Kinetics and Equilibrium Studies for the Removal of Mn and Fe from Binary Metal Solution Systems Using a Romanian Thermally Activated Natural Zeolite

In the present study, the sorption behavior of iron (Fe) and manganese (Mn) from a binary metal solution system onto thermally activated natural zeolite was studied. Batch adsorption experiments were carried out to investigate the effects of zeolite quantity, particle size, and activation temperature. Equilibrium studies were carried out to evaluate the adsorption capacity of the thermally activated natural zeolite. The obtained results showed that the thermally activated natural zeolite favored the removal of Fe over Mn, due to competition between them. Elemental analysis of the activated zeolite samples obtained by energy-dispersive X-ray analysis (EDX) indicated a Si/Al ratio >4, which is specific for clinoptilolite-type zeolite. The removal of Fe and Mn was best described by the Langmuir model, indicating the formation of a monolayer on the surface of the activated natural zeolite. The kinetic results revealed that the experimental data were best fitted by the pseudo-second-order model for both metals. The results suggest that a new natural zeolite from Rupea quarry, Brasov County, Romania could be used as a potential adsorbent for removal of Fe and Mn from binary metal solution systems, addressing the lack of information about this material from this region.