Fabrication of MNPs/rGO/PMMA Composite for the Removal of Hazardous Cr(VI) from Tannery Wastewater through Batch and Continuous Mode Adsorption

Abstract

Herein, we report the synthesis of magnetic nanoparticle (MNP)-reduced graphene oxide (rGO) and polymethylmethacrylate (PMMA) composite (MNPs/rGO/PMMA) as adsorbent via an in situ fabrication strategy and, in turn, the application for adsorptive removal and recovery of Cr(VI) from tannery wastewater. The composite material was characterized via XRD, FTIR and SEM analyses. Under batch mode experiments, the composite achieved maximum adsorption of the Cr(VI) ion (99.53 ± 1.4%, i.e., 1636.49 mg of Cr(VI)/150 mg of adsorbent) at pH 2, adsorbent dose of 150 mg/10 mL of solution and 30 min of contact time. The adsorption process was endothermic, feasible and spontaneous and followed a pseudo-2nd order kinetic model. The Cr ions were completely desorbed (99.32 ± 2%) from the composite using 30 mL of NaOH solution (2M); hence, the composite exhibited high efficiency for five consecutive cycles without prominent loss in activity. The adsorbent was washed with distilled water and diluted HCl (0.1M), then dried under vacuum at 60 °C for reuse. The XRD analysis confirmed the synthesis and incorporation of magnetic iron oxide at 2θ of 30.38°, 35.5°, 43.22° and 57.36°, respectively, and graphene oxide (GO) at 25.5°. The FTIR analysids revealed that the composite retained the configurations of the individual components, whereas the SEM analysis indicated that the magnetic Fe3O4–NPs (MNPs) dispersed on the surface of the PMMA/rGO sheets. To anticipate the behavior of breakthrough, the Thomas and Yoon–Nelson models were applied to fixed-bed column data, which indicated good agreement with the experimental data. This study evaluates useful reference information for designing a cost-effective and easy-to-use adsorbent for the efficient removal of Cr(VI) from wastewater. Therefore, it can be envisioned as an alternative approach for a variety of unexplored industrial-level operations.

Batch mode and continuous flow adsorption of hydrocarbon pollutants from refinery wastewater using graphene oxide derived from fish scales

“…This may be attributed to higher stream flow rates that cause a reduced contact time needed for complete adsorption and breakthrough concentration, the adsorbent in the fixed bed column becomes rapidly saturated, and the contact time is insufficient for the complete adsorption of hydrocarbons on the GO surface in the fixed bed column. 35 Fig. 11 shows the results.…”

Special Issue: Advanced Nanocomposite Materials Based on Graphene Oxide/Reduced Graphene Oxide: Potential Applications and Perspectives

“…Ullah et al described the nanocomposite synthesis of magnetic nanoparticle (MNPs) and r-GO in polymethylmethacrylate (PMMA) [9]. The combination of the high performance of PMMA (due to its mechanical and physical properties) with active adsorbents, such as GO magnetized using FeCl 3 and FeSO 4 salts, was proven to be an interesting approach for the removal of hazardous Cr(VI) from tannery wastewater through batchand continuous-mode adsorption [9].…”