Aniruddha Kumar

Experimental study on demineralization of coal with Pseudomonas mendocina strain B6-1 bacteria to obtain clean fuel

We present the results of the investigations carried out on the demineralization of coal of the Rajmahal Gondwana basin of India using Pseudomonas mendocina strain B6–1. Petrographically these coals are characterized by high concentration of inertinite macerals with subordinate amount of vitrinite and liptinite macerals. The mineral matter content occurs in high concentration which gives a high ash yield. This coal contains relatively high content of major, minor and trace elements when compared with the Clarke values in coal. After the bacterial treatment a considerable reduction in the elemental content of oxygen, hydrogen and sulphur was seen. Reduction in the ash content (>5%) was achieved and variable degrees of removal of the various major, minor and trace element concentration was also noticed. Nearly 59% removal of Mn, 53% of Na, 13% of Fe was achieved among the major/minor elements while nearly 54% of As, 41% of Cd, 39% of Cu, 34% of Ni, 32% of Zn, 13% of Cr, 43% of Co and 66% of Pb could be removed. Arsenic, Fe and Ca have a strong positive correlation with the ash removal percentage indicating that the samples having increased concentration of these elements are prone to demineralization with Pseudomonas mendocina strain B6–1. Whereas the elements like Ni, Zn, Cr and Cu maintain a strong negative correlation with the ash removal percentage indicating that their enrichment could have hampered the process of demineralization.

Demineralization of Rajmahal Gondwana coals by bacteria: Revelations from X-ray diffraction (XRD) and Fourier Transform Infra Red (FTIR) studies

The present paper entails the results of the demineralization of the Rajmahal Gondwana coals of India with Pseudomonas mendocina strain B6-1 and its signatures revealed in the X-ray Diffraction (XRD) and Fourier transform infrared (FTIR) spectra. The XRD study reveals the reduction of pyrite phase in the coal samples after bacterial treatment due to bio-oxidation of pyrite and the appearance of few new phases of jarosite. Moreover, the intensity of jarosite peaks has been noticed to increase after the bacterial treatment. The FTIR spectra of the bacterial treated Rajmahal coal samples indicate shifting of the absorption peaks as compared to the control samples. The oxidation of pyrite due to the bacterial action and its conversion into jarosite is indicated by the stretching of OH bond at 630 cm−1 peak. While the bacterial action on clay minerals in all the samples is indicated by the stretching of bonds at 1114 cm−1 to 430 cm−1 peaks.

Desulfurization of selected hard and brown coal samples from India and Indonesia with Ralstonia sp and Pseudoxanthomonas sp

The present paper entails the investigations on the removal of total sulfur (S t ) from the coal samples of four coal and lignite fields of India and Indonesia by Ralstonia sp and Pseudoxanthomonas sp. Minimum desulfurization (in relative%) was observed in Nagaland coals (India) which contain maximum quantity of S t (6.86%) among the samples of the studied area while higher removal (in relative%) was observed in coals containing relatively low quantity of S t . Nevertheless, a positive correlation exists between S t and removal percentage in samples of all coalfields indicating an increase in removal% with increasing concentration of S t . The removal percent (with respect to its initial S t ) by Pseudoxanthomonas sp in the investigated area is in order of: Vastan (mean 41.84%) > Indonesian (mean 34.16%) > Nagaland (mean 18.26) coals. In case of removal by Ralstonia sp the order of removal % can be put as: Vastan (mean 45.50%) > Rajpardi (mean 42.93%) > Indonesian (mean 20.22%) > Nagaland (mean 11.83%) coals.

Environmentally Sensitive Major and Trace Elements in Indonesian Coal and Their Geochemical Significance

Coal samples from Tarakan basin of East Kalimantan, Indonesia are analyzed for selected major and trace elements and significance of the relationships established among them. They contain high concentrations of Ca, Fe, Mn, Na, K, Cd, Cu, Cr, Ni, Pb, and Zn as compared to Clark’s values for upper continental crust and bituminous coals. The correlation matrix among them indicates a positive relation of Cr, Fe, Mn, Na, K, and total sulphur with inorganic matter. This indicates their derivation from a detrital source. However, Ni and Ca have shown a strong affinity with organic matter.

Petrographic considerations in demineralization of coal with bacteria: A new dimension in understanding the clean coal technology

The present study reveals that there is close relation between the petrographic composition of coal and removal of major, minor and trace elements/metals with bacteria. While increase in total huminite concentration has favoured the removal of Cr, Ni, Pb and Mg, there is good removal of Cd and Cu with increase in liptinite content. Inertinite is found to be favourable for the removal of Cd, Fe and K. It is therefore important to take into consideration the petrographic composition of coal when trying for the beneficiation of coal with bacteria. This will be helpful in designing suitable strategy for the removal of environmentally sensitive elements/metals with the help of bacteria and to obtain clean fuel from coal.

Petrological considerations for the demineralization of Rajmahal coals with Pseudomonas mendocina B6-1

The present study entails the results of the petrological coniderations for demineralization of Rajmahal Gondwana coals with Psudomonas mendocina B6-1. Inertinite group macerals are the dominant constituents of these coals, followed by vitrinite group, while liptinite occurs in low concentration. The amount of Mineral matter is moderately high. The concentration of major, minor and trace elements is high when compared with Clarke values. After the treatment of these coals with Pseudomonas mendocina strain B6-1, a significant reduction in the elemental content of oxygen, hydrogen and sulphur was observed. A gradual reduction of pyrite phase due to bioleaching was identified and its signatures were reflected in the XRD spectra and FTIR absorption bands. Over 5 % reduction in the ash content and decrease of major, minor and trace element to variable degrees were also noticed. Fe, As, and Ca positively correlate with the ash removal percentage indicating that the samples with high concentration of these elements were prone to demineralization with Pseudomonas mendocina strain B6-1 whereas Ni, Zn, Cr and Cu, negatively correlate with the ash removal percentage and shows that their enrichment impeded the process of demineralization. With increasing concentration of vitrinite the removal of major/minor/trace elements also increased which is attributed to the possible association of these elements with the mineral matter occurring as superficial mounting and superficial blanketing over the vitrinite macerals. This could facilitate the bacterial access to the elements to act upon and remove it to the variable extent. Some minerals occur intergrown with inertinites causing restricted bacterial action owing to the nonexposure of the mineral particles and less surface area available to the bacteria for bioleaching. Sulfur removal strongly relates with increase in inertinite content and decrease in liptinite content. This appears that sulfur associated with liptinites have shown difficult removal condition. The maximum removal of the trace elements like Cd, Cu, Co, Zn and Pb was observed from the ‘banded dull coal’ samples of the Rajmahal basin while maximum removal of major/minor elements like Fe, Ca and Mg was noticed from the ‘banded bright coal’ samples. However, maximum removal of Mn and As was also observed in the samples of ‘banded coal’.

Sequestration of Metals from Coal Using Bacteria: Environmental Implications on Clean Coal Energy

Burning of coal in power plants generates a huge amount of ash containing heavy metals posing environmental pollution. These metals, when they enter into water, air, and soil, ultimately affect human health through the food chain and food web processes. The physicochemical methods available for the removal of minerals and trace elements from coal are not only costly but also generate secondary sludge and create pollution problems. A bacterial technique is successfully used to remove hazardous metals from coal through oxidation, acidification, and adsorption, thereby improving the fuel quality.

Bacterial desulphurization of low-rank coal: A case study of Eocene Lignite of Western Rajasthan, India

ABSTRACT High sulfur lignite samples collected from Giral mine was subjected to desulfurization using bacteria Burkholderia sp. GR 8–02 isolated from native lignite. A removal of 50.69% of total Sulfur (St) has been observed. The reduction in hydrogen and ash content was found up to 2.92% and 14.78%, respectively. In addition, relative carbon (up to 12.81%) and nitrogen (up to 34.52%) has also been increased. An increase in the relative concentration of volatile matter and fixed carbon (up to 19.47% & 3.29%) has been detected. In addition, the desulfurization of high sulfur lignite with Burkholderia sp. GR 8–02 increased the calorific value from 5.24% to 20.74%.