Characterization and exploitation of black shale as unconventional source of biohydrogen: a case study from the Abu-Tartur mine, Western Desert, Egypt

• Published in: Arabian journal of geosciences 2020-06, Vol.13 (12), Article 467
• Main Authors: El-Habaak, Galal, Khalaphallah, Rafat, Hassan, Mokhles, Askalany, Mohamed, Abdel-Hakeem, Mahmoud
• Format: Article
• Language: English
• Subjects: Analytical methods; Bacteria; Biodegradation; Biogas; Biohydrogen; Clay; Clay minerals; Deserts; Earth and Environmental Science; Earth science; Earth Sciences; Exploitation; Fermentation; Illite; Illites; Kerogen; Methanogenic bacteria; Microscopes; Minerals; Mixed layer; Montmorillonite; Montmorillonites; Nucleic acids; Nucleotide sequence; Organic matter; Original Paper; Outcrops; PCR; Polymerase chain reaction; Pyrolysis; rRNA 16S; Scanning electron microscopy; Sedimentary rocks; Sepiolite; Shale; Shales; Smectites
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-020-05482-9

Biohydrogen is a specific type of biogas produced by the anaerobic degradation of organic matter in the absence of methanogenic bacteria. Depending on the high sensitivity of methanogenic bacteria to oxygen, the surface outcrops of black shale are expected to be unfavorable environments for methanogenic bacteria. At this point, the present study sheds more light on the potential production of biohydrogen from Abu-Tartur black shale, as an example, located in the Western Desert of Egypt. A combination of analytical techniques including the LECO C230-carbon analyzer, Rock-Eval pyrolysis 6, optical and scanning electron microscopes, X-ray diffractometer, pH meter, polymerase chain reaction, and 16S ribosomal RNA analysis was used for the current work. The anaerobic fermentation was conducted at different solid densities 9%, 11%, 13%, and 15% for 5 weeks. Also, the influence of clay minerals on biohydrogen production along with the biodegradation of clay minerals on fermentation is considered. The overall results indicate the majority of samples are fair to good in organic richness (0.92–1.35 wt% TOC). The studied kerogen is classified as immature type III associated with montmorillonite, illite-montmorillonite mixed layer, and sepiolite. The low degree of thermal maturity is consistent with the high percentage of smectite expandable layers “> 60%.” On fermentation, noticeable volumes of biogas (average 10.2 cubic centimeters) were gradually adsorbed by clay minerals with increasing the total solid content from 9 to 15%. XRD patterns of fermented samples reveal the disappearance of montmorillonite and illite-montmorillonite mixed layer, with the persistence of sepiolite reflection peaks. On the other hand, the ribosomal sequence analysis “16S rRNA” refers to the absence of methanogenic bacteria and the dominant occurrence of Bacillus sp. and Lysinibacillus sp., which are well known for their ability to produce biohydrogen.