In this work, the removal of zinc and lead (Zn2+and Pb2+) from aqueous solutions was investigated using a Brazilian bofe clay. The mineral clays were characterized through XRD analysis and CEC. A finite bath system was used to evaluate the main effects of pH values in the range from 3.0 to 5.0 and Zn2+and Pb2+initial concentrations (from 10 to 50 mg/L) on the removal process capacity. The combinations of the XRD and CEC showed characteristics of the group smectite clays. Up to 3.38 mg/g of Lead removal capacity (99.97% efficiency) was reached and values as high as 98.47 % of removal Zinc efficiency and 3.93 mg/g of removal capacity were reached in the assays. Thus indicating that the use of Bofe clay has great potential in the removal of Lead and Zinc.

The clays are emerging as excellent alternative materials in the process of removing organic and inorganic contaminants, that due to it's physicochemical characteristics, it’s easy to obtain and also for low cost. The initial objective of this ( study was to characterize the clay Chocolate B by the techniques of X-ray diffraction (XRD) and cation exchange capacity (CEC). In addition, the testing of finite bath under certain conditions (pH, concentration) in order to better evaluate the efficiency of clay in the removal of heavy metals zinc and lead. It was used a factorial design 22 with addition at the central point, being evaluated the percentage removal (% Rem) and the removal capacity (qeq) by Chocolate B Clay. It was observed that the Chocolate B clay belongs to the smectites group. The results have shown promise in the removal process of the metals zinc and lead by Chocolate B clay.

Heavy industrial activities result in contamination of waste water with many heavy metals, including cadmium, nickel, lead, mercury. Within this context becomes a growing concern of the population and environmental agencies regarding water contamination by heavy metals from industrial effluents. Because of this problem, this paper aims to study and evaluate the main properties of natural Brasgel clay in order to remove cadmium from synthetic effluents, analyzing its kinetic adsorption and its isothermal balance. Once clays exhibit good cation exchange capacity, selectivity and regenerability and for this reason has aroused interest in the use as an adsorbent. As finite bath testing we found that the Brasgel clay, removed approximately 90% of cadmium. The Langmuir model presented best fit to the experimental data, adequately describing the dynamics of adsorption. Kinetic tests indicated that the cadmium removal process by natural Brasgel clay apply the mechanism of the pseudo-second-order rate model, a time of 20 minutes and required to reach equilibrium. Thus, the results indicated that Brasgel clay can be used as an adsorbent for the removal of cadmium from contaminated effluent.

This objective of this study was to produce organoclay, analyze it, and evaluate its use in the process of removing oil emulsion from an oil–water system. The organoclay was prepared by the direct method and was characterized using X-ray diffraction, Cation Exchange Capacity (CEC), and Infrared Spectroscopy (IV). A finite bath system was used to evaluate the effects on the removal capacity, using a stirring speed (A) of between 100 and 300 rpm and an initial concentration of oil-water solution (C0) evaluated in the range of 100 to 500 mg/L. The XRD and infrared results indicated that CTAC was intercalated between the layers of Bofe clay. The percentage of oil removal from oil-in-water emulsions was between 55.99 and 96.62%. These results indicate that OC can potentially remove up to 97% oil from oil-in-water emulsions. Consequently, the OC could be considered an excellent medium for treating oily water.

In this work, natural and thermally modified Chocolate B clays were used for batch adsorption of Pb 2+ and Zn 2+ from an aqueous solution. The materials were characterized by X-ray diffraction, X-ray fluorescence spectroscopy, nitrogen adsorption, and cation exchange capacity. The tests were performed in a finite bath following a 2 2 factorial design, with the variables: pH and initial concentrations of metal. Results revealed that the thermal treatment caused alterations on the Chocolate B clay structure and decreased the specific surface area. Affinities between Pb 2+ or Zn 2+ and Chocolate B clay were found with adsorption capacities up to 3.36 and 3.72 mg.g -1 , respectively. The maximum adsorption capacities were 6.79 mg.g -1 for Pb 2+ and 3.35 mg.g -1 for Zn 2+ using thermally activated clay. The Langmuir and Freundlich models were used for the adsorption equilibrium analysis, and the Langmuir model provided the best fit for sorption isotherms. The adsorption kinetics was evaluated by two models: pseudo-first-order and pseudo-second-order. The pseudo-first-order kinetic model represented well the mechanism of interaction involved during Pb 2+ adsorption into the pores of the clay. However, the two models represented well the mechanism of interaction of Zn 2+ adsorption into the pores of the clay.