Characterization of hydrochars produced by hydrothermal carbonization of rice husk

Abstract

Abstract. Biochar is the carbon-rich product obtained when biomass, such as wood, manure or leaves, is heated in a closed container with little or no available air. In more technical terms, biochar is produced by so-called thermal decomposition of organic material under limited supply of oxygen (O2), and at relatively low temperatures (<700 °C). Hydrochar differentiates from biochar because it is produced in an aqueous environment, at lower temperatures and longer retention times. This work describes the production of hydrochar from rice husks using a simple, safe and environmentally-friendly experimental set-up, previously used for degradation of various wastewaters. Hydrochars were obtained at 200°C and 300°C and at residence times ranging from 2 to 16 h. All samples were then characterized in terms of yield, surface area, pH, conductivity and elemental analysis and two of them were selected for further testing with respect to heating values and heavy metal content.

Physical and chemical characterization of biochars derived from different agricultural residues

“…Thermal analysis is a useful method to study the structure of biochar materials (Kalderis et al, 2014;Mimmo et al, 2014). In this work, all biochar samples showed a similar thermaldegradation profile (Fig.…”

Insight into biochar properties and its cost analysis

“…Thus slow pyrolysis and HTC are two of the most efficient BC conversation technologies which can be used for a wide range of feedstocks [1]. A majority of BCs produced by HTC are more acidic than by pyrolysis [55,59]. One of the most important properties of HTC-BC is that it is easily biodegradable (dominated by alkyl moieties),…”

Factors driving the carbon mineralization priming effect in a sandy loam soil amended with different types of biochar

“…The organic carbon limits have been fixed according to the International Biochar Initiative (2012) and the recommendations of Schmidt et al (2012), who described that the organic carbon content of pyrolysed chars fluctuates between 10 % and 95 % of the dry mass, depending on the feedstock and process temperature used. With respect to volatile matter (VM) and fixed carbon (FC), values over 20 % and 40 % of VM and FC can be considered high according to biochar prepared from different feedstocks as sewage sludge Méndez et al, 2012), rice husk (Kalderis et al, 2014), eucalyptus wood or poultry litter Lu et al, 2014). Finally, BET surface area values should be preferably higher than 150 m 2 g −1 (Schmidt et al, 2012), values over 750 m 2 g −1 being very high and of the same order as montmorillonite.…”