Potential of Clay-Based Geomaterials for Passive Treatment of Brackish and Saline Waters

The increasing salinity and water scarcity of water resources are major problems in semi-arid or arid regions. This study examines the possibilities of a hybrid geomaterial based on clay to treat passively water bodies that are brackish or saline made from locally available Moroccan clays. A quaternary composite was developed by combining ghassoul with kaolinite as well as red ferruginous and illite and green ferruginous illite, to benefit from their complementary physicochemical characteristics. Chemical and mineral analyses reveal the synergistic impact of a high cation exchange capacity as well as iron oxide-driven anionic interaction as well as the stability of the structure. Simulated batch adsorption tests were carried out at beginning NaCl dosage of 1100 mg/L and using different weights of adsorbents. The results demonstrate a gradual reduction in equilibrium salinity as increasing clay dosage, and the maximum capacity for adsorption of 18 mg/g. Adsorption behavior was studied with the help of Langmuir as well as Freundlich isotherm model. While Langmuir analysis yields reliable estimates of the adsorption capacity however, the Freundlich model gives more accurate results, which indicates the multilayer and heterogeneous adsorption that is controlled by several active sites. The results confirm the fact that the composite of hybrid clay permits simultaneous reduction of sodium and chloride ions by combining Ion exchange and surface adsorption processes. With a potential desalination efficiency of 20–30 %, this low-tech solution is a viable and economical alternative for saline water pre-treatment or partial desalination to support ecologically responsible water management strategies in water-poor regions.