Production, optimization, and characterization of Ethiopian variant Prosopis juliflora based biodiesel.

Considering the need for biodiesel production from non-edible oil sources and taking into account the fact that Prosopis Juliflora (JF) is identified as a highly invasive species in Ethiopia, this research focuses on biodiesel production from a possible and promising alternative feedstock. The objective of this study is to analyze Ethiopian variant Juliflora based biodiesel (JFB) production through transesterification, carry out optimization by exploring the effects of various process parameters and characterization of functional groups (with GC-MS,FT-IR and NMR) including rheological behavior, not yet been reported earlier. As per ASTM protocol testing, the methyl ester of Juliflora has been found to have the following main fuel properties: kinematic viscosity (mm2/s) 3.395, cetane number 52.9, acid number (mgkoh/g) 0.28, density (gm/ml) 0.880, calorific value (MJ/kg) 44.4, methyl ester content (%) 99.8, and flashpoint (°C) 128, copper strip corrosion value 1a,%FFA (free fatty acid) 0.14. When compared with those of diesel, the viscosity, density, and flash point of JFB are seen to be higher than those of diesel, although it has a similar calorific value but more importantly higher than most of the other biodiesels. Based on an assessment using response surface methodology, methanol concentration together with catalyst loading, temperature, and reaction time are determined to be the most important influencing process parameters. The best molar ratio for methanolysis was observed to be 6:1 with a catalyst concentration of 0.5 wt% at 55 °C for 60 min for biodiesel yield at 65%. The JFB maximum yield of 130 ml at 70 min and the minimum yield of 40 ml at 10 min demonstrate that as mixing time increases, JFB yield tend to increase up to a certain time limit. The maximum raw oil yield rom crushed seed with hexane solvent was observed to be 480 ml within 3 days from 2.5 kg of crushed seed. The Fourier transform infrared analysis (FT-IR) revealed the presence of all desired functional groups necessary for biodiesel on OH radicals at wave numbers of 3314.40 cm-1, Aliphatic methyl C-H at 2942.48 cm- 1 with a functional group (CH-3-,-CH2-), and methylene C-H at 2832.59 cm-1. The gas chromatography-mass spectrometer (GC-MS) study confirmed the higher ester content present in the JFB with a higher unsaturation level of 68.81%. The fatty acid, oleic acid has a lower saturation level of 4.5%, while palmitic acid has a lower threshold level of 2.08%. The Rheometer test showed that shear stress and viscosity reduced with increasing temperature within the range of biodiesel requirements, and the Newtonian behavior was confirmed. The JFB has a fairly high viscosity and shear rate at low temperatures. The 1H NMR (nuclear magnetic resonance) study established that JFB has a necessary ingredient; and aliphatic resonances occur in the chemical shift region of 1.5-3.0 ppm. Significant regions indicate protons bound to heteroaromatics, aldehydes, as shown by 13C NMR spectrum. The findings from the FT-IR, GC-MS, 1H NMR, and 13C NMR are in agreement thus validating the presence of numerous functional groups in JFB as such. Since JFB possesses the requisite biodiesel fuel attributes, Prosopis Juliflora need to be pursued as a promising biodiesel feedstock in Ethiopia for alleviating the burden of imported fuels while also addressing difficulties with emissions released by the combustion of fossil fuels.

Plant-driven removal of heavy metals from soil: uptake, translocation, tolerance mechanism, challenges, and future perspectives.

Increasing heavy metal (HM) concentrations in the soil have become a significant problem in the modern industrialized world due to several anthropogenic activities. Heavy metals (HMs) are non-biodegradable and have long biological half lives; thus, once entered in food chain, their concentrations keep on increasing through biomagnification. The increased concentrations of heavy metals ultimately pose threat on human life also. The one captivating solution for this problem is to use green plants for HM removal from soil and render it harmless and reusable. Although this green technology called phytoremediation has many advantages over conventional methods of HM removal from soils, there are also many challenges that need to be addressed before making this technique practically feasible and useful on a large scale. In this review, we discuss the mechanisms of HM uptake, transport, and plant tolerance mechanisms to cope with increased HM concentrations. This review article also comprehensively discusses the advantages, major challenges, and future perspectives of phytoremediation of heavy metals from the soil.

Influence of fuel moisture content and reactor temperature on the calorific value of syngas resulted from gasification of oil palm fronds.

Biomass wastes produced from oil palm mills and plantations include empty fruit bunches (EFBs), shells, fibers, trunks, and oil palm fronds (OPF). EFBs and shells are partially utilized as boiler fuel while the rest of the biomass materials like OPF have not been utilized for energy generation. No previous study has been reported on gasification of oil palm fronds (OPF) biomass for the production of fuel gas. In this paper, the effect of moisture content of fuel and reactor temperature on downdraft gasification of OPF was experimentally investigated using a lab scale gasifier of capacity 50 kW. In addition, results obtained from equilibrium model of gasification that was developed for facilitating the prediction of syngas composition are compared with experimental data. Comparison of simulation results for predicting calorific value of syngas with the experimental results showed a satisfactory agreement with a mean error of 0.1 MJ/Nm³. For a biomass moisture content of 29%, the resulting calorific value for the syngas was found to be only 2.63 MJ/Nm³, as compared to nearly double (4.95 MJ/Nm³) for biomass moisture content of 22%. A calorific value as high as 5.57 MJ/Nm³ was recorded for higher oxidation zone temperature values.

Study on tar generated from downdraft gasification of oil palm fronds.

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study.