STUDY OF THE SORPTION OF NI²⁺, CO²⁺, AND V⁴⁺ CATIONS IN A THREE-COMPONENT SYSTEM USING MODIFIED ZEOLITE

Abstract

Introduction. Cobalt, nickel, and vanadium are toxic heavy metals that can concentrate and accumulate in soil, wastewater, groundwater, and even in the human body. One of the effective ways to address these problems is the use of accessible adsorbents capable of purifying various types of water. According to the analysis of literature data, the most suitable sorbents are natural and modified forms of zeolites. The aim of the study was to investigate the sorption properties of nickel(II), cobalt(II), and vanadium(IV) ions using the saturation method from aqueous solutions with zeolites modified by guar gum. Results and discussion. The sorption efficiency of the modified zeolite in multimetal systems was investigated, and it was established that the obtained sorbent simultaneously absorbs all cations. It was shown that, unlike natural zeolite, a high degree of sorption by the modified zeolite is achieved both for a cation with a fixed concentration and for one with a variable concentration. The degree of uptake of the sorbed cations is determined by the combination of two cations with constant and equal contents and the concentration of the variable cation. In all the studied systems, a high degree of cation sorption (from 75.0 to 99.5%, depending on the process conditions) occurs in the region with a low concentration of the variable cation (0.5–10 mg/L). Conclusion. It was revealed that in multimetal systems competitive adsorption of cations occurs. Series of sorption efficiency for the cations were obtained, as well as data on the initiating influence of the variable cation—under conditions of its increased concentration—on the sorption of other ions present in the system. In the system “Ni²⁺ – Co²⁺ – V⁴⁺ – MPC – H₂O” with variable C(Co²⁺) and saturated solutions, the Co²⁺ cation initiates the sorption efficiency of the modified sorbent toward V⁴⁺ and Ni²⁺ cations: RV (66.6%) > RCo (42.4%) > RNi (13.4%). With variable C(Ni²⁺), the Ni²⁺ cation increases the sorption efficiency of V⁴⁺ and Co²⁺ ions: RV (63.6%) > RCo (1.8%) > RNi (3.8%).