Characterization of charcoal and firewood ash for use in African peri-urban agriculture

Abstract

Background: Ample quantities of ashes generated from domestic biomass energy combustion in Ghanaian kitchens are currently disposed of despite their potential agricultural value. This study aimed to investigate the potential agricultural value of charcoal and firewood ashes in terms of differences in the chemical and mineralogical compositions, and to identify the suitability of aqua regia, H 2 SO 4 , vinegar and distilled water to extract plant nutrients (Ca, Mg, K, Na, and P). The chemical compositions were determined by atomic absorption spectrometry after extractions with aqua regia, H 2 SO 4 , vinegar and distilled water while mineralogy was determined by X-ray powder diffraction. Results: The charcoal ash had 0.2 units, 13 ds m −1 , and 7% higher (P < 0.05) pH, EC, and CCE, respectively, than the firewood ash, whereas the latter had 6, 17, 43, and 139 µg g −1 higher (P < 0.05) As, Cu, Mg, and Zn contents, respectively, and more minerals with 86% being Mg-rich. Calcite and calcium oxide were the dominant minerals occurring in both ashes followed by calcium manganate (CaMnO 3). Aqua regia and vinegar were suitable for Ca, acidic solutions for Mg, H 2 SO 4 and aqua regia for P with Na and K being virtually soluble in all solutions. Lead, Mn, Ni, and Zn had values in the order of hundreds. Conclusions: Although the ashes differ, they both contain trace elements whose bioavailability may differ and may not necessarily lead to plant uptake after field application. This offers an opportunity for further research into the threshold trace element contents of wood ash and their relationship with plant uptake in different soil pH and soil types.

Thermal and mechanical characteristics of local firewood species and resulting charcoal produced by slow pyrolysis

“…Biomass provides about 12-15% of global energy needs [4]. In developing nations, biomass is the main energy source for over 80% of the population [5]. Over 3 billion people rely on the traditional use of solid biomass for cooking and heating purposes [6,7].…”

Adsorption and desorption of nutrients from abattoir wastewater: modelling and comparison of rice, coconut and coffee husk biochar

“…(2015) shows that rice husks produce a significant proportion of ash in their natural state. Neina et al. (2020) also revealed that the high concentration of ash content is associated with an increase in EC values.…”

“…Additionally, study done by Lohri et al (2015) shows that rice husks produce a significant proportion of ash in their natural state. Neina et al (2020) also revealed that the high concentration of ash content is associated with an increase in EC values. In other studies, high ash content was found to harm the results of using biochar for nitrogen and phosphorus removal, as well as the sorption of ammonium and phosphate from aqueous solution by biochar generated from phytoremediation plants (Dai et al, 2020;Zeng et al, 2013).…”

Synthesis and Processing Parameter Optimization of Nano-Belite via One-Step Combustion Method

“…Rice husk ash is rich in amorphous silica with a highly microporous cellular structure [ 29 , 30 ], which may have an adverse effect on the final products as the highly microporous structure could absorb a lot of water, impeding a further reaction of belite. The main elements in charcoal ash are Ca, Mg, K, Na, and P [ 31 ], thus adding more irrelevant elements into the final reaction product system. Therefore, it is apparent that kerosene, ethanol, and urea are better compared to rich husk and charcoal to be used as the fuel agent.…”