Application of 1D and 2D MFR reactor technology for the isolation of insecticidal and anti-microbial properties from pyrolysis bio-oils

Valuable chemicals can be separated from agricultural residues by chemical or thermochemical processes. The application of pyrolysis has already been demonstrated as an efficient means to produce a liquid with a high concentration of desired product. The objective of this study was to apply an insect and microorganism bioassay-guided approach to separate and isolate pesticidal compounds from bio-oil produced through biomass pyrolysis. Tobacco leaf (Nicotianata bacum), tomato plant (Solanum lycopersicum), and spent coffee (Coffea arabica) grounds were pyrolyzed at 10°C/min from ambient to 565°C using the mechanically fluidized reactor (MFR). With one-dimensional (1D) MFR pyrolysis, the composition of the product vapors varied as the reactor temperature was raised allowing for the selection of the temperature range that corresponds to vapors with a high concentration of pesticidal properties. Further product separation was performed in a fractional condensation train, or 2D MFR pyrolysis, thus allowing for the separation of vapor components according to their condensation temperature. The 300–400°C tobacco and tomato bio-oil cuts from the 1D MFR showed the highest insecticidal and anti-microbial activity compared to the other bio-oil cuts. The 300–350 and 350–400°C bio-oil cuts produced by 2D MFR had the highest insecticidal activity when the bio-oil was collected from the 210°C condenser. The tobacco and tomato bio-oil had similar insecticidal activity (LC₅₀ of 2.1 and 2.2 mg/mL) when the bio-oil was collected in the 210°C condenser from the 300–350°C reactor temperature gases. The 2D MFR does concentrate the pesticidal products compared to the 1D MFR and thus can reduce the need for further separation steps such as solvent extraction.     

Green sand reclamation using a fluidized bed with an attrition nozzle

The objective of this study was to determine the technical feasibility of green sand reclamation using attrition in a gas–solid fluidized bed. Reclamation of foundry sand is becoming important as it may help solve concerns related to transportation and dumping of the used sand, and reduce production costs by recycling sand. The crucial step in green sand reclamation is the removal of small clay particles that are bound to the sand particles.For this study two different types of green sand were used and supplied by two different foundries. Tests were performed in a fluidized bed equipped with an attrition nozzle operating at pressures of either 350 or 550 kPa (50 or 80 psig). Attrition experiments for one green sand were performed on either unburned or burned (calcined) green sand, to determine the effect of prior calcination of the green sand on its reclamation potential by attrition. Calcination temperatures of over 700 °C were employed, and the results suggest that calcination facilitates the removal of clay from the green sand.Green sand was analyzed for clay and organic content, acid request, and particle size before and after attrition. Attriting calcined green sand produces the best results. Also experiments conducted at the highest attrition pressure of 550 kPa gave good results. According to the mass balance, the mass lost during the attrition process may be limited to less than 14%, and this could be considered acceptable. The volume of air required for the attrition nozzle is rather high and this may adversely affect the economics of the process.     

Correction to: Human behavior and Homo-mammal interactions at the first European peopling: new evidence from the Pirro Nord site (Apricena,Southern Italy)

The Science of Nature - Female-only colour polymorphism is rare in birds, but occurs in brood parasitic cuckoos (Cuculidae). Obligate brood parasites leave incubation and parental care to other...