Evolution of Phosphorus-Containing Groups on Activated Carbons during Heat Treatment

Wang, Yongfang; Zuo, Songlin; Yang, Jianxiao; Yoon, Seong Ho

doi:10.1021/acs.langmuir.7b00095

Cited by 79 publications

(44 citation statements)

References 45 publications

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“…Esse espectro é dominado por um sinal na região próxima de 0 ppm, típica de grupos fosfatos. 18,22 O sinal obtido na amostra carbonizada (amostra PC700) é similar, mas bem mais intenso (o número total de transientes acumulados para a obtenção desse espectro foi ~1400). Nesse espectro é possível observar um desdobramento do sinal devido a grupos fosfatos, com a presença de sinais secundários em torno de -3 e -10 ppm, possivelmente associados a grupos fosfatos em cadeias.…”

Section: Difração De Raios Xunclassified

“…Nesse espectro é possível observar um desdobramento do sinal devido a grupos fosfatos, com a presença de sinais secundários em torno de -3 e -10 ppm, possivelmente associados a grupos fosfatos em cadeias. 18,22 No caso da amostra ativada (amostra PCHP3-1), o sinal é muito mais intenso; apenas 32 transientes foram somados para dar origem ao espectro exibido na Fig. 5b.…”

Section: Difração De Raios Xunclassified

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Production of Phosphorus-Containing Activated Carbons From Coffee Husk and Application in Adsorption Processes

et al. 2020

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The present research investigates the production of activated carbons from natural resources using methods of chemical activation and the use of these activated carbons for the adsorption of organic molecules in aqueous media. The lignocellulosic precursor used for the activated carbon preparation was coffee husk, which is an agricultural waste generated during coffee production in many regions of Brazil. The activation was achieved by the reaction between phosphoric acid (H 3 PO 4) and the raw coffee husk. The materials were characterized by thermogravimetry, textural analysis, infrared spectroscopy, solidstate nuclear magnetic resonance and X-ray diffraction. From the analysis of the produced activated carbons, it was found that the H 3 PO 4 : coffee husk weight ratio of 3:1 results in a phosphorus-containing material with a well-developed porosity; larger amounts of H 3 PO 4 resulted in negligible increase in the specific surface area. The sample prepared with the 3:1 weight ratio was applied in liquid phase adsorption experiments, with studies of the kinetics of methlylene blue adsorption and the application of Langmuir and Freundlich theoretical models to the equilibrium adsorption isotherms. O presente trabalho envolve a preparação de carvões ativados a partir de precursores naturais utilizando métodos de ativação química e estudos sobre a aplicação desses carvões ativados em processos de adsorção em fase líquida. Como precursor, foi utilizada a palha de café, material de origem vegetal com características de rejeito agrícola produzido em grandes quantidades em várias partes do Brasil. A ativação foi conduzida por reação do precursor cru com ácido fosfórico (H3PO4). Os materiais foram caracterizados por termogravimetria, análise textural, espectroscopia no infravermelho, espectroscopia por ressonância magnética nuclear no estado sólido e difração de raios X. A partir dos vários carvões produzidos em diferentes condições, foi encontrado que a proporção em massa de ácido fosfórico:palha de café de 3:1 na ativação resultou em carvões ativados contendo fósforo e apresentando elevada porosidade; maiores teores de ácido não levaram a alterações significativas na área superficial específica. A amostra produzida com a razão 3:1 foi a seguir utilizada em ensaios de adsorção em fase líquida, sendo investigada a cinética de adsorção do corante azul de metileno, assim como a aplicação das isotermas de Langmuir e Freundlich para descrição das isotermas de adsorção em equilíbrio.

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Section: Difração De Raios Xunclassified

Production of Phosphorus-Containing Activated Carbons From Coffee Husk and Application in Adsorption Processes

et al. 2020

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“…During the modification process, phosphates from dissociated H 3 PO 4 interact with the graphite-like crystallites of the biochar. This interaction results in P-O-C linkages on the modified biochar to form a net negatively charged surface as (Wang et al 2017). The synthesized M SP B-HPO as a carbonaceous material is able to adsorb the pH modified Dfc via π-π interactions and these interactions are controlled by the changes in pKa of Dfc because changes in the pKa values can affect Dfc to take on cationic, neutral, or anionic character (Jiang et al 2015;Lonappan et al 2018).…”

Section: Effect Of Ph On the Adsorption Of Dfc By M Sp B-hpomentioning

confidence: 99%

Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution

Bagheri

Abu-Danso

Iqbal

et al. 2019

Environ Sci Pollut Res

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In this study, Moringa seed powder (M SP ) was pyrolyzed at 450°C to synthesize Moringa seed powder biochar (M SP B) and treated with phosphoric acid (H 3 PO 4 ) to synthesize phosphate-modified Moringa seed powder biochar (M SP B-HPO) as an adsorbent for the removal of diclofenac (Dfc) from aqueous solution. Fourier transform infrared (FTIR) analysis, energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and pH point of zero charge (pH pzc ) were conducted to give more insight into the adsorbent's properties. The SEM analysis showed the transformations in the surface morphology from the parent material to the synthesized materials after the thermal and acid treatment. EDS analysis revealed the variation in the elemental composition of the materials prior to and after adsorption of Dfc ions. The FTIR analysis showed changes and peak intensities of functional groups involved in Dfc removal. The pH pzc showed the charge carried by M SP B-HPO in different pH conditions. Isotherm data best matched the Sips model, and the pseudo-second-order model best described the adsorption kinetics. The maximum adsorption capacity of M SP B-HPO by Sips model was found to be 100.876 mg g −1 .

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“…The oxidation states and chemical nature of surface phosphorus species play a critical role in tuning the sizes and uniformity of RuNCs. High‐temperature thermal treatment can vary the oxidation states and the contents of phosphorus species on the surface of carbon (P‐C‐T, in which T denotes the calcination temperature) . The evolution of surface phosphorus species was carefully investigated by XPS after the thermal treatment of as‐prepared P‐C under N 2 in the temperature range of 400–800 °C (see Figure S4 for nanostructures of P‐C‐T).…”

Section: Figurementioning

confidence: 99%

“…A downshift in the P 2p binding energy about 0.5 eV was observed below 600 °C; however, this shift was normalized for the P‐C samples calcined at 700 °C and 800 °C. We further fitted the P 2p peak into four contributions, including P=O, C‐O‐P, C‐P‐O and C 3 ‐P‐O at 135.7, 134.3, 133.3, and 132.1 eV, respectively (see Figure S6 for chemical structures of those P‐containing species) –. The detailed fitting results are summarized in Table .…”

Section: Figurementioning

confidence: 99%

Ultrafine and Ligand‐Free Precious Metal (Ru, Ag, Au, Rh and Pd) Nanoclusters Supported on Phosphorus‐Doped Carbon

Liu

Zhong

et al. 2018

Chemistry A European J

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We report the use of phosphorus-doped carbon (P-C) as support to grow ultrasmall (1-3 nm) and ligand-free precious metal nanocrystals (PMNCs) via chemical reduction. We show that the valence states of surface phosphorus species are critical in tuning the affinity between the carbon support and metal precursors, which rationally controls the loading size and uniformity of resultant PMNCs. Five kinds of PMNCs, including Ru, Ag, Au, Rh, and Pd, were grown in situ to demonstrate the key role of surface phosphorus sites on the P-C support. As a proof-of-concept application, Ru nanocatalysts with an average diameter of 1.0±0.2 nm supported on P-C were examined for the electrocatalytic hydrogen evolution reaction (HER). Ultrasmall and ligand-free Ru nanocatalysts exhibited superior HER activity and stability compared to its counterparts with surface agents or larger sizes. An overpotential of 27.6 mV (vs. reversible hydrogen electrode) for Ru nanocatalysts was achieved at a current density of 10 mA cm . This novel method opens a new avenue to immobilize ligand-free and well-dispersed PMNCs on carbon; and, more importantly, it provides a new library of supported PMNCs with high catalytic activity.

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Evolution of Phosphorus-Containing Groups on Activated Carbons during Heat Treatment

Cited by 79 publications

References 45 publications

Production of Phosphorus-Containing Activated Carbons From Coffee Husk and Application in Adsorption Processes

Production of Phosphorus-Containing Activated Carbons From Coffee Husk and Application in Adsorption Processes

Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution

Ultrafine and Ligand‐Free Precious Metal (Ru, Ag, Au, Rh and Pd) Nanoclusters Supported on Phosphorus‐Doped Carbon

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