Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

The Catalytic Valorization of Lignin for the Production of Renewable Chemicals

and Fuels Changzhi Li,† Xiaochen Zhao,† Aiqin Wang,† George W. Huber,†,‡ and Tao Zhang*,† †State Key Laborotary of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China ‡Department of Chemical and Biological Engineering, University of WisconsinMadison, Madison, Wisconsin 53706, United States

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

Chromium, in the trivalent form (Cr(III)), is an important component of a balanced human and animal diet and its deficiency causes disturbance to the glucose and lipids metabolism in humans and animals. In contrast, hexavalent Cr (Cr(VI)) is highly toxic carcinogen and may cause death to animals and humans if ingested in large doses. Recently, concern about Cr as an environmental pollutant has been escalating due to its build up to toxic levels in the environment as a result of various industrial and agricultural activities. In this review, we present the state of knowledge about chromium mobility and distribution in the environment and the physiological responses of plants to Cr with the desire to understand how these processes influence our ability to use low cost, environmentally friendly biological remediation technologies to clean up Cr-contaminated soils, sediments, and waters. The use of biological remediation technologies such as bioremediation and phytoremediation for the cleanup of Cr-contaminated areas has received increasing interest from researchers worldwide. Several methods have been suggested and experimentally tested with varying degrees of success.

Chromium in the environment: factors affecting biological remediation

Literature regarding the biochemistry of aluminum and eight similar ions is reviewed. Close and hitherto unknown similarities were found. A hypothetical model is presented for the metabolism, based on documented direct observations of Al3+ and analogies from other ions. Main characteristics are low intestinal absorption, rapid urinary excretion, and slow tissue uptake, mostly in skeleton and reticuloendothelial cells. Intracellular Al3+ is probably first confined in the lysosomes but then slowly accumulates in the cell nucleus and chromatin. Large, long-lived cells, e.g., neurons, may be the most liable to this accumulation. In heterochromatin, Al3+ levels can be found comparable to those used in leather tannage. It is proposed that an accumulation may take place at a subcellular level without any significant increase in the corresponding tissue concentration. The possible effects of this accumulation are discussed. As Al3+ is neurotoxic, the brain metabolism is most interesting. The normal and the lethally toxic brain levels of Al3+ are well documented and differ only by a factor of 3-10. The normal brain uptake of Al3+ is estimated from data on intestinal uptake of Al3+ and brain uptake of radionuclides of similar ions administered intravenously. The uptake is very slow, 1 mg in 36 years, and is consistent with an assumption that Al3+ taken up by the brain cannot be eliminated and is therefore accumulated. The possibility that Al3+ may cause or contribute to some specific diseases, most of them related to aging, is discussed with the proposed metabolic picture in mind.

Metabolism and possible health effects of aluminum.

Removal of copper and nickel ions from aqueous solutions by grape stalks wastes

Chromium(III) and the glucose tolerance factor

Chemical characterisation of bark and of alkaline bark extracts from maritime pine grown in Portugal.

https://digituma.uma.pt/bitstream/10400.13/3375/1/C13%20solid-state%20nuclear%20magnetic%20resonance%20and%20Fourier%20transform%20infrared%20studies%20of%20the%20thermal%20decomposition%20of%20cork.pdf

13C solid-state nuclear magnetic resonance and Fourier transform infrared studies of the thermal decomposition of cork.

The catalytic effect of molybdovanadophosphate heteropolyanions (HPAs) on the delignification of wood by oxygen has been investigated The VO2+ ions produced via the dissociation of HPA in acidic conditions are suggested to have a much stronger catalytic effect on the oxidation of lignin than parent HPA The influence on delignification of the pH, medium composition and the partial reduction of HPA prior to its use in catalysis are discussed in terms of the reaction mechanisms Kinetic studies show that the catalyst diffusion in the wood tissue is the rate-limiting step of delignification, while the lignin oxidation rate is determined by the HPA/VO2+ catalytic oxidation step

J. D. Pedrosa De Jesus

Papers

Chromium(III) and the glucose tolerance factor

Chemical characterisation of bark and of alkaline bark extracts from maritime pine grown in Portugal.

13C solid-state nuclear magnetic resonance and Fourier transform infrared studies of the thermal decomposition of cork.

Oxidative delignification in the presence of molybdovanadophosphate heteropolyanions: mechanism and kinetic studies

Synthesis and Characterization of Tin Niobates