification, PEEK can be modified by chemical treatment, physical treatment, or surface coating with bioactive substances. For PEEK composite material, adding bioactive filler into PEEK through the melting blending method or 3D printing technology can increase the biological activity of PEEK. In addition, some modification methods such as sulfonation treatment of PEEK or grafting antibacterial substances on PEEK can enhance the antibacterial performance of PEEK. These strategies aim to improve the bioactive and antibacterial properties of the modified PEEK. The researchers believe that these modifications could provide valuable guidance on the future design of PEEK orthopedic implants.

Enhancing the mechanical properties and hydrophobicity of heat-treated wood by migrating and relocating sulfonated lignin

Abstract Heat-treated wood (HTW) has better dimensional stability but worse mechanical strength than untreated wood. This study aimed to overcome this shortcoming by sulfonating lignin in Balfour spruce (Picea likiangensis var. balfouriana) wood with sulfurous acid and Na2SO3 followed by heat treatment. The mass loss of as-prepared HTW decreased while the crystallinity index increased slightly compared with those of HTW without sulfonation pretreatment. The cellulose structure of the as-prepared HTW was not damaged by the sulfonation pretreatment. The as-prepared HTW showed a higher MOE, MOR, and compressive strength (CS) of 34, 32, and 22%, respectively, compared with the HTW without sulfonation treatment. The improved mechanical properties were attributed to the increase of the relative mass fraction of lignin in the secondary walls of wood, as sulfonated lignin could migrate with water from the compound middle lamellae into the secondary wall under the combined driving forces of a concentration difference and steam pressure. These findings provide a way to enhance the mechanical properties of HTW while gaining better hydrophobicity.

Efficient conversion of glucose into 5-HMF catalyzed by lignin-derived mesoporous carbon solid acid in a biphasic system

A lignin-derived mesoporous carbon solid acid (LDMCS) catalyst was prepared by high temperature carbonization and subsequent sulfonation treatment using alkali lignin as the carbon source and KCl as a salt template. The prepared LDMCS has an irregular mesoporous structure with a narrow pore size distribution (concentrated at 4 nm), large specific surface area (1123.0 m2 g−1) and high -SO3H group density (2.20 mmol g−1). Compared with other types of solid acids reported in the literature, the prepared LDMCS catalyst has equivalent or better catalytic performance in the catalytic conversion of glucose to 5-hydroxymethylfurfural (5-HMF). A glucose conversion of 97.7% and a 5-HMF yield of 57.8% were obtained with the aqNaCl-THF (1:3) biphasic solvent system under the optimized reaction conditions with reaction temperature of 160 °C, reaction time of 2.5 h, and catalyst loading of 1 mg mg−1. More importantly, the 5-HMF yield still reached 40.9% after 5 cycles of the catalyst use, indicating that there was no significant loss of catalytic activity.

In situ preparation of porous metal-organic frameworks ZIF-8@Ag on poly-ether-ether-ketone with synergistic antibacterial activity

Poly-ether-ether-ketone (PEEK) is a promising material in oral repair and orthopedic implantation field due to its stability and proper elastic modulus. However, the lack of simple but effective strategy to functionalize PEEK and improve its antibacterial function hinders its further biomedical application. In this study, a sulfonated 3D porous PEEK is fabricated via sulfonation treatment, and then decorated with the in situ synthesized zeolitic imidazolate framework-8 (ZIF-8), in which Ag+ ions were loaded with high loading capacity. Surface morphology, roughness, chemical composition and hydrophilicity of all the substrates were evaluated in details, suggesting Ag+ ions loaded ZIF-8 on sulfonated PEEK (SPZA) was successfully prepared. The antibacterial activity of pristine and functionalized PEEK was evaluated by inhibition zone test, spread plate assay, growth curve, and morphology of bacteria. Experimental results demonstrate that the SPZA has effectively bacteriostatic performance against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The excellent antimicrobial activity is attributed to the synergistic effect of Ag+ and Zn2+ ions released continuously from SPZA. This work provides a promising route for surface modification of PEEK and offer a potential candidate for biomedical implants.

Synthesis of a sulfated-group-riched carbonaceous catalyst and its application in the esterification of succinic acid and fructose dehydration to form HMF

A novel sulfated-group-riched sulfonated carbonaceous catalyst with high acidic strength and adjustable ratio of acidic groups was designed in the paper, where glucose and benzyl chloride were hydrothermally carbonized first followed by sulfonation treatment. Various physicochemical techniques were used to characterize the catalyst such as IR, 13C MAS NMR and XPS spectra, NH3-TPD, XRD patterns and TG curve. Then, it was applied in the esterification of succinic acid and fructose dehydration to form HMF. Compared to commercial Amberlyst-15 catalyst, such carbonaceous solid acid exhibited excellent catalytic activity and thermal stability, which was attributed to its higher amount of sulfonic acid group.

Sulfonic acid-functionalized core-shell Fe3O4@carbon microspheres as magnetically recyclable solid acid catalysts

Green and recyclable solid acid catalysts are in urgent demand as a substitute for conventional liquid mineral acids. In this work, a series of novel sulfonic acid-functionalized core-shell Fe3O4@carbon microspheres (Fe3O4@C-SO3H) have been designed and synthesized as an efficient and recyclable heterogeneous acid catalyst. For the synthesis, core-shell Fe3O4@RF (resorcinol-formaldehyde) microspheres with tunable shell thickness were achieved by interfacial polymerization on magnetic Fe3O4 microspheres. After high-temperature carbonization, the microspheres were eventually treated by surface sulfonation, resulting in Fe3O4@C-x-SO3H (x stands for carbonization temperature) microspheres with abundant surface SO3H groups. The obtained microspheres possess uniform core-shell structure, partially-graphitized carbon skeletons, superparamagnetic property, high magnetization saturation value of 10.6 emu/g, and rich SO3H groups. The surface acid amounts can be adjusted in the range of 0.59–1.04 mmol/g via sulfonation treatment of carbon shells with different graphitization degrees. The magnetic Fe3O4@C-x-SO3H microspheres were utilized as a solid acid catalyst for the acetalization reaction between benzaldehyde and ethylene glycol, demonstrating high selectivity (97%) to benzaldehyde ethylene glycol acetal. More importantly, by applying an external magnetic field, the catalysts can be easily separated from the heterogeneous reaction solutions, which later show well preserved catalytic activity even after 9 cycles, revealing good recyclability and high stability.

Efficient valorization of biomass-derived furfuryl alcohol to butyl levulinate using a facile lignin-based carbonaceous acid

The preparation and application of biorenewable carbon-based catalyst are attracting increasingly attention in the field of green and sustainable chemistry. Here, a facile and low-cost lignosulfonate-based carbonaceous solid acid (LSS) was availably prepared via directly sulfonating lignosulfonate that was from sulfite pulping industry, and used to catalyze biomass-derived furfuryl alcohol to yield versatile butyl levulinate. The fabrication and properties of LSS were highly sensitive to the sulfonation conditions (i.e., lignosulfonate-to-H2SO4 ratio and temperature). The physicochemical properties of the as-prepared LSS were well characterized using BET surface area, acid–base titration, SEM, XRD, FT-IR, XPS, and TGA techniques. The LSS contained –SO3H, –COOH and phenolic –OH groups and was ideal to perform the reaction of furfuryl alcohol with n-butanol to obtain butyl levulinate in yield higher than 95% at 110 °C for 8 h with catalyst dosage of 15 g/L. Meanwhile, the catalyst deactivated increasingly with a recycle number that was attributed to the adsorption of formed polymeric by-products on the active catalyst sites, and the slightly deactivated catalyst after plain sulfonation treatment was found to remain active with an almost unchanged product yield in consecutive cycles. This work highlights an economic, eco-friendly, sustainable and promising protocol for catalytic upgrading of bio-based compounds.

Crosslinked Sulfonated Poly(vinyl alcohol)/Graphene Oxide Electrospun Nanofibers as Polyelectrolytes.

Taking advantage of the high functionalization capacity of poly(vinyl alcohol) (PVA), bead-free homogeneous nanofibrous mats were produced. The addition of functional groups by means of grafting strategies such as the sulfonation and the addition of nanoparticles such as graphene oxide (GO) were considered to bring new features to PVA. Two series of sulfonated and nonsulfonated composite nanofibers, with different compositions of GO, were prepared by electrospinning. The use of sulfosuccinic acid (SSA) allowed crosslinked and functionalized mats with controlled size and morphology to be obtained. The functionalization of the main chain of the PVA and the determination of the optimum composition of GO were analyzed in terms of the nanofibrous morphology, the chemical structure, the thermal properties, and conductivity. The crosslinking and the sulfonation treatment decreased the average fiber diameter of the nanofibers, which were electrical insulators regardless of the composition. The addition of small amounts of GO contributed to the retention of humidity, which significantly increased the proton conductivity. Although the single sulfonation of the polymer matrix produced a decrease in the proton conductivity, the combination of the sulfonation, the crosslinking, and the addition of GO enhanced the proton conductivity. The proposed nanofibers can be considered as good candidates for being exploited as valuable components for ionic polyelectrolyte membranes.

Esterification of levulinic acid into ethyl levulinate catalyzed by sulfonated bagasse-carbonized solid acid

A sulfonic carbon-based catalyst (C-SO3H) was successfully prepared by sulfonating incompletely carbonized sugarcane bagasse. The optimized catalyst of high activity in the esterification of levulinic acid (LA) with ethanol was produced under sulfonation at 150 °C for 15 h with a 75 mL/g sulfonation ratio. The prepared catalysts were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), and elemental analysis (EA). The bagasse-carbonized catalyst was porous, and the porous structure remained unchanged after sulfonation treatment. Moreover, the introduced acidic group was the catalytic center. A high yield of ethyl levulinate (ELA) of 88.2% was obtained at 120 °C for 9 h. The sulfonic carbon-based catalyst could be reused at least five times and still exhibited great stability. The application of the sulfonic carbon-based catalyst was not only the effective use of biomass resources but also promoted the production of various high value chemicals.

Development of Hierarchical Porous MOF‐Based Catalyst of UiO‐66(Hf) and Its Application for 5‐Hydroxymethylfurfural Production from Cellulose

AbstractDue to its widely green and sustainable properties, cellulose is identified as a green and sustainable alternative for the preparation of valuable biofuels and chemicals. In this study, Poly‐Pickering HIPEs (PHs) was synthesized as the precursor by using Pickering high internal phase emulsion (HIPE) as templates and PHs‐SO3H was prepared after sulfonation treatment. We chemically grafted UiO‐66(Hf)‐type MOFs onto PHs‐SO3H in order to synthesize a novel catalyst for the transformation of cellulose into 5‐HMF, which made clear that HMF yield was improved in the presence of the catalyst. What's more, the 5‐HMF yield of 49.6% was obtained under the optimal conditions of 50 mg cellulose, 30 mg catalyst, 60 min of reaction time and 120 °C of reaction temperature. The catalyst is recyclable four cycles without crucial loss of catalytic activity.