From Counting Heat of Organic Combustion to Determining Heat of Anaerobic Digestion

Tue, 21 Apr 2026 03:46:38 +0000

Organic combustion and anaerobic digestion are two important types of redox reactions. The former uses molecular oxygen as oxidizing agent and organic carbon as reducing agent. The latter uses organic carbons as both oxidizing agent and reducing agent. Anaerobic digestion is represented by Buswell’s equation. It is composed of series of bioredox and biohydrolysis reactions. To count heat of anaerobic digestion, structural formula and heat of formation of organic matter are required. To overcome these restrictions, this research establishes a simple equation for determining heat of anaerobic digestion. Hess’s Law is used to convert organic combustion equations to Buswell’s equation. Then, the corresponding thermochemical equation for standard heat of anaerobic digestion is deduced. This research concludes that: (i) ideal standard heat of anaerobic digestion is equal to zero, (ii) heat of bioredox is dependent on Buswell’s electron, (iii) standard heat of biohydrolysis is equal to the negative value of standard heat of bioredox, and (iv) standard Gibbs free energy change is equal to the negative product of temperature times standard entropy change.

Derived Mathematical Equations for Counting Heat of Dark Fermentation, Heat of Bioredox, and Heat of Biohydrolysis

Tue, 21 Apr 2026 04:01:38 +0000

Combustion and dark fermentation are two important types of redox reactions. The former uses molecular oxygen as the oxidizing agent and the latter uses proton as the oxidizing agent. Dark fermentation is represented by Buswell’s equation for biohydrogen, which is composed of two sub-reactions: bioredox and biohydrolysis. Unlike heat of combustion, heat of dark fermentation is a concept that is rarely explored. In this research, with the help of Hess’s law, reactions of organic combustion and molecular hydrogen combustion are converted to Buswell’s equation for biohydrogen. The corresponding thermochemical equation for dark fermentation can then be identified accordingly. Based on a given chemical formula in the form of either empirical formula or structural formula, the relationship between standard heat of dark fermentation, standard heat of bioredox, and standard heat of biohydrolysis is established. Using the derived mathematical equations, standard heat of dark fermentation, standard heat of bioredox, and standard heat of biohydrolysis are determined.

International Journal of Chemistry, Issue: Vol.18, No.2

From Counting Heat of Organic Combustion to Determining Heat of Anaerobic Digestion

Derived Mathematical Equations for Counting Heat of Dark Fermentation, Heat of Bioredox, and Heat of Biohydrolysis