RETRACTED: Preparation and characterization of activated carbons from                     winemaking wastes and their adsorption of methylene blue

Alcaraz, Lorena; Fernández, Ana López; García‐Díaz, Irene; López, Félix A.

doi:10.1177/0263617418770295

Cited by 54 publications

(58 citation statements)

References 48 publications

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“…The highest obtained R 2 correlation coefficient values were for the Langmuir isotherm, which are displayed in Figure 7 each of the studied temperature. The calculated values qm increase with the temperature, in accordance to previous studies related to the MB adsorption by ACs obtained from different wastes [29,30]. In addition, the calculated values are similar to the qm experimental obtained (between 411-813 mg•g -1 ).…”

Section: Thermodynamic Adsorption Studiessupporting

confidence: 90%

“…Commercial ACs are mostly obtained from biomass waste [19,20]. Besides, many researches have been developed on the employ of biomass as a precursor of carbon active such as residues derives form tea, coffee or grapes and olives bones [6,21,22]. Within its wide variety of applications, the most common is the use of AC to removal several pollutants from wastewater due to its simplicity and low cost [9,18,[23][24][25].…”

Section: Introductionmentioning

confidence: 99%

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Extraction of Polyphenols and Synthesis of New Activated Carbon from Spent Coffee Grounds

Ramón-Gonçalves¹,

Alcaraz²,

Ferreras³

et al. 2019

Preprint

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A valorization process of spent coffee grounds (SCG) was studied. Thus, a two-stage process, a stage of extraction of the polyphenols and a stage of obtaining activated carbon (AC) by a carbonization process, was performed. The extraction was carried out with a hydro-alcoholic solution in a pressure reactor, modifying time and temperature. To optimize the extraction of polyphenols, a two-level factorial design with three replications at the central values was used. The best results were obtained by performing the extraction at 80 °C during 30 min, using a mixture of EtOH:H2O 1:1 (v/v) as extraction solution. Caffeine and chlorogenic acid were the most abundant compounds in the analyzed extracts, ranging from 0.09 to 4.8 mg∙g-1 and 0.06 to 9.7 mg∙g-1, respectively. The precursor obtained in the extraction stage were transformed into AC. An experimental design was realized in order to analyze the influence of different variables in the AC obtained process (reaction time and amount of potassium hydroxide used). Actived carbons with BET specific surface (SBET) comprised between 1600 m2∙g-1 and 2330 m2∙g-1 had a microporous surface. Under the optimum conditions, the obtained AC presented a maximum adsorption capacity of methylene blue (qm) between 411 mg∙g-1 and 813 mg∙g-1.

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Section: Thermodynamic Adsorption Studiessupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Extraction of Polyphenols and Synthesis of New Activated Carbon from Spent Coffee Grounds

Ramón-Gonçalves¹,

Alcaraz²,

Ferreras³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, the q m = 121.95 mg g −1 is higher than previous studies (Table 4), suggesting that our green-prepared rGO is an excellent option for conventional materials. Although activated carbon seems to be more profitable to be used for the removal of MB [68] (Table 4), its adsorption equilibrium time (150 min) is higher compared to the present study (30 min), most importantly, rGO has a wide range of applications from composites to high frequency devices [21].…”

Section: Temperaturementioning

confidence: 57%

The Adsorption of Methylene Blue on Eco-Friendly Reduced Graphene Oxide

et al. 2020

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Recently, green-prepared oxidized graphenes have attracted huge interest in water purification and wastewater treatment. Herein, reduced graphene oxide (rGO) was prepared by a scalable and eco-friendly method, and its potential use for the removal of methylene blue (MB) from water systems, was explored. The present work includes the green protocol to produce rGO and respective spectroscopical and morphological characterizations, as well as several kinetics, isotherms, and thermodynamic analyses to successfully demonstrate the adsorption of MB. The pseudo-second-order model was appropriated to describe the adsorption kinetics of MB onto rGO, suggesting an equilibrium time of 30 min. Otherwise, the Langmuir model was more suitable to describe the adsorption isotherms, indicating a maximum adsorption capacity of 121.95 mg g−1 at 298 K. In addition, kinetics and thermodynamic analyses demonstrated that the adsorption of MB onto rGO can be treated as a mixed physisorption–chemisorption process described by H-bonding, electrostatic, and π − π interactions. These results show the potential of green-prepared rGO to remove cationic dyes from wastewater systems.

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“…An almost linear relationship between Q e and A BET was observed (not shown). Thus, the highest Q e was found with cluster stalks-derived AC (Alcaraz et al, 2018) with A BET equal to 2662 m 2 /g and produced by KOH activation. Although the area was very high, it is necessary to take into account the time and the high amount of water used for washing samples prepared by chemical activation, and that KOH is highly corrosive and even potentially harmful for equipment and operators.…”

Section: Isotherms Studiesmentioning

confidence: 93%

Hydrothermal pre-treatment, an efficient tool to improve activated carbon performances

Mbarki

Selmi

Kesraoui

et al. 2019

Industrial Crops and Products

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In this study, the successful preparation of activated carbons from Corn Stigmata, either through direct pyrolysis and activation or through a preliminary additional hydrothermal carbonisation (HTC) step, was reported. It was shown that the latter allowed producing higher carbon yield, higher carbon content and higher BET area (A BET) after 2h of activation with CO 2 than what was observed for activated carbons (ACs) prepared in the same conditions but without HTC. The AC having the most developed porous texture, A BET = 1111 m 2 /g, was further investigated by FTIR, SEM and potentiometric titration, and its pH at point of zero charge was determined. Its performances in terms of methylene blue (MB) adsorption were studied and discussed in relation to its textural and chemical characteristics. Due to its very heterogeneous surface, the fractal Brouers-Sotolongo model was the most relevant for describing both kinetic and equilibrium adsorption data. The calculated thermodynamic parameters also showed that MB adsorption was spontaneous on this material. The high MB uptake at room temperature, compared to many other results published in the literature, further confirmed the interest of Corn Stigmata-derived hydrochars as precursors of activated carbons.

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RETRACTED: Preparation and characterization of activated carbons from winemaking wastes and their adsorption of methylene blue

Cited by 54 publications

References 48 publications

Extraction of Polyphenols and Synthesis of New Activated Carbon from Spent Coffee Grounds

Extraction of Polyphenols and Synthesis of New Activated Carbon from Spent Coffee Grounds

The Adsorption of Methylene Blue on Eco-Friendly Reduced Graphene Oxide

Hydrothermal pre-treatment, an efficient tool to improve activated carbon performances

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