Industrial and municipal wastewaters are potential resources for production of microalgae biofuels. Dalton – the Carpet Capital of the World generates 100–115
million
L of wastewater
d
−1. A study ...was conducted using a wastewater containing 85–90% carpet industry effluents with 10–15% municipal sewage, to evaluate the feasibility of algal biomass and biodiesel production. Native algal strains were isolated from carpet wastewater. Preliminary growth studies indicated both fresh water and marine algae showed good growth in wastewaters. A consortium of 15 native algal isolates showed >96% nutrient removal in treated wastewater. Biomass production potential and lipid content of this consortium cultivated in treated wastewater were ∼9.2–17.8
tons
ha
−1
year
−1 and 6.82%, respectively. About 63.9% of algal oil obtained from the consortium could be converted into biodiesel. However further studies on anaerobic digestion and thermochemical liquefaction are required to make this consortium approach economically viable for producing algae biofuels.
The present investigation deals with the synthesis of ternary transition metal alloy nanoparticles of FeCoNi and graphene templated FeCoNi (FeCoNi@GS) by one-pot reflux method and there use as a ...catalyst for hydrogen sorption in MgH2. It has been found that the MgH2 catalyzed by FeCoNi@GS (MgH2: FeCoNi@GS) has the onset desorption temperature of ~255 °C which is 25 °C and 100 °C lower than MgH2 catalyzed by FeCoNi (MgH2: FeCoNi) (onset desorption temperature 280 °C) and the ball-milled (B.M) MgH2 (onset desorption temperature 355 °C) respectively. Also MgH2: FeCoNi@GS shows enhanced kinetics by absorbing 6.01 wt% within just 1.65 min at 290 °C under 15 atm of hydrogen pressure. This is much-improved sorption as compared to MgH2: FeCoNi and B.M MgH2 for which hydrogen absorption is 4.41 wt% and 1.45 wt% respectively, under the similar condition of temperature, pressure and time. More importantly, the formation enthalpy of MgH2: FeCoNi@GS is 58.86 kJ/mol which is 19.26 kJ/mol lower than B.M: MgH2 (78.12 kJ/mol). Excellent cyclic stability has also been found for MgH2: FeCoNi@GS even up to 24 cycles where it shows only negligible change from 6.26 wt% to 6.24 wt%. A feasible catalytic mechanism of FeCoNi@GS on MgH2 has been put forward based on X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Photoelectron Spectroscopy (XPS), and microstructural (electron microscopic) studies.
Synthesis of ternary FeCoNi@GS alloy by one pot method and its application as catalyst for improving de/rehydrogenation properties of MgH2. Display omitted
•Synthesis of FeCoNi@GS by one pot method.•FeCoNi@GS has been used as catalyst for MgH2.•MgH2 catalyzed by FeCoNi@GS show excellent cyclability.•Formation enthalpy of MgH2: FeCoNi@GS is reduced by 19.26 kJ/mol of H2 as compared to ball milled MgH2.
It is imperative to slash the cost of algal oil to less than $50 bbl⁻¹ for successful algal biofuel production. Use of municipal wastewater for algal cultivation could obviate the need for freshwater ...and the nutrients—N and P. It would also add CO₂ through bacterial activity. Chlorella minutissima Fott et Nova dominated the entire phycoflora year around and through each stage of the wastewater treatment at the oxidation pond system of Wazirabad (Delhi) in India. The ability to grow so profusely in such varied and contrasting situations made this alga unique. Besides pollution tolerance, it grew heterotrophically in dark under acidic conditions and as a mixotroph in presence of light over a range of organic C substrates. It could utilize both ammoniacal and nitrate nitrogen, survived anaerobicity, 5% NaCl and −10 bar of osmotic stress. C. minutissima grew at pH 4-11 and raised the pH set initially by 1 to 3 units in 7.5 h. It showed gigantism and largely kept afloat in presence of utilizable organic carbon, while flocculated in mineral medium and on aging. The alga also possessed potential for biofuel production. The studied parameters indicate why C. minutissima was a potential biomass builder in municipal sewage and could be used to determine which other alga(e) may serve the purpose.
Improved wastewater management with beneficial utilization will result in enhanced sustainability and enormous cost savings in industries. Algae cultivation systems viz. raceway ponds, vertical tank ...reactors (VTR) and polybags were evaluated for mass production of algal consortium using carpet industry (CI) untreated wastewater. Overall areal biomass productivity of polybags (21.1gm−2d−1) was the best followed by VTR (8.1gm−2d−1) and raceways (5.9gm−2d−1). An estimated biomass productivity of 51 and 77tonsha−1year−1 can be achieved using 20 and 30L capacity polybags, respectively with triple row arrangement. Biomass obtained from algal consortium was rich in proteins (∼53.8%) and low in carbohydrates (∼15.7%) and lipids (∼5.3%). Consortium cultivated in polybags has the potential to produce 12,128m3 of biomethane ha−1year−1. To be economically viable, the capital expenditure for polybag reactors needs to be reduced to $10m−2 for bioenergy/biofuel production.
The growth response of Chlorella vulgaris was studied under varying concentrations of carbon dioxide (ranging from 0.036 to 20%) and temperature (30, 40 and 50oC). The highest chlorophyll ...concentration (11 µg mL-1) and biomass (210 µg mL-1), which were 60 and 20 times more than that of C. vulgaris at ambient CO2 (0.036%), were recorded at 6% CO2 level. At 16% CO2 level, the concentrations of chlorophyll and biomass values were comparable to those at ambient CO2 but further increases in the CO2 level decreased both of them. Results showed that the optimum temperature for biomass production was 30oC under elevated CO2 (6%). Although increases in temperature above 30oC resulted in concomitant decrease in growth response, their adverse effects were significantly subdued at elevated CO2. There were also differential responses of the alga, assessed in terms of NaH14CO3 uptake and carbonic anhydrase activity, to increases in temperature at elevated CO2. The results indicated that Chlorella vulgaris grew better at elevated CO2 level at 30oC, albeit with lesser efficiencies at higher temperatures.
The present investigations are focused on the effect of different Ti-based catalysts (Ti, TiO2, TiCl3 and TiF3) on de/re-hydrogenation characteristics of nanocrystalline MgH2. Desorption temperature ...of milled MgH2 lowers from 380 to 350, 340, 310 and 260 °C with the addition of Ti, TiO2, TiCl3 and TiF3 respectively. The rehydrogenation characteristics are also improved through the deployment of Ti-based catalysts. Among all Ti based additives, TiF3 is found to be the most effective catalyst for hydrogen sorption from nano MgH2. The better catalytic effect of TiF3 over other Ti-based catalyst can be explained on the basis of temperature programmed reduction (TPR) studies. TPR experiments performed for different Ti additives, reveals that there is no oxidation/reduction reaction below 400 °C except for TiF3. The TPR profile of TiF3 shows some oxidation/reduction reaction exhibits at 200 °C. In order to further improve the sorption characteristics and cyclability of TiF3 catalyzed nano MgH2, we have investigated the effect of SWCNTs in MgH2+TiF3 sample. De/rehydrogenation characteristics reveal the synergistic effect of SWCNTs and TiF3 in MgH2+TiF3 sample. The details of the improvement in sorption behavior of MgH2–TiF3 in presence of SWCNTs are described and discussed.
•Catalytic effect on of Ti based catalysts on MgH2 are compared.•The synergistic effect of SWCNTs and TiF3 studied in details.•The SWCNTs enhances the cyclability of TiF3 catalyzed MgH2.•SWCNTs also acts as a support for nanoparticles.
Hydrogen is a renewable energy carrier that is one of the most competent fuel options for the future. The majority of hydrogen is currently produced from fossil fuels and their derivatives. These ...technologies have a negative impact on the environment. Furthermore, these resources are rapidly diminishing. Recent research has focused on environmentally friendly and pollution-free alternatives to fossil fuels. The advancement of bio-hydrogen technology as a development of new sustainable and environmentally friendly energy technologies was examined in this paper. Key chemical derivatives of biomass such as alcohols, glycerol, methane-based reforming for hydrogen generation was briefly addressed. Biological techniques for producing hydrogen are an appealing and viable alternative. For bio-hydrogen production, these key biological processes, including fermentative, enzymatic, and biocatalyst, were also explored. This paper also looks at current developments in the generation of hydrogen from biomass. Pretreatment, reactor configuration, and elements of genetic engineering were also briefly covered. Bio-H2 production has two major challenges: a poor yield of hydrogen and a high manufacturing cost. The cost, benefits, and drawbacks of different hydrogen generation techniques were depicted. Finally, this article discussed the promise of biohydrogen as a clean alternative, as well as the areas in which additional study is needed to make the hydrogen economy a reality.
•This reviewed has focused on sustainable and pollution-free Hydrogen energy.•Various technological ways for producing hydrogen are reviewed.•Renewable biomass as the primary feedstock for Hydrogen production is highlighted.•Bio-hydrogen production's challenges and advances were mentioned.
The surge of interest in bioenergy has been marked with increasing efforts in research and development to identify new sources of biomass and to incorporate cutting-edge biotechnology to improve ...efficiency and increase yields. It is evident that various microorganisms will play an integral role in the development of this newly emerging industry, such as yeast for ethanol and Escherichia coli for fine chemical fermentation. However, it appears that microalgae have become the most promising prospect for biomass production due to their ability to grow fast, produce large quantities of lipids, carbohydrates and proteins, thrive in poor quality waters, sequester and recycle carbon dioxide from industrial flue gases and remove pollutants from industrial, agricultural and municipal wastewaters. In an attempt to better understand and manipulate microorganisms for optimum production capacity, many researchers have investigated alternative methods for stimulating their growth and metabolic behavior. One such novel approach is the use of electromagnetic fields for the stimulation of growth and metabolic cascades and controlling biochemical pathways. An effort has been made in this review to consolidate the information on the current status of biostimulation research to enhance microbial growth and metabolism using electromagnetic fields. It summarizes information on the biostimulatory effects on growth and other biological processes to obtain insight regarding factors and dosages that lead to the stimulation and also what kind of processes have been reportedly affected. Diverse mechanistic theories and explanations for biological effects of electromagnetic fields on intra and extracellular environment have been discussed. The foundations of biophysical interactions such as bioelectromagnetic and biophotonic communication and organization within living systems are expounded with special consideration for spatiotemporal aspects of electromagnetic topology, leading to the potential of multipolar electromagnetic systems. The future direction for the use of biostimulation using bioelectromagnetic, biophotonic and electrochemical methods have been proposed for biotechnology industries in general with emphasis on an holistic biofuel system encompassing production of algal biomass, its processing and conversion to biofuel.
PDF