Graphene Oxide/Fe-Based Composite Pre-Polymerized Coagulants: Synthesis, Characterization, and Potential Application in Water Treatment

Abstract

<jats:p>This study presents for the first time the synthesis and characterization of GO (graphene oxide), PFSiC (polyferric silicate chloride), and hybrid GO-PFSiC derivatives, aiming to enhance synergistically the performance of coagulation, when applied for the treatment of water. The structure and the morphology of composite GO-PFSiC coagulants were studied in detail by the application of FTIR, XRD, and SEM characterization techniques. Furthermore, the proposed coagulants were applied for the treatment of simulated turbid surface water. The effects of the reagent’s dosage, pH value, and experimental/operational conditions on the coagulation efficiency, applied mainly for the removal of turbidity, were examined. The results, obtained from the FTIR and XRD measurements, showed the presence of a bond between the PFSiC and the GO surface, indicating that the PFSiC particles are distributed uniformly on the surface of graphene, which was also confirmed by the SEM images. Especially, the composite compound GO-PFSiC1.5-15-0.5 presents the most uniform distribution of iron on the surface of graphene oxide and exhibits the optimum coagulation efficiency, while it significantly reduces the turbidity for doses above 3–5 mg/L, i.e., achieving the respective legislation limit as proposed by WHO. Specifically, at the alkaline pH values (&gt;7.9), the removal of turbidity reaches 96%. Consequently, the results of this study render these materials as potential coagulant agents for further research and applications, aiming to also achieve the co-removal of other water components.</jats:p>

Simple Scalable Fabrication of Laser-Induced Graphene Composite Membranes for Water Treatment

“…Also, when the PVA concentration was increased further from 3% to 5%, nonhomogeneous membrane coatings resulted and these membranes were not analyzed further, while the 2.5% LIG-PVA Next, sludge water (initial NTU of ∼100) taken from a membrane bioreactor was filtered using the series of LIG-PVA membrane composites (Figure 2a,b). 25 The turbidity was lowest when the 2.5% LIG-PVA composite was used (0.60 NTU) and water appeared clear (Figure 2a, inset). In comparison, using only a LIG membrane, the resulting turbidity was ∼10 NTU, and a membrane without LIG gave ∼17 NTU.…”

“…Next, sludge water (initial NTU of ∼100) taken from a membrane bioreactor was filtered using the series of LIG-PVA membrane composites (Figure a,b) . The turbidity was lowest when the 2.5% LIG-PVA composite was used (0.60 NTU) and water appeared clear (Figure a, inset).…”

Morphological Characterization and Lumped Element Model of Graphene and Biochar Thick Films

“…C 2021, 7, 36 2 of 13 ecologically friendly [13,14]. Furthermore, it has the capability to seize carbon from the environment therefore it is considered carbon negative material, which is very useful given the fact that carbon emissions are ever increasing [15].…”

“…Biochar is obtained as a result of pyrolyzing organic wastes [12]. Since its synthesis does not require harsh solvents and other petroleum-based materials therefore it is considered ecologically friendly [13,14]. Furthermore, it has the capability to seize carbon from the environment C 2021, 7, 36 2 of 13 therefore it is considered carbon negative material, which is very useful given the fact that carbon emissions are ever increasing [15].…”

A Mini Review of Recent Findings in Cellulose-, Polymer- and Graphene-Based Membranes for Fluoride Removal from Drinking Water

“…Recently, graphene has attracted wide attention of researchers in various fields due to its excellent properties, such as chemical and thermal stability, as well as the mechanical flexibility and large specific surface area that make it a potential candidate as an effective adsorbent [56,57]. However, because graphene sheets consist of hexagonally arrayed sp 2bonded carbon atoms [58], they can only adsorb substances through van der Waals forces.…”