Adsorption of chlorophenols by multi-walled carbon nanotubes treated with HNO3 and NH3

Liao, Qiu; Sun, Jing; Gao, Lian

doi:10.1016/j.carbon.2007.12.009

Cited by 87 publications

(43 citation statements)

References 11 publications

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“…Due to their high surface area and large micropore volume, CNTs are also considered to be extremely good adsorbents and since the first report of their successful removal of dioxins [1], CNTs have been utilized for the sorption of a large number of different organic compounds from water [2][3][4][5][6][7][8]. The sorption properties of CNTs can be modified by chemical oxidation treatments using sodium hypochlorite (NaOCl), hydrogen peroxide (H 2 O 2 ), potassium permanganate (KMnO 4 ), and nitric acid (HNO 3 ) [2,5].…”

Section: Introductionmentioning

confidence: 99%

“…The sorption properties of CNTs can be modified by chemical oxidation treatments using sodium hypochlorite (NaOCl), hydrogen peroxide (H 2 O 2 ), potassium permanganate (KMnO 4 ), and nitric acid (HNO 3 ) [2,5]. Such oxidation treatments are able to remove impurities and hemispherical caps, increasing the surface area and introducing oxygen-containing functional groups [6,9], hence altering the sorption properties for organic chemicals [2,3,5]. For example, following treatment with acid, CNTs become more suitable for the sorption of low molecular weight and relatively polar trihalomethane molecules [3].…”

Section: Introductionmentioning

confidence: 99%

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Kinetics and thermodynamics of sorption of nitroaromatic compounds to as-grown and oxidized multiwalled carbon nanotubes

Shen

Shan

Dong

et al. 2009

Journal of Colloid and Interface Science

154

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The sorption kinetics and thermodynamics of 1,3-dinitrobenzene (DNB), m-nitrotoluene (mNT), p-nitrophenol (pNP), and nitrobenzene (NB) on as-grown and nitric acid-oxidized multiwalled carbon nanotubes (MWCNTs) were investigated. The sorption kinetics was well described by a pseudo-second-order rate model, while both Langmuir and Freundlich models described the sorption isotherms well and the sorption thermodynamic parameters of equilibrium constant (K 0 ), standard free energy ( G), standard enthalpy ( H), and standard entropy changes ( S) were measured. The values of H and G suggested that the sorption of nitroaromatics (NACs) onto MWCNTs was exothermic and spontaneous. The structure, number, and position of nitro groups of NACs were the main factors affecting the sorption rate and capacity. Treatment of the MWCNTs with nitric acid increased both the surface area and the pore volume and introduced oxygen-containing functional groups to the MWCNTs, which depressed the sorption of NACs onto MWCNTs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetics and thermodynamics of sorption of nitroaromatic compounds to as-grown and oxidized multiwalled carbon nanotubes

Shen

Shan

Dong

et al. 2009

Journal of Colloid and Interface Science

154

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“…The cause of this event is the existence of many available empty sites for adsorption at first; with the passage of time, the occupation of the remained sites becomes difficult because of the repulsive force between the solute molecules between the solid phase and the solution (38). In another study conducted by Liao et al on the adsorption of chlorothenols by multiwalled carbon, an equilibrium time of 30 minutes was obtained (39). As seen in Figure 5, the effect of initial phenol concentration on the adsorption process showed that by increasing phenol concentration, removal efficiency was decreased.…”

Section: Effects Of Contact Time and Primary Phenol Concentrationmentioning

confidence: 97%

Evaluation of removal efficiency of phenol from synthetic aqueous solutions by Citrullus colocynthis seed ash

Salari

Afsharnia

Moteallemi

et al. 2018

Environ Health Eng Manag

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Background: Phenol is a prevalent pollutant found in many industrial wastewaters, and it is paid singular attention because of its special features like high toxicity, carcinogenic properties, and vital gathering ability that affects the health of humans and the environment. One of the most important technologies for the removal of phenol is the use of adsorbents. The current study investigated the removal of phenol from synthetic aqueous solutions using Citrullus colocynthis seed ash. Methods: This study is experimental and was conducted on a pilot scale. The efficiency of phenol removal by C. colocynthis seed ash was evaluated in a batch system, and different parameters such as initial concentration of phenol (10, 20, 50, and 80 mg/L), contact time (2, 5, 10, and 30 minutes), pH (2-12), adsorbent dose (0.5, 1, 3, 5, and 10 g/L), and temperature were studied. Excel software was used for data analysis. The adsorption process was modeled with Freundlich and Langmuir isotherms at controlled temperatures. Results:The results showed that the highest removal rate of phenol was obtained at a pH of 2 (83.4%), initial phenol concentration of 20 ppm (66.4%), adsorbent dose of 5 g/L (86.8%), and contact time of 10 minutes. The evaluation of correlation coefficients showed that the phenol adsorbed by C. colocynthis seed ash was in greater accordance with the Freundlich model than the Langmuir model. Conclusion:In general, the results of this study revealed that C. colocynthis seed ash has suitable potential for use in removing phenol from aqueous solutions on operation and practical scales due to its low cost and easy access. Keywords: Phenol, Adsorption, Citrullus colocynthis Citation: Salari S, Afsharnia M, Moteallemi A, Ghasemi M. Evaluation of removal efficiency of phenol from synthetic aqueous solutions by Citrullus colocynthis seed ash.

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“…New materials such as multiwalled carbon nanotubes (MWCNTs) also have the potential for effective removal of organic compounds like phenol, chlorophenols, nitroaromatic compounds, etc. (Sheng et al 2010;Shen et al 2009;Arasteh et al 2010;Abdel Salam et al 2010;Ji et al 2010;Liao et al 2008;Tóth et al 2011;Wiśniewski et al 2012;Li et al 2013). However the relatively large surface area and the high sorption capacity of MWCNTs are compromised by their strong hydrophobic character, which results in self assembled aggregates.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneity of multiwalled carbon nanotubes based on adsorption of simple aromatic compounds from aqueous solutions

et al. 2014

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The surface heterogeneity of multiwalled carbon nanotubes (MWCNTs) is studied on the basis of adsorption isotherms from dilute aqueous phenol and dopamine solutions at various pH values. The generalized Langmuir-Freundlich (GLF) isotherm equation was applied to investigate the cooperative effect of the surface heterogeneity and the lateral interactions between the adsorbates. The theoretical isosteric heats of adsorption were obtained assuming that the heat of adsorption profile reveals both the energetic heterogeneity of the adsorption system and the strength of the interactions between the neighboring molecules. The adsorption energy distribution (AED) functions were calculated by using algorithm based on a regularization method. The great advantage of this method is that the regularization makes no assumption about the shape of the obtained energy distribution functions. Analysis of the isosteric heats of adsorption for MWCNTs showed that the influence of the surface heterogeneity is much stronger than the role of the lateral interactions. The most typical adsorption heat is 20-22 kJ/mol for both phenol and dopamine. After purification of nanotubes, heat value for phenol dropped to 16-17 kJ/mol. The range of the energy distribution is only slightly influenced by the surface chemistry of the nanotubes in the aqueous conditions.

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Adsorption of chlorophenols by multi-walled carbon nanotubes treated with HNO3 and NH3

Cited by 87 publications

References 11 publications

Kinetics and thermodynamics of sorption of nitroaromatic compounds to as-grown and oxidized multiwalled carbon nanotubes

Kinetics and thermodynamics of sorption of nitroaromatic compounds to as-grown and oxidized multiwalled carbon nanotubes

Evaluation of removal efficiency of phenol from synthetic aqueous solutions by Citrullus colocynthis seed ash

Heterogeneity of multiwalled carbon nanotubes based on adsorption of simple aromatic compounds from aqueous solutions

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