Sorption of Heavy Metal Ions of Chromium, Manganese, Selenium, Nickel, Cobalt, Iron from Aqueous Acidic Solutions in Batch and Dynamic Conditions on Natural and Synthetic Aluminosilicate Sorbents

Abstract

Zeolites are materials with known sorption properties. The sorption is thought to progress mainly by ion exchange with Na+, K+, Mg2+, Ca2+ or H+ from the zeolite exchange sites. The aim of the study was to compare the sorption properties of natural and synthetic zeolites on the example of the removal of selected metals from aqueous acidic solutions. Uptake experiments for selected ions of chromium, manganese, selenium, nickel, cobalt, and iron were performed using the batch and kinetic column methods. The sorption of the individual metal ions in mg per 1g of sorbent was determined for each sorbent. The relative affinity sequence of the examined cations toward the various sorbent was presented. The Langmuir model was used to model the adsorption equilibrium. Vermiculite under 1 mm of diameter (SF), Na-X, and Na-A were proved to be the most suitable for the individual uptake of studied metal ions. It was observed that the behavior of selenium ions differed from the remaining ones which was interpreted that selenium undergoes adsorption in the anionic form. The fixed-bed column studies were performed using Na-A, ensuring the sorption of selenium in the presence of iron(III) ions. The experiments were conducted using Na-X zeolite pre-loaded by Fe(III) as well as unmodified sorbent eluted by an equimolar mixture containing 100 ppm of Fe and Se. Obtained results prove that selenium sorption improves if other metal ions such as iron appear in the acidic solution. That efficient selenium sorption conditions can be applied to remove selenium which was recognized as toxic at higher levels.

Usage of Sorbent-Catalyst to Accelerate the Oxidation of Manganese

“…Solutions of manganese sulfate in artesian water were used as working media, which had the following characteristics: hardness H = 4.4-4.8 mg-eq/dm 3 , alkalinity A = 4.2-4.7 mgeq/dm 3 , pH 7.7-7.79, concentration of calcium ions [Ca 2+ ] = 3.4-3.8 mg-eq/dm 3 , concentration of chlorides [Cl -] = 80 mg/dm 3 , concentration of sulfates [SO 4…”

“…The consumption of the magnetite-modified KU-2-8 cation exchange resin was 20 cm 3 /dm 3 . The concentration of manganese ions in the solution for static studies was 1-30 mg/dm 3 .…”

“…where: C 0 and C -initial and equilibrium concentration of manganese (II) ions in solution, mg/dm 3 .…”

“…The consumption of solutions was 10 cm 3 /min. The sample volume was 250-1000 mg/dm 3 . The concentration of manganese and pH were determined in the selected samples, and the residual hardness was also determined using artesian water.…”

“…Recently, the works describing the processes of extraction of manganese ions from water by using sorption methods have been published. [Biela et al, 2016, Flieger et al, 2020. Sorbents with a supported catalyst film, preferably manganese oxide, are often used to increase the purification efficiency.…”