35 results about "Potassium chromate" patented technology

The invention belongs to the technical field of crystal defect testing, and particularly relates to an FPD testing method for a monocrystalline silicon wafer micro-viewpoint defect, which comprises the following steps: accurately cutting off the head and the tail of a silicon rod to eliminate an end defect, and preparing a pure substrate by adopting an A-surface machine grinding / B-surface maintaining asymmetric treatment and segmented cleaning process; after pretreatment with a specifically proportioned corrosive liquid, carrying out temperature-controlled etching by using potassium dichromate-hydrofluoric acid to form a characteristic V-shaped pattern on the surface, and realizing visual identification by corresponding different defects to different patterns; gridding detection points are designed based on stress distribution, laser positioning coordinate mapping is performed, an imaging-correction-noise reduction-segmentation-intelligent classification algorithm chain is constructed to realize full-automatic detection, and a detection-analysis-optimization full-process data driving quality control system is established through visual data such as a thermodynamic diagram and a type matrix. And large-scale production of semiconductor silicon wafers is supported.

The present application relates to a special coating for water-cooled wall surface of coal-fired boiler, in particular to a coating for water-cooled wall surface of coal-fired boiler, a preparation method and application thereof. The coating comprises nano-tungsten powder, tungsten carbide, rare earth compound, sodium borate, potassium chromate, rock asphalt, binder, modifier, dispersant, defoaming agent, curing agent and solvent. The coating is fused on the water-cooled wall surface of coal-fired boiler, the obtained coating has good interface bonding with the water-cooled wall base material, low porosity, avoids the penetration of corrosive gas and liquid, solves the corrosion problem of water-cooled wall, and also avoids the reduction of coating hardness and wear resistance; the coating is not easy to wear and damage in long-term use, can improve the high-temperature resistance, hardness, corrosion resistance and wear resistance of the water-cooled wall surface of boiler, effectively prolongs the service life of the water-cooled wall surface of boiler, and further ensures the safe and stable operation of coal-fired boiler.

The invention discloses a fluoride-salt-free and nitrate-free steel plate enamel high-temperature titanium creamy yellow cover glaze as well as a preparation method and application thereof, and belongs to the technical field of enamel. The cover glaze is prepared from quartz, anhydrous borax, rutile, potassium feldspar, trisodium phosphate, potassium carbonate, potassium dichromate and zinc oxide according to a specific mass ratio. The preparation method comprises the following steps: mixing the raw materials, melting at 1300 + / -10 DEG C in a pure oxygen environment, and quenching after wiredrawing to detect a molten state. The overglaze completely avoids the use of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are solved from the source, the fluorine content of the product is not detected through detection, the product meets the European Union REACH regulation limit value requirements, and meanwhile, the overglaze has good hue, luster and firing adaptability, is suitable for a steel plate matrix, has the firing temperature of 840-880 DEG C and the firing time of 820-830 minutes, and has good application prospects. The method can be used for producing green and environment-friendly enamel products.

The invention provides a method and device for detecting chlorine components in an oilfield chemical agent and application, and the method for detecting the chlorine components in the oilfield chemical agent comprises the following steps: pretreating a sample, and extracting the total chlorine components in the sample to obtain a to-be-detected solution containing the total chlorine components of the sample; mixing a potassium chromate aqueous solution with the to-be-detected solution; diluting the silver nitrate aqueous solution into a standard working solution with a concentration gradient; dropwise adding the standard working solution into the to-be-detected solution according to the concentration sequence from low to high until the color of the solution is just changed; and recording the consumption drop number of the standard working solution under each concentration so as to calculate the total chlorine component content. According to the method, a series of standard working solutions diluted by the silver nitrate aqueous solution with the concentration gradient are prepared, so that the measuring range is enlarged, the method is suitable for detecting the oilfield chemical agents with different chloride ion concentrations, and the chlorine content in the oilfield chemical agents can be rapidly detected.

The invention discloses a method for measuring dissolved oxygen in aquaculture tail water by a spectrophotometric method based on an iodine-ascorbic acid-potassium dichromate system, and belongs to the technical field of water quality detection. The method comprises the following steps: sequentially adding a manganese sulfate solution and an alkaline potassium iodide solution into a to-be-detected culture tail water sample, sealing a container, fully reacting, and standing after the reaction is finished to completely precipitate Mn2O3; adding a citric acid solution, sealing, reacting, completely dissolving the precipitate and releasing the iodine elementary substance, adding water and an ascorbic acid-potassium dichromate mixed color developing agent into the solution after the reaction is finished, fixing the volume, sealing, uniformly mixing, and carrying out a color developing reaction in a dark place; a blank sample is used for reference, the culture tail water subjected to color development is placed in a sample pool of a spectrophotometer, the spectrophotometric value of the sample is measured at the wavelength of 360 nm, and the dissolved oxygen concentration is calculated according to a standard curvilinear equation. The method provided by the invention reduces the detection limit of the traditional spectrophotometric method, and has the advantages of high sensitivity, strong anti-interference capability, high speed and rapidness in operation, wide application range, greenness and environmental protection.

The embodiment of the invention relates to a method for measuring the chloride ion concentration in water-based drilling fluid, which comprises the following steps: acquiring the voltage of a chloride ion sensor in various standard liquids with known concentrations at a preset constant temperature, and establishing a calibration corresponding relation between the voltage and the chloride ion concentration; diluting a to-be-detected water-based drilling fluid sample into a to-be-detected mixed solution according to a fixed proportion; and maintaining the to-be-measured mixed solution at the constant temperature, measuring the voltage of the to-be-measured mixed solution by using a chloride ion sensor, determining the concentration value of the to-be-measured mixed solution based on the calibration corresponding relation, and calculating the actual chloride ion concentration value of the water-based drilling fluid by combining the fixed proportion. According to the embodiment, a traditional chemical titration agent is abandoned, the potential safety hazard that an operator makes contact with toxic strong acid and carcinogenic potassium chromate is eliminated, the water-based drilling fluid to be detected is adjusted to the optimal linear range of a chloride ion sensor through quantitative dilution, and the detection efficiency and timeliness are greatly improved.

The application discloses a steel plate enamel high-temperature titanium milk yellow face glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The face glaze is prepared from quartz, zero-water borax, rutile, potassium feldspar, trisodium phosphate, potassium carbonate, potassium dichromate and zinc oxide according to specific mass proportions. The preparation comprises raw material mixing, smelting at 1300+ / -10 DEG C under a pure oxygen environment, and rapid cooling after wire drawing detection of the smelting state. The face glaze completely avoids the use of fluorinated salt and nitrate, eliminates fluorine emission and environmental protection equipment blockage problems from the source, the fluorine content of the product is not detected through detection, meets the limit value requirements of the EU REACH regulation, has good color, gloss and firing adaptability, is suitable for a steel plate substrate, has a firing temperature of 840-880 DEG C, and can be used for the production of green and environmentally-friendly enamel products.

The application discloses a kind of light absorption material glass for high-definition ultra-short inverter and preparation method thereof, and the light absorption material glass includes the following weight percentage components: quartz sand 40-50%, boric acid 6-12%, alumina 7-15%, sodium carbonate 1-10%, potassium carbonate 1-10%, lithium carbonate 0-2%, basic magnesium carbonate 0-3%, calcium carbonate 0-5%, barium nitrate 1-3%, zirconium oxide 0-3%, copper oxide 1-3%, potassium permanganate 3-6%, potassium chromate 0.2-1%, diiron trioxide 1-5%, cobalt trioxide 1-6%, nickel oxide 1-6%, vanadium pentoxide 1-6%, cerium oxide 0-1%. The light absorption material glass of the application is used for preparing ultra-short inverter, which can effectively improve the transmittance and resolution of ultra-short inverter.

The invention relates to the technical field of chemical analysis, and relates to a method for measuring the content of an iron phase in iron-containing dust slime, which comprises the following steps: 1, preparing an iron-containing dust slime sample, and carrying out ball milling processing on the iron-containing dust slime to obtain an iron phase sample; 2, weighing an iron phase sample A0, placing the iron phase sample A0 in a container, adsorbing magnetic substances in the iron phase sample A0 by adopting a magnet, respectively weighing the adsorbed magnetic substance A1 and the remaining sample A '0, and detecting the content of magnetic metal iron in the magnetic substance A1 by utilizing a potassium dichromate method; step 3, mixing the residual sample A '0 with anhydrous sodium carbonate according to a mass fraction ratio of 1: (2-5), marking the mass fraction ratio of the anhydrous sodium carbonate to the residual sample A' 0 as k, and marking the fully ground and uniformly mixed sample as A '' 0; respectively detecting the contents of wFe < 1 >, wFe < 2 > and wFe < 3 > in the weighed uniformly mixed sample by using a potassium dichromate method; and 4, carrying out normalization calculation on the content results obtained in the step 2 and the step 3 to finally obtain the contents of total iron (TFe), metallic iron (MFe), ferrous iron (Fe < 2 + >) and ferric iron (Fe < 3 + >) in the iron phase sample A0.

The invention discloses fluoride-salt-free and nitrate-free low-temperature titanium creamy yellow surface glaze for steel plate enamel as well as a preparation method and application of the surface glaze, and belongs to the technical field of enamel. The cover glaze is prepared from quartz, borax anhydrous, trisodium phosphate, titanium dioxide, potassium feldspar, magnesium carbonate, potassium carbonate, potassium dichromate and zinc oxide according to a specific mass ratio. The preparation method comprises the following steps: mixing the raw materials, melting at 1300 + / -10 DEG C in a pure oxygen environment, and quenching after wiredrawing to detect a molten state. The overglaze completely avoids the use of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are solved from the source, the fluorine content of the product is not detected through detection, the limit value requirement of the European Union REACH regulation is met, meanwhile, the overglaze has good hue, luster and firing adaptability and is suitable for a steel plate matrix, the firing temperature is 760-800 DEG C, and the firing time is 2-3 hours. The method can be used for producing green and environment-friendly enamel products.

The invention discloses a preparation method of a high-entropy oxide catalyst for CO2 hydrogenation, and belongs to the field of catalyst preparation. Comprising the steps that hydrated salt particles of Co, Ni, Cu and Zn are selected and put into a ball mill to be evenly ground for 30 min; adding alkaline sylvite to provide an alkaline environment for the catalyst system, and continuously grinding for a period of time; adding potassium chromate and an oxidation catalyst system, continuously grinding for a period of time to oxidize Co < 2 + > into Co < 3 + >, and reducing the potassium chromate into an oxide; and washing the ground product with a solvent to prepare the CoCrNiCuZnOx catalyst. The preparation method has the beneficial effects that mechanochemical synthesis is carried out by adopting a ball milling method, the catalyst can be prepared only through room-temperature grinding and subsequent washing steps, the requirement of high-temperature calcination is avoided, and the energy consumption and the cost are remarkably reduced. The method is simple, efficient and suitable for large-scale commercial production.

The invention belongs to the technical field of nano materials, and particularly relates to a preparation and transfer method of an inclined chromic oxide single-crystal nanosheet. The preparation method specifically comprises the following steps: uniformly mixing potassium chromate and chromic chloride to obtain precursor powder; transferring the precursor powder into a porcelain boat, and covering the surface of the precursor powder with a molecular sieve; enabling the oxide layer of the SiO2 / Si substrate to face downwards and obliquely cover the molecular sieve; and then transferring into a vacuum tube furnace, heating and reacting, and cooling to obtain the inclined chromic oxide single crystal nanosheet on the surface of the SiO2 / Si substrate. The inclined chromium oxide single crystal nanosheet is placed on other clean substrates, and the chromium oxide single crystal nanosheet is transferred to other clean substrates through mechanical pressing. The method provided by the invention has the advantages of good controllability, good repeatability, high yield, low cost, no pollution in transfer and the like.

This invention discloses a method for degreasing ceramic packing, relating to the field of degreasing technology. The method involves preparing a degreasing solution, injecting it into the packed tower, and circulating it using a reflux pump. The degreasing solution includes sulfuric acid, potassium dichromate, and hydrogen peroxide. This invention employs an innovative degreasing solution that effectively removes siloxanes from the surface of the ceramic packing, significantly improving clogging and eliminating clogging issues after a period of use, thus meeting production requirements.

The invention discloses a fluoride-salt-free and nitrate-free medium-temperature titanium creamy yellow overglaze for steel plate enamel as well as a preparation method and application of the overglaze, and belongs to the technical field of enamel. The cover glaze is prepared from quartz, anhydrous borax, rutile, potassium feldspar, magnesium carbonate, trisodium phosphate, calcium carbonate, potassium dichromate and zinc oxide according to a specific mass ratio. The preparation method comprises the following steps: mixing the raw materials, melting at 1300 + / -10 DEG C in a pure oxygen environment, and quenching after wiredrawing to detect a molten state. The overglaze completely avoids the use of fluoride salt and nitrate, eliminates the problems of fluoride emission and environmental protection equipment blockage from the source, the fluorine content of the product is not detected through detection, the product meets the European Union REACH regulation limit value requirements, has good hue, luster and firing adaptability, is suitable for a steel plate matrix, has the firing temperature of 800-840 DEG C and the firing time of 20-30 minutes, and can be widely applied to the production of steel plates. The method can be used for producing green and environment-friendly enamel products.

The application discloses a steel plate enamel medium-temperature titanium milk yellow face glaze free of fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The face glaze is prepared from quartz, zero-water borax, rutile, potassium feldspar, magnesium carbonate, trisodium phosphate, calcium carbonate, potassium dichromate and zinc oxide according to specific mass proportions. The preparation comprises raw material mixing, smelting at 1300+ / -10 DEG C under a pure oxygen environment, and rapid cooling after wire drawing detection of the smelting state. The face glaze completely avoids the use of fluorinated salt and nitrate, eliminates fluorine emission and environmental protection equipment blockage problems from the source, the fluorine content of the product is not detected through detection, meets the limit value requirements of the EU REACH regulation, has good color, gloss and firing adaptability, is suitable for a steel plate substrate, has a firing temperature of 800-840 DEG C, and can be used for the production of green and environmentally-friendly enamel products.

A method for measuring the ferrous iron content in a laterite nickel ore, comprising the following steps: (1) decomposing a laterite nickel ore sample by using a first mixed acid solution to obtain a sample solution; (2) mixing a second mixed acid solution and the sample solution, and dropwisely adding sodium diphenylamine sulfonate to the obtained mixed solution as an indicator; (3) titrating the mixed solution by using a potassium dichromate standard solution, a titration endpoint being reached when the color of the solution changes to purple blue; and (4) calculating the ferrous iron content in the laterite nickel ore sample on the basis of the consumption amount of the potassium dichromate standard solution, wherein the first mixed acid solution in step (1) comprises a sulfuric acid solution and a hydrofluoric acid solution, and the second mixed acid solution in step (2) comprises a sulfuric acid solution, a phosphoric acid solution and a boric acid solution.

The invention discloses a method for manually detecting chlorine ion content in gas water. The method comprises the following steps: acquiring to-be-detected gas with a certain volume; introducing the coal gas to be detected into a potassium hydroxide solution until no new precipitate is generated; filtering by using quick quantitative filter paper until the water is clear and has no obvious color; transferring the filtered liquid into a 250mL conical flask, adding two drops of phenolphthalein indicator, and adjusting the pH value by using a nitric acid solution until the pH value is just changed to be colorless from red; and adding a potassium chromate indicator, and titrating with a silver nitrate standard titration solution until brick red appears. Through the systematic pretreatment and manual titration steps, the chlorine ion content in the gas water can be rapidly, accurately and reliably measured; the time of the whole process is controlled within 30 minutes from sampling to titration completion; the pretreatment and determination time required by traditional manual titration is greatly shortened.

The invention discloses a method for determining the content of free chlorine in a chlorine-containing organic matter, which comprises the following steps: a) mixing a sample to be detected with the volume of V sample and a water-insoluble organic solvent to form a mixed organic phase, then adding a water phase containing neutral salt or a phosphate buffer solution with the pH value of neutral with the volume of V water, and oscillating; b) after standing and layering, separating a water phase; c) adding a potassium chromate indicator into the water phase with the volume of Vwater ', titrating with a silver nitrate standard solution with the concentration of C until the water phase becomes red, and recording the volume V of the consumed silver nitrate standard solution; d) blank test: under the condition of not adding the sample, repeating the steps a) to c), and recording the volume V0 of the consumed silver nitrate standard solution; and e) substituting the obtained V sample, V water, V water ', C, V0 and V into the following formula to calculate the free chlorine content WCl. According to the method, through a specific organic medium environment, effective separation of free chlorine and main interferents is realized, and the determination is accurate.

The invention discloses a device and a method for on-line measurement of chloride ions in sewage of a urea hydrolyzer, an outlet of a first sampling valve is communicated with a reaction center through a coil cooler, a filter tube, a cation exchange column and a reverse osmosis unit in sequence, and a luminescent tube is arranged on one side in the reaction center; a color sensor is arranged on the other side in the reaction center; an outlet of the second demineralized water reagent bottle, an outlet of the phenolphthalein indicator reagent bottle, an outlet of the nitric acid solution reagent bottle, an outlet of the sodium hydroxide solution reagent bottle, an outlet of the potassium chromate solution reagent bottle and an outlet of the silver nitrate standard solution reagent bottle are communicated with an inlet of the multi-channel switching valve, and an outlet of the multi-channel switching valve is communicated with the reaction center; according to the device and the method, the chloride ion concentration in the sewage of the urea hydrolyzer can be measured on line.

The invention relates to a method for selectively and efficiently separating and recovering chromium from vanadium and chromium slag leaching liquid. According to the technical scheme, the method comprises the steps that vanadium and chromium slag sub-molten salt is subjected to alkaline leaching, and vanadium and chromium slag leaching liquid is obtained; and the vanadium and chromium slag leaching solution is put into an evaporation device to be evaporated and concentrated, and the vanadium and chromium slag alkaline leaching concentrated solution is obtained. Putting the vanadium and chromium slag alkaline leaching concentrated solution into a crystallizer, adding a potassium-containing additive into the vanadium and chromium slag alkaline leaching concentrated solution, and carrying out reaction, solid-liquid separation and washing under a first stirring condition to obtain potassium sodium chromate crystals and a post-crystallization solution; dissolving the potassium sodium chromate crystal to obtain a potassium sodium chromate solution, and adjusting the pH value with sulfuric acid; and adding sodium sulfite into the potassium sodium chromate solution, reacting under a second stirring condition, and carrying out solid-liquid separation to obtain a chromium hydroxide solid. And calcining the chromium hydroxide solid to obtain chromium sesquioxide. The method has the characteristics of simple process, low cost, strong adaptability and environmental friendliness, is suitable for the vanadium-chromium-containing solution with high strong alkalinity, and is good in vanadium-chromium separation effect and high in chromium recovery rate.

The invention discloses a method for quantitatively determining cellulose in a plant sample. The process comprises a series of precise steps for extracting and measuring the cellulose content, and calibration is carried out by using a standard starch curve. Initially, a plant leaf sample is freeze-dried at a temperature of-30 DEG C to-40 DEG C for at least 3 days to ensure complete freezing, and then ground and screened through a 40-60 mesh screen. And then storing the dried sample at-20 DEG C for further use. 0.05 g of a dried sample is transferred into a 50 ml centrifugal tube, and 10 ml of acetate-nitrate is added into the centrifugal tube; putting the mixture into a boiling water bath, heating for 25 minutes, and stirring; after heating, centrifuging a sample at 8000rpm for 15 minutes, and then washing with deionized water; and adding a potassium dichromate-sulfuric acid mixture to further treat the sample. A series of starch standard substances are prepared and are subjected to similar treatment with plant samples, and a cellulose quantitative standard curve is established. And finally, measuring the absorbance of the sample liquid at 610nm by using an ultraviolet spectrograph, so as to determine the cellulose content according to the prepared standard curve. The method provides a reliable, accurate and repeatable method for quantifying cellulose in plant tissues.

The invention discloses a chloride ion-free esterified fiber micro-smoke firecracker medicament and a preparation method thereof. Comprising sodium bicarbonate, potassium hydroxide or sodium hydroxide, castor oil, methyl acetate, ethyl formate, ferrocene, manganese dioxide, potassium dichromate and corncob powder fibers. The invention relates to an environment-friendly environment-friendly detergent, which is characterized by comprising 15-25 parts by weight of sodium bicarbonate, 4-10 parts by weight of potassium hydroxide or 8-12 parts by weight of sodium hydroxide, 12-22 parts by weight of castor oil, 25-35 parts by weight of methyl acetate, 25-35 parts by weight of ethyl formate, 6-8 parts by weight of potassium dichromate, 10-22 parts by weight of ferrocene, 2-5 parts by weight of manganese dioxide, 100-200 parts by weight of corncob fiber, and 6-8 cubic meters of water. The preparation method comprises the following steps: crushing a fiber coarse material, soaking in a pool, boiling, rinsing, carrying out centrifugal spin-drying, air-drying, squeezing, distilling, carrying out esterification reaction, adding elements such as potassium, sodium, iron, manganese and the like, sieving, mixing and the like to prepare a finished product. The invention has the advantages of no chlorine salt and sulfide, slight smoke, no toxicity, no pungent smell, no harm to human body, safety, environmental protection and the like.

The invention relates to a method for measuring iron content in a sodium ferric phosphate material, which comprises the following steps: weighing a sodium ferric phosphate material sample to be measured, adding carbon quantum dots, and uniformly grinding to obtain mixed powder; adding the mixed powder into a hydrochloric acid solution, heating for dissolving, cooling to room temperature after the powder is completely dissolved, and filtering to obtain filtrate to be detected; adding a sodium tungstate indicator into the filtrate to be detected, then adding a titanium trichloride solution until the solution becomes stable light blue, and then adding a potassium dichromate standard solution until the light blue disappears and the solution becomes colorless; adding sulfur-phosphorus mixed acid and a sodium diphenylaminesulfonate indicator into the colorless solution, titrating by using a potassium dichromate standard solution until the solution is kept in a light purple state for more than 30 seconds and does not fade, and recording the volume V of the potassium dichromate standard solution consumed by titration; and calculating the iron content according to a formula. According to the method disclosed by the invention, iron in the sodium ferric phosphate material can be rapidly detected, and the accuracy is high.

This application relates to the field of environmental monitoring and water quality analysis technology, and in particular to a mixed reagent, test reagent tube, and digestion method for COD detection of petrochemical wastewater. The components, by mass percentage, are: sulfuric acid 75.0–90.0%, potassium dichromate 0.5–1.0%, silver sulfate 1.0–2.7%, scandium sulfate 0.01–0.07‰, potassium hydrogen phthalate 0.1–0.25‰, glucose 0.1–0.25‰, with the remainder being pure water; the mixed reagent does not contain mercuric sulfate. This application enables mercury-free and highly efficient digestion of high-salt, high-organic-content petrochemical wastewater, improves the oxidation efficiency of benzene compounds and polycyclic aromatic hydrocarbons, reduces the detection limit to below 5 mg / L, and the wastewater is easy to treat, combining high accuracy with environmental friendliness.

The invention discloses purple ceramic ink as well as a preparation method and application thereof. The purple ceramic ink is prepared from the following raw materials: metastannic acid, light calcium carbonate, quartz powder, potassium dichromate, calcium fluoride, potassium chromate, a solvent and a dispersing agent. When the purple ceramic ink is used for preparing domestic porcelain, bright purple can be generated, the color development effect is good, and the color development requirement of the domestic porcelain can be met.

An in-situ detection method for the oxalic acid content in rhizosphere soil according to an embodiment of the present invention includes: preparing a substrate solution by using sulfuric acid, rhodamine, potassium dichromate / potassium bromate; mixing oxalic acid with the substrate solution to obtain fluorescent standard substances with different oxalic acid concentrations and soaking different fiber membrane media to obtain first fiber membrane media at different oxalic acid concentrations; excavating a soil profile for in-situ cultivation of root plants; after culturing for a period of time, covering the rhizosphere soil with another fiber membrane media soaked in the substrate solution and continuing in-situ cultivation to obtain a second fiber membrane media after in-situ cultivation; respectively performing fluorescence spectral imaging on each of the first fiber membrane media and the second fiber membrane media; fitting a linear regression equation by using the imaging photos of the first fiber membrane media; substituting the gray values of each pixel in the imaging photo of the second fiber membrane media into the linear regression equation to generate a two-dimensional spatial distribution of the oxalic acid concentration in the rhizosphere soil.

The invention provides a flower-like Bi2CrO6 oxygen production photocatalyst and a preparation method thereof, and belongs to the technical field of photocatalytic material preparation. According to the preparation method, bismuth nitrate and potassium chromate are taken as raw materials, and microwave heating is carried out at a relatively low temperature (100 DEG C), so that the reaction can be completed within 2 hours. The preparation method disclosed by the invention is mild, low in energy consumption, simple, rapid and energy-saving, and experimental equipment is provided. The prepared bismuth chromate photocatalyst sample is uniform in size, has a large specific surface area and rich active sites, and has higher catalytic activity due to the fact that the sheet thickness is reduced and the migration distance of electrons and holes from the interior of a semiconductor to the surface is shortened.

This invention relates to the field of photocatalysts, and more particularly to a Bi8(CrO4)O 11 Preparation and application of photocatalysts. In this invention, a yellow transparent potassium chromate solution is added dropwise to a white emulsion of bismuth nitrate pentahydrate, and the mixture is continuously stirred to obtain an orange-yellow emulsion. This emulsion is then transferred to a reaction vessel and reacted at 160–190 °C for 6–12 h. After natural cooling to room temperature, an orange-red precipitate is obtained. The precipitate is filtered, collected, thoroughly washed with deionized water, and then freeze-dried to obtain orange-red Bi8(CrO4)O. 11 Photocatalyst. The Bi8(CrO4)O prepared in this invention... 11 Photocatalysts, with suitable band positions, can efficiently generate ·OOH with moderate oxidizing power as the main active species, and have excellent performance in inhibiting the over-oxidation of intermediate products in continuous reactions.

Methods and compositions for rapid verification of cleaning performance on surfaces in cleaning-in-place (CIP) systems and in cleaning-in-place (COP) systems and in high flow areas. The solution comprises alkali metal hydroxide; one or more oxidizing compounds, wherein the one or more oxidizing compounds comprise sodium hypochlorite, potassium hypochlorite, sodium persulfate, potassium persulfate and monopersulfate; and one or more compounds selected from the group consisting of potassium permanganate, sodium permanganate, potassium dichromate, and sodium dichromate. In some examples, the solution also includes potassium tripolyphosphate, sodium tripolyphosphate, or other tripolyphosphate. The substrate is in contact with the solution, and a chromogenic reaction may occur indicating the presence of an organic substance or non-organic contaminant. The chromogenic reaction may occur within less than 30 minutes and at a temperature of 10 DEG C to 60 DEG C.

Systems and processes for the determination of chloride in water using an automatic chloride titration. The system includes a solenoid valve that controls the flow of titrate from a titrate container, a color sensor, and a microcontroller. During titration of a silver nitrate solution, the color sensor detects the intensity of color in a sample container having a water sample and a color indicator such as potassium chromate. When a specific color intensity appears in the sample container, the microcontroller receives a signal from the color sensor and sends a signal to the solenoid valve to stop the flow of titrate from the titrate container.