FIBROUS CHEMISORBENT-AMFOLITE BASED ON THE COMPLEX COMPOUNDS OF NICKEL (II) CHLORIDE AND ETHYLENEDIAMINE

Abstract

The principal possibility of using the nickel (II) chloride complex with ethylenediamine (EDA) as a reagent for the creation of impregnated fibrous chemisorbents-amfolite (IFCS-A), which depending on the operating conditions can absorb acidic (SO2) and basic (NH3) gases, has been investigated. The sorption of water vapor by IFCS–Ni–EDA, obtained by impregnating a fibrous material with aqueous solutions of nickel (II) chloride complexes with EDA at different molar ratios Ni: N (1/k) was determined under static conditions, the nature of the effect of the pre-absorbed water on this process was stated. It was found the increasing the amount of EDA in combination with NiCl2 to decrease in the hydrophilicity of the obtained IFCS-A samples. Water adsorption isotherms are convex with respect to the P/Ps axis and are of type III according to C. Brunauer, L. Deming, U. Deming, Е. Teller classification. This type of isotherms is characteristic of the adsorption of gases and vapors by non-porous solids, and the weak adsorbent-adsorbate interaction causes a small amount of adsorption at low values of the relative vapor pressures of water.capacity and the heat of sorption of water molecules in the first layer has been determined. Under static and dynamic conditions the absorption of sulfur dioxide by the obtained IFCS–Ni–EDA samples was studied. It is shown the SO2 uptake process, going predominantly through the chemisorption mechanism, occurs only in the presence of «free» water formed with the formation of diamonium hydrosulfite (pyrosulfite) on the carrier fibers surface. It has been established the values of the SO2·H2O static chemisorption increase with increasing EDA content to k value in IFCS–Ni–EDA samples. Taking into account the literature data it is shown that the property of sulfur dioxide chemisorbing under static conditions of IFCS-A can be placed in the order: IFCS–Ni–EDA > IFCS–Ni–MEA > IFCS–Cu–PEPA. It is shown that the obtained IFCS–Ni–EDA can be used for absorption of acidic and basic gases at Ni : N = 1:1 ÷ 1:3. ratio. The protective action time of substantially IFCS–Ni–EDA (1.5 ÷ 2.0 times) exceeds the analogous values of existing IFCS-A based on complex compounds of copper (II) sulfate with ammonia and nickel (II) chloride with monoethanolamine and hexamethylenetetramine. IFCS–Ni–EDA is recommended for use in equipping of respiratory protection devices – lightweight gas-dust respirators.

Keywords

• хемосорбція
• комплексоутворення
• етилендіамін
• хлорид нікелю (ii)
• ок-сид сірки (iv)
• аміак
• ізотерма