Cement-Induced Coagulation of Aqueous Graphene Oxide with Ultrahigh Capacity and High Rate Behavior

Abstract

Graphene oxide (GO) has excellent physicochemical properties and is used in multiple areas. However, the potential toxicity and environmental problems associated with GO increase its risk to the ecological system. In this study, cement was employed as a coagulant to eliminate GO from aqueous solutions. The effects of the cement dosage, the contact time, and the concentration and volume of the aqueous GO solution on the GO coagulation capacity were investigated in detail. The results showed that the dosage of cement had a significant effect on the coagulation process, and coagulation equilibrium was achieved in less than 1 h. Compared to coagulants used to remove GO from water in other reports, cement exhibited an ultrahigh coagulation capacity of approximately 5981.2 mg/g with 0.4 mg/mL GO solution. The kinetic analysis showed that the GO removal behavior could be described by a pseudo second-order model. The in-depth mechanism of GO coagulation using cement included Ca2+-induced coagulation of GO and adsorption by the hydrated product of cement paste. The present study revealed that cement could be a very cheap and promising material for the efficient elimination of GO from aqueous solutions.

Eco-Friendly Reduction of Graphene Oxide by Aqueous Extracts for Photocatalysis Applications

“…It is also clarified that after the reduction of GO, the 2D band moved towards a higher value that suggests the stacking of the graphene layers. Since GO has different types of functional groups that can prevent the stacking of graphene layers, but after reduction due to the decrease of such functional groups, some graphene layers are stacked, and form multilayer RGO [ 18 , 46 ]. Figure 5 shows: (a) GO (unreduced), (b) HAB3 RGO- Capsicum 20% and (c) GOB3 RGO- Larrea 20%.…”

Visible light active dye-sensitizing titanium dioxide/graphene composites with excellent photocatalytic activity

“…The analysis reveals that the lattice stripe spacing of its 001 crystal plane is 0.34 nm, which is consistent with the previous literature. 17 Fig. 1d shows that TiO 2 is an elliptical rod-shaped nanoparticle with a length of approximately 33-35 nm and a width of 20 AE 2 nm.…”

Synergistic effect of graphene oxide and hydroxylated graphene on the enhanced properties of cement composites

“…1c), suggesting that a strong chemical bonding between GO and Ca 2+ . 41,42 Similarly, the D and G peaks in the spectrum of HO-G@Ca 2+ also exhibited a slight blue shi compared to that of HO-G, indicating that there was a weak interaction between Ca 2+ and HO-G.…”