Removal Of Hydrazine From Water

Iranian Scientists Use Enzyme Nanoparticles to Deoxygenate Water Fed to Steam ...

"There are two physical and chemical methods for oxygen removal from the water fed to steam boilers," Afzal Karimi, member of the Scientific Board of University of Tabriz, said.

"Since the safety of the user, the product in contact with the vapor and the environmental pollution have become highly important issues in the modern world, all industries try to reduce the environmental pollution."

Karimi continued, "Many industries use hydrazine that is highly toxic and has a high range of operation temperature. In this project, we produced nanoparticles containing an enzyme that is compatible with the environment and the user. I draw your attention to the fact that the removal of dissolved oxygen by using enzyme does not have any disadvantages of the chemical compounds, to the extent that no solid particle is formed at lower temperatures and at an appropriate reaction rate."

Elaborating on the details of the research, he said, "Glucose adsorbs the oxygen dissolved in water through an enzyme oxidation, and produces gluconate and hydrogen peroxide. In this research, glucose oxidase was stabilized on a bed of manganese dioxide nanopore in order to increase the load and performance of the enzyme in continuous processes. In addition to providing an appropriate bed for enzyme stabilization, this base acts as a catalyst for hydrogen peroxide decomposition and it completes the deoxygenation chain."

According to the researcher, this plan is successful since it is environmentally-friendly and safe, and it can economically compete with the similar chemical methods.

Derivatization Ion Chromatography for the Determination of ...

Abstract

A simple, rapid and accurate method for the determination of monoethanolamine (MEA) in PHWR steam-water circuits has been developed. MEA is added in the feed water to provide protection against corrosion while hydrazine is added to scavenge dissolved oxygen. The quantitative determination of MEA in presence of hydrazine was accomplished using derivatization ion chromatography with conductometric detection in nonsuppressed mode. A Metrosep cation 1-2 analytical column and a Metrosep cartridge were used for cation separation. A mixture of 4 mM tartaric acid, 20% acetone and 0.05 mM HNO . Cation separation was carried out in nonsuppressor mode on a Metrosep cation 1-2 analytical column (125 × 4 mm) connected in series with a Metrosep cartridge. The Metrosep cartridge is used as a precolumn to protect the analytical column.

Reagents used were of analytical grade and obtained from Sarabhai M. Chemicals, Baroda, India. Deionised water (18 MΩ) obtained from a Barnstead water purification system (Barnstead, Boston, Mass, USA) was employed throughout. OnGuard-H cartridge was obtained from Dionex (Sunnyvale, Calif, USA). Stock standard solutions (1 g L ) were prepared for MEA and hydrazine. The working standard mixtures for calibration were prepared weekly from the stock standard.

Different eluents were tested for the separation of MEA and hydrazine because both coeluted from the analytical column (Table 1 ). In each case, three different compositions (0.5, 1, 4 mM) and three different flow rates (0.8, 1.0, 1.2 mL min 2.4. Sample Pretreatment

Steam generator water sample was passed through OnGuard-H cartridge to remove interfering cations (alkali and transition metal ions). The recommended guidelines for the use of OnGuard cartridges supplied by Dionex Corp. (Sunnyvale, Calif, USA) were followed. OnGuard-H cartridge was washed with 10 mL deionised water. About 5 mL of the sample solution was loaded on the cartridge and allowed to flow at the rate of 2 mL min . The first 3 mL of elute was rejected and the next 2 mL was collected. Before injection into the ion chromatograph, sample solutions were diluted (1 : 1) with mobile phase in order to maintain the same pH. This step also ensures that amines are in the protonated form.

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