The solvent sublation of Reactive Red 2 from water solutions

Presented work has researched the removal of Reactive Red 2 from water solution by solvent sublation. Solvent sublation is an innovative technology, which is an improved version of ion flotation, the use of which does not form foam. The implementation of this method of wastewater treatment provides for the simultaneous separation of the aqueous phase and the pollutant, followed by concentration of the pollutant. This process allows to remove both inorganic and organic pollutants from the aquatic environment. Reactive Red 2 is an anionic dye and widely used for printing and dyeing cellulose fibers, silk and wool. The dye is toxic and carcinogenic. Wastewater contaminated with this dye must be cleaned to eliminate the negative impact on the environment. The process of removing Reactive Red 2 is carried out with the following operating parameters: column diameter – 3.5 cm; gas – nitrogen; gas consumption – 60 ÷ 75 cm³/min; the volume of the aqueous phase – 200 cm³; the volume of the organic phase – 10 cm³; initial dye concentration – 10 mg/dm³. Hexadecyltrimethylammonium bromide is selected as a surfactant to form a poorly soluble hydrophobic compound. The organic phase is isoamyl alcohol. The effect of some parameters on the degree of dye removal has been experimentally studied: process duration, pH of the aqueous phase, molar ratio dye:surfactant, gas bubble size. According to the results, the highest degree of Reactive Red 2 removal is 96 % with a process duration of 10 minutes, pH – 6, molar ratio dye:surfactant = 1:2, and gas bubble size – 40 μm. The experimental results confirm that the proposed solvent sublation technology guarantees a sufficient level of wastewater treatment from anionic dyes. The selected method can be used in local wastewater treatment systems with subsequent return of water to the process. This solution is economically viable and will significantly reduce the level of pollution of natural reservoirs with dyes