Efficient removal of Sr ions from water utilizing a novel Ni-/Fe-doped spongy apatite through fixed bed column system: optimization and realistic application

Enhanced Adsorption of Toxic and Biologically Active Levofloxacin Residuals from Wastewater Using Clay Nanotubes as a Novel Fixed Bed: Column Performance and Optimization

“… 24 Also, the higher bed heights provide a high residence time for the LVOX molecules in contact with active sites of KNT particles of the fixed bed, which in turn results in a considerable increase in the quantities of the captured molecules. 25 , 26 …”

“…The higher flow rates resulted in a low residence time for the LVOX molecules in contact with the KNT particles. 25 This reduces the uptake chances of the LVOX molecules by the active receptors of KNTs, which in turn affect negatively the final capacity of the bed and the performance of its column system. 27 , 28 The total retention of LVOX by the KNT bed at flow rates of 5, 10, 15, and 20 mL/min are 1670.6, 3079.7, 3712.9, and 4386.6 mg, respectively.…”

“… 24 , 29 These models are highly effective in addressing the performance of the KNT bed based on the capacity of the KNT bed, the saturation concentration of LVOX, and the time interval for 50% breakthrough value. 25 The KNT adsorption results for LVOX were fitted with the three models by a linear regression process considering the representative equations of the models from eqs 1 to 3 for the three models in order: …”

“…This model gives information about the expected saturation interval for the KNT bed by the LVOX molecules as well as their adsorbed reactions considering the concentration at a certain value. 25 This model assigns the LVOX uptake rates related essentially to the breakthrough properties of the KNT bed. 24 The properties of the KNT bed column system showed a very high R 2 that emphasizes the agreement with the Yoon–Nelson model behavior ( Figure 5 G–I and Table 2 ).…”

“…Such significant enhancement in both the lifetime of the column and its capacity in the removal of LVOX with increasing the KNT bed height related essentially to the associated reduction in the axial dispersion of the mas transfer, which prompts the diffusion of the LVOX molecules within the KNT bed . Also, the higher bed heights provide a high residence time for the LVOX molecules in contact with active sites of KNT particles of the fixed bed, which in turn results in a considerable increase in the quantities of the captured molecules. , …”