Production of humic acids from lignites and subbituminous coals by alkaline-air oxidation

Juan, Roberto; Ruiz, Carolina Castillo; Andrés, José Manuel Palao; Estévez, Mercedes

doi:10.1016/0016-2361(90)90167-o

Cited by 9 publications

(2 citation statements)

References 7 publications

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“…At lower temperatures and concentrations, NaOH extracts humic and fulvic acids from low rank coal (Hofrichter and Fritsche, 1996;Juan et al, 1990;Novak et al, 2001). Juan et al (1990) used alkaline agents to extract humic acids from lignite and subbituminous coal. Their results showed that longer extraction times and lower alkaline concentrations released the largest quantity of humic acids.…”

Section: Sodium Hydroxidementioning

confidence: 99%

Bioassay of chemically treated subbituminous coal derivatives using Pseudomonas putida F1

Huang

Urynowicz

Colberg

2013

International Journal of Coal Geology

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Section: Sodium Hydroxidementioning

confidence: 99%

Bioassay of chemically treated subbituminous coal derivatives using Pseudomonas putida F1

Huang

Urynowicz

Colberg

2013

International Journal of Coal Geology

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“…Another approach that could explain the pelletization behavior of the oxidized coal/KOH mixture is related to the formation of humic substances during the oxidation treatments of coals. It is well-known that the oxidation of coals produces changes in their macromolecular structure ,,− and represents an ideal inverse diagenetic process, resulting in a higher content of extractable humic matter. − In our study, during the preparation of the coal/KOH slurry, the presence of a relatively high amount of a viscous black liquor (humic matter) was observed for most of the pelletizable slurries. Neither raw coals nor all oxidized samples from coal A presented these coal-soluble fractions.…”

Section: Resultsmentioning

confidence: 57%

Effect of the Pre-oxidation of Coals in the Preparation of Chemically Activated Carbon Pellets

2010

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Activated carbon pellets have been prepared by extrusion of a mixture of oxidized coal and KOH, followed by a carbonization process. Three coals with several ranks (semi-anthracite, sub-bituminous, and lignite) have been selected as carbon precursors and oxidized with different treatments (HNO3, H2O2, and air treatment). The coal rank, oxidation conditions, and coal/KOH ratio are important parameters to obtain activated carbon pellets. It has been deduced that the formation of a suitable pelletizable slurry from oxidized coals is obtained when two conditions come together: (i) the presence of an appreciable amount of surface oxygen groups and (ii) the use of a KOH solution. The best results have been obtained using sub-bituminous coal, air oxidation at 200 °C for 48 h, and KOH solution between 10 and 20 wt %. Under these conditions, activated carbon pellets can be obtained, avoiding the use of a binder. The obtained samples are essentially microporous materials, showing a narrow micropore size distribution, which make them interesting for CH4/CO2 separation.

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Formation of humic acids from air-oxidized Alaskan subbituminous coals

Ogunsola

Rao

1993

Fuel

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Production of humic acids from lignites and subbituminous coals by alkaline-air oxidation

Cited by 9 publications

References 7 publications

Bioassay of chemically treated subbituminous coal derivatives using Pseudomonas putida F1

Bioassay of chemically treated subbituminous coal derivatives using Pseudomonas putida F1

Effect of the Pre-oxidation of Coals in the Preparation of Chemically Activated Carbon Pellets

Formation of humic acids from air-oxidized Alaskan subbituminous coals

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