Gravimetric Evaluation of the Synergistic Effect between Potassium Iodide and Formaldehyde on Corrosion Failure Inhibition of Cold Rolled Steel in 1 M Hydrochloric Acid

An atomic-absorption spectrophotometry for rapid, sensitive, and precise determination of arsenic in biological samples is described. Arsine can be rapidly evolved from arsenic solution in 2 N hydrochloric or sulfuric acid by using zinc powder tablets together with potassium iodide and stannous chloride solution as the reductant. Thus, arsenic can be determined by atomic-absorption spectrophotometrically by introducing arsine into an argon-hydrogen flame and reading the absorption signal of arsenic at 1937 A. To obtain optimum conditions for the determination of arsenic in biological samples, various factors were examined. The optimum range of acidity was about 1.5-3 N in hydrochloric acid when potassium iodide and stannous chloride concentrations were kept at 1.6% and 0.8%, respectively. The addition of at least one piece of zinc tablet (about 0.5 g) was enough to obtain the highest and constant recovery of arsenic as arsine. The sensitivity of the method for 1% absorption was evaluated to be 0.7 ppb of arsenic and linearlity of the absorption vs. concentration was good up to 1μg/20 ml (50 ppb). Effect of several ions on the method was also examined. Satisfactory results were obtained by applying the proposed method to the analysis of arsenic in several biological materials, which were previously digested by a conventional method using sulfuric-nitric acid mixture.

The synergistic effect of 2-chloromethylbenzimidazole (2-CBI) and potassium iodide (KI) for mild steel in 1 M hydrochloric acid solution was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that, with the addition of 100 ppm potassium iodide, the inhibition efficiecy (IE) of 100 ppm 2-CBI in 1 M hydrochloric acid had been improved from 91.14% to 96.15%. And synergistic parameter of 100 ppm 2-CBI with different amounts of potassium iodide is always greater than 1. The adsorption of potassium iodide combining with 100 ppm 2-CBI obeys to the Langmuir adsorption isotherm. Thermodynamic adsorption parameters, including ΔG0ads, ΔHa and ΔSa of the adsorption of the combinned inhibitor, as well as the Ea of the mild steel corrosion in 1 M HCl with the combinned inhibitor, were calculated.

Determination of antimony in ores and related materials by continuous hydride-generation atomic-absorption spectrometry after separation by xanthate extraction

Corrosion inhibition of low carbon steel, stainless steel types 316 and 304 in hydrochloric acid by potassium iodide was investigated at different temperatures using weight loss and polarization electrochemical techniques. Potassium iodide was found to be an excellent inhibitor for steel alloys with an efficiency reaching 97 % at 0.1 M of inhibitor concentration. Activation parameters were calculated using Arrhenius and transition state equations. The fraction of surface coverage calculated from corrosion rate data followed Langmuir adsorption isotherm by the formation of a monolayer on the metal surface. These results were confirmed by a kinetic–thermodynamic model. Activation and adsorption studies were fitted successfully to two mathematical equations: polynomial and exponential.

Method for the separation of platinum, palladium, rhodium, iridium and gold by solvent extraction

Determination of arsenic in ores, concentrates and related materials by continuous hydride-generation atomic-absorption spectrometry after separation by xanthate extraction

The microdetermination of soluble iodides with N-bromosuccinimide

No discussion of the use of inhibitors in acid solution is complete without mentioning the phenomenon of synergism. Synergism also operates in corrosion protection where an enhanced inhibition may be related to interaction between inhibitor compounds. This effect has been observed since the earlier days of inhibitor technology and continues to be a potent tool in the development of acid inhibitors for specialized uses. Hence, in this paper, the corrosion inhibition behavior of mild steel (MS) in 1 M hydrochloric acid in the presence of 4-hydroxy coumarin (4HC) and potassium iodide (KI) has been investigated using the mass loss method and electrochemical techniques. The inhibitive performance of 4HC is considerably enhanced by the addition of KI. The addition of KI to different concentrations of 4HC has intensified its efficiency through considerable reduction in the mass loss, corrosion current density , double layer capacitance , and increase in charge transfer resistance . The calculated synergism parameter “” is greater than unity, thereby proving the fact that the improvement in inhibition efficiency of 4HC, generated by the addition of KI, is due to synergism.

LONDON Chemical Society, November 3.—Dr. Gilbert in the chair.—The following papers were read:—On citraconic and mesaconic ethers arid malic and fumaric acids, by W. H. Perkin. The author has carefully investigated the physical properties of the methylic and ethylic ethers of citra- and metaconic acids. Dr. Gladstone has also measured their refractive indices. The citraconic ethers boil at a higher temperature than the mesaconic ethers, but their specific gravities, magnetic rotatory power, and refractive indices are lower. Only one anhydride can be obtained from maleic and fumaric acids, one from citra- and mesaconic acids, and one from α and β coumaric acids. Maleic anhydride can be obtained directly from malic acid by heating with an excess of acetylie chloride.—On the action of potassium cyanide on bismuthous nitrate, by M. M. P. Muir. A puce-coloured body is formed, Bi7(CN)6O15; by heating with strong potash Bi4O7 is obtained.—On the atomic weight, of bismuth, by M. M. P. Muir. The author has analysed bismuthous chloride, and obtained as a mean atmospheric weight 210.46, but he is not satisfied with the results, and hopes to obtain better numbers by the synthesis of bismuthous iodide.—Additional observations on the halogen salts of bismuth, by M. M. P. Mnir.—Note on the action of sulphuric acid on zinc and tin, by M. M. P. Muir and C. E. Robbs.—On the volumetric estimation of bismuth in the form of oxalate, by M. M. P. Muir and C. E. Robbs.—Note on the influence of water on the reaction between potassium iodide and chlorine, by M. M. P. Muir and R. Threlfall.—Laboratory notes, by M. M. P. Muir. I. Lecture experiment showing the effect of “a” time, “b” temperature, “c” mass. This consists in adding a solution of bismuth iodide in hydriodic acid to-each of three beakers, one containing 100 cc. of cold water, 100 cc. of hot water, and 500 cc. of eoM water. 2. The solution of manganese dioxide and manganese ores in hydrochloric acid is much hastened by potassium iodide. 3. A new method of detecting tin in the presence of antimony: by boiling with metallic copper and testing for stannous salt with mercuric chloride. 4. To detect the haloid acids in presence of nitrous and nitric acids.—On suberone, by R. S. Dale and C. Schorlemmer.—On sulphonic acids derived from isodinaphthyl, by Watson Smith and T. Takamatsu.—On phenyl aphthalene, by Watson Smith and T. Takamatsu.—On dimethylmalonic acid and dimethylbarbituric acid, by L. T. Thome. The author confirms the conclusions arrived at by Conrad and Guthzeit.

The methods for the determination of the trivalent and tetravalent manganese oxide in manganese and reduced manganese ores were examined. With acetylacetone the trivalent manganese ion forms a stable complex without any oxidizing action on acidified potassium iodide. In the presence of acetylacetone, manganese-tetrachloride, the resultant product of an ore sample dissolved in hydrochloric acid, loses chlorine and forms stable trichloride. The chlorine thus liberated chlorinates the acetylacetone, liberating iodine in an acid medium, if potassium iodide is present. Thus, by estimating the iodine liberated it is possible to determine the tetravalent manganese oxide in the presence of the trivalent manganese oxide. Although the method gives a positive error when the acetylacetone complex oxidizes potasium iodide if the acidity is high in a sample containing ferric iron, reasonable results can be gained if potassium iodide is added after the ferric iron has been reduced with stannous chloride. Hence the trivalent manganese oxide in an ore sample can be calculated by subtracting the value of tetravalent manganese, obtained as above, from the sum of trivalent and tetravalent manganese equivalent to the available oxygen obtained with ferrous sulfate method, as reported in Part 6.

Determination of antimony species with fluoride as modifier and flow injection hydride generation inductively-coupled plasma emission spectrometry

Iodate, bromate and hypochlorite were determined as iodine by flow injection amperometry at a platinum or glassy carbon electrode by injecting them into an eluent 0.20 M in hydrochloric acid and 0.024 M in potassium iodide or an eluent 2 M in sulphuric acid and 0.12 M in potassium iodide. The rectilinearity range is from 10–3 to 10–7M. Organic compounds that can be oxidised or iodinated by iodine were determined on-line by injecting them in acidic solution into an iodate-iodide eluent and observing the decrease in the iodine signal. The determination was also performed by injecting a pre-reacted solution of iodine and the organic compound and monitoring the excess of iodine.

PurposeThe purpose of this study is to investigate starch mucor (SM) in potassium iodide (KI) as corrosion inhibitor of aluminium in hydrochloric acid (HCl) medium.Design/methodology/approachThe SM in KI was characterized by gravimetric, scanning electron microscopy, electrochemical impedance spectroscopy measurements, potentiodynamic polarization and gas chromatography-mass spectrometer techniques. The inhibition efficiency was optimized using response surface methodology.FindingsThe result revealed that the inhibitor inhibited corrosion at a low concentration with the rate of inhibition increasing as the concentration of the inhibitor increased. The inhibition efficiency increases as the temperature was increased with slight incorporation of the inhibitor (SM in KI). This indicates that the corrosion control is both inhibitor (SM in KI) and temperature dependent.Originality/valueThe research results can provide the basis for using SM in KI as corrosion inhibitor of aluminium in HCL medium. Mixed-type inhibitor nature of SM was proved by cathodic and anodic nature of the polarization curves.

Total antimony was determined by inductively coupled plasma atomic emission spectrometry (ICP AES) using hydride vapor generation. A1 g wet, 0.25 g dry, or 10 mL water sample was digested by one of 2 distinct methods in a 10 mL graduated Kimax culture tube on a programmed heating block by heating with nitric acid and then boiling in a mixture of sulfuric acid and perchloric acid. For soils, a 0.25 g sample was digested in a 10 mL volumetric culture tube with hydrochloric acid. After digestion, the samples were treated with hydrochloric acid and potassium iodide. The antimony was then reduced by sodium borohydride to stibine (SbH3) in a simplified, continuous-flow manifold. A standard pneumatic nebulizer effected the gas–liquid separation of SbH3, which was then quantified by ICP AES at 231.147 nm. The instrument detection limit was 0.41 μg/L. Recoveries from 10 matrixes were 80 to 100%, with a typical relative standard deviation of 5.3%. The digestion and analysis methods demonstrated statistical control for samples of environmental and biological interest and are especially well suited to analysis of small samples. This method requires no additional apparatus for hydride generation or sample introduction.

A hydride generation-atomic absorption method for the rapid and precise determination of arsenic and antimony in geological materials is described. Samples (0.050.5g) were decomposed with perchloric, nitric, and hydrofluoric acids and potassium permanganate, and then evaporated nearly to dryness. The residue was dissolved by adding 20 ml of 6 M hydrochloric acid, 2 ml of 20 % potassium iodide, 5 ml of 10 % aluminium chloride, and 2 ml of 10 % ascorbic acid solutions. Arsenic or antimony hydride was generated with 1 % sodium tetrahydroborate, 2 M hydrochloric acid and 5 % malic acid solutions using an automated hydride generator, and introduced to a quartz cell atomizer. The limit of detection was 0.05 ppm for 0.5 g of the samples, and the relative standard deviation was smaller than 16 % for a content larger than 0.1 ppm. The time required for determining both arsenic and antimony in ten samples was about four hours. The method recommended here was successfully applied to the analysis of a variety of geological reference samples from the U. S. Geological Survey, Geological Survey of Japan, and National Bureau of Standards.