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Petroleum coke secondary resource

Carbon-rich solid produced from heavy petroleum-processing residues, treated here as a residual material resource rather than coal-derived coke, coking coal, the carbon element, graphite, combustion ash or oil-sands tailings. The accepted experiment uses material described by its authors as petroleum coke from Navanagar Metcoke Limited, Jamnagar, Gujarat. The paper also calls the sample metcoke; its precise manufacturing route and green, calcined or needle-coke grade are not established. This record retains that source-assigned feed identity without creating a grade-specific owner. Laboratory sulfur-content reduction does not establish recovered sulfur, metal recovery, retained fuel quality or industrial deployment.

Microbial & Biochemical Mechanisms (1)

Sequential culture treatment associated with lower residual sulfur content

bioleaching Microbial

Associated Organisms: Acidithiobacillus thiooxidans (NCBITaxon:930)

Two sequential one-week treatments with a culture assigned by the authors to Thiobacillus thiooxidans were followed by lower total sulfur concentration in retained petroleum-coke solids. Bioleaching denotes the source's culture-treatment operation; the measured endpoint is residual solid sulfur, not a quantified dissolved-sulfur flux or isolated product. The paper's general iron/pyrite and sulfur-oxidation discussion does not demonstrate the operative pathway or the removed sulfur species in this feed.

Experimental Context & Analytical Limits:
Materials and Methods pp. 82-83 report a culture collected from a Rajgir hot-water spring, without a strain accession, sequencing result or documented identification method. The medium is called 9K and is described at pH 2.5 and 35 degrees C for culture growth; the source culture is separately reported at pH 3.54. Table 2 lists reagent masses but no preparation volume, so concentrations are not inferred. An Erlenmeyer flask received petroleum coke, medium and 5 mL culture. Batch solid loading, liquid volume, particle fraction, exposure temperature, agitation and aeration are not separately resolved. A petroleum-coke-plus-medium comparison without added culture is described, but its numerical outcome is not reported and sterility is not demonstrated. After one week, material was filtered using Whatman No. 4 paper and approximately 1 g retained residue was assayed by the source-named Eschka method. Previously treated solids then received fresh culture for a second week and were reassayed. The roughly 1 g table weights are analytical portions, not established treatment batch sizes. Three determinations and LSD entries are printed without defining independent biological replication or the uncertainty calculation.
Curated Evidence Points:
Tables 3-5 on p. 83 give residual total sulfur concentrations of 6.31-6.34% before treatment, 5.42-5.52% after the first week and 0.40-0.47% after retreating those solids for a further week. The source reports an initial mean of 6.32%, a first-stage value of 5.46% and about 13.5% reduction. These observations support a sequential culture-associated change in solid composition under the reported conditions, without establishing the incremental effect of inoculation.
Table 5 reports 92.56-93.67% sulfur removal alongside final solid concentrations of 0.40-0.47%. These percentages are consistent in scale with concentration reductions relative to the initial feed, not an additional 93% recovery from the first-stage residue. Some individual table percentages do not exactly reproduce a common initial 6.32% denominator. No remaining-solid mass, liquid sulfur inventory, sulfur-species balance, recovered sulfur product or carbon yield is given; concentration changes cannot be treated as whole-feed recovery yields.
The described uninoculated comparison has no separately reported numerical result, preventing a microbial effect-size calculation and leaving acid-medium chemistry and other causes unresolved. Pyrite, sulfate and organic sulfur are discussed generically on pp. 83-85 without source-specific phase/speciation measurements. The discussion refers to Figure 1, but no Figure 1 graphic appears in the inspected complete five-page original. Reagent-volume, culture-identity and replication gaps further limit mechanistic attribution. Facility production capacity is not the scale of this flask experiment, and the claimed economic and fuel-use benefits are not directly tested.
Context_only Source: ncbi930
Current taxonomy maps the historical name Thiobacillus thiooxidans to Acidithiobacillus thiooxidans. This nomenclatural mapping does not validate the Rajgir culture assignment, establish purity or identify it with any type strain listed by NCBI.

Sources & References

  1. tripathi2010: Tripathi, Singh and Gupta (2010), Desulphurization of petroleum coke. Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika 18(1):81-85, June 2010. Complete official five-page Hindi article with English abstract; Materials and Methods pp. 82-83, Tables 1-5 pp. 82-83 and Discussion pp. 83-85. Repository handle 123456789/10142.
    https://nopr.niscpr.res.in/handle/123456789/10142 (accessed 2026-10-15)
  2. ncbi930: NCBI Taxonomy 930, Acidithiobacillus thiooxidans, species; retrieved taxonomy XML lists Thiobacillus thiooxidans as a synonym. This resolves the source-assigned species name, not the experimental strain identity.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=930 (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T11:37:18Z codex (GPT-6; codex) CREATE Created a petroleum-coke residual-resource record with qualified sequential culture-associated sulfur-content evidence.

Record source: data/records/petroleum-coke.yaml