Indian Institute of Technology Kharagpur

About: Indian Institute of Technology Kharagpur is a education organization based out in Kharagpur, India. It is known for research contribution in the topics: Computer science & Dielectric. The organization has 16887 authors who have published 38658 publications receiving 714526 citations.

Performance evaluation of microalgae for concomitant wastewater bioremediation, CO2 biofixation and lipid biosynthesis for biodiesel application

Abstract: This study was directed towards evaluating the potential of microalgae for simultaneous wastewater treatment, CO2 biofixation and lipid biosynthesis for biofuel application. The cultivation potential of various microalgal species in domestic wastewater (DWW) was studied in shake-flasks. The microalga, Scenedesmus sp. showed superior results in terms of the maximum specific growth rate of 0.44 d− 1, biomass yield of 0.43 g L− 1, biomass productivity of 61.4 mg L− 1 d− 1 and total lipid content of 23.1%. Subsequently, the performance evaluation of Scenedesmus sp. with respect to biomass growth, lipid accumulation, CO2 biofixation rate and nutrient uptake was carried out at different CO2 concentrations in a photobioreactor. The culture supplemented with 2.5% (v/v) CO2 was found most suitable and resulted in highest biomass productivity, total lipid content, lipid productivity, and CO2 consumption rate of 196 mg L− 1 d− 1, 33.3%, 65.17 mg L− 1 d− 1 and 368 mg L− 1 d− 1, respectively. The microalga could bioremediate ammonium, nitrate, phosphate and chemical oxygen demand (COD) efficiently from the wastewater to the extent of 70–98%. The FAME composition of the microalgal lipid was found encouraging for biodiesel application as saturated: unsaturated fatty acid ratio was favorable to about 1.2:1. The study indicates that Scenedesmus sp. can efficiently utilize DWW for its growth instead of using synthetic culture medium and can produce a significant amount of biomass at 2.5% CO2 for biofuel application.

Adsorption/photocatalytic activity and fundamental natures of BiOCl and BiOClxI1−x prepared in water and ethylene glycol environments, and Ag and Au-doping effects

Abstract: BiOCl and BiOCl x I 1− x were synthesized in two different solvents of ethylene glycol (EG) and water, and their natures were examined by scanning electron microscopy (SEM), electron transmission microscopy (TEM), X-ray diffraction, UV–vis absorption and Raman, Fourier-transform infrared, and photoluminescence spectroscopy. The Ag and Au-doping effects on the fundamental nature and photocatalytic activity of BiOCl and BiOCl x I 1− x were investigated in detail. SEM revealed that 3D flower-like and 2D plate-like microstructures were formed with EG and water solvents, respectively. The as-synthesized samples were tested for the adsorption and photocatalytic degradation of methyl orange and Rhodamine B, with the flower-like 3D-structure showing superior adsorption performance relative to the stacked 2D plate-like structures. Upon introducing iodine into BiOCl, we observed a dramatic increase in the adsorption ability and Brunauer–Emmett–Teller surface area, with an order of 2D BiOCl x I 1− x ( x = 0.8, 0.6 and 0.4). The dye degradation performance was further markedly enhanced under irradiation by visible light. However, a small amount of Ag and Au-doping drastically negated the adsorption and photocatalytic performance. The photocatalytic mechanism was elucidated by an indirect chemical probe method using active species scavengers, and photoluminescence spectroscopy. On the basis of the results obtained, we propose a dye-sensitized photodegradation mechanism, and the active species play roles in the order of OH ≪ O 2 − ≈ h + under visible light irradiation.

Recent developments in biological hydrogen production processes

Abstract: Biohydrogen production technology can utilize renewable energy sources like biomass for the generation of hydrogen, the cleanest form of energy for the use of mankind. However, major constraints to the commercialization of these processes include lower hydrogen yields and rates of hydrogen production. To overcome these bottlenecks intensive research work has already been carried out on the advancement of these processes such as the development of genetically modified microorganisms, the improvement of the bioreactor design, molecular engineering of the key enzyme hydrogenases, the development of two stage processes, etc. The present paper explores the recent advancements that have been made till date and also presents the state of the art in molecular strategies to improve the hydrogen production.