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Combustion characteristics (reactivity and reactivity evaluation, ignition index ( D i ), burn-out index ( D f ), combustion performance index ( S ) and combustion stability index ( R W )) and thermo-oxidative degradation kinetics of plane tree seeds (PTS) were investigated. Oxidation analysis shows that PTS exhibits stable and high combustion activity, where comparison of ignition and burn-out index values showed that a more developed pore structures of PTS particles exist, and higher volatile matter content is present. Results are also confirmed through derived experience constant value ( ζ ) and which were compared with other energy sources. It was established that different maximal reaction rate values at various heating rates point out the PTS complex nature, which is stimulated with carbon oxidation reactions and volatile matter release. Kinetic analysis has shown that process can be divided into two stages: devolatilization stage (280–380 °C) and char combustion stage (380–600 °C). In order to obtain a stable solid product, rich in carbon, the PTS shows good performance but with application of high-temperature processing conditions. [ABSTRACT FROM AUTHOR]

Activated carbon was prepared using plane tree seed as a cheap and renewable raw material. The samples were prepared by carbonization under N 2 atmosphere up to 850 °C, and activation in CO 2 atmosphere at different both temperatures (750 and 850 °C) and times of activation (0.3, 1 and 2 h). The influence of activation parameters on physicochemical properties was studied by XRPD, Raman spectroscopy, FTIR, N 2 physisorption, SEM and electrochemical methods. The pore structure was correlated to the specific capacitance and the amount of hydrogen stored, in alkaline, neutral and acidic electrolyte solution. The relationship of asymmetrical shape of CV curves with the porosity of samples has served to better understand some unclear issues related to the complex mechanism of charge storage. The sample activated at 850 °C for 2 h displayed the best behavior. At a high scan rate of 300 mV s −1 , its capacitance, amounted to ∼26.8 μF cm −2 ∼19.69 μF cm −2 and ∼25.8 μF cm −2 in KOH, Na 2 SO 4 , and H 2 SO 4 solutions, respectively. [ABSTRACT FROM AUTHOR]

Highlights • Perspective biofuel for replacement of low energy lignites with HHV = 15.86 MJ kg−1. • Pyrolytic products were stimulated by decomposition of cellulose and lignin fractions. • Catalytic activities of mineral content and influencing the devolatilization kinetics. • The great abundance of PAH compounds was identified from carbonized material. • Promoted graphitization of bio-char where Al acts as a pulsar in acceleration process. Abstract This paper describes the pyrolysis of Poplar fluff (from Populus alba) using on-line apparatus, and carbonization process at 850 °C using the fixed bed reactor. Characteristics of pyrolysis products were examined. Elemental and chemical analyses were shown that Poplar fluff has higher energy content characterized by increased content of fibrous structure (particularly cellulose). Independent parallel reactions model very well describes devolatilization process. It was found that increased amount of extractives can significantly affect on increased release of light gaseous products, but declining hydrocarbons, mostly the alkanes. Liquid product is mainly composed of phenolics, aldehydes, acids, esters and ketones. The carbonization process produces the great abundance of polycyclic aromatic hydrocarbons (PAH's), where naphthalene is the most abundant. Mechanism for PAH's formation was suggested. This study represents the first step in a much wider and more comprehensive way in thermal conversion processes of this type of fuel. [ABSTRACT FROM AUTHOR]

[Display omitted] • Re-heating improves bio-char performances related to increase of its hygroscopicity. • Higher heating rates cause that heat flux inside bio-char sample becomes weakened. • Products amounts from lower-PAH decompositions are regulated by heating rates tune up. • Naphthalene allows high gas yields by pushing decomposition toward high temperatures. • Change in kinetic model with temperature reproduce true kinetic compensation effect. This paper provides insights into understanding the physical and chemical changes that take place during re-heating process of Poplar fluff bio-char derived by carbonization at high operating temperature (850 °C). Bio-char re-heating experiments were performed by simultaneous TGA-DTG-DSC techniques in N 2 atmosphere at 5, 10, 15 and 20 °C min−1. Kinetic modeling of the process was done through implementation of model-free and model-based approaches. It was identified that re-heating process contains two stages. The first was described by single consecutive reaction step (up to 200 °C) which is attributed to removal of physisorbed moisture at surface and in pores of carbonized material, while second was described by multiple reactions, including one consecutive step and two competitive steps. In the last, consecutive pathway includes reduction of PAH compounds (400–600 °C) into smaller ones, changing degree of condensation of carbon structure continuously. Competitive steps encompass competition between C 10 H 8 (naphthalene) (700–780 °C) and C 9 H 8 (indene) (700–750 °C) molecules decomposition. It was found that used heating rates have great influence on regulating the amount of gaseous (combustible) products from these reactions. It was established that internal heat and mass transfer processes control the release of products. Changing the pyrolysis mechanism with temperature of carbonized bio-char is the main factor for occurrence of true kinetic compensation effect, which is also discussed by applied isothermal life-time analysis. [ABSTRACT FROM AUTHOR]

This paper investigates the ability of waste apricot (Prunus armeniaca) kernel shells (AKS) bio-char prepared by single-step carbonization process at 850 °C (residence time of 1 h) for possible removal of toxic elements and organic micro-pollutants. The experiment that was performed as well as parameters used proved to be optimal for bio-char production as adsorbing medium, where last issue is validated by multiform material characterization techniques. It has been shown that the produced bio-char possess highly-porous morphology features, with large specific surface area (328.570 m2 g−1). The obtained product was characterized by various pore sizes (including super-micropores and mesopores with maximum pore size of 2.24 nm) structures. Preliminary results are indicated that obtained bio-char can shows increased affinity to possible adsorption of the small organic molecule contaminants upgraded by its physico-chemical properties. Cost estimation of AKS bio-char production substantiated its cost effectiveness and its good physical and chemical properties for future design in batch adsorption and regeneration tests. It was established that AKS produced bio-char was 2.5 times cheaper than the commercially available activated carbon. Bio-char exhibits promising removal performances for potential adsorption of heavy metal and organic micro-pollutants from wastewaters systems, as indicated by material textures and spectroscopy measurements. Image 1 • Aprikot kernel shell (AKS) based bio-char produced by high-temperature carbonization. • High-porous with large specific surface area (328.570 m2 g−1) prepared bio-adsorbent. • Ideal precursor for preparation of environmentally friendly activated carbon (AC). • Favored non-polar attractions on hydrophobic surface of bio-char. • Removal of organic toxic elements from water environments. [ABSTRACT FROM AUTHOR]

Nanoparticles of ceria–ruthenium oxide solid solutions with composition Ce 1− x Ru x O 2−δ ( x =0.005–0.02) were successfully produced by self–propagating room temperature synthesis using reaction between metal nitrates and sodium hydroxide. These compositions were characterized by X–ray powder diffraction (XRD), Raman spectroscopy, specific surface area, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X–ray spectroscopy (EDX). The experimental measurements were complemented by calculations based on the ion–packing model. XRD analysis revealed the presence of single–phase solid solutions with CeO 2 fluorite structure (regardless of dopants concentration) and Raman spectroscopy confirmed the presence of the RuO 2 phase. Electrochemical impedance spectroscopy (EIS) measurements of sintered samples at different temperatures showed that the small ionic radius dopant reduces oxygen vacancies mobility that is responsible for the conductivity of these ceramics. [ABSTRACT FROM AUTHOR]

Microporous zeolite templated carbon (ZTC) was synthesized by impregnation method using zeolite Y (Na-form) as a template, and furfuryl alcohol as a carbon precursor. The characterization was carried out by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy, nitrogen physisorption, elemental analysis and electrochemical methods. Physisorption measurements evidenced high micropore volume of obtained material (∼0.43 cm 3 g −1 ). The charge storage ability in aqueous KOH, H 2 SO 4 and Na 2 SO 4 solutions was systematically studied by cyclic voltammetry, galvanostatic charging/discharging and complex impedance measurements. Specific coulombic capacitance, the hydrogen storage, H ZTC bonding and relaxation time of adsorption were found to be dependent on the type of electrolyte. Neutral Na 2 SO 4 aqueous solution was found to be the best for supercapacitor application, thanks to: i) the highest available voltage window ii) lowest corrosion and iii) highest capacitance amounting to 123 F g −1 at 1 A g −1 . [ABSTRACT FROM AUTHOR]