77 results about "Potassium dichromate" patented technology

The invention relates to the technical field of multi-water quality analysis, in particular to a full-automatic water quality COD analysis method and device.The method comprises the steps that an absorbance spectrogram and electrochemical characteristics of a target water sample in a first preset wave band are obtained, and an original signal set is generated; obtaining dynamic characteristics of fusion liquid of the target water sample and the potassium dichromate solution in a second preset wave band, and performing characteristic level fusion on the dynamic characteristics and the original signal set to generate a reaction characteristic set; manifold learning and feature optimization processing are carried out on the reaction feature set, and an optimized feature set is generated; performing hybrid neural network modeling processing according to the optimized feature set, and outputting a preliminary COD predicted value; and after the preliminary COD predicted value is corrected, a correction result is verified, and a COD analysis set is generated. According to the invention, multi-source signal data can be efficiently integrated and deeply optimized, and the defects of low analysis efficiency and accuracy caused by insufficient data processing capability in complex water sample analysis in the prior art are overcome.

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 belongs to the technical field of wastewater treatment, and discloses a method for treating electroplating wastewater by using bioreduction of biogas slurry and combined iron bio-oxidation, which is a secondary combined use technology for removing various heavy metals in electroplating wastewater by iron bio-oxidation, comprising the following steps: (1) collecting fermentation biogas slurry, and performing ultraviolet irradiation sterilization after aeration; (2) adding potassium dichromate solution and fresh nutrient solution to the sludge system, and culturing anaerobic sludge; (3) adding treated biogas slurry to the anaerobic sludge, and repeatedly domesticating chromium-reducing microorganisms; (4) configuring a mixed solution of comprehensive electroplating wastewater and biogas slurry according to a certain proportion; (5) building a primary treatment biological reactor, and reducing Cr(VI) in wastewater by anaerobic biological reduction under the promotion of pyrite; and (6) building a secondary biological reactor filled with straw biomass charcoal, and generating iron oxides under the action of functional bacteria to continue adsorbing Cd, Cu and Ni ions in wastewater.

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 relates to the technical field of slide processing. The invention discloses a slide treatment method for improving wall adhesion of 293T cells. The slide processing method comprises the following steps: preparing a cleaning solution; putting the slide into the cleaning solution, soaking, taking out the slide, washing the slide with deionized water, and putting the slide into a drying oven for drying; immersing the dried slide into PLL treatment liquid for 3-7 minutes, taking out and airing; wherein the cleaning solution is prepared from the following raw materials: potassium dichromate, water and concentrated sulfuric acid; the PLL treating fluid is poly-L-lysine with the mass concentration of 0.05%-0.15%, and the solvent is deionized water. The invention further discloses the slide prepared by the slide treatment method for improving the wall adhesion of the 293T cells. According to the slide treatment method, the adhesive force of the slide to 293T cells can be effectively improved, and the cell adherence is enhanced.

The application provides a method for detecting the titer of vitamin B12 in a fermentation liquor. The method comprises the following steps: preparing a potassium dichromate solution, a hydrochloric acid solution and a potassium dihydrogen phosphate solution, mixing the three solutions with the vitamin B12 fermentation liquor under certain conditions to generate cyanocobalamin, and then testing the titer of the cyanocobalamin by using a high performance liquid chromatography. The titer of the vitamin B12 detected by using the method is consistent with the titer detected by using a sodium cyanide method. The operation method greatly reduces the safety risk of an analyst caused by using the sodium cyanide, and the operation method is simple, easy to manage in a laboratory and can save the testing cost.

The invention belongs to the technical field of magnesium-aluminum magnesium alloy surface treatment, and particularly relates to a magnesium-aluminum alloy surface yellow ceramic film layer and a color control method thereof, and the method comprises the following steps: immersing a pretreated magnesium alloy into an electrolyte containing a coloring agent, and carrying out micro-arc oxidation to generate different yellow ceramic film layers on the surface of the magnesium-aluminum magnesium alloy; the coloring agent is one or two of potassium dichromate, potassium permanganate and anhydrous cupric sulfate; by adopting the method disclosed by the invention, uniform, smooth and compact ceramic film layers with different yellow colors can be generated on the surface of the magnesium-aluminum alloy. Six ceramic film layers with different yellow colors are prepared, the cost is low, the protection function and the decoration function can be achieved, and the requirements of different application scenes are met.

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 present invention relates to a reagent combination for determining the chemical oxygen demand (COD) in a liquid medium, wherein the reagent combination comprises a first reagent, wherein the first reagent is an acidic solution of mercuric sulfate (HgSO4); a second reagent, wherein the second reagent is an acidic solution containing potassium dichromate (K2Cr2O7); and a third reagent, wherein the third reagent is an acidic solution, characterized in that at least the second reagent or at least the third reagent also contains potassium aluminum sulfate (KAl(SO4)2·12H2O).

The application discloses a kind of aluminum lithium alloy passivation methods, the passivation aluminum lithium alloy is successively included from inside to outside, aluminum lithium alloy core, passivation layer growth film, passivation layer coating film;The sum thickness of the passivation layer growth film and the passivation layer coating film film is 1~1.5 μm;Specifically using potassium dichromate, using magnetic stirrer, forms the passivation film on the surface of aluminum lithium alloy;Aluminum lithium alloy can be added into solid propellant after passivation of the application.The application forms dense passivation film on the surface of aluminum lithium alloy, effectively prevents and insulates the influence of external water vapor on aluminum lithium alloy, maintains the stability of aluminum lithium alloy during storage and use.

The application discloses a testing method for the content of divalent iron ions in EDTA chemical cleaning solution, and aims at the problem that the existing titration method cannot accurately determine the content of divalent iron ions due to the interference of EDTA. Instead of adopting a complex separation step, the method eliminates the interference through two steps. First, the to-be-tested solution is adjusted to be acidic to weaken the complexing capacity of EDTA, and then a sulfur-phosphorus mixed acid solution is added. The strong acidity of sulfuric acid is used to inhibit the complexing reaction and avoid hindering titration. The whole process is based on the principle of titration method, and does not need expensive instruments and reagents, and is low in cost. The operation is simple and does not need professional skills. The application adopts the high-stability potassium dichromate standard solution, reduces the calibration frequency, realizes rapid, convenient, accurate and low-cost determination, and is suitable for on-site detection requirements.

The invention relates to the technical field of determination of chemical oxygen demand (COD) of a catalyst, in particular to a rapid COD determination method for an improved catalyst system, chemical oxygen demand (COD) serves as a key index for measuring the content of reducing substances in a water body, and the content of the reducing substances in the water body is determined through oxidation treatment of potassium dichromate. The amount of potassium dichromate consumed by the oxidized reducing pollutants in the water sample corresponds to the mass concentration of oxygen, and the measurement result directly reflects the pollution degree of the water body. COD is one of core parameters for water environment monitoring and treatment, a traditional COD determination method takes a potassium dichromate oxidation method as a reference, but has the problems of low reaction efficiency, long time consumption, incomplete oxidation caused by a single catalyst, weak anti-interference capability and the like, depends on manual operation, and is inconvenient to operate. In the prior art, the requirements of modern environment monitoring on rapidness, accuracy and automation are difficult to meet due to large reagent dosage and high secondary pollution risk, and for a complex water sample, a traditional method is easy to cause determination deviation and insufficient in data sharing and remote monitoring capability, so that the intelligent development of water environment monitoring is restricted.

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 invention discloses a method for manufacturing a reprinting mold, which comprises the following steps of: providing a patterned nickel layer with an optical holographic pattern; the patterned nickel layer is placed in a vacuum chamber with the pressure ranging from 10 <-3 > torr to 10 <-5 > torr, and oxygen plasma is introduced towards the patterned nickel layer in a plasma sputtering mode at the flow ranging from 80 sccm to 120 sccm, so that a plasma type oxide layer covering the optical holographic pattern is formed; forming an electroformed nickel layer on the plasma type oxide layer through electroforming; and separating the electroformed nickel layer from the patterned nickel layer and the plasma type oxide layer on the patterned nickel layer, so that a reprinting holographic pattern corresponding to the optical holographic pattern is formed on the electroformed nickel layer. Therefore, the plasma type oxide layer is formed under the specific implementation conditions (for example, oxygen plasma is introduced at the flow rate of 80-120 sccm) in the sputtering step, so that the plasma type oxide layer can be separated from the electroformed nickel layer under the condition that the structure is not damaged, and then a strong oxidant containing potassium dichromate is replaced.

The present invention relates to a reagent combination for determining chemical oxygen demand (COD) in a liquid medium, the reagent combination comprising a first reagent wherein the first reagent is an acidic solution of mercury sulfate (HgSO4); a second reagent, wherein the second reagent is an acidic solution comprising potassium dichromate (K2Cr2O7); and a third reagent, where the third reagent is an acidic solution, characterized in that at least the second reagent or at least the third reagent further comprises potassium aluminum sulfate (KAl (SO4) 212H2O).

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 provides a method for determining the resultant amount of elements in an iron-based sodium electric precursor based on the total iron content, and the method comprises the following steps: dissolving the iron-based sodium electric precursor by using an acid, then adjusting the pH value by using an alkali to precipitate iron ions so as to obtain an iron precipitate, and then dissolving the iron precipitate by using an acid so as to obtain an iron-containing solution; ferric ions in the iron-containing solution are reduced, and a solution containing ferrous ions is obtained; the method comprises the following steps: removing redundant reducing agents, adding an indicator into a solution containing ferrous ions, titrating by adopting a potassium dichromate standard solution until the solution is colorless and mutates into purple, measuring the total iron content, and calculating the element sum according to the total iron content and the molar ratio of elements in the iron-based sodium electric precursor measured by adopting an ICP (Inductively Coupled Plasma) method. The method comprises the following steps: firstly reducing all Fe < 3 + > in a sample into Fe < 2 + >, then titrating and testing the total iron content by adopting a potassium dichromate standard solution, and then converting the resultant of the elements according to the molar ratio of the elements.

Application of Lysinibacillus fusiformis in removing hexavalent chromium from eutrophic wastewater, belonging to the field of microbial technology. The strain is preserved in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, with the preservation address being No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, the preservation number being CGMCC No. 10053, and the preservation name being Lysinibacillus fusiformis WTXJ1-4, and the preservation date is November 25, 2014. Through single-factor experiments and orthogonal experiments for optimization, the suitable biological adsorption conditions of this strain for hexavalent chromium in eutrophic wastewater were determined as follows: pH 2.0, initial potassium dichromate concentration 50 mg / L, adsorption time 24 h, wet cell mass dosage 1.0 g / L, adsorption temperature 34 °C, and rotation speed 160 r / min. When reaching equilibrium under these optimized adsorption conditions, the removal rates of hexavalent chromium and total chromium in eutrophic wastewater by viable cells of WTXJ1-4 reached 91.6% - 94.8% and 42.2% - 43.8% respectively. Lysinibacillus fusiformis Viable cells of WTXJ1-4 have strong adsorption-reduction ability, tolerance and resistance to hexavalent chromium in eutrophic wastewater, and their effective ranges are potassium dichromate concentrations of 0 - 100 mg / L, 100 - 300 mg / L, and 300 - 500 mg / L respectively.

The invention relates to the technical field of phosphogypsum harmlessness, in particular to a formula and method for curing soluble phosphorus, eutectic phosphorus, soluble fluorine and ammonia nitrogen in fresh phosphogypsum of a rotary table type vacuum filter. Comprising the following components: ardealite, calcium hydroxide, anionic polyacrylamide, magnesium chloride, aluminum chloride, deacetylated chitin, potassium dichromate and deionized water. Agents adopted by the invention are common industrial agents which are convenient to purchase on a large scale. The medicament is low in cost and has no special requirements for storage and transportation. The agent cost for harmlessly treating each ton of fresh phosphogypsum of the large rotary table type vacuum filter is lower than 30 yuan. According to the method, the concentration of fluoride in the phosphogypsum leachate can be effectively controlled to be 4 mg / L or below.

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 utility model provides a device for detecting the grain irradiation dose of laboratory mice, and relates to the field of laboratory mouse detection agent storage devices, the device comprises a storage assembly, the storage assembly comprises a bottle body, a bottle neck, a bottle cap, a label and a marking line, the bottle neck is located at the top of the bottle body, the bottle body is used for storing a potassium dichromate solution, the bottle cap is located at the top of the bottle neck, and the label is located at the bottom of the bottle neck. The bottle cap is used for sealing the bottle body, and the marking line is located at the joint of the bottle cap and the bottle neck. By arranging the bottle body, the bottle neck and the bottle cap, the effect of storing the potassium dichromate solution is achieved, the bottle body is used for providing a storage space, the bottle neck and the bottle cap are used for sealing the potassium dichromate solution, and therefore the potassium dichromate solution can be prevented from being polluted, and by arranging the marking lines, the potassium dichromate solution can be conveniently stored. The effect that the bottle cap can be conveniently cut open is achieved, detection use can be carried out, by arranging a label, capacity labeling can be conveniently carried out on a potassium dichromate solution, and detection use is convenient.

The invention discloses a method for quickly testing chemical oxygen demand, which comprises the following steps of: 1, preparing a test solution which comprises the following components: A, a potassium dichromate solution (c is equal to 0.0250 mol / L); b, a mercury sulfate solution (100g / L); c, a silver sulfate-sulfuric acid solution (10g / L); 2, preparing a standard water sample; step 3, preparing a comparison reference sample, sequentially adding the standard water sample, the reagent B and the reagent A into the colorimetric tube, uniformly shaking, adding the reagent C into the colorimetric tube by using a pipette, uniformly shaking, and standing until the reaction is finished; 4, developing the water sample to be detected, sequentially adding the water sample to be detected, the reagent B and the reagent A into the colorimetric tube, uniformly shaking, adding the reagent C into the colorimetric tube by using the pipette, uniformly shaking, and standing until the reaction is finished; and 5, carrying out color comparison on the to-be-detected water sample obtained in the step 4 and a comparison reference sample.

The present invention provides a rapid method for wet digestion of high-phosphorus iron ore, which can quickly and accurately decompose high-phosphorus iron ore to meet the testing requirements of scientific research and industrial production for multi-element analysis of high-phosphorus iron ore. The present invention uses a mixed acid digestion method to decompose difficult-to-digest high-phosphorus iron ore, optimizes the addition ratio of each acid, determines the optimal decomposition conditions, and uses potassium dichromate titration and quinoline gravimetric method to respectively determine the iron and phosphorus content in the high-phosphorus iron ore. At the same time, the ICP standard curve method is used to analyze the content of impurity elements in the ore. Experimental results show that the sample is completely decomposed and the measurement results are reliable. This method is fast, convenient, and has good reproducibility, providing an accurate and rapid method for daily batch analysis of high-phosphorus iron ore.

The invention belongs to the technical field of battery materials, and particularly discloses a pretreatment process of PAN-based carbon fibers and application of the PAN-based carbon fibers in preparation of a high-activity flow battery electrode material. The method comprises the following steps: soaking a polyacrylonitrile (PAN) precursor in an aqueous solution containing a pretreating agent such as potassium dichromate, and carrying out chemical pretreatment, so that the surface of the PAN fiber is subjected to primary structural transformation; and respectively carrying out pre-oxidation and carbonization treatment on the obtained material to obtain the PAN-based carbon fiber electrode material with the catalyst on the surface. When the obtained carbon fiber material is used as an electrode material of the all-vanadium redox flow battery, the electrode reaction kinetics of the positive electrode and the negative electrode of the battery can be effectively improved, and the energy conversion efficiency and the rate capability of the battery are improved. The method is easy to operate, compared with a traditional electrode preparation technology, energy consumption is low, the process is simple, large-scale production is easy to achieve, and the method has good application prospects in the field of vanadium battery electrode materials.

The invention discloses a visible-light-responsive ternary Z-type semiconductor composite material and a preparation method and application thereof. According to the composite material, a heterojunction is formed by nesting an Al2O3 / Cr2O3 compound and protonated C3N4. The specific preparation method comprises the following steps: preparing potassium dichromate into an aqueous solution, adding concentrated sulfuric acid to react, and adding an organic solvent and alkali to adjust the pH value; heating the solution of which the pH is adjusted, adding aluminum chloride and ammonia water to react, and filtering, drying, roasting and grinding a solid product to obtain Al2O3 / Cr2O3 compound powder; calcining urea, and then carrying out acid pickling and drying treatment to obtain porous graphite phase carbon nitride powder; al2O3 / Cr2O3 compound powder and porous graphite phase carbon nitride powder are mixed in proportion and suspended with water, and then the ternary Z-type semiconductor composite material is prepared through ultrasonic stirring, centrifugation and drying. Under the irradiation of visible light, the degradation rate of the composite material on ibuprofen in 6 hours reaches 97.58%, the degradation rate constant is 15 times that of pure C3N4, and the composite material still keeps high efficiency under the condition of alkalescence, namely pH = 7.9. The degradation rate of the composite material still reaches 80.44% after four times of circulation.

The invention relates to a method for rapidly determining the amino acid content of a copper-containing plating solution, which comprises the following steps: respectively preparing a potassium dichromate-sulfuric acid-silver sulfate mixed solution and a potassium dichromate-sulfuric acid mixed solution, and respectively sampling in a digestion colorimetric tube as a reagent tube A and a reagent tube B; establishing an amino acid standard curve; the method comprises the following steps: taking a to-be-detected solution of a copper-containing plating solution, putting the to-be-detected solution into a reagent tube A for digestion, and after digestion is finished, reducing the temperature to room temperature to obtain a sample A; taking the other part of to-be-detected copper-containing plating solution, putting the to-be-detected copper-containing plating solution into a reagent tube B, and washing and cooling the wall of the reagent tube to obtain a sample B; and determining the absorbance of the sample A by taking the sample B as a determination zero point according to the amino acid standard determination curve to obtain the amino acid content in the sample A. According to the method, pretreatment is not needed, direct determination can be achieved, and compared with a traditional determination method in which pretreatment is needed for eliminating metal ion interference and then determination is conducted, the steps are simple, the determination range is wide, and good application prospects are achieved.

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 method comprises the following steps: weighing a certain amount of soil samples, putting the soil samples into a triangular flask, adding an ethylenediamine tetraacetic acid disodium salt solution with specific concentration and volume, a potassium dichromate solution and concentrated sulfuric acid containing silver sulfate, uniformly shaking, standing and oxidizing in a heat preservation environment, and carrying out gradient elution to obtain the easily oxidized organic carbon in the soil. Then adding sodium diphenylaminesulfonate and a ferrous sulfate solution for titration, and determining the easily oxidized organic carbon after titration is completed. According to the method, the detection efficiency and accuracy are remarkably improved through operations such as complexing of ethylenediamine tetraacetic acid disodium salt with metal ions, catalytic oxidation of silver ions, accurate indication of an end point by an indicator, optimization of the concentration of an oxidizing agent, the use amount of sulfuric acid and oxidation time, and the like, and many problems existing in a traditional potassium permanganate oxidation method are effectively solved. Compared with a traditional method, the method has the advantages of being easy and convenient to operate, high in detection efficiency, accurate and stable in result and the like, the requirement for measuring the soil easily-oxidized organic carbon in batches can be better met, and powerful support is provided for soil quality evaluation and related carbon research.

The invention discloses a photoelectrocatalysis COD (Chemical Oxygen Demand) water quality on-line monitoring system and a detection method, and belongs to the technical field of water quality analysis. Aiming at the pain points that a traditional potassium dichromate method needs a strong acid high-temperature toxic reagent, the detection time is long, the maintenance cost is high, a UV method is poor in interference resistance, and an existing photoelectrocatalysis method is unstable in light source, insufficient in automation and the like, the system adopts a composite photoelectrode and an integrated thin-layer electrolytic tank integrating three electrodes and is matched with a UV-LED light source; a miniature shading shutter is introduced to eliminate the influence of unstable current at the moment when a light source is turned on; meanwhile, a miniature constant potential rectifier (for controlling the potential of a working electrode and collecting light current), a multi-way valve, a two-position three-way valve, a peristaltic pump, a water sample-electrolyte mixer and a bubble sensor (for preventing bubble interference and realizing metering liquid inlet) are integrated, so that a miniaturized and full-automatic integrated structure is formed. The detection method sequentially comprises the following steps of: rinsing the system, stabilizing a light source, uniformly mixing a water sample and electrolyte, pumping into a thin-layer pool, opening a shutter to carry out photoelectrocatalysis detection (applying bias voltage by a constant potential rectifier and recording photocurrent), calculating a COD value by combining photocurrent integration with a calibration curve, and carrying out waste discharge reset. Meanwhile, a standard liquid calibration process and a quality inspection process are matched. The device is researched and developed on the basis of the photoelectrochemical degradation principle, does not need strong acid, high temperature and toxic chemical reagents, is short in detection time, low in detection lower limit, high in anti-interference capability and low in maintenance cost, and can realize high-precision monitoring of water quality COD.

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.