Removal of the As(V) and Sr(VI) from the water using magnetite/3D-printed wollastonite hybrid adsorbent

Abstract

In this study, the structure, morphology and composition of the synthesized magnetite/3D-printed wollastonite (3D_W/M) composite were characterized, and its adsorption performance with respect to As(V) and Cr(VI) were studied. Magnetite (MG) modified 3D printed wollastonite was obtained by two step procedure: modification of 3D_W with 3-aminoproylsilane (APTES) followed by controlled magnetite (MG) deposition to obtain 3D_W/M adsorbent. The structure/properties of 3D_W/M were confirmed by applying FTIR, XRD, TGD/DTA, and SEM analysis. The adsorption properties of hybrid adsorbents were carried out for As(V) and Cr(VI) removal - one relative to the initial pH value, the adsorbent mass, the temperature, and the adsorption time. Time-dependent adsorption study was best described by pseudo-second order equation, while Weber Morris analysis showed that intraparticle diffusion controled diffusional transport. Similar activation energy, 17.44 and 14.49 kJ?mol-1 for adsorption As(V) and Cr(VI) on 3D_W/M, respectively, indicated main contribution of physical adsorption. Determination of adsorption parameters was performed by applying different adsorption isotherm models, and the best fit was obtained using Freundlich model. The adsorption capacity of 24.16 and 29.6 mg g-1 for As(V) and Cr(VI) at 2?C, Co = 5.5 and 5.3 mg L-1, respectively, were obtained. Thermodynamic study indicated favourable process at a higher temperature. Preliminary fixed-bed column study and results fitting with Bohart-Adams, Yoon-Nelson, Thomas, and Modified dose-response model showed good agreement with results from the batch study.

Hexavalent Chromium Removal from Industrial Wastewater by Adsorption and Reduction onto Cationic Cellulose Nanocrystals

“…Another relevant aspect is the value of the energy of activation, E A = 45.45 kJ·mol −1 . This value is relatively higher but in the order of magnitude of the energy of activation found by applying V, Ti-bearing magnetite (VTM) humic acid-modified particles and Magnetite/3D-Printed Wollastonite Hybrid, where 17.408 and 14.49 kJ·mol −1 were calculated, respectively [ 45 , 46 ]. The difference in Temkin’s heat of sorption can be caused by the sequential adsorption-reduction process involved in the CCNC application instead of pure adsorption processes.…”