Desalination of brackish water for household drinking water consumption using typical plant seeds of semi arid regions

Abstract

The goal of this work was to study the salt sorption capacity of biological materials, such as seeds from several different plant species typical of semi arid regions, and their use in the desalination of brackish water in small quantities, sufficient for household drinking water consumption. The sorption capacity of salt was tested for ten different biological materials. The salinity of the water was determined before and after contact with the biological material. Umbu seeds (Spondias tuberosa Arruda Câmara) were considered the most appropriate material, after treating and drying at different temperatures. The prepared material showed that the process met the Langmuir model. The maximum adsorption capacity of sodium by the material at 30, 40 and 50 °C was estimated to be: 52.6, 165 and 250 mg g−1 respectively. Thus, 1 L of brackish water with salinity between 0.6‰and 1.2‰, as the samples tested in this work, may have its sodium chloride content removed using only 1 g of the seeds treated as described in this study if the water is heated to 50 °C. The thermodynamic analysis indicated that the adsorption process is physical and exothermic and that the interactions between the biological material and sodium occurred spontaneously.