Modification of the surface chemistry of activated carbons

Figueiredo, José L.; Pereira, M.F.R.; Freitas, M.M.A.; Órfão, J.J.M.

doi:10.1016/s0008-6223(98)00333-9

Cited by 2,790 publications

(2,072 citation statements)

References 25 publications

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“…The concentration of the evolved CO and CO 2 increased from 1200 to 380 mmol g À1 , respectively, for the AC, to 5140 and 3040 mmol g À1 , for the ACNA. This strong increase in the concentration of functional groups upon nitric acid oxidation, as observed in Table 2, is mainly attributed to the presence of large amounts of surface acidic carboxylic groups (CO 2 peak maxima 510-720 K) and phenols (CO peak maxima 900-990 K) on the material [22,23,25]. The introduction of functional groups decomposing as CO and CO 2 on the surface of the materials ACHP and ACSA is rather modest.…”

Section: Catalysts Characterizationmentioning

confidence: 89%

“…1 and the corresponding concentration of the monitored species gathered in Table 2, allowing the comparison of the total amounts of functional groups introduced on the surface of the carbon samples subjected to the different liquid phase treatments. The TPD results also allow the identification and quantification of the functional groups present on the materials surface by peak assignment and deconvolution procedures, as described elsewhere [22,23]. The release of CO ( Fig.…”

Section: Catalysts Characterizationmentioning

confidence: 99%

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Activated carbons treated with sulphuric acid: Catalysts for catalytic wet peroxide oxidation

et al. 2010

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Section: Catalysts Characterizationmentioning

confidence: 89%

Section: Catalysts Characterizationmentioning

confidence: 99%

Activated carbons treated with sulphuric acid: Catalysts for catalytic wet peroxide oxidation

et al. 2010

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“…above 400 °C (third step), since the oxidizing atmosphere used is different from that one used by these authors. 23,24 In addition, it can be observed that the activated carbon samples have similar decomposition profiles in the TGA curves with intense exothermic peaks (DTA) related to the thermal decomposition of matter organic, so that the last mass loss steps, which occur overlapped, can also be related to the carbon skeleton of the ACs, leading to ash with average percentage of 7.4%. The data related to qualitative analysis by EDX for identification of the main metal elements in form of its oxides are shown in Table 1.…”

Section: Tg-dta Of the Activated Carbonsmentioning

confidence: 97%

“…23 For the range 30 -100 °C, the FT-IR spectrum (a) shows bands located at around 3700 and 1500 cm -1 corresponding to adsorbed water, while between the ranges of 170 -400 and 530 -580 °C the spectrum (b) shows CO 2 as a thermal decomposition product of the carboxylic and lactonic groups respectively. 24 For the ranges of 400 -530 and 580 -600 °C, the FT-IR spectrum (c) shows CO as the main product released. In the first range, the three bands of high intensity are probably related to the thermal decomposition of the phenolic and lactone surface groups, whereas the second range is due to the quinone groups.…”

Section: Analysis Of the Surface Groups By Ft-ir And Tg-dta/ft-irmentioning

confidence: 99%

Thermogravimetric and spectroscopic study (TG–DTA/FT–IR) of activated carbon from the renewable biomass source Babassu

Oliveira¹,

Andrade²,

Trindade³

et al. 2016

Quim. Nova

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carbons (ACs) with well-developed microstructure and high microporosity were obtained from biomass by potassium hydroxide activation. The preparation process consisted in producing carbon materials in the ratios of activating agent to raw material 70:30, 50:50, 30:70 and 25:75 (w/w) characterized by thermal analysis coupled to spectroscopy (TG-DTA / FT-IR), scanning electron microscopy (SEM), N 2 adsorption isotherms at -196 °C and activation isotherm at 500 and 600 °C for 3.0 h. Specific surface areas (SBET) within 728 and 1712 m 2 g -1 and (S mic ) within 1054 and 1923 m 2 g -1 were obtained, while the micropores surface area was calculated using the Dubinin-Astakhov (DA) equation and the pore size distribution calculated from density functional theory (DFT) was found to be in the range 1.09 -1.77 nm. Adsorption isotherms were fitted using Langmuir and Freundlich non-linear models and the adsorption capacity determined for methylene blue dye was between 27.13 and 459.20 mg g -1 .

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“…It was reported that acidic oxygen surface complexes (e.g. carboxylic, phenolic, and lactonic groups) would be introduced predominantly onto activated carbons when they were treated with oxidizing agents such as H 2 O 2 and HNO 3 (Castilla et al, 1995;Figueiredo et al, 1999). Therefore, the lower pH pzc of the modified activated carbon shown in Table 1 is probably due to the formation of acidic function groups on the surface.…”

Section: Comparison Of Modified Activated Carbonsmentioning

confidence: 98%

Catalytic decomposition of hydrogen peroxide and 4-chlorophenol in the presence of modified activated carbons

et al. 2003

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The objective of this research was to examine the heterogeneous catalytic decomposition of H 2 O 2 and 4-chlorophenol (4-CP) in the presence of activated carbons modified with chemical pretreatments. The decomposition of H 2 O 2 was suppressed significantly by the change of surface properties including the decreased pH pzc modified with oxidizing agent and the reduced active sites occupied by the adsorption of 4-CP. The apparent reaction rate of H 2 O 2 decomposition was dominated by the intrinsic reaction rates on the surface of activated carbon rather than the mass transfer rate of H 2 O 2 to the solid surface. By the detection of chloride ion in suspension, the reduction of 4-CP was not only attributed to the advanced adsorption but also the degradation of 4-CP. The catalytic activity toward 4-CP for the activated carbon followed the inverse sequence of the activity toward H 2 O 2 , suggesting that acidic surface functional group could retard the H 2 O 2 loss and reduce the effect of surface scavenging resulting in the increase of the 4-CP degradation efficiency. Few effective radicals were expected to react with 4-CP for the strong effect of surface scavenging, which could explain why the degradation rate of 4-CP observed in this study was so slow and the dechlorination efficiency was independent of the 4-CP concentration in aqueous phase. Results show that the combination of H 2 O 2 and granular activated carbon (GAC) did increase the total removal of 4-CP than that by single GAC adsorption.

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Modification of the surface chemistry of activated carbons

Cited by 2,790 publications

References 25 publications

Activated carbons treated with sulphuric acid: Catalysts for catalytic wet peroxide oxidation

Activated carbons treated with sulphuric acid: Catalysts for catalytic wet peroxide oxidation

Thermogravimetric and spectroscopic study (TG–DTA/FT–IR) of activated carbon from the renewable biomass source Babassu

Catalytic decomposition of hydrogen peroxide and 4-chlorophenol in the presence of modified activated carbons

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