H2SO4 Acid Research Articles

Oxidation of Organics using Mn(H2PO4)2 as a Catalyst for Rapid Determination of COD of Industrial Saline Effluents

Abstract Chemical Oxygen Demand (COD) is a water quality parameter which indicates concentration of organic compounds as oxygen equivalents in aqueous effluent samples. Determination of COD is frequently done using APHA Standard Method which requires 2 h digestion time. There is need for improving the method to reduce analysis time. In this paper, we report the comparative study for determination of COD by Standard Method using Ag2SO4 and a rapid method using Mn(H2PO4)2 as a catalyst for different industrial effluent samples having different chloride concentration. A kinetic study has been carried out by varying time interval, HgSO4 dose and catalyst dose in different concentrated H3PO4:H2SO4 acid mixture ratio. The optimum conditions for industrial sample having low chloride concentration are 0.3g Mn(H2PO4)2, per 15 ml of 1:6 H3PO4: H2SO4, 0.2gm HgSO4 and digestion time of 5 min., whereas the sample having high chloride concentration requires 0.4 g of HgSO4 and digestion time of 20 min. The results obtained from the rapid COD determination method in this study and conventional method is found to be comparable. A water quality analyst would be able to save on digestion time by >90 %, if he chooses to perform the COD test as per the rapid method described herein.

Study on strength and durability characteristics of lime sludge based blended cement concrete

The present investigation is focused on developing ternary blended cement concrete mix of different grades 30 MPa, 50 MPa and 70 MPa containing fly ash, silica fume and lime sludge in different proportions. The optimum content of these materials was obtained after several trails. Mechanical properties such as compressive, flexural and split tensile strength of ternary blended cement concrete were determined and compared with the control mix (without any supplementary cementitious material). The chemical resistance of ternary blended cement concrete was also studied by exposing it to acids HCl and H2SO4 at 5% concentration. Acid mass loss factors (AMLF), acid strength loss factor (ASLF) and acid durability factor were determined, and the results were compared with control mix. Short term chloride ions penetration was also investigated like rapid chlorination penetration test and accelerated corrosion penetration test on control mix and ternary blended cement concrete. The results indicated that there is a significant improvement in the mechanical properties, shown better resistance in an acid environment and chloride ion penetration.

Platinum nanoparticles decorated graphene nanoribbon with eco-friendly unzipping process for electrochemical sensors

Abstract In this study, an innovative large-scale synthesis of graphene nanoribbons (GNRs) with the eco-friendly unzipping process (only 0.1 mL H2SO4 acid solution for 1.0 mg carbon nanotube) was proposed. Nearly 100% yields of carbon nanotube derived GNRs was achieved by the proposed procedure. Through the longitudinal unzipping method, abundant oxygen-based functional groups were formed at the edges of GNRs, thus offering tremendous advantages for material synthesis and design. Furthermore, the reduction of platinum precursor to form platinum nanoparticles (PtNPs) can be facilitated by the functional groups on GNR surface for specific sensing. In fact, PtNPs played a role in connecting nodes to synergize the synthesized composite. The composite of PtNPs/GNRs could be further utilized as non-enzymatic biosensing materials against either oxidative or reductive analyte. Two essential biomarkers, namely hydrogen peroxide (H2O2) and β-nicotinamide adenine dinucleotide (NADH), were chosen to prove the feasibility of the proposed biosensors. From the experimental results of the amperometric analysis, sensitivities of the modified PtNPs/GNRs electrode toward H2O2 (378.5 µA/mM/cm–2) and NADH (724.3 µA/mM/cm–2) were obtained. The composite of PtNPs/GNRs has been verified to be a potential material for electrochemical biosensing with attractive sensitivity, selectivity, and stability.

A novel acid modified alumina adsorbent with enhanced defluoridation property: Kinetics, isotherm study and applicability on industrial wastewater.

Excessive fluoride contamination in ground and surface water is hazardous to human health. Adsorptive removal is a better option for defluoridation due to its simplicity and efficient working property. In the current research, an attempt was made for the removal of fluoride ions from wastewater by a novel adsorbent synthesized with alumina and H2SO4 acid by acidic activation. The adsorbent was characterized for physio-chemical properties by several analytical methods (SEM, EDX, FTIR, XRF, TGA, XRD, HI and pHZPC). The specific surface area of acid activated alumina (AAA) adsorbent was found to be 87.44 m2/g. The batch scale experiments were conducted to study the effect of initial pH, adsorbent dose, stirring rate, and contact time on the defluoridation efficiency of AAA adsorbent. The experimental data of isotherm study was found to follow the Freundlich isotherm model. The maximum adsorption capacity of fluoride on AAA was 69.52 mg/g at 318 K. The nature of adsorption was found to be endothermic and spontaneous. The adsorption kinetic data followed the pseudo-second-order model. The fluoride removal efficiency of alumina with and without acid activation resulted in 96.72% and 63.58%, respectively. The regeneration capability, reusability, applicability on industrial effluent and economic value were investigated.

Growth of Highly (111)-Oriented Nanotwinned Cu with the Addition of Sulfuric Acid in CuSO4 Based Electrolyte

We reported that highly (111)-oriented nanotwinned Cu (nt-Cu) can be grown by DC electroplating using a CuSO4 based electrolyte in our previous study. However, in practical applications, the addition of H2SO4 is required to improve uniformity of the Cu films. In this study, we added H2SO4 in the CuSO4 based electrolyte with different concentrations, ranging from 50 to 110 g/L. It is found that nt-Cu can be fabricated with the addition of the H2SO4 acid at the current densities from 5 A/dm2 to 11 A/dm2. The ratios of (111) to (200) or (111) to (220) X-ray reflections are extremely high, indicating that the (111) preferred orientation is very strong. The texture fraction and texture coefficient could not precisely determine which Cu films contain columnar (111) nt-Cu grains. We propose a criteria to predict the columnar (111) nt-Cu microstructure by the ratios of (111) to (200) and (111) to (220) X-ray reflections. When both ratios exceed 1000, the fabricated Cu films could possess columnar (111) nt-Cu grains.

Acid-Treated PEDOT:PSS Polymer and TiO2 Nanorod Schottky Junction Ultraviolet Photodetectors with Ultrahigh External Quantum Efficiency, Detectivity, and Responsivity.

Vertically aligned TiO2 nanorods (NRs) were synthesized on a fluorine-doped tin oxide-deposited glass substrate by the hydrothermal method. A Schottky junction ultraviolet photodetector was fabricated by spin-coating of the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) polymer on TiO2 NRs. For the improvement of device performance, the electrical conductivity of the polymer was increased by adding dimethyl sulfoxide (DMSO) and concentrated H2SO4 acid. The diode parameters, i.e., work function, series resistance, and ideality factor, were studied for all devices. Photoresponse behavior of the TiO2 nanorod/PEDOT:PSS junction was studied upon illumination of white light of intensity 80 mW/cm2. Our acid-treated sample demonstrated the highest photocurrent value, which is 10 times larger than that of DMSO-treated and 39 times larger than that of the untreated sample. Our acid-treated device showed superior external quantum efficiency (∼12 560%), responsivity (∼34.43 A/W), and detectivity (∼1.6 × 1011 Hz1/2/W) at ∼340 nm wavelength under -1 V bias.

Esterification Bio-oil using Acid Catalyst and Ethanol

Fuel energy sources are limited. It is necessary to obtain alternative energy that can be reached. Bio-oil is one of the promising renewable energy that production of bio-oil derived from agricultural wastes and industrial wastes by fast pyrolysis process but the quality bio-oil is not good as bio-fuel it needs upgrading method. One of the methods to upgrading bio-oil is using esterification. Esterfication method reduces viscosity, density, and ash. The purpose of this research was to increasing bio-oil quality by type of acid catalyst. Catalyst used was H2SO4, HCl and citric acid, concentration catalyst was used according to free fatty acid (FFA) and free fatty acid was 5.09 before esterification. The bio-oil after esterification show FFA lower than 2.00 and indicate it worked. Esterification with acid catalyst shows some critical change like acid number, viscosity kinematic, density, pH, and ash. The result found acid number 0.64, 1.02 and 3.39 Mg of KOH/g, viscosity kinematic 11.61, 11.83, and 13.64 cSt @40°C, density 1.11, 1.12 and 1.21 kg/dm3 @20°C, pH values 2.05, 2.33 and 3.06, ash 0.0003, 0 and 0.004. The concentration catalyst according to FFA with esterification process has a good impact on bio-oil characteristics according to standards and its high activity.

Study of the kinetics of the magnesium leaching from serpentine bearing chromite overburden rocks for mineral carbonation

ABSTRACT Characterisation and leaching studies have been carried out on serpentinite rock samples collected from Sukinda mines, India. Dissolution characteristics of samples have been studied using HCl, H2SO4 and HNO3 acid. Effect of particle sizes, solvent concentrations, reaction temperatures and reaction time have been investigated. It was found that Mg recoveries vary between 54.95% and 98.12%. Leaching of fine particles of <53 µm sizes using H2SO2 solution of 1 M at 70°C for 2 h can recover maximum 93% Mg with lowest Si content (6.6%). Kinetic studies indicated that dissolution of Mg follows product layer diffusion mechanism and activation energy calculated was 37.88 kJ mol−1. CO2 treatment of leach liquor resulted in precipitation of magnesium carbonates and hydroxides at a solution pH adjustment between 7 and 10. The study revealed that these rocks can be used for CO2 fixation and H2SO4 can be the best solvent.

Intensification of the Sulfuric Acid Alkylation Process with Trifluoroacetic Acid

H2SO4 alkylation of isobutane and butene is one of the primary commercial processes used to produce alkylates. This work presents a technology for the intensification of sulfuric acid alkylation with the addition of trifluoroacetic acid (TFA). The addition of TFA increased the solubility of isobutane in H2SO4, decreased its viscosity, and adjusted the acidity of H2SO4. With the addition of TFA, the selectivity of C8 was dramatically improved from 36.8 to 95.7%. The TFA content, stirring speed, reaction temperature, volume ratio of acid to hydrocarbon (H/C), molar ratio of isobutane to 2‐butene (I/O), reaction time, and reuse of H2SO4/TFA were also investigated in this work. Compared with the conventional process, the new technology provided a considerably higher quality alkylation with considerably lower energy consumption. © 2018 American Institute of Chemical Engineers AIChE J, 65: 113–119, 2019

ELECTROCHEMICAL BEHAVIOR OF MILD STEEL IN HCL 1M MEDIUM WITH THE PRESENCE OF ROSE MYRTLE LEAVES EXTRACTION

As the growing interest on green corrosion inhibitors, plant extracts have gradually showed the potential in replacing the traditional hazardous chemicals due to the eco-friendly and economy characteristics. Previous study reported that rose myrtle leaf-extract (Rhodomyrtus tomentosa, Myrtaceae) was as an efficient corrosion inhibitor for rust removal process of mild steel in H2SO4 acid medium. This study presents the corrosion inhibition assessments of rose myrtle leaf-extract on mild steel surface in HCl 1M solution. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods have been used to study the corrosion behaviors of mild steel. The corrosion rate, corrosion current and corrosion potential results indicate that only small amount of the leaf-extract (2% vol.) was required for high inhibition efficiency (Hin=83.9%). By affecting on both anodic and cathodic branches of the Tafel plot, the corrosion inhibition mechanism is proposed by an adsorption forming different barriers on the steel surface.Green inhibitor, Rhodomyrtus tomentosa, steel corrosion, EIS

Superacidity of P(OH)3 and SO(OH)2 derivatives of cyclopentadiene and vinylcyclopentadiene in the gas phase: A computational DFT analysis

Strong Brønsted acids were designed using a simple strategy of replacing double-bonded oxygen atoms in mineral acids H3PO4 and H2SO4 with cyclopentadiene and vinylcyclopentadiene moieties, followed by a substitution with strong electron-withdrawing cyano groups. Their intrinsic gas-phase acidity was assessed by the B3LYP density functional theory calculations employing the 6-311++G(d,p) basis set, and many highly potent superacids were identified. The pronounced acidity of these conjugates is due to two predominant factors, namely, (i) an increase in the aromaticity of the five-membered ring on deprotonation, as evaluated through the NICS parameters, and (ii) an extension of the conjugated π-network enabled by the cyano groups that efficiently distribute an excess negative charge over a large number of atoms in conjugate bases. The SO(OH)2 derivatives are generally more acidic than the corresponding P(OH)3 counterparts so that the ΔHacid values for the SO(OH)2 and P(OH)3 derivatives with CN substituents evaluated here are 260-266 and 263-272 kcal mol−1, respectively. Given the growing interest in highly acidic molecules together with related acidic catalysts and metal complexing agents, the results presented here should direct the attention toward utilizing proposed systems as improved organic materials, and their synthesis is highly recommended.

Extraction study of Vanadium from Pre-Processed Gibbsite- bearing shale, Abu Thor area, Southwestern Sinai, Egypt, by using Amberlite IRA743 anion exchange resin,

This work is concerned with study the affecting parameters on the recovery of V from pre-processed gibbsite bearing shale sample which assays 0.045% of V which obtained from Abu Thor area, Southwestern Sinai, Egypt. The original sample (0.05 % V) was previously treated to selectively extraction of Cu, Cd and U through applying H2SO4 acid agitation leaching. The present study work involves alkaline dissolution of the sample residue with NaOH solution at the obtained optimum conditions. However ion exchange process was applied by using anion exchange resin, Amberlite IRA743. About 97.25% of the extracted V was already regenerated by using 4% H2SO4. Not less than 98.2% of V was precipitated as hydrated V2O5 by using NH4OH solution via strongly oxidation by the addition of 0.25g KClO3 at 75 oC with continuous stirring for 2h. The latter was dried in the oven at 120 oC to prepare the final V product V2O5 (red cake). The overall process was designed in a technical flowsheet.

Microwave-assisted conversion of novel biomass materials into levulinic acid

Levulinic acid is considered one of the most important platform chemicals. It is currently produced mainly from lignocellulosic biomasses. However, there are also other abundant biomass materials, which could be used as raw materials for levulinic acid production. In this work, levulinic acid was produced from two novel biomasses in the presence of Bronsted (H2SO4) and Lewis acid (CrCl3·6H2O or AlCl3·6H2O) catalysts. The studied materials were carbohydrate-rich potato peel waste and sporocarps of the fungus Cortinarius armillatus. Reaction conditions, i.e., time, temperature, H2SO4, and Lewis acid concentrations, were studied by utilizing full 24-factorial experimental designs. Microwave irradiation was used as the heating method. Based on the results, the reaction temperature and the H2SO4 concentration had the greatest impact on the yield of levulinic acid. The highest yield obtained in this study from potato peel waste was 49% with 180 °C for reaction temperature, 15 min for reaction time, and 0.5 and 0.0075 M for the concentrations of H2SO4 and CrCl3, respectively. When Cortinarius armillatus was used as the raw material, the highest yield was 62% with 180 °C for reaction temperature, 40 min for reaction time, and 0.5 and 0.0075 M for the concentrations of H2SO4 and CrCl3, respectively.

A new reaction system to determine nonlinear chemical fingerprint and its use in Panax ginseng identification method based on double reaction system

A new reaction system to determine nonlinear chemical fingerprint (NCF) and its use in identification method based on double reaction system was researched. Panax ginsengs, such as ginseng, American ginseng and notoginseng were identified by the method. The NCFs of the three samples of Panax ginsengs were determined through two nonlinear chemical systems, namely system 1 consisting of sample components, H2SO4, MnSO4, NaBrO3, acetone and the new system, system 2 consisting of sample components, H2SO4, (NH4)4Ce(SO4)2, NaBrO3 and citric acid. The comparison between the results determined through systems 1 and 2 shows that the speed to determine NCF through system 2 is much faster than that through system 1; for systems 1 and 2, the system similarities of the same kind of samples are ≥ 98.09% and 99.78%, respectively, while those of different kinds of samples are ≤ 63.04% and 86.34%, respectively. The results to identify the kinds of some samples by system similarity pattern show that both the accuracies of identification methods based on single system 1 and 2 are ≥ 95.6%, and the average values are 97.1% and 96.3%, respectively; the accuracy of the method based on double system is ≥ 97.8%, and the average accuracy is 99.3%. The accuracy of the method based on double system is higher than that based on any single system.

Synthesis, characterization and electrochemical evaluation of anticorrosion property of a tetrapolymer for carbon steel in strong acid media

Abstract A novel tetrapolymer (TP) consisting of carboxylate, sulphonate, phosphonate and sulfur dioxide based co-monomers was synthesized using Butler cyclopoymerization technique. The synthesized tetrapolymer was characterized using FTIR, 1H-NMR, 13C NMR and elemental analysis. The performance of the tetrapolymer as a corrosion inhibitor for St37 carbon steel in 15% HCl and 15% H2SO4 acid media was assessed using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), potentiodynamic polarization (PDP) and electrochemical frequency modulation (EFM) techniques. The influence of addition of a small amount of KI on the corrosion inhibition efficiency of TP was also assessed. Results obtained showed that the tetrapolymer moderately inhibited the corrosion of St37 steel in the acid media with protection efficiency of 79.5% and 61.1% at the optimum concentration of 1000 mg·L− 1 studied in HCl and H2SO4 media respectively. On addition of 5 mmol·L−1 KI to the optimum tetrapolymer concentration, the protection efficiency was upgraded to 90.6% and 93.5% in HCl and H2SO4 environment, respectively. The enhanced performance of the polymer in the presence of KI is due to synergistic action deduced from synergism parameter (S1) which was found to be greater than unity. The tetrapolymer afforded the corrosion inhibition of St37 steel in the acid media by virtue of adsorption of the polymer molecules on the steel surface which was confirmed by ATR-FTIR analysis of the adsorbed film extracted from the steel surface. TP + KI formed complex with St37 steel surface in H2SO4 solution but not in HCl solution.

Anion Exchange and Catalytic Functionalization of the Zirconium-Based Metal–Organic Framework DUT-67

A postsynthetic treatment with diluted solutions of the inorganic HCl or H2SO4 acids was applied to functionalize the eight connected Zr-based metal–organic framework DUT-67 (DUT = Dresden Universi...

Investigation of V(V)/V(IV) Redox Reaction in Mixed Acid Electrolyte Using X-Ray Absorption Spectroscopy

The performances of all-vanadium redox flow batteries (VRB) can be improved by increasing the electrode kinetics and/or by increasing the solubility of the electroactive species involved in the process [1]. The concentrations of vanadium species in the electrolyte determine the total electrolyte volume and energy density of the system, albeit relatively low for VRBs, between 30-50 Wh/kg [2]. Higher vanadium concentrations are desirable to achieve reasonable energy densities. It has been shown that the solubilities of V(II), V(III) and V(IV) species in H2SO4 increase with increasing temperature and decreasing acid concentration. Precipitation of V(II), V(III) and V(IV) have been reported at temperature below 10°C. V(V) however, does not precipitate as a sulphate but undergoes thermal precipitation by an endothermic reaction to form V2O5 at temperatures > 40°C. The maximum ion concentration is therefore set by the operating temperature of the VRB which lies between 10 and 40°C. The preferred electrolyte composition for this temperature range is a total vanadium ion concentration between 1.6-2 mol/L and a total sulfate concentration of 4-5 mol/L [3]. It is critical to stabilize V(V) species against thermal precipitation. One solution to increase both thermal stability and solubility of V(V) electrolyte is the use of a mixture of H2SO4 and HCl acids as supporting electrolyte [4], [5]. It has been reported that by using this electrolyte the V(V) solubility is increased to 2.5 mol/L while the electrolyte is stable in a temperature range between -5 and 50°C. Initially we investigated the kinetics of V(V)/V(IV) redox couple in sulfuric acid and mixed electrolyte (H2SO4+HCl) using oxidized glassy carbon electrode surface [6]. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used for the electrochemical investigation. Additionally, the thermal and chemical stability of the V(V) and V(IV) electrolytes in H2SO4 and mixed H2SO4 + HCl were investigated using X-Ray absorption spectroscopy. Detailed knowledge regarding the V(V) coordination sphere in H2SO4 and mixed acids are of significant interest for understanding electrolyte stability but also for elucidating the V(V) electrochemical reduction mechanism. Finally, the change in atomic coordination sphere of V(V) and V(IV) electrolytes in H2SO4 and H2SO4/HCl were investigated in fresh and aged samples using K-edge EXAFS, which is sensitive to both the electronic configuration and the atomic structure around the V, Cl and S atoms.

Odporność odlewniczego stopu magnezu AZ91 na korozję elektrochemiczną

The article presents the results of AZ91 cast magnesium alloy resistance to electrochemical corrosion. The basic material and welding joints obtained by TIG method (141) were evaluated. The mass loss and corrosion time at specific concentrations of the H2SO4 acid solution were assumed as a criterion of resistance to electrochemical corrosion. It was found that an increase in the acid solution concentration significantly affects the rate of corrosion of alloy, thus causing a greater degradation of its surface and a higher mass loss. It was also noticed that the corrosion rate decreases when the experiment time is extended. After 72 h, this speed drops below 0.1 g/(cm2•day), which is caused by the inhibition of the corrosion as a result of the neutralization of the acid solution.

Corrosion Inhibition of Carbon Steel in HCl and H2SO4 Acids by Novel 1,3,4-Thiadiazolium-2-Phenylamine Salts

Corrosion Inhibition of Carbon Steel in HCl and H2SO4 Acids by Novel 1,3,4-Thiadiazolium-2-Phenylamine Salts

Direct Contact Membrane Distillation for Separation of Hcl From A Mixture of Acids

HCl is separated from HCl –H2SO4 solution by membrane distillation process(MD). The flat –sheet membranes made from polyvinylidene fluoride (PVDF) and polypropylene (pp.). Plate and frame these types of membrane where used in the process. The feed is a mixture of HCl and H2SO4 acids compositions depended on metals treated object.HCl concentration increased in the permeate during the process but sulfuric acid increased gradually in the feed .During the concentration of solution acids concentrations in the feed at the beginning were 50 g/dm3 of sulfuric acid and 50 g/dm3 of hydrochloric acid at 333K feed temperature the permeate flux was 71 dm3/m2.d. At a higher concentration of HCl in the feed 111g /dm3 and 61 g/ dm3 of sulfuric acid at the feed temperature 333K volume permeate flux was 57 dm3/ m2.d . At a higher concentration of sulfuric acid in the feed 161 g/dm3 and 60 g/dm3 of HCl decrease the permeate flux from 71 to 35 dm3/m2.d at 333K . The permeate flux increase from 35 at 333K to 85 at 343 K increase the temperature caused an increase in permeate flux. Increases in sulfuric acid concentration from 50 to 161 g/dm3 decrease the volume permeate flux from 71 to 35 dm3 /m2.d, HCl concentration was achieved a higher value 9.1 g/dm3 during the process at the feed concentration 161g/dm3 of sulfuric acid and 60g/dm3 of hydrochloric acid at feed temperature 343K.&#x0D;