Synergistic coagulation of GO and secondary adsorption of heavy metal ions on Ca/Al layered double hydroxides

Functionalized Graphene-Based Materials as Innovative Adsorbents of Organic Pollutants: A Concise Overview

“…Nanofiltration with filters of Teflon or PTFE, vacuum filtration and centrifugation are employed nowadays to separate graphene-derived nanomaterials from aqueous media, however, this increases operational costs. Therefore, coagulation agents, such as ZnO and MgO, should be employed after adsorption in order to ease its separation from adsorbate and minimize graphene's adverse influences on the environmental balance after its release (Wang et al, 2017d;Yao et al 2017). On the other hand, many researchers have applied magnetic nanoparticles successfully to the graphene basal plane via non-covalent functionalization (Shi and Ye, 2015) as an alternative for aggregation and ultracoagulation, processes which add new chemicals after pollutant removal.…”

“…(Cobos et al, 2018;Xue et al, 2018;Wang et al, 2017b;Wang et al, 2016b). Therefore, some disadvantages can also be pinpointed: high investment and syntheses cost, specific reactants may be needed to perform functionalization and certain operational conditions necessary, increasing the consumption of energy and other resources (Mahmoud et al, 2018); extensive reaction time is pointed out by some articles as a considerable obstacle in chemical functionalization, which increases its costs (Sainsbury et al, 2016); covalent functionalization generally is physically irreversible, hence reactants and graphene structures becomes irrecoverable ; despite graphene itself being reported as non-toxic by some works (Lazarevic-Pasti et al, 2018;Mahmoud et al, 2018), functionalized graphene may releases byproducts in the form of gases and ionic species during its synthesis reaction and washing; since their toxicity and harm to human health are not yet entirely known, their disposal in the environment may be treated as a liability (Yang et al, 2013a;Hu and Zhou, 2013); some functionalized graphenes are rather difficult to separate after the adsorptive process, requiring elevated energy consumption and complex operations, such as centrifugation, nanofiltration, decantation and precipitation in large tanks, which demands elevated costs of assembly, operation and maintenance (Yao et al, 2017;Zou et al 2016a), depending on the adsorption nature.…”

Designing Dual-Function Nanostructures for Water Purification in Sunlight

“…It means that two types of LDHs were grown and interacted with the layers of graphene oxide. The presence of graphene oxide caused narrowing for the d-spacing among the layers of LDHs because of grown of LDH over the layers of graphene oxide [26]. In addition, presence of graphene oxide caused appearance of new phase at 0.45 nm and 0.30 nm.…”

A novel synthesis of TiO2/GO nanocomposite for the uptake of Pb2+ and Cd2+ from wastewater

“…Recentlty, extensive efforts have applied to prepare graphene oxide constructed hybrid nanocomposites [22][23][24]. Nevertheless, there is still a technological void in research for which ideal porosity has to be reached for adsorption.…”