Papers by Keyword: KMnO₄

Abstract: MnO₂ nanoparticles were prepared by one-step redox under room temperature. The sample was characterized by XRD, SEM, TEM and FT-IR. The results indicated that the MnO₂ nanoparticles was amorphous δ-MnO₂ with the uniform size of 10-20nm in particle diameter, which can be seen by XRD patterns. The four peaks appear at 2θ = 23.24°,36.1°,45.42°and 64.38°, respectively. FT-IR results showed the 519 cm^-1 as Mn-O features manganese dioxide absorption. The effect of the pH, nanoMnO₂ dosage, reaction time, reaction temperature and initial concentration were studied on the removal of reactive brilliant blue. It was found that the removal ability of reactive brilliant blue was the best under the selected conditions: pH was 3.0, dosage of nanoMnO₂ was 0.05g, KN-R solution concentration was 5mg / L, reaction time was 2h, temperature was 25°C.

Abstract: The static crucible method was employed to effects of different additions and coal mixing ratios on burning rate. The optimal amount was 4% and mixing ratio was Semicoke-Jincheng coal=7:3. XRD and TGA techniques were used to characterize combustion process. The combustion-supporting mechanism was that Mn⁷⁺(CO^-)₇ weakens the bridged bond binding force among carbon structure units and changes lattice structure. Heat storage preparation time is shortened which accelerates pulverized coal combustion.

Abstract: This study focused on the performances of an integrated KMnO₄ oxidation and diatomite adsorption method in the treatment of fresh landfill leachate. The optimal conditions and influential parameters for oxidation and adsorption were determined. The results showed that under optimum oxidation conditions for KMnO₄, the removal rates of COD_Cr and ammonia nitrogen reached 46% and 32% respectively. And the removal rates of COD_Cr and ammonia nitrogen contained in leachate increased up to 98% and 90% after absorbed by diatomite.

Abstract: The surface modification process for coarse wool fiber which was oxidized by KMnO₄ first, and then MnO₂ covering on the fiber was reduced with Na₂SO₃ was studied. The method for surface modification of coarse wool fiber was determined from comparative analysis, the optimum oxidation process was as follows: concentration of KMnO₄ at 3g/L, time 15min, temperature 50°C, ratio of water and wool fiber was 50:1, and the optimum reduction process: Na₂SO₃ concentration at 20g/L, time 8min, temperature 55°C, ratio of water and wool fiber was 50:1. Compared with original wool fiber,the breaking strength and fineness of modified coarse wool fiber decreased, while the moisture regain increased from 15% to 18%.

Abstract: The grafting copolymerization was studied for improving the filtration efficiency of the PP melt-blown non-woven. The experiment was made of three steps: firstly, the optimum conditions were attained by the orthogonal experiments; secondly, the effect regularities of main factors on reaction were discussed; thirdly, the water absorbability and the structure of the grafted sample were analyzed. The results show that the water absorbability of the grafted product significantly improves.

Abstract: In order to achieve high removal rate and high-quality processing on SiC wafer, we carried out the CMP processing experiment with the new type CMP machine (Bell-jar) by using the slurry with the addition of strong oxidant (KMnO₄). It was found that the high speed CMP processing was achieved by controlling the concentration of KMnO₄ in the slurry, the pH of slurry and the processing atmosphere. By using the slurry with the addition of KMnO₄ of 0.1mol/L, the removal rate was the fastest up to 1019nm/h in the fixed pH of 6. By use of the slurry of pH 3, the removal rate of C-face of SiC wafer was 1695nm/h On the other hand, the fastest removal rate of Si-face of SiC wafer was only 51nm/h by using the slurry whose pH is 7. In the open air atmosphere, the removal rate was 915nm/h, which was higher than that at the higher and lower atmospheric pressure.

Abstract: This formation of bromate during ozonation of polluted source water has long caused great concerns. This paper used KMnO₄ to control the bromate formation during water ozonation. KMnO₄ was added 10 min prior ozone to oxidize the organic pollutants. The initial Br- concentration was 1000 μg/L. The results showed that the bromate formation efficiency was low (<5%) during KMnO₄-ozone oxidation. Among KMnO₄ dose, ozone dose, and source water TOC, the single most important factor for bromate formation was the ozone dose. When the ozone dose was 3 mg/L or higher, the bromate concentration exceeded the national standard no matter what level of KMnO₄ was used. The organic pollution level had little influence on the bromate formation.

Abstract: KMnO4 was selected as oxidizers for the oxidation and degradation of cafeteria wastewater. The treatment effects were evaluated by the changes of COD and BOD5 parameters. Orthogonal experiments were designed to optimize the processing conditions based on the single affected factor. The optimized controlling conditions for KMnO4 treatment process were KMnO4=0.3 mmol/L, pH=2, reaction time=60 minutes respectively. The COD removal ratios using KMnO4, ClO2, Fenton reagent treatment were 26%, 55% and 82% respectively. It showed that of Fenton was highest. But after its oxidation, it created other refractory substance and the produced sludge was also difficult to settle down. When using ClO2, the pH in process is closer to neutral, thus saved large quantity of acid. The treatment using KMnO4 showed there was little refractory precipitation, but its COD removal was too low.

Abstract: In this paper the influence of carbon nanotubes (CNTs) on anticorrosion properties was discussed. KMnO4 modified carbon nanotubes were added into Waterborne PolyUrethane, then galvanized steel sheets were dipped into this composites to get a thin film and dried at 120 °C for 60 seconds. SEM observation show the film thickness was 3 µm and CNTs were dispersed in the polymer matrix. XRD demonstrated that some KMnO4 decomposed into K2MnO4 and MnO2. Polarization curves demonstrated the film exhibited excellent anticorrosion when the amount of KMnO4 modified CNTs was 6%.

Abstract: In order to develop an environmental friendly passive films on galvanized steel sheet, a chromium-free passive solution based on waterborne polyurethane (WPU) and Manganate was studied. The results show that the optimized compositions in passive solution are KMnO4 6g/L, (NH2)2CS 5g/L and WPU 150g/L. The passive films were prepared by dipping steel substrates into the passive solution for 10 seconds and drying at 120 °C for 30 seconds. SEM observation shows that the film’s thickness is about 1.5 µm. XRD patterns indicates that the chromate-free passive films mainly consisted of MnO2 and K2MnO4. Anticorrosion tests indicate that the chromate-free passive films can provide an excellent barrier to corrosive agents.