Sorption of Cd²⁺, K⁺, F^–, and Cl^– on some tropical soils

Abstract

The potential for the retention of K+, Cd2+, F–, and Cl– by lateritic soils from the Botucatu (an important sandy aquifer in the southeastern part of Brazil) and Serra Geral (a clayey material) formations and three mixtures of these soils is examined. Batch equilibrium results are presented for both single salt (CdCl2 and KF) and multiple salt (CdCl2 + KF) solutions. The soil retention parameters are obtained by fitting sorption models (linear, Freundlich, and Langmuir) to the experimental isotherm plots using linear and nonlinear regression analyses. The results show that the so called varying soil:solution ratio isotherms (VSI) are in fact less variant in terms of pH than constant soil:solution isotherms (CSI). However, because of restrictions related to the VSI approach and the "soil solution ratio effect," the CSI approach is considered to be a more reasonable way of constructing sorption isotherms. It is shown that under certain conditions, the Cl– anion can be sorbed while for others it is not sorbed. Sorption was observed for F– and K+. The sorption of Cd2+ is also shown to be highly sensitive to leachate chemistry. It is shown that a knowledge of pH0 is quite important for the interpretation of sorption data.Key words: sorption, inorganic chemicals, isotherms, tropical soils.

Adsorption Behavior of Potassium Ion on Planting Materials

“…The cation exchange capacity (CEC, meq/100 g) was measured to evaluate the adsorption capacity, determined by an ammonium acetate method. 19 The samples were saturated by rinsing twice with ammonium acetate solution (pH 7.0) and once with isopropanol. The absorbed ammonium was extracted by leaching the samples with acidified sodium chloride solution.…”

Determinação de parâmetros para indicar a atenuação natural de lixiviado de resíduos sólidos por diferentes solos

“…Uma vez conhecida a capacidade de atenuação dos materiais que podem ser utilizados para a preparação da base compactada abaixo dos aterros sanitários, faz-se necessário conhecer a dinâmica para monitoramento da interação solo-lixiviado. Barone, 1989), ou seja, manter o solo (compactado e saturado) em contato direto a solução contaminante sem fluxo hidráulico (Johnson et al, 1989;Leite; Paraguassú & Rowe 2003).…”

Nigerian Lateritic Clay Soils As Hydraulic Barriers To Adsorb Metals. Geotechnical Characterization And Chemical Compatibility

“…Wide acceptance of the use of compacted clays as landfill liners is largely based on experience in North America and Europe, with less investigation on the use of lateritic clayey soils found in other parts of the world [2,3]. Lateritic soils are widespread in some countries in Africa such as Nigeria [4,5].…”