Petroleum refining operations such as hydroprocessing and fluid catalytic cracking (FCC) generate huge quantities of spent catalysts containing toxic and valuable metals (Ni, V, Mo, Co, W, Al, etc.), ...the management of which is a serious environmental issue. Besides environmental concerns, the different metals present in the spent catalysts are also a valuable commodity to modern industries. Therefore, these spent catalysts also provide an opportunity to use it as a source of value to the refiners. In recent years, a biotechnological based leaching process ‘bioleaching’ has emerged as a promising eco-friendly technique for the extraction of metals from these refinery spent catalysts. Among various bioleaching agents such as archean, bacterial, or fungi, the process mediated by the fungi (Aspergillus niger, Penicillium simplicissimum, and many others) is gaining attention owing to the high metal extraction ability of the various fungal produced metabolites (organic acids) under moderately acidic conditions. Furthermore, the ability of these fungi to withstand wide process conditions (pH, spent catalyst concentration, substrate types, etc.), high metal toxicity and use of low-cost organic substrate make them an ideal candidate for bioleaching. In this review article, we shed light on the role and mechanisms of fungi involved in extracting different metals from spent hydroprocessing and FCC catalysts. Key process parameters that affect the efficiency of fungal based bioleaching are discussed. The techno-economic challenges associated with the process are elaborated, and the needed future research directions to promote its commercial applications are highlighted. Based on our analysis, it can be argued that the fungi bioleaching has potential, however, some challenges (slower kinetics, and health and safety) should be addressed before the process can be scaled up for the commercial application.
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•Fungal bioleaching of petroleum refinery spent catalyst has been reviewed in detail.•The reaction mechanisms of each fungus are described.•Key techno-economic and environmental challenges are discussed.•Prospects for fungal bioleaching processes are discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A series of copper complexes were prepared from N4 – substituted Schiff base ligands having structure Cu (L)2 Cl2 ; where L= p-methoxybenzylidene ethylenediammine, p-nitrobenzylidene ...ethylenediammine, p- chloroacetophenone ethylenediammine, p-methoxy acetophenone ethylenediammine, p-nitro acetophenone ethylenediammine. All copper complexes were characterized by various physico-chemical techniques like melting point,TLC, elemental analysis,IR,H1-NMR,LC-MS,UV-Visible spectra. The magnetic moments and electronic spectral studies suggested distorted octahedral geometry for all the complexes. The monoanionic ethylene diammine ligands act in a bi dentated mode, binding through azomethine nitrogen atoms.. The synthesized compounds were screened for their in vitro antibacterial activity using Disc Diffusion method against two strains of gram negative and gram positive bacteria. Tetracycline antibiotic was used as positive control in this test. All the compounds showed significant antibacterial activity in the range of 1-10 mg/ml. Antioxidant activity of the all copper complexes was screened using the DPPH scavenging assay. In this activity ascorbic acid was used as a positive control .All complexes exhibited potent antioxidant activity in the range 50-75%. These compounds would be evaluated further for their possible DNA binding, cleavage, antifungal and anti-diabetic activities.
Dairy wastewaters (DWW) are rich in several pollutants, including high biochemical oxygen demand (BOD) and chemical oxygen demand (COD), and their unsafe disposal may cause damage to the environment. ...In this study,
Chlorella vulgaris
(identified as NIES:227 strain based on 28s rRNA sequencing) was isolated from the freshwater habitat of the Ganga River at Haridwar, India, and further tested for its efficacy in treating DWW. The phycoremediation experiments were conducted using three different DWW concentrations (0, 50, and 100%), operating temperatures (20, 25, and 30 °C), and light intensities (2000, 3000, and 4000 lx) using response surface methodology. Results showed that after 16 days of experiments, a significant (
P
< 0.05) reduction in BOD (96.65%) and COD (87.50%) along with a maximum biomass production of 1.757 g/L was achieved using 57.72% of dairy industry wastewater, 24.16 °C of reactor temperature, and 3874.51 lx of light intensity. The RSM models had coefficient of determination (
R
2
) values above 0.9459 with a minimum difference between measured and predicted responses. Therefore, the findings of this study suggest that the isolated
C. vulgaris
can be effectively used to treat dairy wastewater along with significant production of algal biomass which can be further used for the generation of low-cost biofuel and other materials.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Eco-friendly, stable and thermally reliable nano enhanced phase change materials (PCMs) with improved thermal property and photo absorbance are vital competencies for solar energy harnessing. In the ...proposed research, we develop and investigate the morphological, chemical, optical and thermal features of biochar-eutectic PCM composite for clean energy storage. Herewith, primarily coconut shell-based biochar nanoparticle (BNP) is synthesized through carbonization process in vacuum oven at 130 °C followed by wet ball milling to reduce the size. Coconut shell being a feasible candidate in terms of economical, pore structured and light weight ensures better binding, uniform dispersion and improved intermolecular attraction with PCM. The synthesized BNP is evenly spread into the surface morphology of inorganic binary eutectic PCM comprising of 62% of sodium sulphate decahydrate (SSD) and 38% of sodium phosphate dibasic dodecahydrate (SPDD). Electromagnetic spectrum absorbance in the range of infrared and visible rays increased from 0.09 to 0.84 (833%) and transmissibility has been reduced from 83.7% to 15.11% with BNP. Developed BNP composite eutectic PCM demonstrate higher thermal conductivity (0.715 W/m⋅K) on comparison with base eutectic PCM (0.464 W/m⋅K) owing to the presence of carbon element and porous nature of BNP. Heat flow curves specifies increment in melting enthalpy of eutectic PCM from 202.3 J/g to 218.1 J/g with energy storage efficiency of 71.7%. On the basis of thermophysical properties obtained, the developed BNP composite PCM is expected to contribute effectively for thermal regulation applications.
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•Carbon based eco-friendly nanoparticle is synthesized using coconut shell.•Agro waste material is exploited as a low-cost & desirable nanoparticle.•Optical absorbance spike by 833% and transmissibility fall by 82%.•Melting and freezing enthalpy depicts an increasing trend with developed nanoparticle.•Degree of supercooling of eutectic PCM curbs from 9.9 °C to 4.2 °C.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Phase change materials (PCMs) utilized for thermal energy storage applications are verified to be a promising technology due to their larger benefits over other heat storage techniques. Apart from ...the advantageous thermophysical properties of PCM, the effective utilization of PCM depends on its life span. Moreover, PCMs which are utilized for different solar thermal energy storage applications are required longer thermal and chemical stability for the extended performance of a system. This review shows the in-depth details on thermal stability and reliability of different PCMs such as organic, inorganic, eutectics, and composites materials for heat storage applications. Different methods for measuring the thermophysical properties along with the classification of PCMs based on applications and temperature ranges have been discussed. This paper also covers the selection criteria and commercial viability of PCMs for different domestic and industrial applications. In addition to this, the effect of thermal cycle testing on the properties of different organic, inorganic, eutectic, and composite PCMs has been summarized. The present article can be highly useful for researchers and practice engineers in the areas related to thermal energy storage applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Phyco-remediation for treatment of dairy wastewater and its potential for biofuel.•Chlamydomonas polypyrenoideum used for integrated approach.•Micro alga showed significant reduction in pollution ...load.•Special significance to nitrate removal.•Higher production of crude bio-oil was achieved in respect of control media used.
This study involves a process of phyco-remediation of dairy industry wastewater by algal strain Chlamydomonas polypyrenoideum. The results of selected algal strain indicated that dairy industry wastewater was good nutrient supplement for algal growth in comparable with BG-11 growth medium. Alga grown on dairy industry wastewater reduced the pollution load of nitrate (90%), nitrite (74%), phosphate (70%), chloride (61%), fluoride (58%), and ammonia (90%) on 10th day of its growth as compared to that of uninoculated wastewater. The lipid content of algal biomass grown on dairy wastewater on 10th day (1.6g) and 15th day (1.2g) of batch experiment was found to be higher than the lipid content of algal biomass grown in BG-11 growth medium on 10th day (1.27g) and 15th day (1.0g) of batch experiment. The results on FTIR analysis of the extracted bio-oil through transesterification reaction was comparable with bio-oil obtained from other sources.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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•Treatment of slaughterhouse wastewater (SHWW) with Chlorella pyrenoidosa.•Maximized growth observed with 50% concentration in 430 mgL−1 of biomass (dry wt.)•COD, NO3– and PO4−3 ...reduction ≈17–31%, 23–42%, 18–48% with 50% concentration of SHWW.•Correlation analysis investigation in between parameters of SHWW and algal strain.•SHWW treatment with Chlorella supports pollutant reduction and biochemical profiles.
Slaughterhouse produce large amount of wastewater, containing high pollutant load in terms of protein, fats and meat pieces, might lead to source of non-point contamination. Various concentrations (25%, 50%, 75%, and 100%) of slaughterhouse wastewater were used to increase the algal biomass production, pollutants removal and biochemical profile analysis under controlled conditions of C. pyrenoidosa. Results showed that the maximum biomass yield 430 mg L−1 was achieved at 50% concentration of wastewater to other concentration of wastewater. Direct relation was observed in between pollution load and nutrient load of SHWW with biochemical profile of C. pyrenoidosa. The COD/BOD ratio (1.9) was found to be significant on the scale of degradability by algal biomass. Sufficient nutrient removal efficiencies (23–42%, 18–48%) and pollutant load efficiencies (17–31%, 7–29%) were observed. Findings showed that slaughterhouse wastewater is rich in nutrients, which can be utilized for algal biomass production and wastewater remediation for future endeavors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nowadays, energy is key consideration in discussions of sustainable development. So, sustainable development requires a sustainable supply of clean and affordable renewable energy sources that do not ...cause negative societal impacts. Energy sources such as solar radiation, the winds, waves and tides are generally considered renewable and, therefore, sustainable over the relatively long term. Wastes and biomass fuels are usually viewed as sustainable energy sources. Wastes are convertible to useful energy forms like hydrogen (biohydrogen), biogas, bioalcohol, etc., through waste-to-energy technologies.
In this article, possible future energy utilization patterns and related environmental impacts, potential solutions to current environmental problems and renewable energy technologies and their relation to sustainable development are discussed with great emphasis on waste-to-energy routes (WTERs).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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