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Disinfection
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
Metabisulfite, bisulfite, or sulfite salts can be used. Automatic or manually fed systems can also be used. If chlorine is used at the site, sulfur dioxide is preferred, since identical equipment can be used for the addition of both chemicals. Alternative dechlorination systems include activated carbon, hydrogen peroxide (H2O2), and ponds (sunlight and aeration). The technology of dechlorination with sulfur dioxide is established but is not in widespread use. It can be used whenever a chlorine residual is undesirable. This usually occurs when the receiving water contains aquatic life sensitive to free chlorine. Dechlorination is generally required when superchlorination is practiced or stringent effluent chlorine residuals are dictated. It will not destroy chlorinated hydrocarbons already formed in the wastewater. It has been reported that about 1% of the chlorine ends up in a variety of stable organic compounds when municipal wastes are chlorinated. Available chlorine residuals can be reduced to essentially zero by sulfur dioxide dechlorination.
Characterization of the degradation of dipyrone (metamizole) in expired oral pharmaceutical products by Raman spectroscopy and principal component analysis (PCA)
Published in Instrumentation Science & Technology, 2023
Luciana Lopes Guimarães, Leandra Paula Marques de Sousa Rosa Nita, Walber Toma, Marcos Tadeu Tavares Pacheco, Landulfo Silveira
The use of antioxidants and chelating agents as stabilizers for dipyrone in aqueous media reduces the risk of hydrolysis. Sodium metabisulfite, an antioxidant that displays antimicrobial activity,[34] is present in all brand formulations in this study. Chelating agents, such as disodium EDTA, are used in liquid preparations as stabilizers for heavy metals and alkaline earth ions in water. All samples included EDTA in their formulations. Also, the decomposition is not due only to hydrolysis; factors such as oxidation and pH may influence the overall degradation.[35] Dubash and Moore (1972)[35] reported that temperature alone does not affect the decomposition of dipyrone other than to accelerate the rate of oxidative loss and the extent of decomposition is markedly reduced when air is excluded from the sample.
Influences of four pretreatments on anthocyanins content, color and flavor characteristics of hot-air dried rose flower
Published in Drying Technology, 2020
Yoon Hlaine Barani, Min Zhang, Bin Wang, Sakamon Devahastin
About 0.025-M potassium chloride (KCl) buffer at pH 1.0 was first prepared by mixing 1.86 g of KCl and 980 mL of distilled water in a beaker. The pH was adjusted to reach the desired value with concentrated hydrochloric acid. The pH of the mixture was measured using a pH meter (Ohaus, Starter 3100, Parsippany, USA). 0.4-M sodium acetate (CH3CO2Na·3H2O) buffer at pH 4.5 was prepared by mixing 54.43 g of CH3CO2Na·3H2O with 960 mL of distilled water in a beaker. The pH was again measured by the pH meter and adjusted to the desired value with concentrated hydrochloric acid. Finally, potassium metabisulfite (K2S2O5) solution was prepared by dissolving one g of K2S2O5 in 5 mL of distilled water.