Adsorption of Phenol from Aqueous Solutions by Carbon Nanomaterials of One and Two Dimensions: Kinetic and Equilibrium Studies

Abstract

Carbon nanomaterials have a great potential in environmental studies; they are considered as superior adsorbents of pollutants due to their physical and chemical properties. Functionalization and dimension play an important role in many functions of these nanomaterials including adsorption. In this research, adsorption process was achieved with one-dimension nanomaterials: single walled and multiwalled carbon nanotubes were used as received and after oxidation treatment also two-dimensional nanomaterials were used: graphene oxide and reduced graphene oxide. Carbon nanotubes were modified by hydrogen peroxide under microwave irradiation. The reduction of graphene oxide was achieved by using ascorbic acid.R2values obtained with the pseudo-second-order model are higher than 0.99. The results demonstrate that Freundlich isotherm provides the best fit for the equilibrium data (R2>0.94).RLvalues are between 0 and 1; this represents favorable adsorption between carbon nanomaterials and phenol. The adsorption process occurs byπ-πinteractions and hydrogen bonding and not by electrostatic interactions. The results indicate that the adsorption of phenol on carbon nanomaterials depends on the adsorbents’ surface area, and it is negatively influenced by the presence of oxygenated groups.

Catalytic wet peroxide oxidation of m‐cresol over novel Fe2O3 loaded microfibrous entrapped CNT composite catalyst in a fixed‐bed reactor

“…The reason is that the pore sizes of mesopores formed by Fe 2 O 3 particles enlarge the size distribution of CNTs. The curves indicate that mesopores with pore sizes between 3 and 5 nm present a wide distribution in supports and catalysts . Besides, the mesoporous and macroporous pore diameter distributions of the MF‐CNT supports and Fe 2 O 3 ‐MF‐CNT catalysts were tested by mercury porosimetry and the results were shown in Figure .…”

“…The curves indicate that mesopores with pore sizes between 3 and 5 nm present a wide distribution in supports and catalysts. 39 Besides, the mesoporous and macroporous pore diameter distributions of the MF-CNT supports and Fe 2 O 3 -MF-CNT catalysts were tested by mercury porosimetry and the results were shown in Figure 4. As can be seen, no pore size was observed between 20 and 100 nm for both samples, and the pore sizes of the macropores in the sample are about 6000-7000 nm.…”

Adsorptive Removal of Phenol from Aqueous Solution by Using Carbon Nanotubes and Magnetic BioChar

“…Equilibrium studies on the adsorption process are important in order to provide information on the adsorbent capacity or amount required to remove a unit mass of pollutant [26][27][28]. An adsorption isotherm indicates the surface properties of an adsorbent or to adsorption capacity towards certain pollutant which usually express by certain constant depends on the model being used.…”

Phenol dissociation on pristine and defective graphene

“…dioxin [3]) that constitute negative impacts on public health and the environment alike. As a solution, adsorption processes stand out in providing a viable clean-up treatment for this matter due to their relatively simple implementation [4]. Moreover in theory, ultrathin nanomaterials, such as graphene, exhibit remarkable properties to assist the adsorption procedure.…”

“…In relations to phenol-graphene interaction, phenolic materials have been used to adsorb epoxy (O) or hydroxyl (OH) in graphene oxide to synthesize graphene [18,19]. For the reverse process, Luz et al reported from their experiment that, phenol adsorbed weakly on graphene in a graphite-like interaction [4]. An experiment by Huang et al suggested the application of defective oxygenated graphene to attract water molecules for humidity sensor [20].…”