• Energy Research

In the present research work, a non-conventional oil i.e., karanja (Pongamia pinnata L.) seed oil was selected to synthesize biodiesel through base catalyzed transesterification reaction. To minimize the FFA (free fatty acid) value of oil, esterification of oil using H2SO4 was carried out before the transesterification. The esterified oil was then subjected to transesterification with methanol in the presence of KOH, yielding karanja oil methyl esters (KOMEs) along with glycerol as a side-product. The transesterification was carried out under optimized reaction parameters such as alcohol to oil molar ratio of 6:1, temperature of 60 °C, KOH concentration of 1.00%, reaction time of 120 min, stirring rate of 750 rpm and maximum KOMEs yield of 95.4% was achieved. Different functional groups in KOMEs were traced via FTIR whereas GC-MS profiling was investigated to characterize different fatty acids in KOMEs. Moreover, fuel characteristics of KOMEs were determined and matched with standards. The findings of this research work support the use of Pongamia pinnata seed oil as a viable non-conventional/non-food oil feedstock for production of good quality biodiesel with value-added perspectives.

Soil acidity is a major problem of agriculture in many parts of the world. Soil acidity causes multiple problems such as nutrient deficiency, elemental toxicity and adverse effects on biological characteristics of soil, resulting in decreased crop yields and productivity. Although a number of conventional strategies including liming and use of organic and inorganic fertilizers are suggested for managing soil acidity but cost-effective and sustainable amendments are not available to address this problem. Currently, there is increasing interest in using biochar, a form of biomass derived pyrogenic carbon, for managing acidity while improving soil health and fertility. However, biochar varies in properties due to the use of wide diversity of biomass, variable production conditions and, therefore, its application to different soils can result in positive, neutral and or negative effects requiring an in-depth understanding of biochar-acid soil interactions to achieve the best possible outcomes. Here, we present a comprehensive synthesis of the current literature on soil acidity management using biochar. Synthesis of literature showed that biochars, enriched with minerals (i.e., usually produced at higher temperatures), are the most effective at increasing soil pH, basic cation retention and promoting plant growth and yield. Moreover, the mechanism of soil acidity amelioration with biochar amendments varies biochar types, i.e., high temperature biochars with liming effects and low temperature biochars with proton consumption on their functional groups. We also provide the mechanistic interactions between biochar, plant and soils. Altogether, this comprehensive review will provide guidelines to agricultural practitioners on the selection of suitable biochar for the reclamation of soil acidity.

The present work reveals variation in the nutritional and antioxidant profiles of Moringaoleifera leaves with regard to four maturity stages (early, mid, penultimate and late). The corresponding yield of 80% methanolic extract (14.21 and 9.69%) and total phenolic contents (TPC) of the extract (95.26 and 38.22 mg GAE/g) from M. oleifera leaves were found to be maximum at early stage and minimum at the later stage. Total flavonoids, ash, protein, vitamin C and β-carotene contents were found to be minimum at the early stage and maximum at later stage (12.26 ± 0.47 to 30.07 ± 1.09 mg/g, 10.36–15.92%,50.3 ± 0.15 to 56 ± 0.77 mg/100 g, 143.14 ± 0.74 to 164.81 ± 0.44 mg/100g, and 89 ± 0.28 to 112.8 ± 1.40 mg/100 g). Amino acids including valine, alanine, leucine and phenylalanine were identified with their least contents at early stages (90.87, 53.07, 55.21, and 48.65 µg/g) and maximum at later stages (197.66, 114.3, 114.2, and 104.5 µg/g, respectively). The levels of different minerals such as Cu, Fe, Mn in M. oleifera leaves at different maturity stages varied from 0.59 to 2.08, 21.96 to 58.68, and 5.56 to 13.84 mg/100 g, respectively. RP-HPLC analysis of the nutritionally rich later-stage leave samples revealed the presence of quercetin as a major component (21.64 mg/kg), followed by benzoic acid, ferulic acid, sinapic acid, gallic acid, and p-coumaric acid with contributions of 13.03, 8.85, 3.39, 2.88, and 1.59 mg/kg, respectively. Overall, a considerable variation in the profile of different nutrients and antioxidants was noted in M. oleifera leaves as maturity progressed. These results support the harvesting of M. oleifera leaves at an appropriate maturity stage to maximize the functional food and nutraceutical benefits of this valuable food commodity.

Biodiesel is an alternative to petroleum-based conventional diesel fuel and is defined as the mono-alkyl esters of vegetable oils and animal fats. Biodiesel has been prepared from numerous vegetable oils, such as canola (rapeseed), cottonseed, palm, peanut, soybean and sunflower oils as well as a variety of less common oils. In this work, Moringa oleifera oil is evaluated for the first time as potential feedstock for biodiesel. After acid pre-treatment to reduce the acid value of the M. oleifera oil, biodiesel was obtained by a standard transesterification procedure with methanol and an alkali catalyst at 60 degrees C and alcohol/oil ratio of 6:1. M. oleifera oil has a high content of oleic acid (>70%) with saturated fatty acids comprising most of the remaining fatty acid profile. As a result, the methyl esters (biodiesel) obtained from this oil exhibit a high cetane number of approximately 67, one of the highest found for a biodiesel fuel. Other fuel properties of biodiesel derived from M. oleifera such as cloud point, kinematic viscosity and oxidative stability were also determined and are discussed in light of biodiesel standards such as ASTM D6751 and EN 14214. The 1H NMR spectrum of M. oleifera methyl esters is reported. Overall, M. oleifera oil appears to be an acceptable feedstock for biodiesel.

The current study describes the emphatic use of response surface methodology for the optimized biodiesel production using chemical and enzymatic transesterification of rice bran and sunflower oils. Optimal biodiesel yields were determined to be 65.3 ± 2.0%, 73.4 ± 3.5%, 96.5 ± 1.6%, 89.3 ± 2.0% and 41.7 ± 3.9% for rice bran oil and 65.6 ± 1.2%, 82.1 ± 1.7%, 92.5 ± 2.8%, 72.6 ± 1.6% and 50.4 ± 2.5% for sunflower oil via the transesterification catalyzed by NaOH, KOH and NaOCH3,NOVOZYME-435 and A.n. Lipase, respectively. Based upon analysis of variance (ANOVA) and Response Surface plots significant impact of reaction parameters under study was ascertained. FTIR spectroscopic and HPLC methods were employed for monitoring the transesterification reaction progress while GC-MS analysis was performed to evaluate the compositional analysis of biodiesel. The fuel properties of both the rice bran and sunflower oil based biodiesel were shown to be technically compatible with the ASTM D6751 and EN 14214 standards. The monitoring of exhaust emission of synthesized biodiesels and their blends revealed a marked reduction in carbon monoxide (CO) and particulate matter (PM) levels, whereas an irregular trend was observed for NOx emissions.

In the present study polystyrene waste (PS) was collected from a drop off site in a local market and pyrolyzed at heating rates of 5, 10, 15 and 20 °C/min and temperature range 40-600 °C under nitrogen condition. The apparent activation energy (Ea) and pre-exponential factor (A) were determined using 6 different kinetic methods. Activation energy and pre-exponential factor were found in the range of 82.3 - 202.8 kJmol-1 and 3.5 × 106-7.6 × 1014 min-1 respectively. The results demonstrated that the calculated values of Ea and A vary with fraction of conversion, heating rates and the applied model. Moreover, pyrolysis of waste polystyrene was carried out in an indigenously manufactured furnace at temperatures ranging from 340 to 420 °C. The composition of liquid and gaseous fractions was determined using gas chromatography-mass spectrometry. Temperature and reaction time were optimized and the results revealed that temperature of 410 °C and exposure time of 70 min are the best conditions for maximum fuel oil production. Methane and ethane were found as the main products in the gas phase constituting about 82% of the gaseous fraction. The liquid products composed of broad range of C2 - C15 hydrocarbons depending on the pyrolytic parameters. A comparison of the composition of pyrolysis oil with standard parameters of diesel, gasoline and kerosene oil suggested that pyrolysis oil from polystyrene waste holds great promise for replacing fuel oil.

The increasing application of biobased lubricants could significantly reduce environmental pollution and contribute to the replacement of petroleum base oils. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates for use as base fluids in formulation of environment friendly lubricants. Although many vegetable oils have excellent lubricity, they often have poor oxidation and low temperature stability. Here in, we report the lubricant potential of Moringa oil, which has 74% oleic acid content and thus possess improved oxidation stability over many other natural oils. For comparison, Jatropha oil, cottonseed oil, canola oil and sunflower oil were also studied. Among these oils, Moringa oil exhibits the highest thermo-oxidative stability measured using PDSC and TG. Canola oil demonstrated superior low temperature stability as measured using cryogenic DSC, pour point and cloud point measurements. The friction and wear properties were measured using HFRR. Overall, it was concluded that Moringa oil has potential in formulation of industrial fluids for high temperature applications.

Abstract There is a need to seek non-conventional seed oil sources for biodiesel production due to issues such as supply and availability as well as food versus fuel. In this context, Milo (Thespesia populnea L.) seed oil was investigated for the first time as a potential non-conventional feedstock for preparation of biodiesel. This is also the first report of a biodiesel fuel produced from a feedstock containing cyclic fatty acids as T. populnea contains 8,9-methylene-8-heptadecenoic (malvalic) and smaller amounts of two cyclopropane fatty acids besides greater amounts of linoleic, oleic and palmitic acids. The crude oil extracted from T. populnea seed was transesterified under standard conditions with sodium methoxide as catalyst. Biodiesel derived from T. populnea seed oil exhibited fuel properties of density 880 kg m−3, kinematic viscosity 4.25 mm2/s; cetane number 59.8; flash point 176 °C; cloud point 9 °C; pour point 8 °C; cold filter plugging point 9 °C; sulfur content 11 mg kg−1; water content 150 mg kg−1; ash content 15 mg kg−1; and acid value as KOH 250 mg kg−1. The oxidative stability of 2.91 h would require the use of antioxidants to meet specifications in standards. Generally, most results compared well with ASTM D6751 and EN 14214 specifications.