Sulfonation Time Research Articles

Fabrication of a macro-micro porous structure on PEEK surface by ultrasound-assisted sulfonation

A multiscale porous surface can significantly improve the osseointegration of biomedical implants, but it cannot be facilely achieved on the Poly-ether-ether-ketone (PEEK) surface. In this work, a macro-micro porous structure was prepared on the PEEK surface by ultrasound-assisted sulfonation. The surface morphologies, chemical compositions, functional groups, surface roughness, and wettability of the porous structures at different sulfonation times were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectrometer (FTIR), laser scanning confocal microscope (LSCM), and contact angle measurement, respectively. The results demonstrate that a macro-micro porous structure is formed on the PEEK surface, with macropore sizes ranging from 50 to 250 μm and micro-sized pore sizes ranging from 0.2 to 1.5 μm. Moreover, the results of in vitro cellular experiments demonstrate that the macro-micro porous structure can promote cell adhesion and proliferation of BMCSc. The formation mechanism of the multiscale porous structures has also been discussed. This novel approach may provide a simple and effective strategy for surface modification of PEEK to improve its mechanical and biological response.

Sulfonation Treatment of Polyether-Ether-Ketone for Dental Implant Uses

There has been a recent uptake in the use of polyether-ether-ketone (PEEK), which is an organic thermoplastic polymer, in the manufacturing of various medical devices, implants, and equipment. Finding the best time and procedure for PEEK after sulfonation is the goal of this research. A total of 30 PEEK discs were sulfonated in this study by immersing them in concentrated (H2SO4) sulfuric acid for various durations and subsequently treated using various post-treatment techniques. Five experiments were carried out, aimed studying the effect of immersion time (5 s–2 min). The methods used as post-treatment were hydrothermal treatment, immersion in NaOH, and washing with acetone. The sulfonation time was measured, and the post-treatment techniques, surface characterizations, were conducted using scanning electron microscopy (SEM) (Electron Optics Instruments, LLC., West Orange, NJ, USA), atomic force microscopy (AFM) (AFM, Vía Burton, CA, USA), and hydrophilic properties. The results were confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The findings of this study demonstrate that sulfonating PEEK caused a structure with a porous network to form in every sample. As the sulfonation time increased, the porous structure became more noticeable and the concentration increased. As a consequence, the roughness of the surface increased notably, and the modified PEEK surface’s wettability improved noticeably. Hydrothermal treatment was determined to be the most successful way for eliminating the leftover sulfuric acid, and sulfonation for 2 min was determined to be ideal. By understanding the best post-treatment procedures and ideal sulfonation duration, a theoretical foundation for the production of sulfonated PEEK for orthopedic uses may be laid.

The Formation Process and Mechanism of the 3D Porous Network on the Sulfonated PEEK Surface.

A three-dimensional (3D) porous network can be prepared on the PEEK surface by sulfonation with enhanced osseointegration and antibacterial properties. However, few studies have been conducted on the formation mechanism of a 3D porous network. In this work, the surface and cross-sectional morphologies, chemical compositions, functional groups, surface wettability, and crystalline states of sulfonated PEEK were investigated at different sulfonation times and coagulant concentrations. The results show that the number of nodular structures and broken fibers on the sulfonated PEEK surface as well as the size of macrovoids in the cross sections increase with increasing sulfonation times when water is used as a coagulant. In contrast, dilute sulfuric acid as a coagulant can inhibit the formation of surface porous structures and macrovoids in the cross sections. Moreover, all of the sulfonated PEEK samples have the same chemical compositions but exhibit better hydrophilicity as the number of microsized pores decreases. It is proposed that non-solvent-induced phase separation (NIPS) occurs during the sulfonation process, and the formation mechanism of surface and cross-sectional morphologies is discussed. Furthermore, it is assumed that the air is trapped in the microsized pores, leaving the surface of the 3D porous network in the Cassie-wetting state. All of these preliminary results throw light on the nature of the sulfonation process and may guide further modification of the structures of sulfonated PEEK.

Synthesis of conjugated microporous polymers rich in sulfonic acid groups for the highly efficient adsorption of Cs+

Conjugated microporous polymers (CMPs) with extended π-conjugated systems and permanent microporous scaffolders have broad application prospects in the treatment of radionuclides in nuclear wastewater. Herein, the Sonogashira–Hagihara coupling process was employed to generate three CMPs, called CMP1–3. CMP1S–3S with different degrees of sulfonation were produced and employed for Cs+ ion adsorption by adjusting the sulfonation time using chlorosulfonic acid as the sulfonating agent. This is the first attempt to apply CMPs containing sulfonic acid groups to Cs+ ion adsorption, which show excellent adsorption properties. CMP1S-48 with the highest surface sulfonic acid group density exhibited the fastest adsorption rate, and it reached adsorption equilibrium on Cs+ ion in an aqueous solution under 1 min. The adsorption process corresponded to the Freundlich isotherm model of multilayer adsorption, with an adsorption capacity of up to 288.1 mg g−1. Compare with CMP2S-48 and CMP3S-48, CMP1S-48 with more sulfonic acid groups shows the highest adsorption capacity. Moreover, the selectivity of CMP1S-48 adsorbing Cs+ ion was exceeded high. Notably, the adsorption mechanism of Cs+ ion by CMP1S–3S involved ion exchange with H+ in the sulfonic acid groups, as well as its complexation and electrostatic attraction with the sulfonic acid groups. This work opens up a new way for CMPs rich in sulfonic acid groups to treat Cs+ ion-contaminated water sources.

Effect of the micro/nanostructured topography of polyetheretherketone on the behavior of MC3T3‐E1 preosteoblasts

AbstractPolyetheretherketone (PEEK) is of interest because of its excellent mechanical properties. However, the bioinert nature of PEEK limits its use in clinical applications. In this study, a series of micro/nanostructures combining nano‐, submicron‐, and microscale on PEEK were fabricated with 0.5, 1, 4, and 6 min of sulfonation time (S1, S2, S3, and S4). Compared to the flat surface on PEEK, the micro/nanostructure of different sizes all significantly promote cell adhesion, proliferation, and osteogenic differentiation of MC3T3‐E1 cells. It is shown that micro/nano‐porous structures with smaller size and lower roughness of S1 enabled faster cell propagation. The results of alkaline phosphatase staining, alizarin red staining, and quantitative real‐time PCR reveal that the osteogenic activity of MC3T3‐E1 cells gradually decreases with the increasement of pore size, indicating that the micro/nanostructured topography of S1 generated substantially increased matrix mineralization and bone‐like nodule formation, compared to the 3D network surface. This work provides an effective strategy for designing biomaterials with potential clinical applications.

Sustainable fabrication of solvent-free cation exchange membrane via tuning sulfonation time of PEEK

Researchers have been looking at novel strategies to lessen the environmental effect of various industrial processes in recent years due to the growing concern over environmental sustainability on a worldwide scale. The creation of eco-friendly materials for electrochemical applications is one such area of focus. By adjusting the poly(ether ether ketone) (PEEK) sulfonation period, this study suggests a unique approach for creating a solvent-free cation exchange membrane utilising sulfonated poly(ether ether ketone) (SPEEK). The goal of this study is to determine how the sulfonation period affects the membrane characteristics in order to improve its electrochemical performance (reducing resistance 9%) and ion exchange capacity (increasing 11%) while reducing the environmental damage caused by solvent use. Potential advantages of this strategy include a decrease in the production of hazardous waste and energy use, ultimately leading to a more sustainable environment.

Tetes Tebu Menjadi Katalis Untuk Proses Pembuatan Biodiesel

Sugar cane is a plant that is processed into crystal sugar because it contains high sugar content. Sugar production produces waste, one of which is molasses waste. This study aims to obtain molasses into a catalyst using the carbonization method and the sulfonation method. The sulfonation method uses variations in the concentration of 2, 4, 6, 8, and 10 N H2SO4 solution and variations in sulfonation time of 2, 4, and 6 hours to get the best molasses catalyst. Catalyst characterization includes surface acidity by acid-base titration, FT-IR, and SEM-EDX. This research also aims to produce biodiesel yield using the best molasses catalyst. The results of surface acidity analysis showed that the best molasses catalyst was obtained at 10 N H2SO4 concentration with 6 hours at 0.907 mmol/gr. FT-IR test results showed the presence of O=S=O functional groups at wave numbers 1149.74 cm-1 and 1038.57 cm-1. SEM and EDX analysis results showed that the molasses catalyst after sulfonation had smaller pores and more sulfur groups on the carbon sheet. The yield of biodiesel produced using a molasses catalyst was 84.51%.

C2-Hydrocarbon Mixture Separation on Polyethylene Membranes with Grafted Sulfonated Polystyrene in H+, Li+ and Na+ Forms

The olefin separation from their mixture with paraffins by facilitated transport membranes is a very important process for the further macromolecular compounds production. Membranes loaded with silver ions, which are responsible for the facilitated olefin transport, are instable with time due to their reduction, while those containing protons catalyze the polymerization of olefins. In this work, membranes based on polyethylene with grafted sulfonated polystyrene in various ionic forms (H+, Li+, Na+) were used for the first time for the separation of the ethylene/ethane mixture. The influence of sulfonation time, relative humidity, and various ionic forms on ethylene separation was studied. The SEM study shows a non-uniform sulfur distribution over the membrane thickness for membranes sulfonated for different reaction times. With increasing sulfonation time and relative humidity the ethylene permeability and the factor of its separation with ethane increase. Separation factors for membranes in the Li+-form are shown to be as high as for membranes in the H+-form. A possible mechanism for the facilitated ethylene transport is discussed.

Kinetic and thermodynamic studies on the esterification of oleic acid ‏with methanol over sulfonated biochar catalyst derived from waste tea dregs

Tea dregs, an abundant and easily found bio-waste, were utilized as a precursor to developing acid biochar (SO3H-TDAC) that was used as a catalyst in producing biodiesel through oleic acid (OA) esterification with methanol. SO3H-TDAC catalysts were prepared through the consecutive carbonization–sulfonation two-step method. The catalyst with the highest sulfonic acid density was obtained at a carbonization temperature of 300 °C, carbonization time of 1 h, sulfonation temperature of 125 °C, and sulfonation time of 5 h and was characterized by multiple characterization methods. The catalyst performance was optimized, and the maximum OA conversion of 95.4% was obtained under the optimum conditions of temperature, time, catalyst concentration, and MeOH/OA molar ratio of 70 °C, 2.5 h, 7.5 wt% to OA, and 12/1, respectively The reaction was well-described by pseudo-first-order kinetics, and the activation energy was calculated as 29.93 kJ mol−1. Moreover, thermodynamic parameters of enthalpy change, entropy change, and Gibbs energy change were computed as 27.6 kJ mol−1, −0.19 kJ mol−1 K−1, and 95.171 kJ mol−1, respectively, indicating the reaction to be endergonic and thermodynamically unfavorable. Finally, after four cycles, the catalyst retained a high OA conversion efficiency of 86.5%, and the original efficiency can be regained via re-sulfonating the spent catalyst.

Effect of sulfonation time on physicochemical, osteogenic, antibacterial properties and biocompatibility of carbon fiber reinforced polyether ether ketone

The carbon fiber reinforced polyetheretherketone (CFR-PEEK) has been increasingly used in orthopedics dentistry due to its excellent biocompatibility and mechanical properties. However, the biological inertness and poor antibacterial activity limit its clinical applications. This paper focused on the performances of CFR-PEEK with porous morphology that were exposed to different sulfonation periods (1, 3, 5, and 10 min, corresponding to CP-S1, CP-S3, CP-S5, and CP-S10, respectively). Residual sulfuric acid was removed by acetone rinsing, NaOH immersion, and hydrothermal treatment before in vitro and in vivo studies. The results showed some significant difference in the physicochemical properties, including energy dispersive X-ray spectroscopy (EDS) map of sulfur atoms, X-ray photoelectron spectroscopy (XPS) of valences of sulfur ions, Fourier transformation infrared spectroscopy (FTIR), hydrophilicity, hardness, and elastic modulus among CP-S3, CP-S5, and CP-S10. However, CP-S5 and CP-S10 were more effective in promoting the proliferation, adhesion, and osteogenic differentiation of seeded bone mesenchymal stem cells (BMSCs) and growth inhibition of S. aureus and P. gingivalis compared with other groups. Furthermore, the CP-S5 and CP-S10 samples achieved better cranial bone repair than the non-sulfonation group in a rat model. Therefore, it can be inferred that both 5 and 10 min are viable sulfonation durations for 30% CFR-PEEK. These findings provide a theoretical basis for developing CFR-PEEK for clinical applications.

Optimization through response surface methodology of 3D printed membrane preparation conditions for use in vanadium redox flow battery: A vanadium/proton selectivity study

AbstractSPEEK membrane applicable in Vanadium Redox Flow Battery (VRFB) have been 3D printed via Fused Deposition Modeling (FDM). Response Surface Methodology (RSM) has been used to optimize conditions for 3D printing membrane. Good membranes characteristics were obtained by manipulating three parameters, namely the printing temperature, the orientation of the printing layer and the sulfonation time. We evaluated the effects of these three variables on the permeability of membranes to protons and vanadium ions. Results have shown that sulfonation is the most significant variable influencing vanadium and proton permeability. The optimal printing conditions were found at 408°C temperature with a horizontal layer orientation, while the best sulfonation is obtained at 6 min. The optimal membrane has an ion exchange capacity of 0.86 mmolg−1, a water uptake ratio of 22%, a VO2+ permeability of 6.1 × 10−8 cm2 min−1, a H+ permeability of 7.0 × 10−6 cm2 min−1, excellent mechanical stability and better H+/VO2+ perm selectivity than conventional sulfonated polyether ether ketone (SPEEK), Fap450 and Nafion211 membranes. The above results show that the 3D‐SPEEK membrane has great advantages and broad prospects for VRFB applications.

Artificial Intelligence Techniques and Response Surface Methodology for the Optimization of Methyl Ester Sulfonate Synthesis from Used Cooking Oil by Sulfonation.

Herein, the impacts of sulfonation temperature (100-120 °C), sulfonation time (3-5 h), and NaHSO3/methyl ester (ME) molar ratio (1:1-1.5:1 mol/mol) on methyl ester sulfonate (MES) yield were studied. For the first time, MES synthesis via the sulfonation process was modeled using the adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and response surface methodology (RSM). Moreover, particle swarm optimization (PSO) and RSM methods were used to improve the independent process variables that affect the sulfonation process. The RSM model (coefficient of determination (R2) = 0.9695, mean square error (MSE) = 2.7094, and average absolute deviation (AAD) = 2.9508%) was the least efficient in accurately predicting MES yield, whereas the ANFIS model (R2 = 0.9886, MSE = 1.0138, and AAD = 0.9058%) was superior to the ANN model (R2 = 0.9750, MSE = 2.6282, and AAD = 1.7184%). The results of process optimization using the developed models revealed that PSO outperformed RSM. The ANFIS model coupled with PSO (ANFIS-PSO) achieved the best combination of sulfonation process factors (96.84 °C temperature, 2.68 h time, and 0.92:1 mol/mol NaHSO3/ME molar ratio) that resulted in the maximum MES yield of 74.82%. Analysis of MES synthesized under optimum conditions using FTIR, 1H NMR, and surface tension determination showed that MES could be prepared from used cooking oil.

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.

Influence of process conditions on the sulfonation of methyl ester synthesized from used cooking oil: Optimization by Taguchi approach

AbstractDeveloping a robust and facile process route for fatty acid methyl ester sulfonate (MES) synthesis is of importance for industrial applications. Herein, Taguchi orthogonal array (OA) approach was used for the first time to establish the optimum process condition for the sulfonation of methyl esters (ME) with chlorosulfonic acid (CSA). According to the experimental design, the most significant parameter was sulfonation temperature, followed by CSA/ME molar ratio. Under the optimum sulfonation conditions (that is, 70°C sulfonation temperature, 2.0 h sulfonation time, 1.5:1 mol/mol CSA/ME molar ratio and 2.0 h aging time), the MES yield and the corresponding signal/noise ratio were 92.08 ± 0.28% and 39.28, respectively. The obtained FTIR and 1H NMR data revealed spectra associated with methyl (CH2 asymmetric and CH2 symmetric stretching vibrations), esters (CO, CO, and OCH3), and sulfonate (SO) groups in the MES sample synthesized under optimal conditions, thus confirming the target MES product. Surface tension measurements revealed that the optimal MES sample had a low critical miscelle concentration of 0.082 g/L at a surface tension of 51.2 mN/m, implying the possibility of better performance.

The correlation of sulfonation reaction kinetics with the degree of sulfonation (DS) and its effects on microstructure and morphology of electrospun fibers for the membrane of fuel cells.

Sulfonation is among the frequently used surface modification methods to endow new surface properties on polymer fibers. Direct sulfonation is the simplest chemical modification via incorporation of sulfonate functional groups onto fibers' surfaces at ordinary conditions. However, the process of functionalization compromises other properties of the electrospun membrane due to the extent of sulfonation reaction that occurred. This study was carried out to determine the effects on microstructure and morphology of crosslinked electrospun polybenzoxazine (PBz) fibers by correlating the reaction kinetics using a specific reaction parameter with the degree of sulfonation (DS). The kinetics of sulfonation reaction for PBz fibers is an electrophilic-based, first-type substitution mechanism where only one sulfonic acid (-SO3H) group is attached to each of the repeating units in the aromatic structure of PBz under ordinary conditions. From a previous study, the rate of change of ion exchange capacity (IEC) was derived as a logarithmic correlation that increased rapidly for some time and became constant. This study employed the derived empirical relationship based on reaction kinetics to correlate the degree of sulfonation (DS) with IEC at varying reaction time. DS was calculated as 55%, 66% and 77%, for 3, 6 and 24 h, respectively. The maximum IEC of 2.71 with the corresponding DS of 100% was obtained theoretically but since sulfonation reaction kinetics at ordinary conditions proceeds at slower phase, it can only attain 86% DS with maximum IEC of 2.44 at a calculated time of 48 h. Sulfonation was confirmed by the functional groups present in the structural composition of PBz fibers using ATR-FTIR which were quantified based on the absorbance in the IR spectra showing an increased peak height with increased reaction time for the first 6 h. Morphological analyses using SEM images revealed an increase in fiber diameter with increased sulfonation time. In addition, the higher reaction time showed the effects of longer acid exposure which compromised the fibers' structural integrity with the presence of broken fibers and defects on fibers' surfaces after 24 h. The electrospun PBz fibers sulfonated for 6 h achieved the highest IEC value with DS of 66% which was enough to attain the balance of degree of sulfonation with electrochemical and morphological properties.

Facile Conversion of Polystyrene Waste into an Efficient Sorbent for Water Purification.

In this work, we convert a plastic waste, i.e., polystyrene (PS), into a sorbent by a simple sulfonation process. The sulfonation time was optimized and the structures of the resulting sulfonated polystyrene (SPS) was characterized by field emission scanning electron microscopy, energy-dispersive X-ray and contact angle tests. The results showed that the sulfonation time of 7 h can introduce abundant sulfonic groups and preserve the self-standing structure. Additionally, the SPS has a three-dimensional porous structure and hydrophilic surface because of the presence of numerous sulfonic groups, which could serve as effective binding sites for immobilizing varying pollutants. Furthermore, as a proof-of-concept, the adsorption performance of the SPS foams was evaluated using three pollutants, namely Pb2+, lysozyme and methylene blue. The adsorption isotherms were fitted by the Langmuir and Freundlich models, while the kinetics of the adsorption processes were analyzed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. It was found that the adsorption isotherms of Pb2+ and lysozyme can be better described by the Langmuir model, leading to maximum equilibrium adsorption uptakes of 10.5 and 15.7 mg g-1 for the adsorption of Pb2+ and lysozyme, respectively. Importantly, the pollutant-saturated SPS is readily regenerated by acid washing, and the recovered sorbents exhibit outstanding cyclic performance. The abundant availability of feedstock, facile preparation and regeneration processes render the SPS foams a promising sorbent for practical applications.

Effect of sulfonating agent in the properties of styrene copolymers for PEMFC membranes

Two different sulfonating agents: sulfuric acid (S) and acetyl sulfate (AcS) were evaluated for chemical modification of poly (styrene-co-butyl acrylate) (StBuA) copolymer, as low-cost membranes. The reaction was carried out by direct sulfonation during 2–5 h of sulfonation time. FTIR confirmed sulfonation through the presence and widening of the several SO3H characteristic absorption bands. The molecular weight decreased after sulfonation, compared with pristine StBuA. TGA thermal analysis showed stability over 150 ᵒC with residues suggesting crosslinking and a glass transition (Tg) enhanced. Even with higher Tg values, sulfonated copolymers became flexible, as seen by their lower complex modulus (E∗). Ion exchange capacity (IEC) ranged from 0.91 to 1.53 meq g−1 and degree of sulfonation (DS) from 7 to 40%. The proton conductivity for sulfonated membranes exhibited similar or higher to Nafion membrane, particularly for S-4h membranes. A Grotthuss mechanism is envisaged for AcS and vehicular mechanism for S membranes.

Development of a new route for cation exchange membrane fabrication by using GO reinforced styrenated oil

A novel route was developed for cation exchange membrane (CEM) fabrication by using GO reinforced styrenated oil polymeric structure and the impact of polymer type (PS/PS-oil), graphene oxide amount (0.5,1,3, and 5 wt%), and sulfonation time (6,12, and 24 h) on the characteristics of prepared membranes (contact angle, water uptake, ion exchange capacity, DS(%), electron conductivity) were investigated for the first time in the current study. The results showed that higher values of water absorption, ion exchange capacity, and electron conductivity were obtained for GO-PS-oil-based membranes compared to GO-only PS based membranes under all experimental conditions. Also, it was seen that ion-exchange capacity and water uptake capacity were directly related to the GO amount and sulfonation time of the polymer. The maximum value obtained for ion exchange capacity was 7.7 meq/g for 5%GO incorporated-PS-oil based membrane sulfonating for 24 h. The obtained IEC values for all experimental conditions in this study are relatively high compared to other PS based membranes studied in the literature. The membrane's electrochemical characteristics (conductivity, flux and permeability) were also determined in an electrodialysis test cell. All obtained results indicated that CEM fabricated by this new approach could be utilized for electrodialysis applications in the future.

Functionalization of Multiwall Carbon Nano-Tube Supported Zinc Oxide Solid Acid Catalyst Using Sulfonate Compound for Transesterification of Schleichera Oleosa L Oil

Biodiesel is an alternative energy obtained through the trasesterification of vegetable oil in the presence of a catalyst. The catalyst plays a very important role in the success of the transesterification process. One way to increase the activity of the catalyst is through chemical modification called functionalization, which generally using SO3 group as a sulfonating agent is known as the sulfonation process. However, the disadvantage of this process is that it uses strong acids which are corrosive, require high temperatures and are not environmentally friendly. This study aims to increase the activity of zinc oxide catalyst supported by multi-wall carbon nano tube (Z/MWCNTs) sulfonated using (NH4)2SO4 as sulfonating agent. The synthesis route includes co-precipitation, sulfonation and precipitation time. The effect of concentration of ammonium sulfate, co-precipitation time, and sulfonating time on yield of biodiesels of kesambi (Schleichera oleosa L) oil (OSOBD) was investigated. The result showed that the activity functionalized Z/MWCNTS catalyst (Z/s-MWCCNTs) could enhance significantly. The results of the catalyst activity test on transesterification of OSO into biodiesel showed that Z/s-MWCNTs gave a high yield of 91% for the functionalized catalyst using ammonium sulfate with a concentration of 35%, co-precipitation time 12 hours and sulfonation time 4 hours. The functionalization of MWCNTS with the sulfonation process using ammonium sulfate has the potential to increase catalyst activity and can increase the efficiency of the transesterification process for non-edible oils, especially kesambi oil.

Sulfonated polydivinylbenzene bamboo-like nanotube stabilized Pickering emulsion for effective oxidation of olefins to 1,2-diol

Sulfonated polydivinylbenzene bamboo-like nanotube (SPDVB) with effective olefins oxidation activity is prepared by combining cationic polymerization and sulfonation. By merely adjusting sulfonation time, SPDVB with different sulfonic acid group (–SO3H) contents is achieved. SPDVB is used as both a solid emulsifier and catalyst to fabricate Pickering emulsion interface catalytic system for oxidizing olefins with 30% H2O2 acting as oxidant/water phase and olefins acting as reactants/oil phase. It is shown that Pickering emulsion interface catalytic system stabilized by SPDVB exhibits enhanced olefins oxidation efficiency than the conventional ones. At the optimum catalyst and reaction condition, the conversion of olefins by Pickering emulsion interface catalytic system stabilized by SPDVB for cyclohexene, 1-methylcyclohexene, cyclooctene, 2,3-dimethyl-2-butene oxidation is higher than 90.00% and the corresponding 1,2-diol selectivity exceeds 93.00% except the selectivity to 1-methyl-1,2-cyclohexanediol. The catalytic system also exhibits excellent cycling performance (>95.00% olefins conversion and >89.00% 1,2-diol selectivity for cyclohexene/2,3-dimethyl-2-butene oxidation after four cycles). A possible mechanism for oxidation of olefins to 1,2-diol by SPDVB stabilized Pickering emulsion is proposed: the high catalytic interface area between sulfonic acid group and H2O2 in water phase enhances the sulfonic acid group of SPDVB to convert into peroxysulfonic acid (catalytic activity centre) firstly; then the formed peroxysulfonic acid attacks the double bond of olefins to form epoxide intermediates, which will be hydrolyzed to 1,2-diol.