Optimized preparation of activated carbon from municipal sewage sludge and application to the adsorption of azo dye from aqueous solutions

Kyung Won Jung, Seon Yong Lee, Young Jae Lee

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Abstract

In this study, the conditions for preparation of active carbon from municipal sewage sludge (MSS) were optimized from application to the efficient removal of the azo dye, Acid Orange 7 (AO7), from aqueous solutions. To maximize the adsorption capacity (response variable) of the MSS-derived activated carbon (MSS-AC), a 3k Box–Behnken design based on response surface methodology was used to simultaneously optimize five important conditions (independent variables), that is, carbonizing temperature (400–600°C), carbonizing time (0.5–2.0 h), impregnation ratio (1.0–3.5 g KOH/g MSS), activating temperature (600–800°C), and activating time (0.5–2.0 h). The optimal conditions were established as carbonizing temperature: 509°C, carbonizing time: 1.25 h, impregnation ratio: 2.3 g KOH/g MSS, activating temperature: 681°C, and activating time: 1.21 h, with an overall desirability function of 0.991. Further, the effects of various key parameters (solution pH, ionic strength, adsorbent dosage, initial concentration, contact time, and temperature) on the adsorption of AO7 on the as-synthesized MSS-AC were elucidated through a series of batch experiments. Adsorption kinetics and isotherm studies revealed that the adsorption process is accurately described by the pseudo-second order and Sips models. The theoretical maximum adsorption capacity of AO7 was found to be ~1410 mg/g at 25°C, which is superior to that of the other adsorbents reported to date. Additionally, the intraparticle diffusion model suggested that the adsorption was controlled by both external surface adsorption and intraparticle diffusion. Thermodynamic studies also suggested that the adsorption of AO7 by MASS-AC is exothermic and is governed by physisorption.

Original languageEnglish
JournalEnvironmental Progress and Sustainable Energy
DOIs
Publication statusAccepted/In press - 2018 Jan 1

Fingerprint

Azo Compounds
Azo dyes
Sewage sludge
Activated carbon
activated carbon
dye
aqueous solution
adsorption
Adsorption
Acids
acid
Impregnation
temperature
Adsorbents
Temperature
Physisorption
sewage sludge
Ionic strength
Isotherms
isotherm

Keywords

  • activated carbons
  • adsorption
  • Box–Behnken design, azo dye
  • Municipal sewage sludge
  • response surface methodology

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Chemical Engineering(all)
  • Water Science and Technology
  • Waste Management and Disposal
  • Environmental Science(all)

Cite this

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title = "Optimized preparation of activated carbon from municipal sewage sludge and application to the adsorption of azo dye from aqueous solutions",
abstract = "In this study, the conditions for preparation of active carbon from municipal sewage sludge (MSS) were optimized from application to the efficient removal of the azo dye, Acid Orange 7 (AO7), from aqueous solutions. To maximize the adsorption capacity (response variable) of the MSS-derived activated carbon (MSS-AC), a 3k Box–Behnken design based on response surface methodology was used to simultaneously optimize five important conditions (independent variables), that is, carbonizing temperature (400–600°C), carbonizing time (0.5–2.0 h), impregnation ratio (1.0–3.5 g KOH/g MSS), activating temperature (600–800°C), and activating time (0.5–2.0 h). The optimal conditions were established as carbonizing temperature: 509°C, carbonizing time: 1.25 h, impregnation ratio: 2.3 g KOH/g MSS, activating temperature: 681°C, and activating time: 1.21 h, with an overall desirability function of 0.991. Further, the effects of various key parameters (solution pH, ionic strength, adsorbent dosage, initial concentration, contact time, and temperature) on the adsorption of AO7 on the as-synthesized MSS-AC were elucidated through a series of batch experiments. Adsorption kinetics and isotherm studies revealed that the adsorption process is accurately described by the pseudo-second order and Sips models. The theoretical maximum adsorption capacity of AO7 was found to be ~1410 mg/g at 25°C, which is superior to that of the other adsorbents reported to date. Additionally, the intraparticle diffusion model suggested that the adsorption was controlled by both external surface adsorption and intraparticle diffusion. Thermodynamic studies also suggested that the adsorption of AO7 by MASS-AC is exothermic and is governed by physisorption.",
keywords = "activated carbons, adsorption, Box–Behnken design, azo dye, Municipal sewage sludge, response surface methodology",
author = "Jung, {Kyung Won} and Lee, {Seon Yong} and Lee, {Young Jae}",
year = "2018",
month = "1",
day = "1",
doi = "10.1002/ep.13008",
language = "English",
journal = "Environmental Progress and Sustainable Energy",
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T1 - Optimized preparation of activated carbon from municipal sewage sludge and application to the adsorption of azo dye from aqueous solutions

AU - Jung, Kyung Won

AU - Lee, Seon Yong

AU - Lee, Young Jae

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Y1 - 2018/1/1

N2 - In this study, the conditions for preparation of active carbon from municipal sewage sludge (MSS) were optimized from application to the efficient removal of the azo dye, Acid Orange 7 (AO7), from aqueous solutions. To maximize the adsorption capacity (response variable) of the MSS-derived activated carbon (MSS-AC), a 3k Box–Behnken design based on response surface methodology was used to simultaneously optimize five important conditions (independent variables), that is, carbonizing temperature (400–600°C), carbonizing time (0.5–2.0 h), impregnation ratio (1.0–3.5 g KOH/g MSS), activating temperature (600–800°C), and activating time (0.5–2.0 h). The optimal conditions were established as carbonizing temperature: 509°C, carbonizing time: 1.25 h, impregnation ratio: 2.3 g KOH/g MSS, activating temperature: 681°C, and activating time: 1.21 h, with an overall desirability function of 0.991. Further, the effects of various key parameters (solution pH, ionic strength, adsorbent dosage, initial concentration, contact time, and temperature) on the adsorption of AO7 on the as-synthesized MSS-AC were elucidated through a series of batch experiments. Adsorption kinetics and isotherm studies revealed that the adsorption process is accurately described by the pseudo-second order and Sips models. The theoretical maximum adsorption capacity of AO7 was found to be ~1410 mg/g at 25°C, which is superior to that of the other adsorbents reported to date. Additionally, the intraparticle diffusion model suggested that the adsorption was controlled by both external surface adsorption and intraparticle diffusion. Thermodynamic studies also suggested that the adsorption of AO7 by MASS-AC is exothermic and is governed by physisorption.

AB - In this study, the conditions for preparation of active carbon from municipal sewage sludge (MSS) were optimized from application to the efficient removal of the azo dye, Acid Orange 7 (AO7), from aqueous solutions. To maximize the adsorption capacity (response variable) of the MSS-derived activated carbon (MSS-AC), a 3k Box–Behnken design based on response surface methodology was used to simultaneously optimize five important conditions (independent variables), that is, carbonizing temperature (400–600°C), carbonizing time (0.5–2.0 h), impregnation ratio (1.0–3.5 g KOH/g MSS), activating temperature (600–800°C), and activating time (0.5–2.0 h). The optimal conditions were established as carbonizing temperature: 509°C, carbonizing time: 1.25 h, impregnation ratio: 2.3 g KOH/g MSS, activating temperature: 681°C, and activating time: 1.21 h, with an overall desirability function of 0.991. Further, the effects of various key parameters (solution pH, ionic strength, adsorbent dosage, initial concentration, contact time, and temperature) on the adsorption of AO7 on the as-synthesized MSS-AC were elucidated through a series of batch experiments. Adsorption kinetics and isotherm studies revealed that the adsorption process is accurately described by the pseudo-second order and Sips models. The theoretical maximum adsorption capacity of AO7 was found to be ~1410 mg/g at 25°C, which is superior to that of the other adsorbents reported to date. Additionally, the intraparticle diffusion model suggested that the adsorption was controlled by both external surface adsorption and intraparticle diffusion. Thermodynamic studies also suggested that the adsorption of AO7 by MASS-AC is exothermic and is governed by physisorption.

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KW - adsorption

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KW - Municipal sewage sludge

KW - response surface methodology

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