Showing papers on "Potassium dichromate published in 2017"

Polymerization of aniline derivatives by K2Cr2O7 and production of Cr2O3 nanoparticles

Abstract: Oxidative polymerization of aniline, anthranilic acid, and aniline-co-anthranilic acid by potassium dichromate Cr(VI) as an oxidant in acidic medium was investigated. In this study, the polymerization process of aniline, o-anthranilic acid as well as aniline/o-anthranlic acid using K2Cr2O7 produced, coordinated Cr(III)/polyaniline (PANI), Cr(III)/polyanthranilic acid (PAA) and Cr(III)/poly aniline-co-anthranilic acid (PANAA). The mechanism of polymerization reaction in the presence of dichromate was hypothesized. The precursor chromium doped polymers were characterized by TGA, FT-IR, UV-visible, XRD analyses. Cr2O3 nanoparticles size were determined using TEM analysis. The calcinations process of synthesized chromium doped PANI, PAA and PANAA yields Cr2O3 nanoparticles 26%, 31%, and 34% wt. respectively. Rhombohedral phase of Cr2O3 particles in the range from 33 to 61 nm was produced from chromium/polyanthranilic acid (PAA) and chromium/poly(aniline-co-anthranilic acid) PANAA. UV- visible analysis showed that optical band gaps (Eg) of doped poly aniline and its derivatives are in the range from1.55 to 1.80 using Tacu's law. The band gap values reveal that the doped chromium emeraldine base can be used as semiconductor materials. Copyright © 2016 John Wiley & Sons, Ltd.

Synthesis and Characterization of Highly Intercalated Graphite Bisulfate

Abstract: Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy (μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO4, K2Cr2O7) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO4 and NaClO3.

Performance of buffered ferric chloride as terminal electron acceptor in dual chamber microbial fuel cell

Abstract: Electrochemical behaviour of buffered ferric chloride (FC) was studied as terminal electron acceptor (TEA) in a dual chamber microbial fuel cell (DCMFC). The DCMFC was operated in batch mode using lactate as substrate and enriched consortium of sulphate reducing and sulphur oxidising bacteria as anodic biocatalysts. To characterise the TEA in terms of open circuit voltage and power density, four DCMFCs were operated individually under similar anodic operating conditions with phosphate buffer (PB), potassium hexacyanoferrate (PF), potassium dichromate (PD) and FC. Results showed that voltage and power generation with FC were highest among the four TEAs. Performance of the four tested buffered catholytes was found to be in the following order: ferric chloride (857 mV; 308.7 mW/m 2 ) > potassium hexacyanoferrate (571 mV; 222 mW/m 2 ) > potassium dichromate (517 mV; 168.6 mW/m 2 ) > phosphate buffer solution (250 mV; 16.87 mW/m 2 ). With the addition of potassium dichromate, potassium hexacyanoferrate and ferric chloride to phosphate buffer, charge transfer resistance (R ct ) declined by 67%, 52.2% and 51.8%, respectively. Ohmic resistance decreased by 36%, 41.6% and 37.6%, respectively. Electrical conductivity of the leachate after coagulation with ferric chloride increased from an initial of 2.54–7.96 mS thus further supporting the decreased resistance. Further, with no optimization, 50 mM/L of ferric chloride could remove 68.3% of COD having initial value of 9600 mg/L in the cathode chamber.

One-step hydrothermal synthesis of In 2.77 S 4 nanosheets with efficient photocatalytic activity under visible light

Abstract: In277S4 nanosheets with the band gap energy of 175 eV were fast prepared via a hydrothermal process The structure, morphology and optical properties of the as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy, respectively Rhodamine B, methyl orange and potassium dichromate solution were used to evaluate the degradation efficiency of the as-prepared samples under the visible light, respectively Experimental results showed that the molar ratio of thioacetamide to indium nitrate hydrate significantly influenced the structure and properties of the as-prepared products With increasing the molar ratio, the degradation efficiency of rhodamine B solution was firstly increased and then decreased When the molar ratio was 4:1, the degradation efficiency of the as-prepared sample reached to 96% in 3 min and 100% in 9 min Moreover, this semiconductor could degrade 88% of methyl orange solution in 30 min and 87% of potassium dichromate solution in 60 min, respectively

A Derivative Spectrometric Method for Hydroquinone Determination in the Presence of Kojic Acid, Glycolic Acid, and Ascorbic Acid

Abstract: A new, simple, and sensitive spectrometric method was developed for hydroquinone (HQ) determination in the presence of other depigmenting agents (kojic acid (KA), glycolic acid (GA), and ascorbic acid (AA)), commonly introduced in skin lightening products. The method is based on the oxidation of the depigmenting agents by potassium dichromate in sulfuric acid medium and subsequent measurement of the amplitude of the first-order derivative absorption spectrum at 268 nm. By applying the zero-crossing method, at this wavelength, the oxidation products of KA, AA, and GA do not interfere in the indirect determination of HQ. Beer’s law was obeyed in the range of 0.22–22 μg·mL−1 HQ, with a detection limit of 0.07 μg·mL−1. The developed method was applied with good results for the first time to the rapid determination of HQ in binary, ternary, and quaternary mixtures, thus proving that it could represent an effective tool for various skin lightening products analyses.

Hexavalent chromium induces reactive oxygen species and impairs the antioxidant power of human erythrocytes and lymphocytes: Decreased metal reducing and free radical quenching ability of the cells.

Abstract: The toxicity of hexavalent chromium [Cr(VI)] in biological systems is thought to be closely associated with the generation of free radicals and reactive oxygen species These species are produced when Cr(VI) is reduced to its trivalent form in the cell This process results in oxidative stress due to an imbalance between the detoxifying ability of the cell and the production of free radicals We have studied the effect of potassium dichromate (K2Cr2O7), a [Cr(VI)] compound, on the antioxidant power of human erythrocytes and lymphocytes under in vitro conditions Incubation of erythrocytes and lymphocytes with different concentrations of K2Cr2O7 resulted in a marked dose-dependent decrease in reduced glutathione and an increase in oxidized glutathione and reactive oxygen species levels The antioxidant power of the cells was decreased, as determined by metal reducing and free radical quenching assays These results show that [Cr(VI)] upregulates the generation of reactive oxygen species and, as a consequence, the cellular antioxidant defences are compromised The resulting oxidative stress may contribute to Cr(VI)-induced cellular damage

Toxicity test and Cd, Cr, Pb and Zn bioccumulation in Phalloceros caudimaculatus

Abstract: The use of animals as bioindicators has been useful, especially in the evaluation of environmental impact of pollutant discharges in aquatic ecosystems. This study, aims to assess the fish Phalloceros caudimaculatus (known as Guaru) as a heavy metal sbioindicator. LC50 (96 h) acute toxicity tests to potassium dichromate salts, cadmium nitrate, lead II nitrate and zinc sulfate, and bioaccumulation of metals such as cadmium, chromium, lead and zinc were conducted. In the bioaccumulation test, for three months standard tanks were used, with different contamination levels above the levels set by local law, a pollution control tank was also set. The following data was obtained in acute toxicity tests LC50 (96 h): Potassium dichromate 164.58 ± 18.75 mg/L, Cadmium nitrate was 29.5 ± 1.21 mg/L, Lead nitrate was 15.5 ± 0.47 mg/L and zinc sulfate was 62.8 ± 2.81 mg/L. The bioconcentration factor (BCF) maintained the order Zn > Pb > Cd > Cr, where the resulting values were considered high for the four elements ranging from 92.4 (Cr) to 1793.1 (Zn). Based on the test results, the Guaru fish proved resistant to the presence of these metals and a showed a high bioaccumulation rate. Thus, it can be used as a bioindicator of heavy metals.

The Impact of Different Copro-preservation Conditions on Molecular Detection of Cryptosporidium Species.

Abstract: Background: We aimed to evaluate different copro-preservation conditions along the duration of one month for a better outcome of molecular diagnosis of Cryptosporidium species. Methods: Ten samples out of 380 fresh stool samples collected from patients with diarrhea proved positive after direct examination, concentration, staining and confirmed by immunochromatographic test. The study was conducted at the Diagnostic and Research Unit of Parasitic diseases, Faculty of Medicine, Ain Shams University at the time interval from July 2014 to December 2015. Each stool sample was preserved in five different conditions; freezing at -20 oC, 70% ethyl alcohol, 10% formalin, 2.5% potassium dichromate (K dichromate) at 4 oC and 2.5% K dichromate at room temperature (RT). Then DNA extraction and nested PCR, with Cryptosporidium oocyst wall protein (COWP) gene were done from each sample at zero time (fresh specimens) as a standard for comparison with the preservation conditions at 10, 20 and 30 d. Results: Sensitivity of studied preservative conditions along the whole study duration showed best outcome from freezing at -20 °C (80%) then K dichromate (4 °C) (73.3%) followed by K dichromate (RT) (66.7%), then alcohol (33.3%), while formalin was the worst (0%) with a highly significant comparative outcome between the different conditions. Along the three extraction intervals, K dichromate (RT), unlike all the rest of conditions lacks the consistent preservative action. Conclusion: Our study highlights freezing at -20 oC to be the most suitable condition for preservation followed by K dichromate at 4 °C, K dichromate at RT, then 70% ethyl alcohol. Formalin (10%) is better to be avoided.

The Effect of Chromium and Boron on the Lipid Peroxidation and Antioxidant Status (In Experiment)

Abstract: Background: Modern ecological situation is characterized by significant impairments as a result of adverse human influence. In this connection, it becomes necessary to study the negative effects of substances on living organisms and ways to reduce them. Objective: This article evaluated the impact of potassium dichromate (K2Cr2O7) and boric acid (H3BO3) on the status of lipid peroxidation (LPO) and antioxidant system (AOS). Methods: The work is performed on 24 male rats of Wistar weighing 180 g to 220 g, were grown in the vivarium of the Central research laboratory of West Kazakhstan state medical University named after Marat Ospanov (Aktobe, Republic of Kazakhstan). Results: An experiment on Wistar rats: 1st-warning; 2nd-received K2Cr2O7; 3rd-H3BO3; 4th-K2Cr2O7 and H3BO. The introduction of K2Cr2O7 intensified LPO and reduced activity of catalase, glutathione peroxidase and superoxide dismutase, the number of sulfhydryl groups. In the group treated with H3BO3-LPO inhibition, activation of AOS. Combined injection of K2Cr2O7 and H3BO3 reduces the content of malondialdehyde, increases the number sulfhydryl groups compared to the group "K2Cr2O7". Conclusions: The results of the study allow asserting that the H3BO3 in the conditions of joint use with K2Cr2O7 has an antioxidant effect, which leads to inhibition of LPO and activation of antioxidant system. Therefore, we first established the antioxidant effect of boric acid in the combined effects of potassium dichromate and boric acid. Our study shows that boric acid when co administered orally with potassium dichromate inhibits the development of chromium-induced oxidative stress in the tissue blood. Based on its efficacy are inhibition of lipid peroxidation and increase antioxidant defense in the blood.

Method for rapidly determining content of organic matter in soil

Abstract: The invention discloses a method for rapidly determining the content of organic matter in soil The method comprises steps as follows: 005-05 g of a soil sample is weighed and added to a digestion tube, 01-03 g of bismuth nitrate is added, and 10-15 mL of a potassium dichromate-concentrated sulfuric acid solution with the concentration being 04 mol/L and 3-5 mL of strong phosphoric acid are added; the digestion tube is placed in a digestion device provided with a graphite heating plate and suitable for simultaneous digestion of large batches of determined samples, accurate heating at 180 DEG C is performed, and organic carbon in the soil is oxidized; residual potassium dichromate in the digestion tube is titrated with a ferrous sulfate standard solution under electromagnetic stirring; then the amount of potassium dichromate consumed by the sample is multiplied by an oxidation correction coefficient, and the content of the organic matter in the soil is calculated The method has the advantages of being high in accuracy, good in repeatability, simple to operate, low in energy consumption, low in cost, capable of saving time and labor, reliable in determined results and the like

Testing method of soil organic matter

Abstract: The invention discloses a testing method of a soil organic matter, and belongs to the technical field of a soil component testing method. The method includes steps of under the condition of heating by an oil bath spot, oxidizing soil organic carbon by excessive potassium dichromate- sulfuric acid solution, and performing titration on the rest potassium dichromate by ferrous sulfate standard solution; calculating organic carbon amount of the consumed potassium dichromate amount according to an oxidization correction coefficient, and then multiplying by a constant 1.724, namely, content of the soil organic matter. The testing method is characterized in that the oil bath spot is a heat-collecting type constant temperature magnetic stirring reaction oil bath spot; when the temperature of the oil bath spot is risen to 185 DEG C, the power source is immediately cut off, the heating of the oil bath spot is stopped; the whole heating process can be completed by means of afterheat of the oil bath. Fluid in a test tube cannot spray, so that the parallelism of testing data is very good, the testing result is more exact; moreover, the whole testing process is safe, easy, energy-saving, high-efficient, and worthy of popularizing.

A 3-step chemiluminescence method for chemical oxygen demand measurement with dichromate oxidizing reagent

Abstract: In this study, the use of potassium dichromate as an oxidizing reagent in the 3-step chemiluminescence (CL) chemical oxygen demand (COD) method, based on the principle of the permanganate COD (CODMn) method (JIS K0102), was developed (3-step CL CODCr method). The sample reacted with an excess of dichromate under heating, and the remaining dichromate was neutralized by a reducing organic compound. Then, the remaining amount of the reducing organic compound was detected in the CL detector using permanganate CL reagent. Six organic compounds – gallic acid, phenol, pyrocatechol, ascorbic acid, pyrogallol, and potassium hydrogen phthalate – were investigated as the reducing organic compounds. The CL kinetics of these compounds with acidic permanganate reagent were studied, and pyrogallol showed the highest signal with the fastest relevant response. Hence, pyrogallol was chosen as the reducing organic compound. The enhancement effects of seven metal ions – Cr(III), Mn(II), Cu(II), Ag(I), Fe(II), Fe(III), and Mg(II) – were investigated. The results showed that Cr(III), Mn(II), Fe(II), and Fe(III) enhanced the signal. Fe(II) and Fe(III) showed the highest enhancement effects, in which the signals increased to 188% and 205%, respectively. However, Fe(II) made the permanganate reagent become less stable due to the reaction between Fe(II) and permanganate and the enhancement decreased significantly with time. Hence, Fe(III) was added to the permanganate reagent at the optimum concentration of 0.45 mmol dm−3. The correlation between the 3-step CL CODCr method and the conventional CODMn for several organic compounds showed a good determination coefficient R2 = 0.9594 (n = 16). The limit of detection was 0.083 mg L−1, using gallic acid as a standard. The method was applied to measurement of river water samples, obtaining results in good correlation with the CODMn method.

Potassium Dichromate Oxidation Methods’ Review and Application for Determination of Soil Organic Matter

Abstract: 本文对重铬酸钾氧化法测定土壤有机质的方法和特点及应用范围进行了论述和评价，并分析不同测定方法对测定土壤有机质含量的影响，比较了各方法的优缺点以及研究中适宜选择的方法，并展望了土壤有机质准确、精密、快速、无污染测定方法的发展趋势。 The potassium dichromate oxidation methods are main methods for determination the content of soil organic matter. Their characteristics and application ranges were discussed and evaluated. The influence of the above methods on the determination the content of soil organic matter was analyzed. The optimal method was chosen by the comparing the advantages and disadvantages of each method. The prospect of accurate, precise and rapid analytical method with less pollution for determining the soil organic matter in future was proposed.

Experimental patch testing with chromium-coated materials.

Abstract: SummaryBackground Chromium coatings on metal alloys can be decorative, and prevent corrosion and metal ion release. We recently showed that handling of a chromium-containing disc resulted in chromium deposition on the skin. Objectives To examine patch test reactivity to chromium-coated discs. Methods We included 15 patients: 10 chromium-allergic patients, and 5 patients without chromium allergy. All were patch tested with potassium dichromate, cobalt chloride, nickel sulfate, and nine different metallic discs. The chromium-allergic patients were also patch tested with serial dilutions of potassium dichromate. Results Positive/weaker reactions were observed to disc B (1 of 10), disc C (1 of 10), and disc D, disc E, and disc I (4 of 10 each). As no controls reacted to any of the discs, the weak reactions indicate allergic reactions. Positive patch test reactions to 1770 ppm chromium(VI) in the serial dilutions of potassium dichromate were observed in 7 of 10 patients. When the case group was narrowed down to include only the patients with a current positive patch test reaction to potassium dichromate, elicitation of dermatitis by both chromium(III) and chromium(VI) discs was observed in 4 of 7 of patients. Conclusions Many of the patients reacted to both chromium(III) and chromium(VI) surfaces. Our results indicate that both chromium(VI) and chromium(III) pose a risk to chromium-allergic patients.

Histopathological changes of heavy metals Nickel Chloride (II) and Potassium dichromate (VI) on the Liver and Kidney of Swiss Male Mice

Abstract: Heavy metals are a very harmful environmental pollu tant, Nickel and chrome induced toxicity and carcinogenicity, with an emphasis on t he generation and role of reactive oxygen species is reviewed. Nickel and chrome are a known as haema totoxic, immunotoxic, neurotoxic, genotoxic, reproductive toxic, pulmonary toxic, nephrotoxic, h epatotoxic and carcinogenic agent. The present study revealed the toxic effects of nickel (Ni) (II ) and chrome (Cr) (VI) on the liver and kidney structure of mature male mice weighing 20-30 g, (10 -13 weeks old), were treated orally with different doses (20, 40 and 60 mg/kg of NiCl 2 and 20, 60 and 100 mg/kg of K2Cr2O7). Dramatic Histopathological changes found in the liver and ki ney of treated animals included degeneration, nuclear pycnosis, cellular swelling,necrosis, conge stion of blood vessels and many others defects . روكذ يف ةيلكلاو دبكلا ىلع مويساتوبلا تامورك يئانثو لكينلا ديرولك ةليقثلا نداعملل ةيجسنلا تاريغتلا ضيبلا نارئفلا ةصلاخلا ,ررضلا ةديدش ةيئيبلا تاثولملا نم ةليقثلا نداعملا ربتعت .ةرحلا روذجلا ديلوت كلذكو ةنطرسمو ةماس رصانع دعي موركلاو لكينلا ثادحإب اوفرعو ريثأت دبكلا ,سفنتلا زاهج ,رثاكتلا زاهج, ةثارولا, يبصعلا زاهجلا, يعانملا زاهج , مدلل ماس ةساردلا يف .ةيلكلا و ظا ةيلاحلا جئاتنلا تره ريثأتلا ةيلكلاو دبكلل يجسنلا بيكرتلا ىلع ماسلا ) ةغلابلا ضيبلا نارئفلا روكذ يف 20 30 ) رمعو (مغ 10 13 ثيح(عوبسا تلموع مفلا ةطساوب ) نيرصنعلا نم ةفلتخم تاعرجب 20,40 , 60 و لكينلا ديرولك رصنع نم مغك/مغلم 20,60 , 100 تاناويحلل ةيلكلاو دبكلا بيكارت يف تدجو ةريثم ةيجسن تاريغت .مويساتوبلا تامورك يئانثو رصنع نم مغك/مغلم ذكو رخنت , ايلاخلا خافتنا ,ةيومدلا ةيعولاا ناقتحا ,سكنت تنمضت ةلماعملا كا كل .ةيونلاا زانت Introduction:

Determination method of activated humic acid

Abstract: The invention provides a determination method of activated humic acid, and particularly relates to an activated humic acid content determination method of humic acid composite fertilizer, humic acid compound fertilizer, and humic-acid-contained compound fertilizer; the activated humic acid includes activated brownish black humic acid and activated fulvic acid, wherein the content of the activated brownish black humic acid is determined by a method of dissolution of citric acid-sodium citrate mixing fluid, acid settlement, alkali dissolution, and then by potassium dichromate oxidization; the content of activated fulvic acid is determined by a method of dissolution of citric acid-sodium citrate mixing fluid, acid settlement, filter liquid resin absorption, NaOH absorption, and potassium dichromate oxidization; the sum of the tested contents of activated brownish black humic acid and activated fulvic acid is the content of humic acid. The method has the advantages of being simple in operation, high in accuracy, and capable of meeting the operation demand of the most enterprises and quality inspection units while controlling the testing bias well.

Pathology of experimentally induced acute toxicity of potassium dichromate in Wistar rats (Rattus norvegicus)

Abstract: Potassium dichromate toxicity was induced in Wistar rats to study hematological, biochemical and histopathological alterations. Twelve Wistar rats weighing 200–250 g were divided into two equal groups, with one group (Group II) receiving potassium dichromate (K2Cr2O7) @ 25 mg/kg b. wt. orally by gavage as a single dose, and the other (Group I) serving as control was given normal diet. The rats were observed for 72 hours and sacrificed post treatment. Clinical signs such as dullness, depression and erection of hairs were observed in Group II rats. Haematology revealed significant (P<0.05) decrease in mean values of Hb, PCV and TEC and significant (P<0.05) increase in mean values of TLC in rats of treatment group. A significant (P<0.05) rise in mean values of plasma creatinine, urea nitrogen, ALT, AST and ALP was recorded in group II rats. Pathological changes comprised of congestion, hemorrhages, degeneration and necrosis in visceral organs. The lesions were prominent and severe in kidneys followed by liver.

Influence of potassium dichromate-zn2+ system on corrosion inhibition of rebar steel in simulated concrete pore solution

Abstract: The inhibition efficiency (IE) of Potassium dichromate - Zn 2+ system in controlling corrosion of rebar steel in Simulated Concrete Pore Solution (SCPS) prepared in well water in the absence and presence of Zn 2+ has been investigated by mass loss study. It can be seen from the data obtained that formulation consisting of 250 ppm of K 2 Cr 2 O 7 and 50 ppm of Zn 2+ provides 98 % of inhibition efficiency. Inhibition was found to increases with an increasing concentration of Zn 2+ . Polarization study confirms the formation of inhibitor film formed on the rebar steel surface. The nature of the protective film formed on the rebar steel surface was examined by UV-Visible, FTIR, CV, SEM, Edx and AFM spectral studies. The results obtained shows that the K 2 Cr 2 O 7 could serve as an effective inhibitor for the corrosion of rebar steel in simulated concrete pore solution.

Method for determining ferric oxide in silica

Abstract: The invention relates to a method for determining ferric oxide in silica. The method comprises the following steps: a silica sample is weighed and dissolved in sulfuric acid and phosphoric acid mixed acid, most ferric iron is reduced with stannous chloride in hydrochloric acid media, titanium(III) chloride is added dropwise to reduce residual ferric iron into ferrous iron with sodium tungstate as an indicator, and excessive titanium(III) chloride is oxidized with potassium dichromate; a potassium dichromate standard solution is used for titration with sodium diphenylamine sulfonate as an indicator; a blank control group test is performed, and the content of ferric oxide in silica is calculated. The method has the advantages that the operation is rapid and efficient and the result is accurate and stable.

Method and reagent composition for measuring chemical oxygen consumption in water

Abstract: The invention relates to the technical field of water analysis, in particular to a method and reagent composition for measuring chemical oxygen consumption in water The method for measuring the chemical oxygen consumption in the water comprises the steps that 1, a water sample to be measured and a reagent I are mixed, the reagent I contains potassium dichromate, concentrated sulfuric acid and a catalyst, the concentration of potassium dichromate ranges from 0062 g/L to 137 g/L, and the sample introduction volume of the reagent I is smaller than or equal to 5 mL; 2, the obtained mixture is decomposed at the temperature higher than 90 DEG C; 3, the chemical oxygen consumption in the water is obtained through calculation According to the method and the reagent composition, the precision and accuracy of the chemical oxygen consumption detecting result can be effectively improved, meanwhile, the sample introduction volume, especially the sample introduction volume of concentrated sulfuric acid can be effectively reduced, and a water sample with high chemical oxygen consumption concentration can be detected The method and the reagent composition can be especially suitable for a micro sample introduction mode, and the smaller the sample introduction volume is, the more obvious the advantages of the method and the reagent composition are

Preparation of Potassium Dichromate Crystals from the Chromite Concentrate by Microwave Assisted Leaching

Abstract: In the present investigation, the oxidizing roasting process of chromite with sodium carbonate to prepare potassium dichromate crystals was studied in the microwave field with air, by heating the chromite and sodium carbonate. The chromite and sodium carbonate heated separately at 1000 °C in the microwave oven (frequency: 2.45 GHz; power 1.5 kW) in order to study the microwave absorption properties. The dielectric constant and dielectric loss factor of the chromite and sodium carbonate examined. Then, chromite with sodium carbonate taken in (1:2) ratio and heated at 750 °C. Thus obtained samples were characterized using various techniques includes Powder-XRD (XRD), Scanning Electron Microscopy (SEM), and X-ray fluorescence (XRF). The XRD pattern reveals the existence of Fe3O4, Fe2O3, NaAlO2, and Na2CrO4. The iron and aluminum were leached out as Fe2O3 and Al(OH)3 respectively. The resulting sample treated with the KCl to prepare potassium dichromate crystals. Finally, potassium dichromate crystals formed.

Industrial sewage treatment agent

Abstract: The invention relates to an industrial sewage treatment agent. The industrial sewage treatment agent is prepared from the following ingredients: polyethyleneimine, mercaptobenzothiazole, octyl phenol polyoxyethylene ether, benzotriazole, ethanolamine, sorbic acid, ammonium dodecyl dimethyl benzyl bromide, isothiazolinone, sodium persulfate, potassium dichromate, aluminum sulfate, potassium sulfite, copper sulfate, sodium gluconate, sodium triphosphate, sodium sulfite, sodium dodecyl sulfonate, cassava starch, active methylsilicone oil, hexamethyl phosphoramide, pentadecanol, glyceryl stearate, L-aspartic acid, propylene oxide, citrulline, ethylene glycol bis(2-aminoethyl ether)tetraacetic acid, dibenzoyl peroxide, gamma-mercaptopropyl trimethoxysilane, inulase, hydroxypropyl methylcellulose and deionized water. According to the product disclosed by the invention, the reaction rate is high, no toxic and harmful gas is produced in a process; the reacted product is stable and cannot be re-decomposed into toxic substances; the product is efficient and non-toxic and is safe to human before and after a reaction; and the sewage treatment efficiency is high.

Method for preparing potassium dichromate crystals by chromic iron ores in microwave field

Abstract: The invention relates to a method for preparing potassium dichromate crystals by chromic iron ores in a microwave field, and belongs to the technical field of chromium salt preparation. The method includes the steps: firstly, uniformly mixing chromic iron ore powder with the particle size smaller than 0.75 micrometer and sodium carbonate solids, heating to the temperature of 750 DEG C by the aid of microwaves, performing reaction for more than 60 minutes, and naturally cooling mixture to the indoor temperature after reaction to obtain oxidizing roasting products; grinding the obtained oxidizing roasting products to powder, adding water to ultrasonically leach to obtain sodium chromate solution, and filtering the sodium chromate solution to remove impurity Fe2O3 solids; continuing to add CH3COOH into the sodium chromate solution removed the impurity Fe2O3 solids to adjust pH (potential of hydrogen) to be smaller than 5, adding KCl solids, performing evaporation and contraction, and filtering, washing and drying cooled crystals to obtain the potassium dichromate crystals. The method is low in reaction temperature and short in technological process, and the conversion rate of chromium is high.

Method for coloring and anodic oxidation of metal surface

Abstract: The invention provides a method for coloring and anodic oxidation of a metal surface. The method comprises the following steps: (1) a part to be machined is cleaned; (2) the anodic oxidation is performed; (3) the part to be machined is dipped in potassium dichromate solution for primary closing treatment after cleaning; the concentration of the potassium dichromate solution is 8 g/L; the temperature of the primary closing treatment is 120 DEG C; and the time of the primary closing treatment is 30 min; (4) the coloring treatment is performed under the condition of existing iron oxalate salt; and (5) the secondary closing treatment is performed to obtain a colored aluminum alloy. The treated workpiece is excellent in wear resisting effect, long in service life and wide in application range.