Conversion Of Microalgae Into Acetic Acid With Metallic Oxides Under Hydrothermal Conditions

The problem of environmental is getting serious with the continuousconsumption of fossil fuels, so the development of clean renewable energyhas become a worldwide trend. As the only renewable carbon resource,biomass energy was paid close attention by many countries, such as UnitedStates, Japan, India, Brazil and so on. At present the use of biomass ismainly focused on the wood and crops (corn, rice and wheat straw etc.).The Journal Science of the United States consider the manufacturingbiofuels by food crops might have aggravated the effects of greenhousegas in turn. Therefore, the development of new biomass is particularlyimportant.Microalgae is a kind of autotroph biomass of wide distribution on theland and sea, high photosynthetic efficiency and huge developmentpotential. As a result, the use and development of microalgae energy isvery meaningful for reducing dependence on imported oil and ensuringnational energy security in our country, even taking up a significantposition in the international energy competition in the future. The researchof microalgae biomass utilization has not been so much studied all over theworld, which is a relatively new research program. Our team hasconducted a lot of research about hydrothermal conversion of producingformic acid, acetic acid and others by glucose, cellulose biomass while notabout microalgae. This research mainly discusses the hydrothermaltransformation of cyanobacteria (spirulina) and green algae (chlorella) in aseries of effect factors under the hydrothermal condition and hadtheoretical study of the reaction pathway.Firstly, this research carried out the feasibility of microalgae biomassinto resource under hydrothermal condition by metallic oxides for spirulinaand chlorella, then through optimized the influencing factors including thekinds of metallic oxides, alkaline concentration, reaction time, temperatureand water filling for acetic acid production. Research indicated that CuO and ZrO2showed the best performance,The residual reaction solidrespectively appeared Cu2O, Cu and ZrO while TiO2played as the catalystfor its only no change in valence state. While the acetic acid yield ofadding other metallic oxides such as TiO2was not that high and there wasno reduzate. All in all, alkaline condition was advantageous to productionof acetic acid from microalgae and the optimum reaction conditions foracetic acid yield:200%theoretical oxidation quantity,2mol/L alkalineconcentration,300oC,2h. In these conditions, CuO could reach35%acetic acid yield for60%water filling while ZrO2reached23%for50%water filling as the oxidant. At last, the reaction mechanism of acetic acidproduction from microalgae were respectively discussed, and verified withthe model compounds.This research could open up a new way of providing the basis guide ofmicroalgae conversion into biological resource for producing acetic acid.Besides of obtaining acetic acid product, it developed a new greensmelting technology at the same time. As a result, this study can not onlyachieve biomass resource, but also provides the solution direction forresources problem and greenhouse effect to a certain extent.