Liquid Sulfuric Acid Research Articles

Valorization of Afzelia bella oilseeds cake in bioethanol production using 1-butyl-3-methyl-imidazolium chloride ionic liquid and dilute sulfuric acid pretreatment

The use of renewable feedstocks and the variability of lignocellulosic feedstocks generating fermentable sugars also offer the advantages of the most abundant, sustainable and competitive non-food biomass. The aim of this study is to valorize the oilcake obtained from non-conventional Congolese Afzelia bella oilseeds, after extraction of the oil used in biodiesel production. The conversion of A. bella oilseeds cake into ethanol was carried out using the two methods of pretreatment (with the synthesized ionic liquid 1-butyl-3-methyl imidazolium chloride and dilute sulfuric acid), followed by hydrolysis with dilute sulfuric acid and fermentation by Saccharomyces cerevisiae. The lignocellulosic composition of the sample was 47.98% cellulose, 28.15% hemicellulose and 22.3% lignin. Pretreatment with 1-butyl-3-methyl-imidazolium chloride (ionic liquid) showed an increase in cellulose content of around 4.25% and hemicellulose content of around 7.7%, with simultaneous delignification of 12.25%. In contrast, with dilute sulfuric acid, the lignin and cellulose content of the sample fell to 3.88% and 1.88% respectively. Hemicellulose content, on the other hand, increased by only 3.58%. After dilute acid hydrolysis (5% H2SO4), the values for total reducing sugar, glucose and xylose were 66.06±1.34 mg.g-1; 36.25 ± 1.2 mg.g-1 and 29.71 ± 0.6 mg.g-1 respectively. The percentage conversion of sugars was 55.16 ± 0.5% for cellulose to glucose and 53.76 ± 0.75% for hemicellulose to xylose. The hydrolyzed product of the complex polysaccharide was then converted to ethanol using commercial yeast. Results showed an ethanol yield of around 10.3%, and Fourier Transform Infrared (FTIR) spectroscopy results confirmed bioethanol production. A. bella oilseeds cakes are therefore a potential source for ethanol production.

Multiobjective Optimization and Sustainability Assessment of an Improved Wet Sulfuric Acid-Based Ionic Liquid Process for the Utilization of Hydrogen Sulfide Using a Symmetry Approach.

Ionic liquids (ILs) are efficient media for the liquid-phase sulfuric acid reaction. Under mild situations, the reaction of H2S with CH4 in ILs happens extremely quick and virtually complete, resulting in liquid sulfuric acid (H2SO4(l)). 1-hexyl-3-methylimidazolium chloride ([hmim][Cl]) ILs were formerly the most effective at capturing and converting H2S. It can convert H2S to H2SO4(l) with a proportion of up to 96%. This study aimed to develop cutting-edge techniques and assess their applicability for different acidic gas capacities and H2S amounts by considering three sustainability metrics which are people (safety), planet (ecological), and profit. Then, to maximize profit while lowering the global warming potential (GWP), fire explosion damage index (FEDI), and toxicity damage index (TDI), a multiobjective optimization (MOO) case was performed. The trade-off between economic, environmental, and safety performance was expressed through Pareto-optimal solutions. The improved wet sulfuric acid (WSA)-based IL method was safer (lower fire and explosion damage index), ecologically friendly (lower GWP), and portable. The findings indicate that the improved WSA-based on IL gives the optimum results compared to conventional WSA processes, such as the profit of 5688$/h increased from 1896$/h, the GWP of 0.0138-ton CO2-eq decreased from 0.0275-ton CO2-eq, the TDI of 6.72 decreased from 13.44, and the FEDI of 6.18 decreased from 20.6, respectively. This discovery opens the door to a viable strategy for capturing and converting H2S from an acid gas stream.

Volcanic ash ice nucleation activity is variably reduced by aging in water and sulfuric acid: the effects of leaching, dissolution, and precipitation.

Volcanic ash nucleates ice when immersed in supercooled water droplets, giving it the potential to influence weather and climate from local to global scales. This ice nucleation activity (INA) is likely derived from a subset of the crystalline mineral phases in the ash. The INA of other mineral-based dusts can change when exposed to various gaseous and aqueous chemical species, many of which also interact with volcanic ash in the eruption plume and atmosphere. However, the effects of aqueous chemical aging on the INA of volcanic ash have not been explored. We show that the INA of two mineralogically distinct ash samples from Fuego and Astroni volcanoes is variably reduced following immersion in water or aqueous sulfuric acid for minutes to days. Aging in water decreases the INA of both ash samples by up to two orders of magnitude, possibly due to a reduction in surface crystallinity and cation availability accompanying leaching. Aging in sulfuric acid leads to minimal loss of INA for Fuego ash, which is proposed to reflect a quasi-equilibrium between leaching that removes ice-active sites and dissolution that reveals or creates new sites on the pyroxene phases present. Conversely, exposure to sulfuric acid reduces the INA of Astroni ash by one to two orders of magnitude, potentially through selective dissolution of ice-active sites associated with surface microtextures on some K-feldspar phases. Analysis of dissolved element concentrations in the aged ash leachates shows supersaturation of certain mineral species which could have precipitated and altered the INA of the ash. These results highlight the key role that leaching, dissolution, and precipitation likely play in the aqueous aging of volcanic ash with respect to its INA. Finally, we discuss the implications for understanding the nature and reactivity of ice-active sites on volcanic ash and its role in influencing cloud properties in the atmosphere.

The effects of coagulant types on the quality and added value of raw rubber materials

Many processing problems still occur, causing the low quality of raw rubber materials and farmers low-income. This can be seen from the use of coagulants, storage methods and the level of cleanliness. This study was aimed at analyzing the quality and added value of raw rubber materials based on the use of coagulant types. This study was conducted in October - November 2021. Fresh latex was obtained from the rubber plantation in Mulyaguna Village, OKI Regency. Completely randomized design was used with 5 treatments and 4 replications. The coagulants used were the recommended ones (liquid smoke, formic acid), and the commonly used by the farmers (sulfuric acid, aluminum sulfate, and TSP fertilizer). The results of the study showed that liquid smoke and formic acid were better than the coagulants commonly used by farmers, which could be seen from the ash content, initial plasticity, and plasticity retention index. The dry rubber contents (DRCs) using liquid smoke, formic acid, sulfuric acid, aluminum sulfate, and TSP fertilizer were 66.081; 62.978; 59.067; 56.202 and 60.796 respectively. Liquid smoke and formic acid provided the added value for raw rubber materials of 1,203/kg IDR and 792/kg IDR compared to sulfuric acid commonly used by farmers.

Reaction Characteristics of Organosolv-Fractionation Process for Selective Extraction of Carbohydrates and Lignin from Rice Husks

The organosolv-fractionation process can act as a biorefinery process because it can separate the main components of biomass, such as lignin and hemicellulose, with high purity. The ethanol-based organosolv-fractionation process was applied to separate carbohydrates and lignin from rice husks, and the extraction behavior was observed according to various reaction variables. Various reaction conditions such as different temperatures (150 °C, 170 °C, and 190 °C), reaction times (30 min, 60 min, and 120 min), and ethanol concentrations (40%, 60%, and 80%) were tested while maintaining the solid:liquid ratio (1:10) and sulfuric acid concentration (0.25 wt.%). Two optimal reaction conditions for the target components were chosen: for sugar recovery, 150 °C, 60 min, and 40% ethanol were used as condition 1, and for lignin recovery, 170 °C, 120 min, and 80% ethanol were used as condition 2. Under condition 1, 91.5% of the glucan was preserved in the residual solid, and 75.0% of the xylan was extracted from the liquid hydrolysate. For condition 2, 59.9% of the lignin was recovered. To properly choose and apply the correct fractionation method and conditions, the reaction behavior (such as carbohydrate retention and extraction), lignin solubilization, and precipitation should be carefully considered.

Modeling sulfuric acid decomposition in a bayonet heat exchanger in the iodine-sulfur cycle for hydrogen production

Accurate simulations of sulfuric acid decomposition are important for the design and control of sulfuric acid decomposers, which are key equipments for nuclear hydrogen production with the iodine-sulfur cycle driven by heat from a very high temperature gas cooled reactor. The present study included sulfuric acid decomposition experiments with measurements of the decomposition fraction and temperature distribution to verify a user defined boiling model that relaxes the coupling between the phase transition and the chemical reactions modeled using a species transport model based on computational fluid dynamics. The heat transfer in the bayonet heat exchanger was simulated numerically including the liquid sulfuric acid phase change, the reversible sulfuric acid decomposition reaction, and the sulfur trioxide decomposition into sulfur dioxide in the catalyst zone. The results show that the proposed method agrees well with experimental data. The sulfuric acid needs to completely decompose before entering the catalyzer to make full use of the catalyst. The decomposition fraction of sulfuric acid decreases significantly with increasing flow rate due to the inadequate retention time in the catalyst zone. The sulfuric acid decomposition rate increases and then tends towards a stable rate with increasing velocity. This study provides a useful model for engineering designs of high-performance sulfuric acid decomposers.

Electrochemical properties of antimony lead electrode in gelled electrolyte prepared by liquid glass and sulfuric acid using polyacrylamide together with polyaniline

AbstractGelled electrolyte is made at different temperatures based on liquid glass and sulfuric acid using two organic additives such as polyacrylamide and polyaniline. The antimony lead electrode is used to study the electrochemical properties of gelled electrolyte through cyclic voltammetry, electrochemical impedance and ionic conductivity determination. The results showed that the gelled electrolyte made at low temperature is in a more favorable form of gel than that at high temperature, the ability to extract water was also overcome. The resistance of charge transfer of lead electrodes operating in an gelled electrolyte environment is all lower than that in sulfuric acid (d = 1.26 g /cm3), in which the presence of PANi together with PAM is recorded as the smallest. When the lead electrode was anodized, the simultaneous formation of PbO with PbSO4 did not appear due to the presence of PANi.

Study on polarization of antimony lead electrode in gelled electrolyte

AbstractGelled electrolyte is prepared from liquid glass and sulfuric acid with various specific weights in the presence of both gelling agents such as polyacrylamide and polyaniline. The antimony lead electrode is polarized by potentiodynamic method in gelled electrolyte compared with sulfuric acid solution (1.26 g/cm3). The results found that not only the overpotential of gas evolution but also the polarization resistance depends on sample preparation conditions. The concentration of PAM at 0.55 wt% contributed to the shift of overpotential of oxygen release in the more positive side but made decreasing the hydrogen escape overpotential compared with H2SO4 solution (1.26 g/cm3). It showed that the presence of PANi together with PAM did not improve the overpotential of oxygen release, but significantly inhibited the hydrogen evolution, although polarization resistance was approximately or smaller than that in H2SO4 solution (1.26 g/cm3).

The influence of leaching parameters on the extraction of vanadium from petroleum coke

The influence of the parameters of the leaching process on the degree of vanadium extraction into the solution from petroleum coke using concentrated (98%) and diluted (10%) sulfuric acids and a hydroxide sodium (12%) as a leaching reagent was studied. Among the measured process parameters were the ratio of solid (coke) and liquid (sulfuric acid) phases, leaching time, acid or alkaline concentration. The process temperature was chosen to be a constant value of 100 °C. The efficiency of vanadium extraction into the solution was estimated by the photometric method and was from 50% to 98%.

Practical methods for rapid seed germination from seed coat-imposed dormancy of Prunus yedoensis

The seeds of Prunus yedoensis have slow and poor germination when intact (with endocarp). Cold and/or warm stratification, washing, and scarification with liquid nitrogen and sulfuric acid, in combination with or without gibberellic acid (GA3) application, were investigated as facilitators for rapid and high germination. No germination was observed without GA3 in any treatment for intact seeds. GA3 treatment for one day significantly shortens the mean germination time (MGT) and improves seed germination percentage. Immersion in liquid nitrogen followed by GA3 treatment, GA3 application to intact seeds and seed coat removed seeds significantly enhanced the germination and MGT to 63 ± 7.6% (8.6 weeks), 71 ± 5.0% (4.7 weeks), and 93 ± 5.1% (0.8 weeks), compared to untreated seeds or stratified seeds (0%) chilled for six months. Depending on the GA3 application method, results could be different in intact seeds. GA3 application with vigorous shaking accomplished higher germination and lower MGT (71 ± 5.0%, 4.7 weeks) than gentle shaking incubation (33 ± 6.0%, 10.4 weeks). The germination inhibitor(s) were located in the seed coat because seed coat extract inhibited germination in decoated seeds. Therefore, coat removal alleviates the inability to promote germination and it has the same beneficial effect as does the application of GA3. According to the results, it suggest that the effective application of GA3 on intact seeds or seed coat removal could overcome seed dormancy in P. yedoensis.

Circular polarization signals of cloudy (exo)planets

Context. The circular polarization of light that planets reflect is often neglected because it is very small compared to the linear polarization. It could, however, provide information on a planet’s atmosphere and surface, and on the presence of life, because homochiral molecules that are the building blocks of life on Earth are known to reflect circularly polarized light. Aims. We compute Pc, the degree of circular polarization, of light that is reflected by rocky (exo)planets to provide insight into the viability of circular spectropolarimetry for characterizing (exo)planetary atmospheres. Methods. We compute the Pc of light that is reflected by rocky (exo)planets with liquid water or sulfuric acid solution clouds, both spatially resolved across the planetary disk and, for planets with patchy clouds, integrated across the planetary disk, for various planetary phase angles α. Results. The optical thickness and vertical distribution of the atmospheric gas and clouds, the size parameter and refractive index of the cloud particles, and α all influence Pc. Spatially resolved, Pc varies between ± 0.20% (the sign indicates the polarization direction). Only for small gas optical thicknesses above the clouds do significant sign changes (related to cloud particle properties) across the planets’ hemispheres occur. For patchy clouds, the disk-integrated Pc is typically smaller than ± 0.025%, with maximum for α between 40° and 70°, and 120° to 140°. As expected, the disk-integrated Pc is virtually zero at α = 0° and 180°. The disk-integrated Pc is also very small at α ≈ 100°. Conclusions. Measuring circular polarization signals appears to be challenging with current technology. The small atmospheric circular polarization signal could, however, allow the detection of circular polarization due to homochiral molecules such as those associated with life on Earth. Confirmation of the detectability of such signals requires better knowledge of the strength of circular polarization signals of biological sources and in particular of the angular distribution of their scattering.

Ionic Liquid and Sulfuric Acid-Based Pretreatment of Bamboo: Biomass Delignification and Enzymatic Hydrolysis for the Production of Reducing Sugars

The present work investigates the efficiency of two pretreatment pathways of biomass, namely ionic liquid (IL) and dilute sulfuric acid (H2SO4) hydrolysis. Both processes are compared in terms of their composition and enzymatic saccharification efficacy. For the IL process, bamboo was dissolved in 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) at different temperatures (90, 110, 130, and 150 °C) for 3 h. These pretreated bamboo samples were then characterized by thermogravimetric analysis and X-ray diffraction to evaluate the biomass crystallinity and thermal decomposition temperature. The crystallinity index, thermal decomposition temperature, hemicellulose, and lignin content of bamboo were found to decrease after [Emim][OAc] pretreatment. Further, the IL pretreated biomass significantly enhanced the enzymatic saccharification of cellulose component of bamboo. The enzymatic hydrolysis rate for IL pretreated biomass was 4.7 times higher than that of the acid pretreated biomass. This was primarily attr...

Enzymatic saccharification of liquid hot water and dilute sulfuric acid pretreated oil palm empty fruit bunch and sugarcane bagasse

Oil palm empty fruit bunch (OPEFB) and sugarcane bagasse (SB) are potential feedstocks for the production of bioethanol. In this study OPEFB and SB were pretreated by liquid hot water and dilute sulfuric acid (3% H2SO4), and continued with enzymatic saccharification. Heating treatment for both methods was conducted in an autoclave at 121 °C for 1 hr. The saccharification was performed up to 72 hours with cellulase enzyme loading of 10, 20, and 30 FPU per g biomass. Results showed that OPEFB and SB pretreated with H2SO4 produced higher reducing sugars than those pretreated by liquid hot water. Higher enzyme loading also resulted in higher reducing sugars. Reducing sugars obtained from enzymatic saccharification of OPEFB were higher than those obtained from SB. The highest total reducing sugars (50.48 g/100 g biomass) was obtained from OPEFB pretreated with 3% H2SO4 at enzyme loading of 30 FPU per g biomass.

Highly Efficient Sulfonic/Carboxylic Dual‐Acid Synergistic Catalysis for Esterification Enabled by Sulfur‐Rich Graphene Oxide

A new sulfonic/carboxylic dual-acid catalyst based on sulfur-rich graphene oxide (GO-S) was readily prepared and used as a highly efficient and reusable solid acid catalyst toward the esterification of oleic acid with methanol for biodiesel production. Higher yields of methyl oleate (98 %) and over 3 times higher turnover frequencies (TOFs) were observed for the GO-S dual-acid catalyst, compared to liquid sulfuric acid or other carbon-based solid acid catalysts. The "acidity" of sulfonic acid groups was enhanced by the addition of carboxylic acid groups as the combination of the two acids enhances their inherent activity by associative interaction.

Efficient and stable PS-SO3H/SiO2 hollow nanospheres with tunable surface properties for acid catalyzed reactions

Facile synthesis of hybrid solid acids with finely engineered surface properties was successfully realized via sulfonation of polystyrene (PS) dispersed in nanopores of silica hollow nanosphere modified with different organic group. It was found that octyl or perfluorinated octyl could efficiently increase the surface hydrophobicity of the hybrid solid acids. Benefited from the facile adjustability of the surface properties, the catalytic performance of the solid acids could be readily improved in both the esterification of lauric acid with ethanol and the transterification between tripalmitin and methanol. The solid acid modified with perfluorinated octyl shows even higher activity than liquid sulfuric acid in the transesterification reaction. The octyl group incorporated in the silica shell could also prevent the leaching of PS-SO3H during the catalytic process.

Kinetics of Vanadium Leaching from a Spent Industrial V2O5/TiO2 Catalyst by Sulfuric Acid

Recovery of vanadium from various sources is important to the environment and industry. This work investigates vanadium leaching from a spent selective catalytic reduction catalyst by sulfuric acid at atmospheric pressure. It includes the effects of stirring speed, solid to liquid ratio, temperature, and sulfuric acid concentration on the vanadium recovery yield. The results show that the vanadium recovery yield increases with increases in temperature, sulfuric acid concentration, and leaching time and decreases with an increase in solid to liquid ratio. The leaching data can not be described well by kinetic models commonly adopted for similar processes in the literature. The Avrami equation, originally developed for crystallization, is found to be most suitable. The leaching is controlled by diffusion in the solid with an activation energy of 5.90 kJ/mol.

Quest for a Material for Sulfuric Acid Superheater/Decomposer for Sulfur-Iodine Thermochemical Cycle for Hydrogen Production

The sulfur-iodine and hybrid-sulfur thermochemical cycles that can utilize high-temperature heat from advanced nuclear reactors have shown promise economically for large-scale production of hydrogen from water. Both of these cycles employ a step to decompose sulfuric acid to sulfur trioxide by heating it above 723 K followed by the catalytic decomposition to sulfur dioxide at a temperature >1073 K depending on the catalyst used. Successful commercial implementation of these technologies is dependent on the development of suitable materials for use in these highly corrosive environments. In this study, a laboratory-scale superheater/decomposer was constructed and used to study the corrosion resistance of natural diamond, synthetic diamond films treated with boron and titanium, silicon carbide, quartz, aluminum nitride, INCONEL, and platinum to sulfuric acid and SO3. However, it appeared that some of these materials catalyzed SO3 to SO2 and O radicals, which also attacked these materials, increasing their corrosion rates.Natural diamonds, synthetic diamond films (treated with boron and titanium), aluminum nitride, and INCONEL have unacceptable corrosion rates above 873 K. Both the boron- and titanium-treated diamond samples completely disintegrated at temperatures >973 K. The high corrosion rates may have resulted from carbons in diamond having a higher preference for oxygen free radicals that were formed during the decomposition process. Oxygen free radical concentrations increased as a function of the increasing temperature.The present study showed that silicon carbide had the best corrosion resistance over the range of conditions at which the superheater would operate. Quartz was also corrosion resistant but became brittle after 30 h of exposure to this harsh environment. Platinum, used as a catalyst to reduce the decomposition temperatures, exhibited almost no corrosion when exposed to decomposition products. However, platinum did corrode when exposed to liquid sulfuric acid at high temperatures.

Alkylation of Thiophenic Compounds with 1-Hexene over Sulfonated Solid Acid Catalysts

Three kinds of carriers were utilised to prepare the corresponding sulfonated solid acid catalysts for the alkylation of two different thiophenic compounds (3-methylthiophene and 3-butylthiophene) with 1-hexene. Though the activity of the sulfonated solid acid catalysts was somewhat lower than that of liquid sulfuric acid, the solid acid catalysts had significant advantages in their easy separation, good recycling, selectivity and performance on reuse.

Reduction of Salmonella and Ammonia Emissions in Broiler Litter Using Sulfuric Acid and Aluminum Sulfate

In recent years an emphasis has been placed on reducing food borne pathogens on the farm. Of particular interest to the poultry industry is Salmonella enterica. In the United States, a common practice in broiler management is the reuse of litter for consecutive flocks; this practice can lead to a Salmonella positive flock causing the colonization of sequential flocks. Reuse of litter can also lead to high levels of ammonia volatilization which can impact broiler health and performance. In this paper, two experiments are presented using chemical litter amendments to reduce both ammonia and Salmonella. In the first experiment, liquid sulfuric acid was applied to litter at one of three application rates; 9.07, 18.14 and 27.21 L/92.9 m . In experiment two, commercially available aluminum sulfate was applied to litter at three different 2 application rates; 22.7, 45.5 and 68.0 kg/92.9 m . In addition, a cocktail of five poultry associated S. enterica 2 serovars was applied to the litter. Salmonella, ammonia, moisture and pH levels were measured immediately before treatments and every 24 hours up to 96 hours. For treated litter, a reduction was seen in ammonia levels 24 hours after application regardless of application rate, the reduction continued for the duration of the experiment (P<0.001). No Salmonella was detected in litter treated with sulfuric acid. Salmonella was recovered in litter treated with aluminum sulfate. The data presented here indicates that sulfuric acid and aluminum sulfate are suitable candidates for reducing ammonia emissions and sulfuric acid as a candidate for Salmonella reduction.

Modeling the Distribution of Sulfur Compounds in a Large Two Stroke Diesel Engine

In many years large low speed marine diesel engines have consumed heavy fuel oils with sulfur contents in the order of 2.5–4.5 wt %. Present legislation requires that the fuel sulfur is reduced, and in the near future the limit will be 0.5 wt % globally. During combustion most of the sulfur is oxidized to SO2 from which a fraction is further oxidized to SO3. SO3 may combine with H2O and condense as liquid sulfuric acid that promotes corrosive wear on e.g. cylinder liners. To extend engine lifetime and reduce costs for lubrication it is pivotal to identify formation of SO3 with respect to operational conditions and sulfur feed. This work presents a computational model of a large low speed two-stroke diesel engine where a 0D multizone approach including a detailed reaction mechanism is employed in order to investigate in cylinder formation of gaseous SO3 where fuel burn rates are based on experimental pressure traces. In contrast to NO the SO3 does not really form at the highest combustion temperatures, but like NO the formation of SO3 is very sensitive to the rate that fresh air mixes with hot combustion products. Consequently a simple mixing rate is proposed and calibrated in order to meet experimental results of NO. For a large low speed diesel engine the model shows that 3–5% of the injected sulfur is oxidized to SO3 that is formed primarily in the temperature range from 2000 to 1300 K during cylinder expansion. In addition the model is used to reduce the full reaction mechanism from 96 to 7 elementary sulfur reactions without compromising the SO3 to SO2 ratio.