Sunflower-biomass derived adsorbents for toxic/heavy metals removal from (waste) water

In recent years, adsorption is assumed to be one of the most widely used and efficient, user-friendly, and low-cost (waste) water purification technique to remove a wide range of pollutants. From that scope, commercial activated carbons, are commonly used as adsorbents. However, due to some crucial disadvantages (e.g. high cost and incomplete regeneration) their use is limited. Agricultural waste/biomass/residues have attracted interest as alternative and efficient adsorbents because they can be utilized without any or after chemical treatment, or can be used as precursors to fabricate activated carbon or biochar. Moreover, agricultural wastes are renewable, inexpensive and abundantly available, essentially non-toxic, and environmentally friendly, thus satisfying the concept of Green or Sustainable Chemistry. This review article emphasizes on the utilization of sunflower-derived adsorbents to remove potentially toxic elements (PTEs) from aqueous media. The effect of crucial adsorption parameters (effect of initial pH, contact time etc.) is discussed in detail. Data obtained from adsorption experiments, thermodynamic and kinetic modeling, and desorption studies are presented and analyzed. The maximum adsorption capacity values obtained for sunflower adsorbents vary between 3.28 and 252.52 mg/g for PTEs, indicating that these materials could be satisfactorily used as alternative adsorbents.