Analysis of the Results of Researching the Degree of Adsorption of Chromium(III) Ions Depending on the Amount of Bentonite in Contaminated Wastewater

Abstract

The degree of adsorption of chromium(III) ions was analyzed depending on the amount of bentonite. Water pollution is the contamination of bodies of water such as lakes, rivers, oceans and groundwater by human activities. All water pollution affects the organisms and plants that live in them. Therefore, in almost all cases, the effect is such that it harms not only individual species and populations, but also natural biological communities. It occurs when pollutants are discharged directly or indirectly into water bodies without proper treatment and removal of harmful components. At the same time, the most relevant are adsorption cleaning methods, which are widely used for deep purification of wastewater, including from organic substances, such as phenols, herbicides, pesticides, aromatic nitro compounds, aromatic substances, dyes, etc. It has been proven that the use of bentonite as a sorbent allows replacing the stage of mechanical separation, which is one of the time-consuming stages of this process. A number of composite sorbents were obtained on the basis of bentonite, in particular, those with magnetic properties, in which a layer of Fe₃O₄ is deposited on the surface of the mineral. The problem of removing heavy metals from wastewater is particularly relevant now. Poorly treated wastewater flows into natural reservoirs, where heavy metals accumulate in water and bottom sediments, thus becoming a source of secondary pollution. Compounds of heavy metals spread relatively quickly throughout the water body.

In the course of the study, it was found that with an increase in the mass of bentonite in the column, the adsorption efficiency increases for all concentration variants, and an increase in the effective volume indicator is also observed. Such research results indicate the choice of a sorbent layer of 20 g as a more successful option. With such sorbent consumption, the degree of purification of the model solution is 83.2 % (С0(Cr³⁺) = 0.5 g/dm3) at the lowest concentration of the pollutant and 70.2 % at the highest initial concentration of chromium ions in the solution (С0(Cr³⁺) = 2.0 g/dm3).

So, the task is solved by the fact that in the method of wastewater treatment by the adsorption method, which consists in the purification of wastewater from heavy metal ions by absorbing them with a layer of sorbent, which is located in an ion-exchange filter, and the purification of wastewater is carried out in a layer of the natural mineral bentonite.

Thus, water pollution is the contamination of bodies of water such as lakes, rivers, oceans, and groundwater by human activities. All water pollution affects the organisms and plants that live in them. Therefore, in almost all cases, the effect is such that it harms not only individual species and populations, but also natural biological communities.