ESTIMATION OF THE SELECTIVITY OF THE ACTIVE CENTERS OF SORBENTS DURING SORPTION OF ECOTOXICANTS FROM MULTICOMPONENT SOLUTIONS

Abstract

A method for assessing the selectivity of active centers upon sorption of sorbates from multicomponent solutions containing three or more pollutants is proposed. The method is based on comparison of the values of specific sorbent capacity for each of the sorbates when they are extracted from single-pollutant (one pollutant) and multipollutant (all contaminants simultaneously) solutions. Both stationary and flowing solutions to be studied contained close and significantly different initial concentrations of eco-pollutants. At the first stage, stationary solutions contained a single pollutant (then all three at the same time) at a given equal (close) initial concentration, the sorbent mass in them being fixed strictly. At a given moment of time ф i, the capacity of the sorbent Qi for each sorbate is estimated. Then the same experiment is carried out with the solutions containing all three pollutants simultaneously. If Qi ( ф i = const) does not depend on the presence of other pollutants, then the selectivity of the active centers of the sorbent takes place. If it decreases with the introduction of other pollutants, the selectivity is absent. At the second stage, the same experiment is carried out in the flow solutions, and at the third stage at the concentration of one the sorbate (10 – 100 times) lower than that of others (flow media). In all cases, the value Qi of each i-th sorbate is also estimated and the same theoretical analysis is carried out. Results of sorption of metal cations (Me (II)) (iron group) on glauconite at practically identical their initial concentrations and Ni (II) from media with high (more than 100-fold) content of hardness cations (Ca (II) and Mg (II)) are presented as an example. The high selectivity of the active sorbent centers is shown.