Adsorption method of purification of stocks from chromium(III) ions by bentonite clays

Abstract

The process of sorption of chromium(III) ions with a stationary sorbent layer of bentonite clays was investigated. The main advantages of using bentonites in water purification technologies are described: powerful geological reserves, cheap process of rock extraction, easy preparation for transportation and use, possibility of using waste sorbents in other technologies that is why there is no need in costly regeneration. The influence of various factors (process duration, an adsorbent layer) on the degree of wastewater purification from chromium ions, the effect of pumping speed on the dynamic capacity of the sorbent was studied and the effective volume was determined. The adsorption efficacy increases with the increase of the adsorbent layer, what can be explained by the development of the active sorption surface. As the initial concentration of chromium ions increases, the time of appearance of the first traces of the contaminant at the exit of the column increases, as well as the total time to channeling. The results of the studies indicate a higher adsorption capacity of modified bentonite with respect to Cr3+ ions compared to its natural formula. The cleaning efficacy of the solution with a concentration of chromium ions of 0.5 g∙dm–3 is increased by 5% when using 15 g of modified bentonite and 6,5% in the case one uses 20 g compared to the natural form.