Sulfonation Time Research Articles

Synthesis of Highly Durable Sulfonated Polyketone Fibers by Direct Sulfonation Reaction and Their Adsorption Properties for Heavy Metals

In this study, sulfonated polyketone (SPK) cation exchange fibers were prepared by direct sulfonation with various concentration of sulfonating agent and sulfonation time. Fourier-transform infrared (FTIR) spectrum analysis was performed to confirm the structure of the sulfonated polyketone cation exchange fibers. The degree of sulfonation (DOS) and water uptake (W.U) of SPK cation exchange fibers were measured by gravimetric method and ion exchange capacity (IEC) was measured by titration method, respectively. The DOS of the SPK cation exchange fibers increased with sulfonation time and concentration of sulfonating agent. The SPK cation exchange fibers sulfonated for 15 min at a mole ratio of 1:2 of polyketone to chlorosulfonic acid had the DOS of 47%, ion exchange capacity 3.36 meq/g, and water content 35.1%, showing the best performance.

Sulfonated Cross-Linked Poly(ether ether ketone) Films with Wrinkled Structures: Preparation and Vanadium Ions Permeability

Wrinkling patterns were fabricated by sulfonation of ion irradiated poly(ether ether ketone) (PEEK). A variety of wrinkling patterns in the micrometer to sub-micrometer range were observed and were controlled by the adsorbed dose and dose rate of the irradiated ions as well as the sulfonation time. Because of the properties of these micro-textured membranes, they are promising for a broad range of applications. In particular, the cross-linked membranes had a very low permeability of vanadium ions, i.e. 1.5 × 10−7 cm2 min−1 due to their wrinkled structures in combination with the Donnan exclusive effect. Open image in new window

Influence of Catalyst Preparation Conditions on Coconut Shell-derived Solid Acid Catalyst Performance for Transesterification

The carbon-based solid acid catalyst is mostly synthesized through a series of incomplete carbonization and sulfonation process. This paper investigates the influence of catalyst preparation conditions on the catalyst performance in biodiesel conversion. Coconut-shell-derived solid acid catalyst was prepared through incomplete carbonization followed by sulfonation using concentrated sulphuric acid. The effect of catalyst preparation variables including carbonization temperature, carbonization time, sulfonation temperature and sulfonation time was evaluated using response surface methodology. The adequacy of the mathematical model represents the process was confirmed by using ANOVA analysis with R2 value of 0.9121 and p-value <0.0001. Optimal process conditions were obtained at carbonization temperature of 469.97 ºC, carbonization time of 3.37 h, sulfonation temperature of 99.14 ºC and sulfonation time of 7.11 h. At these conditions, the coconut shell-derived catalyst able to catalyse the transesterification reaction and achieved >80% FAME conversion. This study uncovers the potential of biomass valorisation into a useful end produc

Study of High Performance Sulfonated Polyether Ether Ketone Composite Electrolyte Membranes.

In this study, high performance composite electrolyte membranes were prepared from polyether ether ketone polymeric material. An initial sulfonation reaction improved the membrane hydrophilicity and its water absorbability and thus enhanced the ionic conductivity in electrochemical cells. Protonic conductivity was improved from 10−4 to 10−2 S cm−1 with an increasing sulfonation time from 72 to 175 h. The effects of blending nano SiO2 into the composite membranes were devoted to improve thermal and mechanical properties, as well as methanol permeability. Methanol permeability was reduced to 3.1 × 10−7 cm2 s−1. Finally, a further improvement in ionic conductivity was carried out by a supercritical carbon dioxide treatment under 20 MPa at 40°C for 30 min with an optimum SiO2 blend ratio of 10 wt-%. The plasticizing effect by the Lewis acid-base interaction between CO2 and electron donor species on polymer chains decreased the glass transition and melting temperatures. The results show that sulfonated composite membranes blended with SiO2 and using a supercritical carbon dioxide treatment exhibit a lower glass transition temperature, higher ionic conductivity, lower methanol permeability, good thermal stability, and strong mechanical properties. Ionic conductivity was improved to 1.55 × 10−2 S cm−1. The ion exchange capacity and the degree of sulfonation were also investigated.

Methyl ester production from palm fatty acid distillate (PFAD) using sulfonated cow dung-derived carbon-based solid acid catalyst

In present work, cow dung was chosen as the raw material to undergo incomplete carbonization process which was held at 500 °C for 2 h. The incomplete carbonized carbon was then sulfonated with H2SO4 at different sulfonation time (2 h, 5 h and 10 h) in studying the relationship between sulfonation time and the activity of the catalyst. From the TPD-NH3 analysis, sulfonated carbon catalyst derived cow dung at 10 h (SCD-(10) catalyst) was chosen due to the higher acid density which is 16,653.49 μmol/g. Meanwhile, the experimental results showed that SCD-(10) catalyst exhibited good catalytic activity with high FFA conversion of 96.5% at optimum parameter of 18:1 methanol to PFAD molar ratio, 4 wt% of catalyst loading and 90 °C reaction temperature within 1 h reaction time. The catalyst was successfully reused for 7 cycles and it was found that the catalytic activity maintained with >90% of FFA conversion for the first three run. SCD-(10) catalyst can be easily recovered and regenerated by simple washing method. Cow dung derived carbon catalyst concluded to be environmentally friendly and efficient for biodiesel production.

Cacao shell-derived solid acid catalyst for esterification of oleic acid with methanol

Cacao shell-derived solid acid catalyst (CS-SAC) was successfully prepared by partial carbonization followed by sulfonation at various temperature (80, 100, 120 °C) and time (4, 6, 8 h) settings. The catalysts were analyzed for their acid densities and tested for their activity in the esterification of oleic acid with methanol at 45 °C for 4 h, with methanol to oleic acid molar ratio of 7:1 and a catalyst loading of 5 %w/w. It was found that increasing the sulfonation temperature at sulfonation times of 4 and 6 h increased the solid’s total acid density and sulfonic acid density thereby increasing its specific catalytic activity. Prolonging sulfonation time at any temperature, however, had no significant effect. The highest specific catalytic activity of 14.0 mmol FAME·g−1 CS-SAC·h−1, which corresponds to 79% conversion of oleic acid was observed for SAC sulfonated at 120 °C for 4–6 h. Prolonged esterification up to 24 h resulted in high conversion of ∼94% even at a low temperature of 45 °C. Although the catalyst was later found to decrease in its activity during reuse, its catalytic activity remained stable after the 3rd cycle at a conversion of 48% of the oleic acid.

Partially sulfonated styrene-(ethylene-butylene)-styrene copolymers: Nanostructures, bio and electro-active properties

Abstract Conductive polymers take much interest because of their electroactive definition as new generation smart biomaterials beside of their potential usage in proton exchange membrane fuel cells. Partially sulfonated styrene-(ethylene-butylene)-styrene (sSEBS) triblock copolymer based films (coded SEBS68 with the content of 68% SEBS, 5% PP, 26,5% Wax and 0,5% stabilizer) have been focused in the present study. Chemical manipulations have been done during the synthesis of the films for formation of nano-scale cylindrical like globular and lamellar like nematic aggregations. Association of the nano aggregations and nano-domains in the films were investigated by using small- and wide-angle X-ray scattering methods. Microscale surface morphologies and features were also examined by a compact non-contact 3D surface profiler system. The results show that the changes in the nanostructures and the surface morphologies are dependent on sulfonation time. With sulfonation time of 4 min, the system could reach optimum physico-chemical properties, including the optimized size of phase segregation tunnels. It was also found that the modified polymer morphologies with nanostructural features are effective on antimicrobial activities against the different test microorganisms studied.

Preparation and performance investigation of a lignin-based solid acid catalyst manufactured from olive cake for biodiesel production

Abstract In this study, the olive cake was successfully developed and applied as a substrate to produce a lignin-based catalyst for biodiesel production. Three lignin-based solid acid catalysts were prepared from the incomplete carbonized alkali lignin using concentrated sulfuric acid. The catalyst underwent a detailed characterization analysis in terms of its functional groups of active sites, surface area, acid sites density and morphological structure. For the catalytic activity test, prepared catalysts were studied for their ability to catalyze both esterification and transesterification reactions of waste vegetable oil (WVO) ≈2 FFA (% w/w). The results revealed that a sulfonated lignin-derived acid catalyst has a high potential to esterify waste vegetable oil to about (92%) conversion. Furthermore, it demonstrated about 57% conversion to fatty acid methyl esters (FAME) under the following optimum condition: sulfonation time of 1 h, catalyst loading of 10 wt %, the methanol-to-WVO molar ratio of 35:1, a reaction temperature of 65 °C and reaction time of 6 h. Also, the results showed that the lignin-based acid catalyst can be reused at least ten times with high FFA conversion (>75%).

Assembly of 1D Granular Structures from Sulfonated Polystyrene Microparticles.

Being able to systematically modify the electric properties of nano- and microparticles opens up new possibilities for the bottom-up fabrication of advanced materials such as the fabrication of one-dimensional (1D) colloidal and granular materials. Fabricating 1D structures from individual particles offers plenty of applications ranging from electronic sensors and photovoltaics to artificial flagella for hydrodynamic propulsion. In this work, we demonstrate the assembly of 1D structures composed of individual microparticles with modified electric properties, pulled out of a liquid environment into air. Polystyrene particles were modified by sulfonation for different reaction times and characterized by dielectric spectroscopy and dipolar force measurements. We found that by increasing the sulfonation time, the values of both electrical conductivity and dielectric constant of the particles increase, and that the relaxation frequency of particle electric polarization changes, causing the measured dielectric loss of the particles to shift towards higher frequencies. We attributed these results to water adsorbed at the surface of the particles. With sulfonated polystyrene particles exhibiting a range of electric properties, we showed how the electric properties of individual particles influence the formation of 1D structures. By tuning applied voltage and frequency, we were able to control the formation and dynamics of 1D structures, including chain bending and oscillation.

Optimization of biodiesel production by solid acid catalyst derived from coconut shell via response surface methodology

The application of solid acid catalyst in biodiesel production eliminates the tedious pretreatment of feedstock and eradicates generation of high volume of wastewater. A novel acid catalyst was prepared via sulfonation of incompletely carbonized coconut shell using concentrated sulfuric acid. The design of experiments were performed using four factor-three-level central composite design coupled with response surface methodology to evaluate the interaction between two factors in order to determine the optimum process conditions. A quadratic model was suggested for the prediction of biodiesel yield. The F-value and p-value of the model were 4.02 and 0.0129, respectively, indicate that the model was statistically significant at 95 per cent confidence interval. In addition, R2 value of the model was 0.8364, which indicates the acceptable accuracy of the model. From the optimization study, it was found that the carbonization temperature, carbonization time, sulfonation temperature and sulfonation time were 422 °C, 4 h, 100 °C and 15 h, respectively. At these optimum conditions the predicted and observed biodiesel yield were 88.15 per cent and 88.03 per cent, respectively, which experimentally verified the accuracy of the model. The use of coconut shell-derived solid acid catalyst in biodiesel production promotes the sustainable and green way of operations.

Preparation of Glucose Carbon-Based Solid Acid Catalyst for Catalytic Hydrolysis of Cellulose

A carbon-based solid acid catalyst was prepared from cheap glucose. The performances of the catalyst were characterized by Fourier transform infrared spectroscopy (FT-IR), and the effect of preparation conditions on catalyst activity was investigated using cellulose hydrolysis as a probe reaction. The results showed that the optimal preparation conditions of the catalyst were: the carbonation temperature 180℃, the carbonation time 7h, FeCl3 0.4g, the sulfonation temperature 110℃, the sulfonation time 11h. Hydrolysis rate was 49.38% by using the glucose carbon-based solid acid catalyst for cellulose hydrolysis reaction. The carbon-based solid acid catalyst was the amorphous carbon structure of –COOH,-OH, -SO3H.

Preparation of Starch Carbon-Based Solid Acid Catalyst

A carbon-based solid acid catalyst was prepared from starch. The performances of the catalyst were characterized by X-ray diffraction (XRD), thermogravimetry (TG), and the effect of preparation conditions on catalyst activity was investigated by using the catalyst surface acidity. The results showed that the optimal preparation conditions of the catalyst were: The ratio of carbon product with the concentration of sulfuric acid 1:20, the carbonation temperature 180°C, the carbonation time 5h, the sulfonation temperature 110°C, the sulfonation time 10h.The carbon-based solid acid catalyst was the amorphous carbon structure, and the considerable heat stability below 170°C.

Functionalized Cycloolefin Polymer Capillaries for Open Tubular Ion Chromatography.

We describe novel cycloolefin polymer (COP)-based open tubular capillary ion exchange columns. COP capillaries (inner diameter of 19-28 μm) were successfully sulfonated at room temperature using a cocktail of ClSO3H (85-95% w/w) and HOAc or H2SO4. The cation exchange capacity is controlled by the sulfonation time and the sulfonation solution composition and can be as high as 300 pequiv/mm2. Following sulfonation, the capillaries were coated with 65-nm-diameter anion exchanger (AEX) latex nanoparticles that attach electrostatically. The typical anion exchange capacities were ∼20 pequiv/mm2. The chromatographic behavior of the AEX latex-coated COP capillaries are greatly dependent on the degree of sulfonation. When the base is heavily sulfonated, neutrals elute after the anions. The position of the water dip varies with the degree of sulfonation; the elution order is normal (water dip appear before anions) only with lightly sulfonated columns. On silica (-SiOH) or poly(methyl methacrylate) (-COOH) surfaces, AEX latex attachment is not stable over long periods in significant concentrations of strong base (e.g., ≥10 mM NaOH). Latex attachment on sulfonated COP surfaces are much stronger; several types show sufficient binding to be used over long periods at practical eluent concentrations, paving the way for suppressed hydroxide eluent ion chromatography (IC), which is discussed in a companion paper. Another interesting feature of COP capillaries lies in their flexibility. If softened at modestly elevated temperatures (e.g., boiling water), they can be coiled down to <1 mm coil radii, revealing, for the first time, the beneficial effects, albeit small, of centrifugal force on mass transfer in open tubular columns.

Investigation and optimization of physicochemical properties of sulfated zirconia/sulfonated poly (ether ether ketone) nanocomposite membranes for medium temperature proton exchange membrane fuel cells

In this study, sulfated zirconia (SZ) nanoparticles were used as inorganic additives in order to improve physicochemical properties of sulfonated poly (ether ether ketone) (SPEEK) membranes especially for fuel cell application at intermediate temperature. Interactive effects of SPEEK sulfonation time and the content of incorporated additive (as the factors) were studied on the proton conductivity and the oxidative stability of the nanocomposite membranes (as the responses) through the response surface method (RSM) using the central composite design (CCD). The optimum parameters were 6.9 h sulfonation time and 5.94 wt. % of sulfated zirconia that represented proton conductivity of 3.88 mS cm−1 (at 100 °C and 100% RH) and oxidative stability of 102 min. The sulfonation time had more effect on both responses. Furthermore, the addition of SZ nanoparticles improved both of oxidative stability and proton conductivity. The morphology, thermal and mechanical properties of optimized nanocomposite membrane were investigated by FESEM, TGA, DSC and tensile strength test, respectively. Also, the XRD, TGA, FTIR, EDX and TEM analysis were conducted to characterize the SZ nanoparticles.

Construction of Grape-like Silica-Based Hierarchical Porous Interlocked Microcapsules by Colloidal Crystals Templates.

We present a facile strategy to prepare grape-like silica-based hierarchical porous interlocked microcapsules (HPIMs) by polystyrene colloidal crystals templates, whose structure is the subtle integration of open mouthed structure, hierarchical porous nanostructure and interlocked architecture. HPIMs are fabricated by replicating colloidal crystals templates that have a hexagonal close-packed structure; thus, theoretically, each microcapsule has 12 open mouths, and these open mouths with mesoporous microcapsule wall construct the hierarchical porous structure. Furthermore, the interlocked architecture of the microcapsules can endow HPIMs with excellent mechanical stability and recyclability. By adjusting sulfonation time, the morphology, shell thickness, and even mesporous size of the HPIMs can be precisely controlled. In addition, HPIMs with various compositions are obtained via this method, such as silica and aminopropyl polysilsesquioxane (APSQ). All these unique features derived from a readily available method will give products with a broader range of applications.

Synthesis and Characterization of Partial Sulfonated PVDF‐co‐HFP Ion Exchange Membranes

SummaryMembranes of Poly (vinylidenedifluoride‐co‐hexafluoropropylene) (PVDF‐co‐HFP) are prepared successfully and investigated for thermal, mechanical and electrochemical properties. A considerable influence in ionic conductivity by varying the time of sulfonation has been achieved. Membranes with higher degree of sulfonation exhibit higher proton transport at room temperature. Herein we prepared a series of PVDF‐co‐HFP membrane by varying sulfonation time (6, 8, 10, 13 &amp; 15 hrs). Mechanical properties have been investigated by UTM (Universal Testing Machine) and thermal study has been done by TGA (Thermogravimeteric Analysis). The electro chemical properties of the membranes are found to be increase without compromising the thermal and mechanical characterises.

Saccharification of cellulosic biomass using sulfonated mesoporous carbon‐based catalysts

A series of sulfonated mesoporous carbon‐based catalysts with intact silica template (MC) were prepared through incomplete carbonization of sucrose followed by sulfonation. The MC catalysts were characterized by use of Fourier Transform‐infrared spectra, N2 adsorption–desorption, and titration method. The effects of preparation conditions such as carbonization temperature, amount of carbon precursor, sulfonation time, and temperature on the structural and acidic properties of the catalysts were investigated. Preparation conditions such as amount of carbon precursor, sulfonation time, and temperature significantly influenced the surface area and acidic properties of MC catalysts. The activity of prepared catalysts in saccharification was tested using cellulose and rice straw as substrates and high saccharification yield can be obtained using these catalysts. In saccharification of cellulose without pretreatment, the highest yield of 25.2% of C6 monosaccharide can be attained after reaction at 180°C for 3 h. In saccharification of rice straw, the total monosaccharide yield of 43.4% can be achieved after reaction at 150°C for 1 h. In addition, it was found that despite the versatility of mesoporous structure in varied chemical reactions has been confirmed, acid amount was the most important property that determined the effectivity of cellulose saccharification. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 574–581, 2016

Assembly route toward raspberry-like composite particles and their controlled surface wettability through varied dual-size binary roughness

Sulfonated PS template/aniline medium method was used to assemble raspberry-like composite particles with varied dual-size binary morphology. The assembly efficiency of SiO2 particles on templates was found to increase with sulfonation temperature as well as sulfuric acid concentration. For sulfonation time one turning point appeared because there existed one balance between microgel structure formation and PSS chains detachment. The optimal preparation condition was finally obtained and proved effective for other types of anionic particles. Wettability of surfaces with varied binary roughness was studied and the results showed that dual-size structure could further improve the hydrophobic performance. The contact angles were found to increase with the size ratio of template particles/outer particles.

Synthesis and Characterization of Sulfonated Poly‐(styrene‐co‐acrylic acid) for Applications as Pronton Exchange Membranes

SummaryPolymeric membranes were prepared using the mass copolymerization of styrene/acrylic acid (St/AA) at 90/10, 92/8 and 94/6 ratios. Divinyl benzene (DVB) was also added at concentrations of 0.1 and 0.001% weight for each St/AA ratio. The obtained copolymers were sulfonated by treating the materials with concentrated sulfuric acid for 0, 30 and 85 minutes to enhance their ion exchange capacities. The materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermal analysis by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), cross‐linking level by gel percentage and acidity through sodium hydroxide titration. The FTIR spectra of the membranes before sulfonation showed the existence of traditional bands that corresponded to the polymer components; some homopolymer main bands were lost, whereas two new bands appeared during the copolymerization reaction. The TGA analyses showed a higher decomposition temperature for the DVB cross‐linked membranes, while DSC did not provide much information due to the hygroscopic nature of the membranes. The gel percentage was effectively related to the DVB level. The membranes acidity increased with increasing acrylic acid content, sulfonation time and DVB percentage; however, the acidic values are highly dependent on the solubility of the materials.

Preparation of raspberry-like silica microcapsules via sulfonated polystyrene template and aniline medium assembly method

Raspberry-like composite particles and microcapsules were prepared with anionic sulfonated polystyrene (PSS) particles as templates and cationic aniline monomer as assembly medium. With the help of the sulfonated microgel shells, aniline and silica particles could not only adsorbed onto template surfaces but also go inward shells and finally form microcapsules with varied silica shell thickness. The sulfonation extent of PSS particles first climbed up and then decreased with sulfonation time due to the competition of sulfonation reaction and PSS chain detachment. The silica content in composite particles and shell thickness of microcapsules followed similar trend with sulfonation extent. The choice of aniline as assembly medium was checked by comparing with methyl methacrylate and [2-(methacryloyloxy) ethyl] trimethylammonium chloride, and it was found that the cationic and water-insoluble properties of aniline are both important for the composite efficiency.