Cadmium removal from wastewater in a fixed-bed column system with modified-natural clinoptilolite-rich tuff

Abstract

A number of treatments to municipal wastewater include advanced oxidation processes such as solar photo Fenton and solar photo-catalytic, biological treatment and the use of specific technologies when wastewater is polluted with heavy metals. Therein, the use of membranes, sorption processes with natural adsorbents and/or composites, and biosorption have proved to remove heavy metals efficiently. This investigation aimed to describe the behavior of the thiourea-modified natural clinoptilolite to remove cadmium from wastewater only filtered and wastewater with biological oxidation, in a column system, considering the properties of ion exchange and adsorption of the modified zeolitic material involving the novelty of this work. The importance of counting on feasible technologies to dispose of water is, without a doubt, a priority, particularly in areas, where average rainfall barely reaches 45 mm. Wastewater was treated in a continuous system with a thiourea-modified clinoptilolite-rich tuff. The initial concentration of cadmium in the wastewater was 2.4 mg/L, and an additional amount was added to reach a level of 31 mg/L. The breakthrough curves were obtained, and a mass balance was applied to the results, which accounted for the constant of adsorption 0.345 m3/kg, with a determination coefficient of 0.754. Finally, the capacity of the column system was evaluated for wastewater with biological oxidation. The results showed a cadmium uptake of 34.17%, which led to suggest a treatment in a two-column series.