Resources, renewable carbon

Renewable carbon resources is a misnomer the earth s carbon is in a perpetual state of flux. Carbon is not consumed such that it is no longer available in any form. Reversible and irreversible chemical reactions occur in such a manner that the carbon cycle makes all forms of carbon, including fossil resources, renewable. It is simply a matter of time that makes one carbon from more renewable than another. If it is presumed that replacement does in fact occur, natural processes eventually will replenish depleted petroleum or natural gas deposits in several million years. Eixed carbon-containing materials that renew themselves often enough to make them continuously available in large quantities are needed to maintain and supplement energy suppHes biomass is a principal source of such carbon. 

The percentage of energy demand that could be satisfied by particular nonfossil energy resources can be estimated by examination of the potential amounts of energy and biofuels that can be produced from renewable carbon resources and comparison of these amounts with fossil fuel demands. 

As an abundant, nontoxic, non-flammable, easily available, and renewable carbon resource, C02 is very attractive as an environmentally friendly feedstock for making commodity chemicals, fuels, and materials [1-7]. In this respect, PEGs-functionalized catalysts have been developed for efficient transformation of C02 into value-added chemicals or fuels such as cyclic carbonates, dimethyl carbonate (DMC), oxazolidinones, organic carbamates and urea derivatives. 

Akiyama, M.,Tsuge,T., and Doi, Y. 2003. Environmental life cycle comparison of poly-hydroxyalkanoates produced from renewable carbon resources by bacterial fermentation. Polym. Degrad. Stab., 80,183-194. 

III. DISTRIBUTION OF RENEWABLE CARBON RESOURCES AND BIOMASS ABUNDANCE... 

III. Distribution of Renewable Carbon Resources and Biomass Abundance... 

Use of Biomass for Hydrogen Production or as a Renewable Carbon Resource... 

AKI03] Akiyama M., Tsuge T., Doi Y., Environmental lifecycle comparison of polyhydroxyalkanoates produced from renewable carbon resources by bacterial fevme n L iorC Polymer Degradation and Stability, o. 80, no. l,p. 183,2003. 

Carbon dioxide (CO2) can be produced in many circumstances and is an easily available renewable carbon resource with the advantages of being inexpensive, abundant, and environmentally friendly. Hence, C02-responsive hydrogels are receiving more and more attention from... 

PHAs have attracted much attention as environmentally compatible materials owing to their production from renewable carbon resources and their unique property of biodegradability. All PHAs contain monomer units with only the configuration, owing to the stereospecificity of the synthesis enzymes. PHAs are stored by bacteria for eventual breakdown and utilization as a carbon source when extracellular carbon... 

Biomass is one t5rpe of carbon-neutral, renewable energy source and has been considered for an attractive resource during the past few decades due to its abundance in the world. Microbial fuel cell (MFC) is one approach to utilize the abundant biomass, and it has the advantage of directly converting biomass into electricity with high columbic efficiency over traditional biomass utilization approaches, such as incineration, gasification, fermentation, etc. 

Chemical exploitation of renewable raw materials has a long tradition. Before the utilization of the fossil carbon resources coal and petroleum, they were the exclusive source of organic raw materials. Even today, a wide range of chemicals is produced on this basis, e.g. natural rubber, cellulose, fatty acids, ethanol and essential oils, citric acid, enzymes and antibiotics. In terms of quantity, around 8% of organic chemicals are recovered from renewable raw materials. Of the 20 Mt of renewable raw materials used annually, oils and fats have the largest share, amounting to some 40% (Figure 3.55). 

With the increasing concern of human society to environmental and energy problems, the family of microbial synthesized polymers poly(hydroxyalkanoates) (PHA) have been attracting more and more attention in both academic and industrial fields due to their complete biodegradability and the renewable carbon resources used to produce them (Doi, 1990 Muller, 1993). 

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