Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

Ihsanullah, Fahad Abdulaziz Al-Khaldi, Basel Abu-Sharkh, Abdalla Mahmoud Abulkibash, Muhammad Imran Qureshi, Tahar Laoui, Muataz Atieh

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

The present study addresses the application of raw and modified carbon nanotubes (CNTs) and activated carbon (AC) for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Surfaces of both the adsorbents were modified by acid treatment. Nitric acid was used to remove impurities and to introduce carboxylic functional groups on the surfaces of CNTs and AC. Raw and modified adsorbents (CNTs and AC) were characterized by scanning electron microscopy, Brunauer–Emmett–Teller surface area analysis, and thermogravimetric analysis. The influence of adsorbent dosage, contact time, agitation speed, and solution pH were evaluated on the Cr(VI) removal efficiency using batch adsorption experiments. The optimum pH for maximum adsorption of Cr(VI) was found to be 3 and 4 for AC and CNTs, respectively. Modified and raw AC were able to remove 99 and 92% of Cr(VI) ions, respectively, at 75 mg adsorbent dosage, agitation speed of 200 rpm, initial Cr(VI) concentration of 1 mg/L, contact time of 4 h, and solution pH 3, while the removal of Cr(VI) ions recorded maximum values of 87 and 80% for modified and raw CNTs under same treatment conditions. However, acid modification of CNTs was found to have no major effect on the percentage removal of Cr(VI) ions at low adsorbent dosage. Adsorption capacities of both the adsorbents were determined using batch adsorption experiments and experimental data were described by Langmuir and Freundlich adsorption isotherm models. However, Langmuir isotherm model was able to best describe the adsorption of Cr(VI) ions on raw and modified forms of CNTs and AC. Maximum adsorption capacity (qe) was found to be 2.024 and 1.805 mg/g for raw and modified AC, while 1.021 and 0.964 mg/g for raw and modified CNTs.

Original languageEnglish
JournalDesalination and Water Treatment
DOIs
Publication statusAccepted/In press - 20 Mar 2015

Fingerprint

Activated carbon
activated carbon
chromium
Chromium
Carbon nanotubes
aqueous solution
Adsorbents
adsorption
Adsorption
Acids
acid
ion
Ions
Contacts (fluid mechanics)
isotherm
effect
carbon nanotube
Nitric acid
nitric acid
Adsorption isotherms

Keywords

  • Activated carbon
  • Adsorption
  • Carbon nanotubes
  • Hexavalent chromium
  • Water treatment

ASJC Scopus subject areas

  • Pollution
  • Water Science and Technology
  • Ocean Engineering

Cite this

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes. / Ihsanullah; Al-Khaldi, Fahad Abdulaziz; Abu-Sharkh, Basel; Abulkibash, Abdalla Mahmoud; Qureshi, Muhammad Imran; Laoui, Tahar; Atieh, Muataz.

In: Desalination and Water Treatment, 20.03.2015.

Research output: Contribution to journalArticle

Ihsanullah ; Al-Khaldi, Fahad Abdulaziz ; Abu-Sharkh, Basel ; Abulkibash, Abdalla Mahmoud ; Qureshi, Muhammad Imran ; Laoui, Tahar ; Atieh, Muataz. / Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes. In: Desalination and Water Treatment. 2015.
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abstract = "The present study addresses the application of raw and modified carbon nanotubes (CNTs) and activated carbon (AC) for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Surfaces of both the adsorbents were modified by acid treatment. Nitric acid was used to remove impurities and to introduce carboxylic functional groups on the surfaces of CNTs and AC. Raw and modified adsorbents (CNTs and AC) were characterized by scanning electron microscopy, Brunauer–Emmett–Teller surface area analysis, and thermogravimetric analysis. The influence of adsorbent dosage, contact time, agitation speed, and solution pH were evaluated on the Cr(VI) removal efficiency using batch adsorption experiments. The optimum pH for maximum adsorption of Cr(VI) was found to be 3 and 4 for AC and CNTs, respectively. Modified and raw AC were able to remove 99 and 92{\%} of Cr(VI) ions, respectively, at 75 mg adsorbent dosage, agitation speed of 200 rpm, initial Cr(VI) concentration of 1 mg/L, contact time of 4 h, and solution pH 3, while the removal of Cr(VI) ions recorded maximum values of 87 and 80{\%} for modified and raw CNTs under same treatment conditions. However, acid modification of CNTs was found to have no major effect on the percentage removal of Cr(VI) ions at low adsorbent dosage. Adsorption capacities of both the adsorbents were determined using batch adsorption experiments and experimental data were described by Langmuir and Freundlich adsorption isotherm models. However, Langmuir isotherm model was able to best describe the adsorption of Cr(VI) ions on raw and modified forms of CNTs and AC. Maximum adsorption capacity (qe) was found to be 2.024 and 1.805 mg/g for raw and modified AC, while 1.021 and 0.964 mg/g for raw and modified CNTs.",
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AU - Abu-Sharkh, Basel

AU - Abulkibash, Abdalla Mahmoud

AU - Qureshi, Muhammad Imran

AU - Laoui, Tahar

AU - Atieh, Muataz

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AB - The present study addresses the application of raw and modified carbon nanotubes (CNTs) and activated carbon (AC) for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Surfaces of both the adsorbents were modified by acid treatment. Nitric acid was used to remove impurities and to introduce carboxylic functional groups on the surfaces of CNTs and AC. Raw and modified adsorbents (CNTs and AC) were characterized by scanning electron microscopy, Brunauer–Emmett–Teller surface area analysis, and thermogravimetric analysis. The influence of adsorbent dosage, contact time, agitation speed, and solution pH were evaluated on the Cr(VI) removal efficiency using batch adsorption experiments. The optimum pH for maximum adsorption of Cr(VI) was found to be 3 and 4 for AC and CNTs, respectively. Modified and raw AC were able to remove 99 and 92% of Cr(VI) ions, respectively, at 75 mg adsorbent dosage, agitation speed of 200 rpm, initial Cr(VI) concentration of 1 mg/L, contact time of 4 h, and solution pH 3, while the removal of Cr(VI) ions recorded maximum values of 87 and 80% for modified and raw CNTs under same treatment conditions. However, acid modification of CNTs was found to have no major effect on the percentage removal of Cr(VI) ions at low adsorbent dosage. Adsorption capacities of both the adsorbents were determined using batch adsorption experiments and experimental data were described by Langmuir and Freundlich adsorption isotherm models. However, Langmuir isotherm model was able to best describe the adsorption of Cr(VI) ions on raw and modified forms of CNTs and AC. Maximum adsorption capacity (qe) was found to be 2.024 and 1.805 mg/g for raw and modified AC, while 1.021 and 0.964 mg/g for raw and modified CNTs.

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KW - Hexavalent chromium

KW - Water treatment

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