Methanesulphonic Acid Solutions Research Articles

Effect of ultrasonic treatment on tin recovery from decommissioned displays in sulphuric, hydrochloric, and methanesulphonic acid solutions

The study investigates the physicochemical patterns of tin leaching from the surface of glass substrates from decommissioned displays in hydrochloric, sulphuric, and methanesulphonic acids. The effects of acid concentration (0.1–1.0 N), duration (10–60 min), temperature (298–353 K), and ultrasonic treatment intensity (UST) (120–300 W/cm2) on leaching performance were evaluated. It was demonstrated that ultrasonic treatment positively impacts sulphuric acid leaching of tin, increasing its recovery by 14–16 %. However, during leaching in hydrochloric and methanesulphonic acid solutions, UST led to a reduction in tin recovery to 28 % and 1.7 %, respectively, due to acid decomposition under ultrasound. The partial reaction orders for tin leaching in HCl, H2SO4, and CH3SO3H were determined to be 0.8, 1.4, and 1.1, respectively, and changed to 1.5, 1.1, and 0.3 under ultrasound for the corresponding acids. An increase in temperature from 298 K to 333 K significantly improved tin recovery in sulphuric and hydrochloric acids. However, raising the temperature to 353 K led to a decrease in tin ion concentration after 10–20 min, likely due to tin hydrolysis and precipitation. The calculated apparent activation energies of tin oxide dissolution in HCl solutions were 40.4 kJ/mol without UST and 22.9 kJ/mol with UST. For H2SO4, the apparent activation energy was 4.0 kJ/mol, increasing to 29.0 kJ/mol under ultrasonic treatment. Therefore, the study showed that tin leaching from glass substrates of decommissioned displays proceeds in a kinetic regime when HCl is used and in a diffusion regime in H2SO4 solutions, with ultrasonic treatment facilitating the transition to a mixed regime.

Targeting fluorescent lamp waste for the recovery of cerium, lanthanum, europium, gadolinium, terbium and yttrium

Owing to the ever-growing demand and supply problems, rare earth elements (REEs) are now considered to be some of the most critical elements. This has focused attention towards their recovery from end-of-life products and industrial waste streams. A hydrometallurgical approach was carried out to assess the recycling potential of REEs from fluorescent lamp waste. In comparison to other efforts in this field, these investigations were carried out using real waste samples originating from a discarded lamp processing facility. Leaching of metals from the waste was studied using nitric, hydrochloric, sulphuric and methane sulphonic acid solutions. Separation of REEs from nitric acid media was investigated using solvent extraction. Batch extraction experiments were carried out using Cyanex 923, a commercial mix of trialkylphosphine oxides. Separation of heavier REEs (terbium, europium and gadolinium) and yttrium from lighter REEs (cerium and lanthanum) is possible due to larger separation factors. Selective stripping of REEs from the co-extractable species (iron and mercury ions) was easily achieved using 4 M hydrochloric acid. Further recovery of the extracted iron and mercury, with either oxalic acid or nitric acid solutions, allows for the subsequent re-use of the organic phase in the process.

VALIDATED IC METHOD FOR DETERMINATION OF CONTENTS OF RESIDUAL AMINO GUANIDINE IN LAMOTRIGINE DRUG SUBSTANCES WITH SUPPRESSED CONDUCTIVITY DETECTOR

This paper describes a validated method for the quantification of amino guanidine in Lamotrigine drug substances and their intermediates using Ion Chromatography (IC), with out any dervitization process. It was analysed using a Ion pac CS17 250 x 4.0 mm column with guard column CG17 50 x 4.0 mm, with a flow rate of 1.5 mL/min with injection volume of 20µL with conductivity detection with CSRS 300 x4.0mm suppressor with suppressor current 40 mA and having only 10 minutes runtime with methanol as diluent. It has the mobile phase of 20% v/v Milli-Q-Water and 80% v/v of 10 mM methane sulphonic acid solution. The method is validated for its Specificity, Precision, Accuracy, Linearity, Ruggedness and solution stability. Aminoguanidine is linear from 1 μg/ml to 25 μg/ml with correlation coefficient 0.9999. Limit of Quantitation of the method is 1 μg/ml and Limit of Detection is 0.3 μg/ml.

The corrosion resistance of 2205 duplex steel in non‐inhibited methanesulphonic acid at elevated temperature

The corrosion behavior of 2205 duplex stainless steel in methanesulphonic acid (MSA) at elevated temperature was investigated. It was proposed that uninhibited MSA could be utilized in acidizing procedures in petroleum wells constructed of 22Cr steel. The MSA was suggested as a substitute for conventional acids such as HCl which require the use of corrosion inhibitors. Corrosion rates of 22Cr steel in MSA solution with or without 24.13 bar CO2 at 150 °C after 6 h of immersion were lower than what is often required by the petroleum industry. In conditions of H2S‐containing MSA, significantly higher corrosion rates were observed.

Surface Morphology Study of Nanostructured Lead-Free Solder Alloy Sn-Ag-Cu Developed by Electrodeposition: Effect of Current Density Investigation

Nanostructured lead-free solder Sn-Ag-Cu (SAC) was developed by electrodeposition method at room temperature. Electrolite bath which comprised of the predetermined quantity of tin methane sulfonate, copper sulfate and silver sulfate were added sequentially to MSA solution. The methane sulphonic acid (MSA) based ternary Sn-Ag-Cu bath was developed by using tin methane sulfonate as a source of Sn ions while the Cu+ and Ag+ ions were obtained from their respective sulfate salts. The rate of the electrodeposition was controlled by variation of current density. The addition of the buffer, comprising of sodium and ammonium acetate helped in raising the pH solution. During the experimental procedure, the pH of solution, composition of the electrolite bath, and the electrodeposition time were kept constant. The electrodeposited rate, deposit composition and microstructure were investigated as the effect of current density. The electrodeposited solder alloy was characterized for their morphology using Field Emission Scanning Electron Microscope (FESEM). In conclusion, vary of current density will play significant role in the surface morphology of nanostructured lead-free solder SAC developed. Doi: 10.12777/ijse.5.2.51-55 [How to cite this article: Yusof, S.M., Hadi, A., and Jai, J. (2013). Surface Morphology Study of Nanostructured Lead-Free Solder Alloy Sn-Ag-Cu Developed by Electrodeposition: Effect of Current Density Investigation. International Journal of Science and Engineering, 5(2):51-55. Doi: 10.12777/ijse.5.2.51-55

Mineralization of phenol by Ce(IV)-mediated electrochemical oxidation in methanesulphonic acid medium: A preliminary study

The mediated electrochemical oxidation (MEO) process using cerium(IV) in methanesulphonic acid (MSA) as the oxidizing medium was employed for the mineralization of phenol in batch and continuous feeding modes. Although nitric acid was an extensively studied electrolyte for organic mineralization reactions in MEO processes it does possess the problem of NO x gas production during the reduction of nitric acid in the cathode compartment of the electrochemical cell. This problem could be circumvented by proper choice of the electrolyte medium such as MSA. The mediator cerium in MSA solution was first oxidized to higher oxidation state using an electrochemical cell. The produced Ce(IV) oxidant was then used for the destruction of phenol. It was found that phenol could be mineralized to CO 2 by Ce(IV) in MSA. The evolved CO 2 was continuously measured and used for the calculation of destruction efficiency. The destruction efficiency was observed to be 85% based on CO 2 evolution for 1000 ppm phenol solution at 80 °C in continuous feed mode.

Electrochemical dissolution of tin in methanesulphonic acid solutions

High-rate electroplating of tin on a moving steel strip is generally carried out in cells with dimensionally stable anodes. To obtain a matt tin deposit a concentrated acidic tin methanesulphonate solution containing a small concentration of sulphuric acid is used. The concentrated tin methanesulphonate solution is prepared by dissolution of tin particles with oxygen in a special column. To describe this dissolution process electrode reactions (namely, reduction of oxygen, hydrogen peroxide and hydrogen ions on a tin electrode and oxidation of tin) were studied using electrochemical techniques. It was concluded that on tin, oxygen is almost entirely reduced to water and that H2O2 cannot corrode tin directly, but its decomposition products, for instance oxygen, can. The exchange current density and the charge transfer coefficient for the investigated electrode reactions are estimated. The dissolution of tin by oxygen is determined by the kinetic parameters of the oxygen reduction reaction and by the mass transfer of (i) dissolved oxygen to and (ii) Sn2+ ions from the tin electrode surface. Hydrogen evolution can be neglected during the dissolution of tin in the presence of oxygen. Moreover, it was found that the rate of tin corrosion increases with (i) increasing H+ concentration, (ii) oxygen concentration, (iii) convection intensity and (iv) temperature. It is likely that the tin surface is not covered with oxygen during corrosion in pure methanesulphonic acid solutions, but an oxide layer may be present on the tin surface during oxygen corrosion in pure sulphuric acid solutions. This oxide layer may hinder the oxygen corrosion of tin.

Electrodeposition of Tin-Lead Alloy on a Rotating Disk Electrode in Methane Sulphonic Acid Solutions

SummaryThe electrodeposition of tin, lead, and tin-lead alloys in methane sulphonic acid (MSA) solutions with stationary and rotating disk electrodes was studied in this paper. The measurements of polarization curves were performed in MSA solutions containing tin, lead or both. Results from kinetic studies indicate that the reductions of tin and lead in MSA plating bath proceed in parallel without interaction. From a system with mixed activation-and-diffusion control, lead was found to be the dominant species in both activation and diffusion controlled processes due to its higher exchange current density and diffusion coefficient.

Trifluoromethanesulphonic acid as an α-helix promoting agent for basic poly(α-amino acids)

Poly-(L-arginine), (Arg) n, usually adopts an extended conformation in aqueous solution. In concentrated aqueous solutions of methane sulphonic acid (MSA) between 2 and 6 mol/l, however, the c.d. spectrum of the α-helix occurs. This α-helix promoting effect of MSA was not observed for poly-( l-lysine), (Lys) n, poly-( l-ornithine), (Orn) n and poly-(N-δ- trimethyl- l-ornithine ) , (Me 3Orn) n, and poly-(N,ϵ- trimethyl- l-lysine ) (Me 3Lys) n. But, if using aqueous solutions of trifluoromethanesulphonicacid (TFMSA), the basic polyamino acids (BPAA) mentioned above attain the α-helical conformation at concentrations below 0.5 mol TFMSA/l with the exception of (Me 3Orn) n. The α-helix promoting effect of TFMSA increases in the following order: (Orn) n < (Lys) n < (Me 3Lys) n < (Arg) n . The specific ellipticity |Φ| 331 of (Arg) n as a function of TFMSA concentration passes a sharp maximum in contrast to a very broad one in MSA solutions. It was found that values of the van't Hoff transition enthalpy ΔH νH obtained for (Arg) n in TFMSA and MSA are between 21 and 35 kcal depending on concentration and ≈ 12 kcal for (Lys) n in TFMSA solution.

The solubility of methanesulphonic acid and its implications for atmospheric chemistry

Abstract The partial pressure of methanesulphonic acid (MSA) was measured above concentrated aqueous MSA solutions at 25°C and used to estimate an equilibrium constant of 6.5×1013 mol2 kg‐2 atm‐1 for the reaction: CH3SO3H(g) = H+(aq)+CH3SO3 ‐(aq). MSA will be effectively scavenged by water in the atmosphere. As a strong acid MSA will displace HCl gas from the marine aerosol and may be responsible for a part of HCl(g) in the remote atmosphere.

Dynamics of xanthan biopolymer in semi-dilute aqueous solution studied by photon correlation spectroscopy. Comparison with solution viscosities

Recent theoretical treatments of molecular motion in entangled solutions of rod-like polymers lead to results which describe the rheological behaviour in terms of the concentration-dependent rotational diffusion coefficient, Dr. Thus a comparison between experimental values for Dr and rheological data is possible and provides an exacting test of such theory. Here dynamic light scattering (DLS) studies of semi-dilute aqueous solutions of xanthan gum are presented and compared with independent rheological data. Despite extensive precautions, unambiguous interpretation of these data is precluded by the known tendency of xanthan for self-association. Such problems appear to be common when dealing with rod-like polymers and indeed many features of the observed DLS and viscometric data for xanthan in water are strikingly similar to published results on other rod-like polymers. In particular, strong correspondences are found when comparing numerical estimates of Dr determined by DLS and shear-rate-dependent viscosities, η(), with a similar analysis of Dr and η() for semi-dilute methanesulphonic acid solutions of poly(p-phenylene-2,6-benzobisthiazole), a rod-like polymer with a reportedly weak potential for self-association. For each system the Dr and η() data are qualitatively consistent with recent modified versions of the Doi–Edwards dynamical theory for entangled solutions of rod-like polymers. However, large (× 100) quantitative discrepancies are found when comparing η(0) and Drvia this theory. A survey of rod-like polymer solvent systems for which Dr and η() are available indicates comparable discrepancies and none produces a completely self-consistent interpretation in terms of the above theory.

Microstructural study of as-extruded and heat-treated ribbons of poly(p-phenylene benzobisthiazole)

Ribbons of poly(p-phenylene benzobisthiazole) (PBT) prepared by extrusion from methane sulphonic acid solution into acid-water coagulation baths, were examined by electron microscopy, wide-angle X-ray scattering and small angle X-ray scattering. Electron diffraction patterns and corresponding dark-field images of as-extruded ribbons suggest that the chains are well oriented in the extrusion direction, with laterally-ordered regions averaging 2 nm in width. Upon heat treatment, the equatorial reflections sharpen and dark-field imaging indicates an increase in lateral order to about 15 nm. Small-angle X-ray scattering patterns show very little scattered intensity except for strong equatorial scattering attributed to voids elongated parallel to the extrusion direction. The absence of distinct crystalline images in 0 0l dark-field is supporting evidence for axial shift of the molecules along the chain axis, as suggested by previous diffraction studies.

Mechanism of denitration of nitroguanidines in concentrated acids. Some new evidence

Previous work on the mechanism of the reversible denitration of nitroguanidines receives support from proton magnetic resonance studies of the nature of nitroguanidines in concentrated sulphuric acid, and some new kinetic results in methanesulphonic acid solutions. The rates of addition of first and second protons in the acid regions used for previous kinetic studies are quite in keeping with a diprotonated nitroguanidine species as the reactive intermediate in denitration. The sites of proton addition (nitrimino- and amino-groups) can also be gauged from the proton spectra. The previous kinetic work is re-analysed in view of the revised H0 data now available, but the original conclusions are unaltered.