Addition Of Inorganic Acids Research Articles

Tailoring Hydronium ion Driven Dissociation-Chemical Cross-Linking for Superfast One-Pot Cellulose Dissolution and Derivatization to Build Robust Cellulose Films.

Concepts of sustainability must be developed to overcome the increasing environmental hazards caused by fossil resources. Cellulose derivatives with excellent properties are promising biobased alternatives for petroleum-derived materials. However, a one-pot route to achieve cellulose dissolution and derivatization is very challenging, requiring harsh conditions, high energy consumption, and complex solubilizing. Herein, we design a one-pot tailoring hydronium ion driven dissociation-chemical cross-linking strategy to achieve superfast cellulose dissolution and derivatization for orderly robust cellulose films. In this strategy, there is a powerful driving force from organic acid with a pKa below 3.75 to dissociate H+ and trigger the dissolution and derivatization of cellulose under the addition of H2SO4. Nevertheless, the driving force can only trigger a partial swelling of cellulose but without dissolution when the pKa of organic acid is above 4.26 for the dissociation of H+ is inhibited by the addition of inorganic acid. The cellulose film has high transmittance (up to ∼90%), excellent tensile strength (∼122 MPa), and is superior to commercial PE film. Moreover, the tensile strength is increased by 400% compared to cellulose film prepared by the ZnCl2 solvent. This work provides an efficient solvent, which is of great significance for emerging cellulose materials from renewable materials.

Energy efficiency of bio-coal derived from hydrothermal carbonized biomass: Assessment as sustainable solid fuel for municipal biopower plant

The utilization of conventional biomass to generate electricity in the biomass thermal power plant is still inefficient due to high content of moisture, high impurity, and low heating value. To explore this limitation, in this research, hydrothermal carbonization (HTC) was selected as a sustainable process for producing green solid fuel or bio-coal with a rich of carbon content from palm shell and bamboo, remarkably as model biomass raw materials. The effect of biomass to water weight ratio (1:1 to 1:10), reaction temperatures (160 – 250 °C), and reaction times (1 – 6 h) were performed under autogenous pressure of promising aqueous media. The effect of organic and inorganic acid adding in the HTC of palm shell and bamboo was discussed. The obtained bio-coal was further well characterized with proximate and ultimate analysis and fuel properties. From the results, increasing reaction temperature and adding of acids led to increase carbon content, resulting to increase HHV of bio-coal. Effects of feedstocks (palm shell and bamboo), temperature, and types of acids revealed significantly results on the bio-coal yield accompanied with carbon content, the higher heating value (HHV), energy densification, and energy yield. The addition of inorganic acid in the HTC of biomass with high cellulose content provided higher HHV improvement than that of stony biomass. The highest HHV of 27.9 MJ/kg was obtained in bio-coal derived from palm shell feedstock with 1:1 water ratio and hydrothermally at 250 °C for 6 h. Surprisingly, this HHV is comparable to high-volatile bituminous coal. Moreover, an evaluating assessment for the utilization of this bio-coal instead of biomass feedstock to generate electricity in the thermal power plant with size of 9.9 MW capacity could reduce 34.4 % of fuel storage size, save nearly 29,709.36 USD/year in transportation costs and diminish CO2 emission during burning by approximately 56,732 tons/25 years.

Form of the catalytically active Pd species during the direct synthesis of hydrogen peroxide

AbstractDirect synthesis of H2O2 could produce H2O2 at lower cost than the Riedl–Pfleiderer process, which would enable the broader use of H2O2 for industrial oxidations. The addition of inorganic acids and halides to the solvent increase H2O2 selectivities on Pd nanoparticles but also dissolve Pd and produce dynamic mixtures of complexes including heterogeneous (Pd0) and homogeneous (Pd2+) species, any of which may contribute to H2O2 formation. We combine kinetic measurements and in operando UV–vis spectroscopy to determine how H2O2 rates and selectivities depend on concentrations of these forms of Pd. Introducing HCl to the solvent increases the concentration of Pd2+ complexes by oxidizing Pd0 nanoparticles. The rates of primary H2O2 formation and H2O2 selectivities do not depend directly on the population of the Pd2+ species for catalysts tested in water or methanol. These results suggest that Pd nanoparticles form H2O2 and detectable homogeneous complexes do not act as catalysts.

Acceleration and simplification of separation by addition of inorganic acid in biodiesel production

Abstract This paper describes a new approach to transesterification stopping and separation improving by the addition of inorganic acid, hydrochloric and phosphoric, to the whole reaction mixture after the reaction. The transesterification of oil was carried out by methanol and potassium hydroxide as the catalyst. The inorganic acid neutralises methoxide ions (formed from methanol and potassium hydroxide) and transforms soaps (formed by oil saponification) to fatty acids, which increases the acid number. The principle of stopping is the neutralization of the methoxide ions only. Best results are achieved by concentrated phosphoric acid with a ratio of 0.25 wt% to oil. The advantage is that separation is relatively fast (5 h) and the biodiesel conforms to EN 14214 without any other purification processes such as centrifugation, wet and dry washing and drying of the ester phase. Moreover, the content of glycerol in the formed glycerol phase is approximately 75%. This method of biodiesel production, which uses neutralization of methoxide ions after the transesterification followed by separation, saves energy because no purification processes are needed and no waste is formed. The biodiesel is more environmentally friendly because less energy is consumed.

Anti-Corrosion Characteristics of Electrodeposited Self-Doped Polyaniline Films on Mild Steel in Low Acidity

Without the addition of inorganic acids, 2,5-Diaminobenzenesulfonic acid (DABSA) molecules form an acid environment, and are then electrochemically copolymerized with AN monomers to generate a self-doped polyaniline (SPAN) film on mild steel substrates. These SPAN deposition films are employed to test the protection efficiency for mild steel in a corrosion environment of HCl and NaCl, respectively. Electrochemical impedance spectroscopy (EIS) and polarization were used to determine the charge transfer resistance (Rct) and corrosion current (Icorr), respectively. The above two parameters Rct and Icorr are combined to evaluate the protection efficiency of SPAN film on mild steel. Experimental results show that the SPAN thin film with the AN/DABSA ratio of 8.8 has the optimal corrosion resistance in 1 M HCl and 1 M NaCl aqueous solutions, respectively.

Contrast of Volatile Fatty Acid Driven and Inorganic Acid or Base Driven Phosphorus Release and Uptake in Enhanced Biological Phosphorus Removal

Addition of an inorganic acid or base was detrimental to net phosphorus removals in short-term batch experiments, suggesting there might be system upset when pH changes. In contrast, addition of volatile fatty acids (VFAs) increased anaerobic phosphorus release and aerobic phosphorus uptake while maintaining or improving net phosphorus removals. The effect of pH change differed if the acid or base added was inorganic versus organic. Volatile fatty acids that resulted in poly-3-hydroxy-butyrate rather than poly-3-hydroxy-valerate resulted in greater net phosphorus removals, and this corresponded to differences in consumption of reducing equivalents. Acetic acid resulted in improved net phosphorus removal compared to sodium acetate, suggesting that acid forms of VFAs might be superior as supplemental VFAs. It is hypothesized that anaerobic phosphorus release following addition of inorganic acid is primarily a result of phosphorus and proton (H+) symport (excretion from the cell) for pH homeostasis, whereas addition of VFAs results in phosphorus and H+ release to maintain the proton motive force.

Treatment of oil/water emulsions using seawater-assisted microwave irradiation

Waste oil emulsions are generated in several manufacturing processes. Such emulsions not only affect the efficacy of wastewater treatment but also influence the water quality of the effluent. Thus, many processes have been developed for demulsifying such materials and salt-assisted microwave irradiation has been shown to be most effective in this respect. In the present study, we propose that artificial seawater can be an economical source of the cations required in this process, termed seawater-assisted microwave demulsification. Our experiments include tests of emulsion characteristics and the effects of microwave operating conditions on demulsification rate and separation efficiency of three oil-in-water (O/W) emulsions. We conducted batch demulsification tests on 50-mL aliquots with an initial oil content of 10 g/L, and found that the separation efficiencies of a cutting-oil emulsion, an olive-oil emulsion, and a cutting-oil/olive-oil mix reached 93.1%, 92.6%, and 93.2%, respectively, using our optimum operating conditions, which were 40 s of microwave irradiation at 700 W, a 60 min settling time, and addition of 12%, 32%, and 20% (all v/v) of artificial seawater, respectively. Using this set of operating conditions, a decrease in solution pH was found to significantly increase the demulsification efficiency after addition of inorganic acid, whereas an increase in the concentration of surfactant, sodium dodecyl sulfate (SDS), resulted in a decrease in efficiency. In addition, our test data were explored using a stepwise regression method, yielding a multivariable equation. This empirical equation was able to describe separation efficiency rather well, after exclusion of tests showing separation efficiency below 40%.

Role of Magic-Sized Clusters in the Synthesis of CdSe Nanorods

The dynamics of the CdSe nanorod synthesis reaction have been studied, giving attention to the kinetics of magic-sized clusters (MSCs) that form as intermediates in the overall reaction. The MSCs have a distinct absorption peak, and the kinetics of this peak give insight into the overall reaction mechanism. In these studies, the reaction mixture consists primarily of Cd(phosphonate)(2) and trioctyl phosphine selenium in a solution of trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO). We find that the rate at which precursors react to form CdSe monomers and the rates at which monomers react to form nanoparticles can be varied by changing the chemistry of the reaction mixture. Decreasing the TOP concentration decreases the extent to which selenium is bound, both in the precursors and on the particles' surfaces, and thereby increases both the precursor to monomer and monomer to particle reaction rates. Decreasing the phosphonate concentration decreases the extent to which phosphonate binds cadmium in the precursors and on the surface of the nanoparticles, also increasing the rates of both reactions. This is also accomplished by the addition of inorganic acids which protonate the phosphonates. The presence of inorganic acids (impurities) is the primary reason that the overall synthesis reaction is faster in solutions made with technical grade rather than purified TOPO. The TOP and phosphonic acid concentrations are coupled because excess phosphonic acids react with TOP, forming TOPO and less strongly binding species, specifically phosphinic acids, phosphine oxides, and phosphines.

Induction of an Oxalate decarboxylase in the Filamentous Fungus Trametes versicolor by Addition of Inorganic Acids

In order to improve yields and to reduce the cost of oxalate decarboxylase (OxDC, EC 4.1.1.2), the induction of OxDC in the white-rot fungus Trametes versicolor was studied in this work. OxDC was induced by addition of inorganic acids including hydrochloric acid, sulfuric acid, and phosphoric acid to culture media. The results showed that all the acids could enhance OxDC expression. The activity of the acid-induced OxDC rose continuously. All of the OxDC volumetric activities induced by the inorganic acids were higher than 20.0 U/L and were two times higher than that obtained with oxalic acid. OxDC productivity was around 4.0 U*L(-1)*day(-1). The highest specific activity against total protein was 3.2 U/mg protein at day 8 after induction of sulfuric acid, and the specific activity against mycelial dry weight was 10.6 U/g at day 9 after induction of hydrochloric acid. The growth of mycelia was inhibited slightly when the pH values in culture media was around 2.5-3.0, while the growth was inhibited heavily when the pH was lower than 2.5.

Studies on the conversion method of pH in the extracted solution of Cochineal by addition of inorganic acids and extraction temperature

Studies on the conversion method of pH in the extracted solution of Cochineal by addition of inorganic acids and extraction temperature

Surfactant Concentration-Dependent Effects of pH on the Interfacial Properties of a Splittable Surfactant

A systematic study was performed to explore the effects of pH on the emulsifying ability and interfacial tension-lowering activity of a commercial splittable surfactant Triton SP-175 at various concentrations. The findings indicate that the addition of inorganic acids had a pronounced influence on the stability of Triton SP-175-stabilized emulsions, and the influence was greatly enhanced with decreasing pH and surfactant concentration. Moreover, the dynamic interfacial tension-lowering activity of the commercial Triton SP-175 surfactant was strongly inhibited by lowering the pH, resulting in a much slower relaxation in dynamic interfacial tension, with the extent depending on the surfactant concentration. However, its equilibrium interfacial tension-lowering activity was only slightly affected by acids. The data demonstrated that dramatic instability of emulsions stabilized by the splittable surfactant Triton SP-175 was induced by acids, along with considerably destroyed dynamic interfacial activity of th...

Comparisons of the effects of pH on the interfacial tension-lowering activity of surfactants Triton X-100 and Triton SP-190

A comparative study was conducted to investigate the effects of pH on the equilibrium and dynamic interfacial tension-lowering activity of a commercial splittable surfactant Triton SP-190 and a common surfactant Triton X-100 at the n-pentadecane/water interface. Equilibrium and dynamic interfacial tensions at the interface of n-pentadecane/aqueous phase containing surfactants were measured by using a Wilhelmy plate tensiometer and a drop volume tensiometer, respectively. It was found that the addition of inorganic acids did not have an effect on the equilibrium and dynamic interfacial tension-lowering activity of Triton X-100 at the interface. However, though the equilibrium interfacial tension-lowering activity of Triton SP-190 was not significantly affected by acids, the dynamic interfacial tension-lowering activity of Triton SP-190 was strongly inhibited at lower pH, resulting in a slower decreasing rate of dynamic interfacial tension. This phenomenon might be explained by the presence of minor surface-active components in the commercial Triton SP-190 surfactant, which dominate the equilibrium interfacial tension behavior at the interface and are not affected by acids. Based on the pH-dependent dynamic interfacial tension data, the percentages of the Triton SP-190 surfactant split under acidic conditions were then estimated. Moreover, the influence of pH was considerably enhanced at small adsorption times and low Triton SP-190 concentrations.

Influence of pH on the stability of oil-in-water emulsions stabilized by a splittable surfactant

A laboratory study was conducted to evaluate the effect of pH on the stability of oil-in-water emulsions stabilized by a commercial splittable surfactant Triton SP-190 by comparison with the results obtained by a common surfactant Triton X-100. The emulsion stability was explored by measuring the volume of oil phase separated and the size of the dispersed droplets. It was found that the addition of inorganic acids did not significantly affect the stability of emulsions stabilized by Triton X-100, but had a profound influence on the stability of emulsions stabilized by Triton SP-190. Moreover, the droplet size of a Triton X-100-stabilized emulsion and its dynamic interfacial activity were insensitive to acids. However, at lower pH the droplet size of the emulsions stabilized by Triton SP-190 was considerably increased. From the dynamic interfacial tension measurements the dynamic interfacial activity of Triton SP-190 at the oil/water interface was found to be strongly inhibited by the addition of acids, resulting in a slower decreasing rate of dynamic interfacial tension. The results demonstrate that the dramatic destabilization of Triton SP-190-stabilized emulsions could be realized by the use of acids, which evidently changed the interfacial properties of the surfactant and resulted in a higher coalescence rate of oil droplets.

The influence of acetic acid on penicillin production

Fed-batch fermentations with Penicillum chrysogenum, strain S 3723, were fed with glucose as carbon source or with a mixture of glucose and acetic acid. When 20% of the carbon source was acetic acid, yields of penicillin-V were 25% higher than in fermentations where glucose was the only carbon source in the feed. The increased yield was due to higher specific productivity and/or cell mass. The effect was seen in fermentations where the carbon source was fed at a constant rate and the pH kept automatically at 6.5 by addition of inorganic acid or base, as well as in fermentations where pH controlled the addition of feed.

Reaction of Dypnone in the Presence of BF3, 85% H3PO4 Complexes

The hydrolytic cleavage of dypnone (3) to benzoic acid (A-cleavage reaction) catalyzed by BFs was found to be promoted considerably by the addition of inorga nic acids. Moreover the condensation of (3) was suppressed t o some extent by the addition of 85% H3POi.Difference in activities of BF3 85% HsPOs complexes and BFg, water complexes for A-cleavage reaction was examined. The rate oHormation of (1) cafalyzed with BF3, 85%H4PO4(BF/(H3PO4+H20)=1(mol/mol)) was about three times faster than with BF3, H20. The former complex was more stable for heat. The order of activity for A-cleavage reaction was as follows;BFs, 8596 HgPOb BFs, H20 BFs 2(85% HgPO4) BF3, 2H20.