| Details: |
I will report on the full conversion (~100%) of oils to biodiesel. This was accomplished by the transesterification of pristine (soybean) oil and restaurant cooked vegetable oil to biodiesel, based on microwave dielectric irradiation as a driving force for the transesterification reaction, and SrO as a solid basic catalyst. This combination has demonstrated excellent catalytic activity and stability. According to 1H NMR spectroscopy and TLC results, this new combination accelerates the reaction, so that the reaction was completed in 10 seconds when stirred, and 40 seconds when unstirred, maintaining a very high conversion (99%) and high efficiency. The catalyst was reused for 10 times and showed the same catalytic power.
We will also demonstrate the direct conversion of as-harvested Nannochloropsis algae into bio-diesel without separating the lipidic phase. The results are based on the use of two novel techniques. The first is a unique biotechnology-based environmental system utilizing flue gas from coal burning power stations for microalgae cultivation. This method reduces considerably the cost of algae production. The second technique is the direct transesterification (a one-stage method) of the Nannochloropsis biomass to bio-diesel production using microwave and ultrasound radiation with the aid of a SrO catalyst. In the early stages of this research the lipidic phase was extracted from the microalgae and transestrification followed it. Later we became courageous and carried out the transesterification directly on the as-harvested microalgae. Full conversion to biodiesel was achieved in 5 minutes.
Fermentation of sugars, which is in general a slow process, forms an inevitable step in the production of ethanol from renewable sources. The aim of the research work is to accelerate the fermentation process. Fermentation of glucose was carried out using Saccharomyces cerevisiae under continuous mild ultra sonication conditions. The kinetics of the fermentation reaction was monitored by 13C NMR spectroscopic analysis and weight loss measurements of the fermentation broth. The reaction rate constant was enhanced by 2.5 and 2.3 times as a result of sonication at 20 and 30 ºC, respectively compared to stirred control experiments, and 10 times faster than the non-stirred fermentation. The acceleration in the fermentation of glucose is observed both at 20 and 40 % concentrations of glucose.
More recently we are concentrating on converting of agricultural wastes to biofuels. The best example of the conversion of biomass to ethanol is our successful conversion of Pine Cones and CHUMUS wastes to ethanol.A simple methodology based on the alkaline pretreatment of the biomass was developed to separate lignin from the pine cone and get cellulose and hemicellulose exclusively.
Figure 1. Pictorial representation of pine cone from pinus radiate and Cicer Arietinum from the fields of KibutsBeerotItzhak, Israel.
In addition, we have successfully converted a macroalgae, Ulva Rigida, into bioethanol getting 16% ethanol from 1 gram of the algae. Finally, I will demonstrate a solar system in which a glucose solution if flowing on a catalyst and is being fermented by to ethanol aided by the Sun irradiation.
|