Humic Modified Fly Ash
[I]Fly ash[FA] showing high sorption efficiency towards humic substances* , is modified with humic substances and then evaluated for biofunctional agricultural uses. Humic-loaded FA is prepared in various humic to FA ratios. The Greek peaty lignite** of the Megalopolis Basin is used as raw material for obtaining both FA and humates.
[II] The reaction is studied at different temperatures 291, 308, 323, 338, and 353 K and at several pH values.The adsorption capacity is found to increase at neutral pH and, also, with rise of temperature, that is, from 760 to 1300 mg humics/g FA at 291 K and 353 K, respectively.
[III] The adsorption proceed stepwise via strong Coulombic and hydrophophic forces of attraction between the two materials. Langmuir, Freundlich, BET, Harkins-Jura, and Dubinin-Radushkevich isotherm models are employed to evaluate the ongoing adsorption to shed light to the physicochemical properties of the sorbent-adsorbate system.
[IV]Both the slow release of adsorbed humic substances during washing and the existence of microbial populations are considered advantageous for employing humic-loaded FA in biological cultivations substituting traditional soil-conditioning materials.
(V) Lastly,the humic modified FA is also very important from an economic point as power plant wastes of the coal reserves worldwide can well be utilized.
*Humic substance( HS) exist as Humic acids(HA), Fulvic acids(FA) and Humin( Hu) Humic acid is a principal component of humic substances, which are the major organic constituents of soil, peat, coal, many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter. It is not a single acid; rather, it is a complex mixture of many different acids containing carboxyl and phenolate groups so that the mixture behaves functionally as a dibasic acid or, occasionally, as a tribasic acid. Humic and fulvic acids{which invariably accompany Humic acids} are commonly used as a soil supplement in agriculture, and less commonly as a human nutritional supplement. Fulvic acids are poly-electrolytes and are unique colloids that diffuse easily through membranes whereas all other colloids do not.
** Greece boasts lignite resources of 4.7 billion tonnes and 3.0 billion tonnes of economically workable reserves.
Reference:
Bioinorganic Chemistry and Applications
Volume 2010 (2010), Article ID 457964, 8 pages
http://dx.doi.org/10.1155/2010/457964 .
I have adsorbed human urine treated with chemicals (to preserve the Nitrogen content ) on fly ash ,which can be used for agriculture . Best from waste .
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