Adsorptive remediation of environmental pollutants using novel graphene-based nanomaterials

Abstract

Pollution of air, water and soil is a worldwide issue for the eco-environment and human society.Removal of various pollutants including inorganic and organic compounds from the environment is a big challenge. Adsorption techniques are usually simple and work effectively. However, the adsorption capacities of materials depend on their porous structure and surface properties. Graphene oxide and graphene are new carbonaceous nanomaterials. Graphene has a large theoretical specific surface area and graphene oxide has functional groups, indicating their potential for the adsorption processes. In the past few years, many investigations have been focused on the applications of graphene or composites in removal of pollutants from air and water. In this paper, we will review recent advances in graphene-related nanomaterials for adsorptive treatment of environmental pollution. Graphene oxide possesses several functional groups and strong acidity, exhibiting high adsorption for basic compounds and cations while graphene shows hydrophobic surface and presents high adsorption to chemicals due to strong π-π interaction. Modification of graphene oxide or graphene with metal oxides or organics can produce various nanocomposites, enhancing adsorption capacity and separation efficiency. Activation of graphene into porous carbonaceous material will be a promising way to further enhance adsorption capacity.

Functionalization of acidified multi-walled carbon nanotubes for removal of heavy metals in aqueous solutions

“…The concentration of the different cations before and after adsorption was determined using atomic absorption spectrometry (Agilent Technologies 200 Series AA). The adsorbed amounts of metal ions onto the acidified functionalized MWCNTs were determined according to the following equations [1]:…”

“…The most heavy metals in polluted waters include Hg, Pb, Ag, Cu, Cd, Cr, Zn, Ni, Co and Mn [1]. The heavy metals cannot be degraded or destroyed as they tend to bioaccumulate in food chains.…”

Nanotechnology: Future of Environmental Air Pollution Control

“…Carbon nanostructures have extremely physical properties like average pore diameter, pore volume, and surface area making them significant for industrial application as nanoadsorbents with high selectivity, affinity, and capacity. Further, the highly reactive surface sites or structures bonds can also play an important role in the adsorption (Gupta and Saleh , 2013;Wang et al, 2013). Moreover, the addition of other functional groups with oxygen can also provide new active sites for adsorption .…”

“…Most of the greenhouse gasses have permenant negative effect on atmosphere because of their capability to remain in the climate for many years. Air contaminants can be remediated and treated by various methods using nanomaterials as adsorbents (Gupta and Saleh , 2013;Wang et al, 2013;Bergmann and Machado, 2015).The creation of the carbon nanomaterials as well as methods to remove high quantities of gas pollutants has greatly investigated in the research field (Terrones et al, 2010;Wang et al, 2013).The properties of nanoadsorbents structure permit a great interaction with organic compounds via noncovalent forces such as hydrogen bonding, electrostatic forces, π-π and hydrophobic interactions, and van der Waals forces (Ren et al, 2011). Furthermore, carbon nanotubes (CNTs) structure allows the combination of one or more surface functional groups (OH, COOH, C=O), which may increase the selectivity and the stability and influences the maximum adsorption capacity of the resulting system (Gupta and Saleh , 2013).…”

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“…Modification of graphene with metal oxides nanoparticles (NPs) can produce various nanocomposites and enhancing adsorption capacity [10]. Among various photocatalytic materials, ZrO 2 NPs have the suitable material for photocatalytic activities because of its semiconducting properties [8,11], low thermal conductivity, water insolubility, catalysis [12][13][14], and optical properties [15,16].…”