Vaibhav V. Goud

Supercritical CO2 fractionation of bio-oil produced from wheat-hemlock biomass.

The biomass i.e. wheat-hemlock used in this study was first characterized for its composition. The physical and chemical characterization of biomass was estimated using proximate analysis, calorific value, crystallinity, devolatilization behaviour, ultimate analysis, ICP-MS of ash, FT-IR, XRD, CHNS, and HPLC analysis. For commercial purpose the same biomass was used for conversion to bio-oil by fast pyrolysis process. Therefore, in order to investigate its composition, the bio-oil was also characterized using proximate analysis, calorific value, whereas the chemical composition of the bio-oil was estimated using CHNS, (1)H NMR, GC-FID and GC/MS. The bio-oil obtained from wheat-hemlock biomass was supplied by Advanced Biorefinery Co. and after the analysis, its composition has been determined. It contains a mixture of hydrocarbons, pyranoids, furanoids, benzenoids and fatty acids/alcohols with 45% of water, which forms azeotrope with organic polar compounds. The supercritical CO(2) (SC-CO(2)) is an advanced method for selective extraction of valuable chemicals from bio-oil without solvent residue. The organic fraction of the bio-oil was isolated by SC-CO(2). It was observed that SC-CO(2) fractions collected at 10 and 25 MPa pressure were enriched with furanoids, pyranoids and bezenoids. Similarly the bio-oil was also fractionated by conventional column chromatographic method and the yields and chemical compositions were compared with fractionated bio-oil obtained using SC-CO(2).

Hydrolysis of bamboo biomass by subcritical water treatment

The aim of present study was to obtain total reducing sugars (TRS) from bamboo under subcritical water (SCW) treatment in a batch reactor at the temperature ranging from 170 °C to 220 °C and 40 min hydrolysis time. Experiments were performed to investigate the effects of temperature and time on TRS yield. The maximum TRS yield (42.21%) was obtained at lower temperature (180 °C), however longer reaction time (25 min). X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) analysis were used to characterise treated and untreated bamboo samples. The XRD profile revealed that crystallinity of bamboo increased to 71.90% with increase in temperature up to 210 °C and decreased thereafter to 70.92%. The first-order reaction kinetic model was used to fit the experimental data to obtain rate constants. From the Arrhenius plot, activation energy and pre-exponential factor at 25 min time were found to be 17.97 kJ mol(-1) and 0.154 min(-1), respectively.

Comparative studies of thermal, oxidative and low temperature properties of waste cooking oil and castor oil

This study compares the thermo-oxidative stability and cold flow properties of waste cooking oil (WCO) and castor oil (CO) as inexhaustible potential raw materials to replace the conventional diesel fuels. The thermo-oxidative stability and high viscosity are the limitations of the vegetable oils to use directly as fuel in diesel engines. Therefore, proper investigation on these physical properties of WCO and CO could help to develop high energy efficient biofuels which could act as an alternative to fossil fuels. This study proposes modern and advanced analytical techniques, i.e., thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) which consumes less time, energy, and requires less quantity of sample to evaluate aforementioned physical properties. For comparison purpose, properties were also found out using conventional ASTM standard methods. Obtained results by TGA and DSC were very much close to the conventional standard methods. WCO used in this study was found to be thermally ...

Optimization and hydrolysis of cellulose under subcritical water treatment for the production of total reducing sugars

Subcritical water (SCW) treatment has gained enormous attention as an environmentally friendly technique for organic matter and an attractive reaction medium for a variety of applications. In this work, hydrolysis of cellulose was studied under SCW conditions in a batch reactor to attain total reducing sugars (TRS) within a reaction temperature and time range of 150 to 250 °C and 10–60 min, respectively. From the experimental results, the highest yield of TRS was 45.04% as obtained at 200 °C and 20 min of hydrolysis time. The characterisation techniques, namely X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used as to determine the structural and compositional changes in the hydrolysed material. Reaction parameters such as temperature, time, and solute loading have been optimised using response surface methodology based on a central composite design. From ANOVA analysis, it was described that the second-order response surface model is highly significant as per Fishers F-test and P-value. A first-order reaction kinetic model was formulated to describe the hydrolysis of cellulose for TRS formation and decomposition. For TRS formation, the activation energy and pre-exponential factor of the Arrhenius equation was found to be 29.16 kJ mol−1 and 0.088 min−1 for 60 min, respectively.

Effect of storage parameters on stability of Jatropha-derived biodiesel

Jatropha curcas L. seeds as a raw material for biodiesel production is a rapidly growing interest over the world because of its high oil content, ecological adaptability, and excellent fuel properties. Though there is an increase in productivity of biodiesel, showing solution for future energy insecurity, there still remains some concern for commercialization due to its susceptibility to degradation during long storage. The aim of this paper is to investigate the effect of temperature and ambient condition on Jatropha biodiesel storage. An experiment was conducted for a period of 12 months, where Jatropha biodiesel stored in three groups at different temperatures (4°C, 25°C, and 35°C) and environmental conditions (exposed in dark, light, and air). At regular intervals, the samples were taken out to analyze acid value, density, kinematic viscosity, and thermogravimetric profile to monitor the quality of biodiesel. Analysis showed that acid value, density, kinematic viscosity, and the onset temperature of volatilization and distillation increases with the increase in storage time of biodiesel samples. However, Jatropha biodiesel stored at 35°C, in contact with ambient air and light showed highest degradation compared to those which were stored at 25°C and 4°C. Among all the parameters studied, high temperature and air exposure are the two most potent parameters which accelerate the degradation process. Along with that, light exposure had mild but significant effect on Jatropha biodiesel degradation over a long storage period.

Biosorption of Cr(VI) on immobilized Hydrilla verticillata in a continuous up-flow packed bed: prediction of kinetic parameters and breakthrough curves

abstract In this work, biomass of Hydrilla verticillata, a waste weed was used in its immobilized form to remove hexavalent chromium from aqueous solutions. The powdered biomass was entrapped in polyvinyl alcohol and packed bed studies were carried out using beads of immobilized H. verticillata. Bed height, influent Cr(VI) concentrations, and influent flow rate were variable parameters for the present study. The overall performance of the biosorbent was satisfactory as very high Cr(VI) uptake (45.83 mg g−1) was observed. Three different models—Bed depth service time (BDST), Yoon–Nelson, and Thomas—were studied and fitted to the experimental data. The correlation coefficient values were all above 0.96, whereas the BDST model fitted the data best. From the Thomas model, Thomas rate constant, K Th was calculated and found to be 0.0215 L mg−1 h−1. The data obtained from the Yoon–Nelson model indicated that τ (148 min at 5 mg L−1) values were very similar to experimental (140 min at 5 mg L−1) results. Desorpti...

Salinity induced lipid production in microalgae and cluster analysis (ICCB 16-BR_047)

This work aimed to gain mechanistic insights into the salt stress mediated enhanced lipid accumulation in microalgae. Two freshwater microalgae were isolated from North Guwahati Assam, and were identified as Chlorella sorokiniana CG12(KR905186) and Desmodesmus GS12(KR905187). The effects of various salts such as NaCl, KCl, MgCl2 and CaCl2 were investigated where CaCl2 exhibited the maximum effect on lipid enhancement up to 40.02% and 44.97% in CG12 and GS12, respectively. Furthermore, the substantial increase was observed in oleic acid content up to 64.18% and 53.46% in CG12 and GS12 in the presence of 25mM and 5mM CaCl2, respectively. Cluster analysis revealed the correlation between lipid profile alterations by varying concentration of salts. Based on the outcomes of the present study, it is hypothesized that Ca2+ plays a decisive role in the cell signaling under salt stress conditions and subsequently enhances the synthesis of lipid molecules.

Effect of light intensity and pH condition on the growth, biomass and lipid content of microalgae Scenedesmus species

The physiological factors for microalgae cultivation are the preliminary steps to overcome the potential biomass demand. In this regard, the influence of light intensity (at six levels: 27, 40.5, 54, 67.5, 81 and 94.5 µmol m−2s−1) and pH conditions (5.0, 6.0, 7.0, 8.0 and 9.0) on the growth and lipid production of Scenedesmus species ADIITEC-II and GUBIOTJT116 was compared in the batch culture. Among the studied species, maximum specific growth (0.334 ± 0.002 day−1) and highest biomass yield (0.41 ± 0.021 g L−1) was achieved for Scenedesmus species ADIITEC-II at light intensity 81 µmol m−2s−1. Similarly, Scenedesmus species GUBIOTJT116 showed increased growth and biomass production at 81 µmol m−2s−1. However, illumination under 94.5 µmol m−2s−1 showed higher lipid production (0.533 ± 0.001 g L−1 and 0.551 ± 0.001 g L−1) for Scenedesmus sp. ADIITEC-II and GUBIOTJT116, respectively. The significant variation in effective pH tolerance, growth and biomass production was observed in the studied pH range. The result obtained in this study provides a potential insight of the strains and could be further explored to improve the biomass and lipid yield.

Jatropha ( Jatropha curcas L.)

The seed oil of Jatropha (Jatropha curcas L.) as a source of biodiesel fuel is gaining worldwide importance. Commercial-scale exploration of Jatropha has not succeeded due to low and unstable seed yield in semiarid lands unsuitable for the food production and infestation to diseases. Genetic engineering is promising to improve various agronomic traits in Jatropha and to understand the molecular functions of key Jatropha genes for molecular breeding. We describe a protocol routinely followed in our laboratory for stable and efficient Agrobacterium tumefaciens-mediated transformation of Jatropha using cotyledonary leaf as explants. The 4-day-old explants are infected with Agrobacterium tumefaciens strain EHA105 harboring pBI121 plant binary vector, which contains nptII as plant selectable marker and gus as reporter. The putative transformed plants are selected on kanamycin, and stable integration of transgene(s) is confirmed by histochemical GUS assay, polymerase chain reaction, and Southern hybridization.

Effect of pre-treatment on solvents extraction and physico-chemical properties of castor seed oil

Extraction of castor oil from castor seed was carried out by Soxhlet method using polar and non-polar commercial solvents at the optimum conditions obtained from the preliminary oil extraction study. The solvents used were hexane, pentane, petroleum ether, cyclohexane, ethylacetate, methanol, and isopropanol. The effect of different process parameters such as temperature, solute to solvent ratio, and extraction time were studied to optimize and compare the extraction efficiency of different solvents. The higher oil yields of 56.07% and 55.22% were obtained by using polar solvents, i.e., ethyl acetate and methanol, respectively. The physico-chemical properties of the castor oil extracted using different solvents were also estimated to determine its quality potential using ASTM methods. Similarly, the performance of seed pre-treatment on the oil yield and the suitability of methanol as a possible extracting and reactive solvent for biodiesel production was also investigated. The pre-treatment of castor seed...