Iodate Solution Research Articles

Effectiveness of enriching lettuce with iodine using 5-iodosalicylic and 3,5-diiodosalicylic acids and the chemical composition of plants depending on the type of soil in a pot experiment

Iodine is a beneficial element for humans, animals and plants. This study was a comparison of the effectiveness of iodosalicylate uptake by lettuce. The experiment included two sub-blocks: organic soil and mineral soil with the addition of the same fertigation of plants (8 times every 7 days) with 10 µM solutions (100 mL/per one plant/one application) of potassium iodate (KIO3), salicylic acid (SA) alone or together with KIO3, 5-iodosalicylic acid (5-ISA) or 3,5-diiodosalicylic acid (3,5-diISA). None of the tested iodine compounds negatively affected the yield of lettuce. When growing plants on mineral soil, plants accumulated more iodine in the leaves than plants grown on peat substrate. The use of 5-ISA allowed for achieving better efficiency of plant biofortification in iodine than the application of KIO3 and 3,5-diISA. The type of soil significantly modified the chemical composition of lettuce.

Comparison of Ascorbic Acid Content in Some Selected Fruits Samples from Makarfi Local Markets, Kaduna State, Nigeria

This study was carried out to determine the ascorbic acid content of some fruits samples sold in Makarfi local market. Six fruits samples were randomly selected and used for the study. The samples were thoroughly washed and rinsed with distilled water. 500 g of each fruit sample (Cucumber, Carrot and Garden egg) were analyzed for both fresh and cooked portions. The samples were crushed and suspensions were made using doubled-distilled water. The extract was filtered to obtained 100 ml from each fruit filtrate which was then placed in a 500 ml volumetric flask and diluted to the mark with distilled water. 25 ml of each solution were treated with 150 ml distilled water and 5 ml of 0.6 molar freshly prepared KI(aq). 5 ml of 1M HCl and 1 ml of starch solution was added to the mixture which was then titrated against a freshly prepared 0.002M potassium iodate solution. The results obtained were used to determine the concentration of ascorbic acid in each sample. The major findings revealed that, fresh cucumber fruit has the highest concentration of ascorbic acid (9.6 x 10-1 mg/L) followed by garden egg ( 7.1 x 10-1 mg/L) and cooked garden egg fruits ( 5.6 x 10-1 mg/L). On the other hand, passion fruit (0.06 x 10-1 mg/L) has the least quantity of ascorbic acid content followed by cooked carrot (1.3 x 10-1 mg/L) and tamarind (2.9 x 10-1 mg/L)respectively. Some recommendations were made amongst which is that farmers should be enlightened to avoid the use of excessive inorganic fertilizers as it may be the factors that degrade the ascorbic acid content of some edible fruits. Vitamin C content of food get reduced by prolonged storage and over cooking because ascorbic acid is water soluble and it is destroyed by heat. Therefore steaming or microwaving should be encouraged. The study was concluded by emphasizing the importance of the consumption of fruits and the advantages of this to human health and general well-being.

Quadruple Fortification of Salt with Iodine, Iron, Vitamins B9 and B12 to Reduce Maternal and Neonatal Mortality by Reducing Anemia and Nutritional Deficiency Prevalence (P24-041-19)

ObjectivesTo develop a quadruple fortified salt(QFS) formulation that provides100 + % of RDA for iodine and vitamin B12 and 30–50% of RDA for iron and folic acid in forms that are organoleptically stable, bioavailable and acceptable to consumers MethodsIodine was sprayed onto salt as an aqueous solution of potassium iodate. Iron was admixed as a solid premix, which was colour masked with TiO2 and encapsulated in soy stearine to provide a water-impervious coating. The iron core was made of ferrous fumarate, which was agglomerated to an average size matching salt grain, i.e., 300–500 μm. Folic acid and vitamin B12 were added either in the iodate spray solution or in the solid iron premix. The premixes and salt were stored at 25, 35 and 45°C at 65% RH for up to a year. The loss of iodine, folic acid and vitamin B12 were monitored. An optimized formulation was tested on the pilot scale at JVS Foods Pvt, Jaipur, India. ResultsFolic acid can be stabilized in the iodine spray solution, and triple fortified salt containing iodine, folic acid and encapsulated ferrous fumarate retained >90% of both the added iodine and folic acid for 6 months. Stable QFS was made by incorporating vitamin B12 in the solid iron premix at a 1:200 ratio. The process was scaled up to produce some 25 kg of iron and B12premix, sufficient for 5 tons of salt, or 500,000 daily doses of salt. Organoleptic testing of Indian meals produced with quadruple fortified salt were found to be acceptable by a consumer panel at the University of Delhi. ConclusionsStable quadruple fortified salt that can provide up to 50% of RDA of folic acid and iron and 100 + % of RDA of vitamin B12 and iodine has been developed. The product was pilot tested and had high consumer acceptability. The formulation could reduce the incidence of maternal and infant mortality at a cost of less than 20¢/annum. Funding SourcesThis research was funded by Grand Challenges Canada through the Saving Lives at Birth program, and by the Bill and Melinda Gates Foundation.

Detoxification of Aflatoxin B1 in Peanut Oil by Iodine Doped Supported TiO2 Thin Film Under Ultraviolet Light Irradiation

Background: Improper storage and raw materials make peanut oil susceptible to Aflatoxin B1 (AFB1). The semiconductor TiO2 photocatalysis technology is an effective technology which is widely used in sewage treatment, environmental protection and so on. Moreover, the photocatalytic efficiency can be improved by doping I. Method: The experiment is divided into two parts. In the first part, supported TiO2 thin film (STF) was prepared on the quartz glass tube (QGT) by the sol-gel and calcination method and the supported iodine doped supported TiO2 thin film (I-STF) was synthesized using potassium iodate solution. In the second part, the photocatalytic degradation of AFB1 was performed in a self-made photocatalytic reactor. The AFB1 was detected by ELISA kit. Results: The photocatalytic degradation of AFB1 has been proven to follow pseudo first-order reaction kinetics well (R2 > 0.95). The maximum degradation rate of 81.96%, which was reached at the optimum iodine concentration of 0.1mol/L, was 11.38% higher than that with undoped STF. Conclusion: The doping of iodine reduces the band-gap of TiO2, thereby increasing the photocatalytic response range. The proportion of Ti4+ in I-STF has decreased, which means that Ti4+ are replaced by I. The I-STF prepared at iodine concentration of 0.1mol/L has good photocatalytic properties.

New approaches for efficient removal of some radionuclides and iron from rare earth liquor of monazite processing

In this article, new two approaches (A and B) are created for the efficient removal of the technically enhanced radium isotopes (228Ra, 226Ra and 223Ra), long-lived radioisotope of lead (210Pb), thorium (Th4+) and iron (Fe3+) from the rare earth chloride (RECl3) liquor produced during the monazite processing. In the first approach ‘A,’ elimination of the undesired species is achieved using a synergistic admixture of sulfate–sulfide solution (SO42−/S2− admixture), while the second approach ‘B’ is performed using an iodate solution (IO3−) as a selective precipitating agent. The results indicated that 14% of radionuclides and Th(IV), 12% of Ln(III) and 40% of Fe(III) were removed from the RECl3 liquor at pH 3. In the first approach ‘A,’ the average percentage removal (%R) of all the undesired species reached ~ 96% using sulfate–sulfide admixture (0.058/0.04 mol/L). In the second approach ‘B,’ the average % R of all undesired species is improved and increased to ~ 99% using potassium iodate solution of 0.155 mol/L. Therefore, iodate solution is considered as an efficient and selective agent for the removal of Ra isotopes, 210Pb, Th(IV) and Fe(III) from RECl3 liquor without loss in Ln(III) at the optimized conditions. In this respect, promising results are obtained for the purification and production of Ln(III) using iodate solution or sulfate–sulfide admixture. Finally, the proposed two approaches are considered to be efficient not only to minimize the radiological human risks but also to eliminate the interfering of Th and Fe ions, to produce highly purified lanthanides from monazite ore.

Influence of collection substrate and extraction method on the speciation of soluble iodine in atmospheric aerosols

Abstract The extraction into aqueous solution of total soluble iodine (TSI), iodide and iodate were examined as a function of extraction times between 5 and 60 min for two different extraction methods and from two types of commonly used aerosol collection substrates. The extraction methods tested were ultrasonic agitation and mechanical shaking, while the substrates were cellulose fibre (CF) and glass fibre (GF). Tests were carried on substrates spiked with known amounts of iodide and iodate and on a pair of ambient aerosol samples collected at the University of East Anglia on both substrates over the same time period. The combination of ultrasonic agitation and CF substrates (which has been used in many published studies of aerosol iodine speciation) was shown to lead to variable recovery of iodine species and changes in speciation over extraction time. Mechanical shaking of GF substrates gave good recoveries of iodide and iodate from spiked experiments and stable speciation with time for the ambient aerosol sample. This combination is recommended for future use in the determination of aerosol iodine speciation. Mechanical shaking also appeared to be preferable to ultrasonic agitation for samples that were collected on CF substrates. The optimised conditions (mechanical shaking of GF substrates for 30 min) were applied to the analysis of samples collected during the Stratospheric ozone: Halogen Impacts in a Varying Atmosphere (SHIVA) cruise in the South China and Sulu Seas in November 2011. The results obtained showed variable proportions of iodide, iodate and soluble organic iodine species in these samples, with iodide concentrations possibly related to airmass history and background chemistry.

Effect of selenium, iodine and their combination on development of Tartary buckwheat sprouts

Tartary buckwheat (Fagopyrum tataricum Gaertn) is becoming more and more popular due to its health benefits for humans. It contains important fibres, vitamins, certain minerals and antioxidants asrutin. Sprouts are a hot trend in the food production and nutrition. Enrichment of sprouts with iodine (I) and selenium (Se) may prevent endemic deficiency of these elements for humans and animals. The aim of the study was to found out the effect of selenate (Se(VI)), iodate (I(V)) and their combination on morphological, physiological and biochemical properties of Tartary buckwheat sprouts. Tartary seedswere soaked in solutions with Se(VI) (20 mg/L), I(V) (1500 mg/L) or in Se(VI) + I(V) (20 mg/L Se(VI) +1500 mg/L (I(V)). Experiment was performed in growth chamber in two repetitions. Measurements were performed three weeks after germination. The solution of iodate and combination of selenate and iodate lowered germination rate of sprouts. There was no effect of the treatments on the amount of chlorophyll a, anthocyanins and UV absorbing compounds. The amount of rutin was the highest in control sprouts. According to physiological measurements, control sprouts and sprouts from treated seeds were not stressed by the treatments.

An indirect application aspect of zeolite modified electrodes for voltammetric determination of iodate

Clinoptilolite nanoparticles (NClin) were Fe(II)-exchanged and used for the modification of carbon paste electrode (Fe(II)-NClin-CPE) in indirect determination of iodate. The voltammetric peak current of Fe(II)/Fe(III) redox system was decreased in the presence of iodate in solution. Sufficient characterization was applied for the raw and modified zeolite and CPE. The electrochemical impedance spectroscopy (EIS) confirmed that Fe(II)-NClin/CPE had the best charge transfer ability with respect to the raw CPE and NClin/CPE. The simultaneous effects of the most important influencing variables of square wave voltammetry (modifier%, solution pH, step potential and amplitude) were studied by designing the experiments by using response surface methodology (RSM). The optimal run obtained at pH2.18, amplitude=0.472 V, modifier%=17.5 and step potential=0.0202V. Under the optimum conditions, the current response of Fe(II)-NClin/CPE was inversely proportional to IO3− concentration in the range of 4–100μmolL−1 with a detection limit of 0.64μmolL−1. Capability of the modified electrode for the determination of iodate in iodofolic pharmaceutical tablet was studied and the obtained results were statistically compared with the results obtained by iodometric titration as a standard method.

Determination of iodine in plants by ICP-MS after alkaline microwave extraction

Iodine is an essential element, important for normal thyroid function. Due to the frequency of health problems associated with its insufficient intake, new or additional sources of iodine have to be investigated. One of them could be iodine enriched plants. Before introduction into the human diet, the iodine content must be known as precisely as possible. A method of iodine determination in various plant samples by inductively coupled plasma mass spectrometry (ICP-MS) after alkaline microwave extraction was optimized. Among the tested ratios between TMAH and water, the ratio 1:5 was found to be optimal, using the following temperature program: 20min ramp to 200°C and 5min hold on 200°C. For measurements, 0.1% TMAH solution was chosen as optimal, using helium in the collision cell. A calibration line, for which standards were prepared in 0.1% TMAH, can be used for quantitative determination of iodine content. Measurement uncertainty was estimated to be around 30% for samples with low iodine content (around 0.2μgI/g) and below 7% for samples with higher iodine content (0.7μgI/g). Detection limits were 20ng/g of sample or less and good repeatability of the measurements and linearity over a wide concentration range were found. The results obtained by the optimized method were compared to those obtained with an independent method (k0-INAA), and they showed very good agreement, proving the accuracy of the determination by ICP-MS. Finally, iodine content was determined in samples with different matrices: pea seeds, pumpkin seeds and buckwheat achenes, from plants foliar sprayed with iodide or iodate solutions at the time of blooming.

Optimization and Validation of Spectrophotometric and Potentiometric Methods for Determination of Lansoprazole and Omeprazole in Pure and Capsules

Two fairly sensitive, simple and accurate methods have been developed and validated for the assay of omeprazole and lansoprazole in pure and dosage forms. The proposed spectrophotometric method was based on the oxidation of the title drugs with acidic potassium iodate solution resulted in liberation of iodine, which was then extracted and measured at λ 520 nm under the optimized experimental conditions. The method was proved to be accurate and precise and the linearity was found to be in the concentration range of 5-200 and 15-200 µg/ml, for omeprazole and lansoprazole, respectively, with apparent molar absorptivities of 2.42×10-4 and 2.01×10-4 lmol-1cm-1, and with the corresponding Sandell sensitivity value of 0.0281 and 0.0473 mgcm-2 for the afore mentioned drugs, respectively. Moreover, the kinetics of these reactions was investigated. On the other hand, the potentiometric method was based on the direct titration of the drugs with acidic N-bromosuccinimide solution with determination of the end point potentiometrically using a platinum indicator electrode under the optimum conditions. The concentration ranges were found to be 25-100 and 15-100 µg/ml with standard deviation of 0.007-0.042 and 0.005-0.034, and with relative standard deviation of 0.79-2.4 and 1.4-2.9 for omeprazole and lansoprazole, respectively. Additionally, the proposed methods could successfully be applied for the determination of the cited drugs in pharmaceutical dosage forms. The relative standard deviations for the results did not exceed 1%, confirming the high precision of the method and reproducibility of the results.

Photolysis of frozen iodate salts as a source of active iodine in the polar environment

Abstract. Reactive halogens play a key role in the oxidation capacity of the polar troposphere. However, sources and mechanisms, particularly those involving active iodine, are still poorly understood. In this paper, the photolysis of an atmospherically relevant frozen iodate salt has been experimentally studied using infrared (IR) spectroscopy. The samples were generated at low temperatures in the presence of different amounts of water. The IR spectra have confirmed that, under near-ultraviolet–visible (UV–Vis) radiation, iodate is efficiently photolysed. The integrated IR absorption coefficient of the iodate anion on the band at 750 cm−1 has been measured to be A = 9.8 ± 0.5 × 10−17 cm molecule−1. The photolysis rate of the ammonium iodate salt was measured by monitoring the decay of ammonium or iodate IR bands (1430 and 750 cm−1 respectively) in the presence of a solar simulator. The absorption cross section of the liquid solutions of ammonium iodate at wavelengths relevant for the troposphere (250 to 400 nm) has been obtained and used to estimate the photolytic quantum yield for the frozen salt. Finally, using an atmospheric model, constrained with the experimental data, we suggest that the photolysis of iodate in frozen salt can potentially provide a pathway for the release of active iodine to the polar atmosphere.

Factors influencing the efficacy of iodine foliar sprays used for biofortifying butterhead lettuce (Lactuca sativa)

AbstractIodine biofortification of butterhead lettuce (Lactuca sativa) via foliar sprays was investigated in field trials, focusing on assessing the influence of the time and application method. The iodine (I) concentrations in the edible plant parts increased when potassium iodide (KI) and potassium iodate (KIO3) solutions were sprayed at doses up to 0.25 kg I ha−1 on different dates close to harvest. Crop yield and marketable quality were not significantly affected by I treatments. A greater efficacy of KI was frequently observed and probably related to its lower point of deliquescence and smaller anion size in comparison with KIO3. KI sprays on butterhead lettuce at different times of the day resulted in a higher I enrichment when applied at 11:00 and 15:00 h. The diurnal variation in I uptake may reflect the impact of fluctuating climatic conditions at the time of application. Iodine treatments at different application dates near harvest led to an increasing I concentration in the vegetable produce that could be related to the rising shoot fresh mass and leaf area. When KI and KIO3 were sprayed simultaneously with commercial calcium fertilizers, fungicides or insecticides, I accumulation in butterhead lettuce was not negatively affected or in some cases even significantly enhanced. The results show that foliar sprays of KI and KIO3 are an effective method to biofortify butterhead lettuce with I and this approach may easily be implemented as a routine method in commercial cultivation.

Regeneration of Aqueous Periodate Solutions by Ozone Treatment: A Sustainable Approach for Dialdehyde Cellulose Production.

A method for easy and fast regeneration of aqueous periodate solutions from dialdehyde cellulose (DAC) production by ozone treatment is presented, along with a direct and reliable simultaneous quantification of iodate and periodate by reversed-phase HPLC. The influence of iodate and ozone concentration, solution pH, and reaction time on the regeneration efficiency was studied, as well as the reaction kinetics. Regeneration of spent periodate solutions by ozone was successfully performed in alkaline medium, which favors the formation of free (.) OH radicals, as supported by the addition of radical scavengers and quantum mechanical calculations. At pH 13 and an ozone concentration of approximately 150 mg L(-1) , periodate was completely regenerated from a 100 mm solution of iodate within 1 h at room temperature. A cyclic process of cellulose oxidation and subsequent regeneration of spent periodate with 90 % efficiency has been developed. So far, commercial applications of DAC have been hampered by difficulties in reusing the costly periodate. This work overcomes this hurdle and presents a highly efficient, clean, and low-cost protocol for the preparation of DAC with integrated periodate recycling, with the possibility of scaling the process up.

μフォーカスCTによる多孔質空隙スケールでの拡散現象の分析

In this study μ-focus X-ray CT was applied to analyze a material flow due to diffusion in porous rocks. Here, one-dimensional diffusion tests were performed using solution of potassium iodate (KI) as a tracer. As representatives of porous rocks, Berea sandstone and Kimachi sandstone were applied, and the diffusion phenomena including pore structures in the pore scale were visualized. In order to extract the density information due to the diffusion, image subtraction method was applied to the CT images. By applying the method, the density increment due to the diffusion and its location was easily extracted. It was found that the KI solute mainly diffuses in the pore networks in the case of Berea sandstone. On the other hand, it was found that the KI migrates not only through pores but also micro pores/fractures in grains in the case of Kimachi sandstone. The difference of diffusion velocity in both samples was also discussed.

Chemical and fruit skin colour markers for simple quality control of tomato fruits

Summary The orientation of this research was to evaluate the classic parameters regarding the external and internal quality of tomato fruits cv. 'Brilliant' at different stages of maturity and to define the dynamics of their changes during the ripening in storage at 18 C. Principal component analysis (PCA) and multivariate canonical discriminant analysis (DA) were used to classify tomato samples according to quality (internal and external) and nutritional value based on fruit mass, fruit skin colour, contents of soluble solids (SS), total titratable acids (TTA), ascorbic acid (AA), and total antioxidant potential (TAP). Several methods are usedfor determining AA content and TAP in plant samples. A simple routine method, direct redox titration with iodate solution and spectrophotometric determination of TAPSP, as described by Singleton and Rossi, also called total phenols, were used respectively. The results show that the stage of maturity (based on fruit skin colour) strongly determines the quality and nutritional value of the tomato fruit. Tomatoes harvested at table maturity (red colour, index a*/b* ≥ 0.85) have a significantly higher nutritional value (in terms of antioxidants - TAPSP and AA content) and overall quality than those harvested at an earlier maturity stage and then ripened in storage. This brings out the importance of short food supply chains and, from the viewpoint of overall fruit quality, it raises doubt about harvesting before reaching table maturity. On the other hand, it is necessary to be extremely attentive when determining optimal maturity, because when the plant becomes over-ripe or when stored, the nutritional value and overall quality decrease drastically. Besides the colour parameters, AA content is the most important chemical marker for a simple quality control. By using a simple and reliable analytical method for determining AA content, such as direct redox titratiation, the monitoring of tomato fruit quality could also be easily performed in situ.

Regeneration and Recycling of Aqueous Periodate Solution in Dialdehyde Cellulose Production

The regeneration of aqueous iodate solution from the regioselective periodate oxidation of softwood cellulose pulp to dialdehyde cellulose using hypochlorite as a secondary oxidant was studied. The influence of oxidation time on the pulp dissolution and regeneration efficacy was examined in particular. In addition, the recycling of regenerated periodate solution back to oxidation was clarified. The solutions from the 10 and 15 min oxidations were regenerated with 100% conversion efficacy when 1.2–1.4 times the stoichiometric amounts of hypochlorite were used. However, the regeneration efficacy decreased when the reaction time in the oxidation increased to 30 min because the content of soluble impurities, which consumed the hypochlorite in the side-reactions, increased significantly as the oxidation reaction proceeded. The regenerated solutions possessed good oxidation performance, showing that periodate was successfully regenerated using hypochlorite and supporting the assumption that periodate can be effectively recycled in the process when short oxidation times are used.

Visible Light Water Oxidation Using a Co-Catalyst Loaded Anatase-Structured Ti1–(5x/4)NbxO2–y–δNy Compound

The photocatalytic activity of anatase-structured Ti(1-(5x/4))Nb(x)O(2-y-δ)N(y) (x = 0.25, y = 0.02; NbN-25) was examined for water oxidation under UV and visible light irradiation. The semiconductor was prepared by sol-gel processing followed by nitridation in flowing ammonia and exhibits an indirect optical gap of 2.2 eV. Ti(1-(5x/4))Nb(x)O(2-y-δ)N(y) was loaded with RuO2 by an impregnation technique, and optimized conditions reveal that 1 wt % RuO2 generates 16 μmol O2 from water with concomitant IO3(-) reduction after 3 h of illumination under simulated solar radiation at a flux of 600 mW/cm(2) illumination, which corresponds to 6-sun AM1.5G illumination (compared to no detectible O2 without the RuO2 cocatalyst). A series of cut-on filters shows that the catalyst-loaded semiconductor evolves O2 for λ ≤ 515 nm, and a gas-phase mass spectrometry isotope labeling experiment shows that irradiating an iodate solution in H2(18)O in the presence of 1 wt % RuO2 loaded on NbN-25 gives rise to catalytic water oxidation: both (36)O2 and (34)O2 are observed. It is unclear whether (16)O arises from IO3(-) or surface reconstruction on the photocatalyst, but ICP-AES analysis of the postirradiated solution shows no dissolved metal ions.

Synthesis and Characterization Of Bismuth (Iii) Iodotungstate, an Exchanger

A number of samples of Bismuth(III) iodotungstate were prepared by mixing the solutions of Bismuth nitrate, Potassium iodate and Sodium tungstate in varying ratios. One of the samples was selected for study because the ion exchange capacity and the yield of the exchanger was found to be satisfactory. The characterization of the exchanger included the determination of the ion exchange capacity of the exchanger by downflow column method and P H titration method. Both the methods exhibited the ion exchange capacity to be 1.0 meq/g. Further studies included the study of IR, TGA, XRD and Distribution studies. IR of the exchanger indicated the presence of the expected components of the exchanger. Thermal gravimetric analysis has clearly shown the loss of weight of exchanger due to the loss of water molecules & other components at different temperatures. X-Ray diffraction pattern proved the exchanger to be amorphous in nature. Chemical stability of the exchanger was studied in different acid and base solutions of different concentrations. The exchanger was heated at different temperatures and after every heating the ion exchange capacity of the exchanger was determined. This shows the decline in the ion exchange capacity on increasing the temperature. Kd values for different metals ion were determined and found the maximum value for Ni ++. Where as minimum value was found to be for Zn ++ . The results appeared to be satisfactory.

Synthesis, Characterization and Analytical Application of Antimony (III) Iodovanadate

Antimony (iii)iodovanadate has been synthesized under varying ratio of antimony trichloride, sodium metavanadate and potassium iodate solutions. The synthesized material shows ion exchange capacity 2.67meq/g for Na + ions. The material has been characterized on the bases of IR, XRD and TGA. The chemical stability of the material has been determined in acid and base solutions of different concentration. Thermal stability of this exchanger has also been determined. Distribution studies exhibit maximum Kd value for Ni ++ and minimum for Pb ++ . The utility of the exchanger is revealed from the binary seperations. The exchanger has been employed

Electroless etching of Si with IO3– and related species

We have previously derived seven requirements for the formulation of effective stain etchants and have demonstrated that Fe3+, Ce4+, and VO2+ + HF solutions are highly effective at producing nanocrystalline porous silicon. Here, we show that Cl2, Br2, I2, ClO3–, BrO3–, IO3–, I–, and I3– induce etching of silicon when added to HF. However, using the strict definition that a pore is deeper than it is wide, we observe little evidence for porous layers of significant thickness but facile formation of pits. Iodate solutions are extremely reactive, and by the combined effects of IO3–, I3–, I2, and I–, these etchants roughen and restructure the substrate to form a variety of structures including (circular, rectangular, or triangular) pits, pyramids, or combinations of pits and pyramids without leaving a porous silicon layer of significant thickness.