Graphene and Graphene‐Based Composites: A Rising Star in Water Purification ‐ A Comprehensive Overview

Abstract

Graphene is an interesting two-dimensional carbon sheet possessing single-layered atom thickness that confers unique physical and chemical properties. The pristine graphene sheets have some limited applications in water purification, but the modification of graphene into the graphene composite by the incorporation of some functional groups or nanoparticles on the surface extensively increases its environmental applications. Recently, graphene nanocomposites have found to show very promising applications in all types of water purification. The present review highlights the recent developments in the applications of graphene and graphene-based composites as adsorbent, catalyst, photocatalyst, electrocatalyst, photoelectrocatalyst, and disinfection and desalination agent in comprehensive water purification systems. We primarily focus on the environmental engineering applications of graphene nanocomposites as sorbent materials for the elimination of toxic inorganic (cationic and anionic), organic, and mixed/multiple pollutants, and as catalysts for the degradation of toxic organic contaminants using catalytic oxidation, photocatalytic oxidation, electrocatalytic oxidation, and photoelectrocatalytic oxidation. We have also discussed the use and feasibility of graphene nanocomposites in water disinfection and desalination. Finally, the future challenges and perspectives are discussed.

Crosslinked Egg White as Eco‐Friendly, Reusable, and Cost‐Effective Biosorbent for Rapid Removal of Indigo Carmine

“…Langmuir and Freundlich isotherms are widely employed models for the clarification of adsorption (or biosorption) of molecules from liquid phase. The Langmuir equation is given as follows: where Q e is the amount of IC per mass of adsorbent (mg g −1 ), Q max is the maximum adsorption capacity (mg g −1 ), C e is the equilibrium IC concentration (mg L −1 ), and K is a constant that is related with the adsorption rate . The Langmuir model is valid for adsorption onto a completely homogenous surface (identical sites with the same adsorption energy), all adsorption sites are equivalent and the surface is uniform .…”

“…Graphene and graphene composites are smart materials and have been used for removal of pollutants. Graphene, graphene oxide, and reduced graphene oxide have been widely used for removal of cationic and anionic dyes, and potentially toxic metal(s) . Surface modified graphene materials have also been widely used for adsorption of different potentially toxic metal(s) .…”

Environmental Applications of Boron‐Doped Diamond Electrodes: 1. Applications in Water and Wastewater Treatment

“…Recently, other materials such as BDD and Ni foam were also tested as cathode material. Use of graphene based materials in electro‐Fenton process improved its performance significantly and is detailed in previous articles ,. Among the cathodes tested the gas diffusion cathode and 3D carbon cathodes (carbon felt and carbon sponge) provide high oxidation/mineralization efficiency in wastewater treatment.…”

“…Use of graphene based materials in electro-Fenton process improved its performance significantly and is detailed in previous articles. [162,163] Among the cathodes tested the gas diffusion cathode and 3D carbon cathodes (carbon felt and carbon sponge) provide high oxidation/mineralization efficiency in wastewater treatment. On the other hand, 3D carbon cathodes are of low cost and can be easily handled.…”

Use of laponite as adsorbents for Ni(II) removal from aqueous solution

“…This equation can be linearized as follows, log q e 5log K F 1nlog c e (12) From the data of log q e vs. log c e , n and K F can be determined from the slope and intercept. This equation can be linearized as follows, log q e 5log K F 1nlog c e (12) From the data of log q e vs. log c e , n and K F can be determined from the slope and intercept.…”