In this study, we prepared 3-aminopropyl-triethoxysilane (APTEOS) functionalized sodium alginate (SA)
porous membrane adsorbent (APTEOS/SA) and tested its adsorption performance for removing of Cr(III)
ions. The physico-chemical properties of the pristine and Cr(III) ions loaded APTEOS/SA were investigated
by FT-IR, SEM-EDX, TG, AFM, and contact angle goniometer methods. To investigate the adsorption
kinetics of Cr(III) ions onto this newly developed APTEOS/SA, we performed a batch of experiments under
different adsorption conditions: solution pH, adsorbent dose, initial Cr(III) ion concentration, adsorption
temperature, and contact time. The APTEOS/SA exhibited an encouraging uptake capacity of 90.0 mg/g
under suitable adsorption conditions. To study the mechanism of adsorption process, we examined
the Lagergren pseudo-first-order and pseudo-second-order kinetic model, the intra-particular diffusion
model, and the Crank model. Kinetics experiments indicated that the pseudo-first-order model displayed
the best correlation with adsorption kinetics data. The Crank model showed that the intra-particle solute
diffusion was the main rate-controlling step. Furthermore, our adsorption equilibrium data could be
better described by the Freundlich equation. We also carried out consecutive adsorption–desorption
experiments eight times to show that the APTEOS/SA has encouraging adsorption–desorption efficiencies.
The results indicates that the prepared adsorbent is promising for using as an effective and economical
adsorbent for Cr(III) ions removal.