Highlighting the Protective Role of Coastal Rivers: Dynamics of Adsorption and Desorption of Naphthalene and Pyrene of Lebna River Sediments (N-E Tunisia)

• Published in: Water, air, and soil pollution air, and soil pollution, 2023, Vol.234 (1), p.4, Article 4
• Main Authors: Achour, Dhouha, Trifi, Mariem, Azouzi, Rim, Charef, Abdelkrim, Rokbani, Salah
• Format: Article
• Language: English
• Subjects: Adsorption; Agricultural land; Analysis; Aromatic compounds; Aromatic hydrocarbons; Atmospheric Protection/Air Quality Control/Air Pollution; Chemical bonds; Climate Change/Climate Change Impacts; Desorption; Domestic wastewater; Earth and Environmental Science; Environment; Environmental monitoring; Exothermic reactions; Fluid filters; Fluvial sediments; Hydrogeology; Industrial wastewater; Isotherms; Kinetics; Marine ecosystems; Marine pollution; Naphthalene; Pollutants; Polycyclic aromatic hydrocarbons; Pyrene; River sediments; Rivers; Sediment; Sediments; Soil pollution; Soil Science & Conservation; Wastewater; Water pollution; Water Quality/Water Pollution; Watersheds
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-022-06002-z

Lebna’s River, located at the northeastern part of Tunisia, receives runoffs from five sub-watersheds in addition to agricultural soils that are rich in organic pollutants, and a discharge place of treated and untreated industrial and domestic wastewater. However, no degradation signs of this river are observed, even though the river sediments are highly polluted with polycyclic aromatic hydrocarbons (PAHs). To have a better comprehension of PAH behavior within the Lebna River, kinetics of individual adsorption of naphthalene and pyrene was carried out. The removal efficiencies of the two pollutants increase due to temperature along with adsorbent doses, and in addition, the pH increases. The two organic pollutant adsorption isotherms of river sediments could be better fitted by the pseudo-second-order reaction and Freundlich isotherm model. Furthermore, the adsorption processes are non-spontaneous and between exothermic and endothermic. The organic pollutants were retained by high energetic chemical bonds which limit the desorption to the greatest level and similarly the river re-pollution. Thus, all adsorption conditions are convenient for eradication of organic pollutants from the river. This confirms that rivers are not only a pollutant sink but they could also be filters of pollutants within the marine ecosystem.