Maximizing the number of oxygen-containing functional groups on activated carbon by using ammonium persulfate and improving the temperature-programmed desorption characterization of carbon surface chemistry

Li, Na; Ma, Xiaoliang; Zha, Qingfang; Kim, Kyung-Soo; Chen, Yongsheng; Song, Chunshan

doi:10.1016/j.carbon.2011.07.015

Cited by 158 publications

(117 citation statements)

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“…Li et al also reported significant decrease in specific surface area from 2311 to 469 m 2 g ¹1 for 24 h in the oxidation of activated carbon using an APS/AC weight ratio of 9.1 at 60°C. 16 19 Additionally sulfuric acid would also play an important role in the oxidation and the decline in specific surface area. The nitric and sulfuric acids mixture was reported to intercalate complete graphite layers and significantly exfoliate the graphite.…”

Section: Resultsmentioning

confidence: 99%

“…15 Li et al studied the maximization of acidic oxygen functional groups of carboxy and lactone groups contributing to the adsorption of heavy metal cations with 2 M ammonium persulfate ((NH 4 ) 2 S 2 O 8 , APS) in 1 M H 2 SO 4 solution and found that oxygen functions could be maximized on the activated carbon (AC) with an APS/AC weight ratio of 9.1 at 60°C for 3 h. 16 In our experiments, 2 M APS in 1 M H 2 SO 4 solution was also used and influence of oxidation temperature and time with a higher APS-solution/AC ratio of 50 cm 3 g ¹1 on the adsorption of Pb(II) ions onto oxidized ACs was investigated, because the higher APS-solution/AC ratio at ambient temperature for oxidizing AC was demonstrated to significantly increase adsorptive removal of Cd(II) ions in our previous study. 17,18 In the present study, effect of equilibrium solution pH on the Pb(II) ions adsorption and changes in textural and chemical properties of oxidized ACs were also examined.…”

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confidence: 99%

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Adsorptive Removal of Pb(II) Ions from Aqueous Solution by (NH4)2S2O8 Oxidized Activated Carbons

Machida

Shimeng

Amano

et al. 2014

Bulletin of the Chemical Society of Japan

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A commercially available activated carbon (AC) was oxidized using 1 M H 2 SO 4 solution containing 2 M (NH 4 ) 2 S 2 O 8 oxidant with the solution to carbon ratio of 50 cm 3 g ¹1 by changing oxidation period ranging 1 to 10 days at ambient temperatures of 20 or 30°C to introduce carboxy groups onto the carbon surface to capture Pb(II) ions. Adsorptive removal of Pb(II) ions from aqueous solution was also examined with the oxidized ACs. The Pb(II) ion adsorption progressed via ion exchange with protons of carboxy groups bound to graphite and 2.2 mmol g ¹1 of Pb(II) could be accommodated at equilibrium pH above 4.0 for ACs oxidized for at least 10 days at 20°C and 4 days at 30°C. Decrease in specific surface area and yield and increase in oxygen and hydrogen content in ACs also observed during the (NH 4 ) 2 S 2 O 8 treatment implied that the oxidation could convert graphite sheets to smaller size by hydrolysis while many carboxy groups would be introduced to the peripherals of the graphite sheets to scavenge Pb(II) ions.Activated carbons (ACs) have long been widely applied for water purification to principally remove organic pollutants such as phenol and nitrobenzene utilizing their hydrophobic nature on the carbon surface. 13 Currently ACs have been extensively utilized and modified by numerous methods to change their structure and surface nature to remove such other contaminants as bulky and polar dye molecules, 4 heavy metal ions, 5,6 and anionic nitrate ions.7 For the removal of cationic heavy metal ions, a negatively charged surface is required; one is a basic site generated by introducing basic nitrogen and oxygen groups on the carbon surface and π-electrons in hydrophobic graphite layers, on the contrary the other is an acidic site such as carboxy groups in which cationic heavy metals are effectively adsorbed via ion-exchange with protons of carboxy groups on the hydrophilic carbon surface, and the ion-exchange mechanism has been supported in the literature.811 Hydroxy, lactone, and other oxygen functional groups, however, did not contribute to heavy metals adsorption very much particularly in acidic and neutral aqueous solution in our previous study. 9 Comparing to basic sites such as amino-groups and π-electrons, acidic carboxy sites adsorb heavy metal cations over a wide pH range from 4 to above 7 although basic sites work in basic solutions above pH 8, thereby increasing carboxy groups is one strategy to enhance the uptake of heavy metal cations.10,12 Kasnejad et al. found that Cu(II) adsorption was increased as much as 3.1 mmol g ¹1 at equilibrium aqueous solution pH about 6 for a commercial activated carbon modified by NH 3 after preoxidation with HNO 3 .13 Rangel-Mendez and Streat examined the effect of electrochemically oxidized activated carbon cloth made from polyacrylonitrile on Cd(II) adsorption and adsorption of 1.2 mmol g ¹1 could be achieved in solution pH above 5 at the expense of the reduction of specific surface area of AC by 35%.14 In this study, ammonium persulfate was used as an oxidant...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Adsorptive Removal of Pb(II) Ions from Aqueous Solution by (NH4)2S2O8 Oxidized Activated Carbons

Machida

Shimeng

Amano

et al. 2014

Bulletin of the Chemical Society of Japan

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“…These functional groups may include carboxyl, anhydride, lactone, phenolic, carbonyl, ether, and pyrone (Li et al, 2011). According to the literature (Gen and Ikuo, 2002;Thrower, 1989), the contents of carboxyl, lactone, phenolic, and carbonyl groups can be analyzed using a titration method.…”

Section: Analysis Of Functional Groupsmentioning

confidence: 99%

Adsorption–desorption characteristics of methyl ethyl ketone with modified activated carbon and inhibition of 2,3-butanediol production

Nien

Chang²,

Chang

2015

Journal of the Air & Waste Management Association

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Activated carbon (AC) is seldom applied for recovering ketone-based volatile organic compounds because of safety concerns. Adsorption of methyl ethyl ketone (MEK) with AC is a highly exothermic reaction that potentially causes fires in AC beds. Moreover, 2,3-butanediol (BDO) is produced in the desorbed solvent, causing yellowing and odor of the recovered solvent. This study applied a continuous adsorption-desorption apparatus for evaluating the operating capacities and BDO concentration in recovered MEK containing modified and original ACs. AC-1 (TAKETA-G2X) was used as the target for modification. The experimental results indicate that using MgO as the modifier increases the ignition point by 12°C and that applying KNO 3 as the modifier reduces the AC ignition point by 28°C (compared with AC-1). The BDO concentration of the desorbed MEK solvent can be reduced by increasing the loading of the modifying agent (Ethanolamine) (Im-1: 3.1 wt%; Im-5: 6.2 wt%). Moreover, applying the AC pretreated with nitrogen (Im-6) as adsorbent significantly reduces the BDO concentration (from 0.123 wt% to 0.073 wt%). Because desorption and purging procedures were performed in N 2 atmospheres, the BDO concentrations of the desorbed MEK solvents were relatively low and ranged from 0.032 wt% to 0.043 wt%. When the MEK concentration was reduced to 2000 ppm, lower BDO concentrations (0.012-0.022 wt%) were measured in the recovered MEK solvent. The way to modify activated carbon and a better desorbing sequence to effectively inhibit the oxidation of MEK to BDO are developed. The results obtained indicate that the BDO concentration in the desorbed solvent was lower than the original MEK solvent (0.023 wt%). Different approaches can be applied simultaneously to achieve high inhibition effects; however, carbon adsorption performance may be negatively affected.Implications: The study is motivated to improve the quality of recovered solvent and reduce fire hazards, particularly when AC is applied for adsorbing a ketone-based solvent (e.g., MEK). The experimental results indicate that the BDO concentration in the recovered solvent can be reduced and the ignition point of AC can be increased by modifying the AC with an appropriate agent.

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“…Moreover, the occurrence of functional groups on the surface of the electrode material and their character has high impact on the whole device. It can be found that the oxygen and nitrogen functional groups are the most commonly studied in the context of the electrochemical performance of materials [8,[11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…The carbons modified by wet methods are more frequently used as adsorbents in environmental applications [1,2,17,22,23]. One of the modifying methods is oxidation with the ammonium persulfate solution [12,24,25]. In the literature, it is noted that the oxidation conditions, including concentration, time and temperature, have a significant influence on the physicochemical properties of the obtained modified, activated carbon [11].…”

Section: Introductionmentioning

confidence: 99%

Persulfate treatment as a method of modifying carbon electrode material for aqueous electrochemical capacitors

Kopczyński

Pęziak-Kowalska

Lota

et al. 2016

J Solid State Electrochem

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The activated carbon was modified by the wet method with a solution of ammonium persulfate at room temperature with different times. Kinetics studies showed that the modification took place mostly during the first 60 min of the process. The physicochemical properties of the obtained carbon were evaluated by thermogravimetric studies, Raman and FTIR spectroscopy, elementary and BET analyses. Furthermore, the fabricated material was applied in symmetric capacitors operated on the three aqueous electrolytes (1 M H 2 SO 4 , 6 M KOH and 1 M Na 2 SO 4 ). Mild conditions of the modification process are optimal to obtain electroactive groups on the carbon surface, which make this material useful in a supercapacitor application. In our studies, we noticed that this type of functional groups mainly appears on the surface of the activated carbon, in the first oxidation stage. With prolonged oxidation, they may transform into undesirable groups. The results show that this kind of modification improves the capacity of all the tested supercapacitors. It was connected mainly with an increase of the carbon material's wettability and in the case of capacitor operated in acid and base electrolytes due to a redox reaction of oxygen functional groups.

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Maximizing the number of oxygen-containing functional groups on activated carbon by using ammonium persulfate and improving the temperature-programmed desorption characterization of carbon surface chemistry

Cited by 158 publications

References 39 publications

Adsorptive Removal of Pb(II) Ions from Aqueous Solution by (NH4)2S2O8 Oxidized Activated Carbons

Adsorptive Removal of Pb(II) Ions from Aqueous Solution by (NH4)2S2O8 Oxidized Activated Carbons

Adsorption–desorption characteristics of methyl ethyl ketone with modified activated carbon and inhibition of 2,3-butanediol production

Persulfate treatment as a method of modifying carbon electrode material for aqueous electrochemical capacitors

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