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This study is focused on the detailed examination of the combustion properties and kinetic analysis of a cellulose acetate fibrous bundle (CAFB), separated from used cigarette filters. It was shown that the faster rate of CAFB heating allows a large amount of heat to be supplied to a combustion system in the initial stages, where the increase in heating rate has a positive response to ignition behavior. The best combustion stability of CAFB is achieved at the lowest heating rate. Through the use of different kinetic methods, it was shown that combustion takes place through two series of consecutive reaction steps and one independent single-step reaction. By optimizing the kinetic parameters within the proposed reaction models, it was found that the steps related to the generation of levoglucosenone (LGO) (by catalytic dehydration of levoglucosan (LG)) and acrolein (by breakdown of glycerol during CAFB burning—which was carried out through glycerol adsorption on a TiO2 surface in a the developed dehydration mechanism) represent rate-controlling steps, which are strongly controlled by applied heating rate. Isothermal predictions have shown that CAFB manifests very good long-term stability at 60 °C (which corresponds to storage in a sea shipping container), while at 200 °C, it shows a sudden loss in thermal stability, which is related to the physical properties of the sample. [ABSTRACT FROM AUTHOR]

This work examined the possibilities and limitations of model-free and model-based methods related to decrypting the kinetic complexity of multi-step thermo-oxidative degradation processes (as a testing system, a [4-(hydroxymethyl)phenoxymethyl] polystyrene resin was used), monitored by thermal analysis (TGA-DTG-DTA) techniques. It was found that isoconversional methods could successfully determine the correct number of process stages and presence of multiple reactions based on derived Ea(α) profiles and identify the negative dependence of the rate constant on the temperature. These methods could not overcome the problem that arose due to mass transfer limitations. The model-based method overcame more successfully the problem associated with mass transfer because its calculation machinery had capabilities for the correct solution of the total mass balance equation. However, a perfect fit with the experimental data was not achieved due to the dependence on the thermal history of the contribution (ctb.) of a given reaction step inside a fitting procedure cycle. On the other hand, through this approach, it was possible to estimate the rate-controlling steps of the process regarding the influence of the heating rate. It was found that for consecutive reaction mechanisms, the production of benzaldehyde and gases in high yields was controlled by the heating rate, where low heating rates were strongly recommended (≤10 K/min). Also, it was shown that the transport phenomenon may be also the rate-determining step (within the set of "intrinsic" kinetic parameters). It was also established that external heat transfer controls the overall rate, where the "pure" kinetic control regime had not been reached but was approached when lowering the temperature and size of the resin particles. [ABSTRACT FROM AUTHOR]

Goal of this work is to establish technical feasibility and fundamentals of producing activated carbon from plane tree seeds biomass for porous materials derivation. Bio-chars produced via carbonization from plane tree seeds precursor were activated in CO2 at 750 and 850 °C, during various residence times. Their surface area and porosity were characterized by N2 adsorption at 77 K. Surface areas energy magnitudes of oxidation reaction by CO2, which are closely related to applied activation temperature. Result showed that high temperature activated carbon had higher gas adsorption as compared to activated carbon obtained from lower temperature during two-hour residence time. Breakthrough behavior was detected at 850 °C where surface reactions dominate, and it is characterized by autocatalytic kinetic model under designed conditions. Both, temperature and CO2 concentration in vicinity of solid surface effect on breakthrough time of adsorbent. Derived bio-chars are converted into high quality activated carbons, with surface area of 776.55 m²/g, where micro-pores with pore diameters less than 2 nm prevail. Produced activated carbons have properties comparable with commercially available activated carbons, which can be successfully used for removal of harmful gaseous pollutants toward air purification. [ABSTRACT FROM AUTHOR]

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]

Raw and pyrolyzed samples of the plane tree seeds (PTS) were tested by various advanced analytical techniques including simultaneous TG-DSC technique, FTIR analysis, X-ray diffraction (XRD) analysis, Raman spectroscopy analysis, GC-MS (gas chromatography-mass spectrometry) analysis and scanning electron microscope analysis, for its characterization procedure and the pre-treatments in possible application in CCS. Nondestructive analytical method (XRD) showed that raw material is typical for carbon-rich material, where was identified increase in interlayer spacing within graphite structure. The XRD results of pyrolyzed sample at 850 °C showed a sudden loss in interlayer spacing. Spectroscopic analyses of pyrolyzed sample demonstrated the presence of typical aromatic structures found in amorphous carbon. Results indicate the high levels of the growth in basal planes of graphite structure in pyrolyzed sample. It was established that integrated reaction model parameters for pyrolysis of untreated PTS sample realistically describe active temperature period required for charcoal forming, under non-isothermal conditions. It was found that mechanical treatment of material results in increase in the number of chemical compounds. Micrograph showed the presence of variety of shapes and structures, where after pyrolysis, some dissipated pores were detected. One of these pores was partially blocked in some places, depending on the size of surface area. The results showed that the resulting char has very good features for further activation process, while the PTS would represent a good candidate in its application in the CCS. [ABSTRACT FROM AUTHOR]

In this work, plane tree seed-based activated carbons (AC) were used for possible application in carbon dioxide capture and storage (CCS) technology. After carbonization process at 850 °C, resulting preliminary AC’s were activated at various temperatures. The high levels of the growth in basal planes of graphite structure in carbonized sample were detected. Also, it was found that the samples activated at 750 and 850 °C have a lower graphitization degree and contained substantially disordered sections and defects, which are characteristic of typical amorphous porous carbons. Process modeling has shown that the CO 2 sorption can be described by multi-parametric continuous distributed reactivity model. Analysis showed the occurrence of gas reduction process, involving gibberellic acid and coenzymes which can produce the methane gas. The highly ordered arrangement of the gas molecules on the carbons was assumed. [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]

The pottery produced from the Rujište deposit in Serbia has been protected under the guidance of UNESCO and the Sector for Intangible Cultural Heritage of Serbia since 2019. A study was conducted to evaluate the mineralogical characteristics of the raw clay from this deposit. This study used various techniques, such as X-ray diffraction (XRD), infrared (IR) spectroscopy, X-ray fluorescence (XRF), and differential thermal analysis (DTA) to characterize the clay. This study found that the clay contained mostly clay minerals (56.3%–41.9%), with illite, smectite, and chlorite as the predominant phases. Other phases identified were quartz, feldspars, carbonates, and iron-bearing minerals (43.8%–58.1%). The chemical analyses revealed a high abundance of silica (>52 wt.%) and alumina (~16 wt.%), with Fe2O3 (~6 wt.%), K2O (~2.8 wt.%), and a similar content of MgO as the main constituents. The physical features that were investigated included the granulometry (clay: ~31%–44%, silt: ~ 26%–23%, and sand: ~ 42%–32%), specific surface area (97 to 107 m2 g−1), cation exchange capacity (12.5–13.7 mmol 100 g−1), and color (yellowish to moderate brown). The preliminary results suggest that most of the raw clay from the Rujište deposit might be suitable for use in traditional pottery manufacture. [ABSTRACT FROM AUTHOR]

The aim of this research was to obtain a carbon solid residue by the carbonization process of biomass in an inert atmosphere which, through physical activation and chemical treatment (using TEOS - tetraethyl orthosilicate) would allow creation of highly porous and spatially distinct ordered bio-SiC ceramics. The results of carbonization experiments at several operating temperatures and activation of carbons with multiple-cycle treatments TEOS clearly showed the possibility of obtaining SiC nano-structures, after performing the carbothermal reduction at 1400 °C. The increase in the activation temperature and the duration time starts the development of the SiC particles inside the porous structure. The XRPD analysis showed that the major SiC polytype has cubic SiC (β-SiC) structure and remainder is hexagonal SiC polytypic (α -SiC) structure. It was established that the carbons obtained from carbonization of the Platanus orientalis L. plane tree fruit (PTF) precursor and activated at 850 °C with longer holding times (1 and 2 h) exhibit β-SiC (cubic) nano-wires. A possible nano-wires increment mechanism was suggested. The obtained results represent significant contribution in understanding the process as well as the main characteristics of SiC nano-materials and their possible applications. • Formation of bio-SiC from biomass feedstock precursor by high temperature processing. • β-SiC with cubic structure and the small amount of hexagonal forms were identified. • Detection of polytype inclusions during nano-cubic β-SiC growth by TEOS treatments. • The formations of SiC polycrystals and nanowires become competitive. • SiC nanowires growth dependent from gaseous phase compositions and reaction condition. [ABSTRACT FROM AUTHOR]

Octacalcium phosphate (OCP) is a material from the calcium phosphate group with a crystal structure similar to hydroxyapatite. The removal process of lead and cadmium in aqueous solution using octacalcium phosphate material was investigated. OCP material was synthesized by the solution precipitation method. The structural and phase properties of OCP before and after the removal process were determined by the X-ray diffraction (XRD) method. Microstructural and semi-quantitative analysis of the material was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS). Characteristic bands and functional group determination were revealed using the Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). As target pollutants, Cd(II) and Pb(II) were chosen in adsorption experiments. Results show that OCP in the first 10 min has a very fast removal rate for Pb(II); the equilibrium state was reached after 10 min with more than 98 % adsorption efficiency. Results for Cd(II), results showed the same removal rate but somewhat lower adsorption efficiency, amounted to approximately 63 %. [ABSTRACT FROM AUTHOR]

Thermo-chemical conversion of cigarette butt filters (CBF) waste was investigated using various thermal analysis techniques (simultaneous TG-DTG-DTA and DSC methods) at different heating rates in an inert atmosphere. Thermo- and thermophysical properties of waste material were discussed, from the point of view of chemical structure and the influence of experimental parameters on the conversion process. It was established that acetyl groups of plasticizer (triacetin) interact with cellulose acetate through dipolar interactions and hydrogen bonding's. Influence of these polar interactions can affect the position of glass transition temperature, Tg, of CBF. Based on estimated value of Tg from DSC analysis, it was found that cellulose acetate present in CBF has degree of substitution equals to 2.8, where the presence of cellulose triacetate was confirmed. It was assumed that an increase of degree of substitution leads to decline in the crystallinity. A decline of crystallinity causes the reduction of hydroxyl groups, leading to less organized chains, and whereby decreasing of inter-molecular interactions through hydrogen bonding. Based on the examination of thermophysical characteristics of the tested material, it was found that both, the heat capacity and the thermal inertia of material linearly increase with temperature, during pyrolysis progression. It was concluded that the type of bio-char produced in this process would have a large capacity to store the heat, which may depend on the formed particles size diameter and porosity. Furthermore, it was inferred that magnitude drops of thermal conductivity, κ, after Tg depends on the material fibrillation. [ABSTRACT FROM AUTHOR]

As representative among biomass feedstocks, Poplar fluff was chosen to analyze the pyrolysis properties of this new biofuel. Thermogravimetry under inert (argon) atmosphere at the heating rates of 5, 10, 15, and 20 °C min−1 was employed in the investigation of thermal processing of studied biomass. The determination of kinetic parameters and estimation of reaction mechanism function were done through application of the state-of-the-art NETZSCH Kinetics NEO software. With this aim, the various model-free models and model-based calculations were implemented. The obtained results showed that the most appropriate kinetic model to describe the thermal decomposition of Poplar fluff sample was n-dimensional acceleratory Avrami–Erofeev model (An) for three-step consecutive reaction mechanism. Governed reaction pathway in pyrolysis process represents fragmentation reactions which arise from levoglucosan decomposing that permits permanent gases and refractory tars, where diffusion-controlled process is involved in the sample devolatilization. The modulated and multiple-step predictions of pyrolysis process were also carried out. [ABSTRACT FROM AUTHOR]

The combustion reactivity of plane tree seeds biomass feedstock was studied using the thermogravimetry. The effects of atmosphere (O2/Ar) and different oxygen concentrations (O2/Ar = 20:80% and O2/Ar = 50:50%) on the combustion characteristics were investigated. When combustion atmosphere changes from O2/Ar = 50:50% to O2/Ar = 20:80% (reducing oxygen concentrations), the burnout temperature increases by 29.50 °C for tested biomass. Obtained results demonstrate the ease of ignition of investigated lignocellulosic material for O2/Ar = 50:50% ratio compared with O2/Ar = 20:80% ratio, and the actual trend is maintained under the condition when the heating rate increases. The reducing of oxygen concentration strongly influenced the amount of final residue products, particularly at higher heating rates (beyond 10 °C min−1). Kinetic analysis applied to investigated process shows strongly dependencies of both the apparent activation energy (E) and pre-exponential factor (logA) with conversion (α), especially in devolatilization and combustion of volatiles reaction stages. Large variation in E is attributed to existence of multiple parallel reactions. In order to solve this problem, the deconvolution technique that uses Fraser–Suzuki function was applied. It was shown that Fraser–Suzuki function fits successfully kinetic rate curves of entire combustion process, assuming the best selected nth-order reaction model. [ABSTRACT FROM AUTHOR]

Thermo-chemical conversion via the pyrolysis of cigarette butt (CB) filters was successfully valorized and upcycled in the pre-carbonization and carbonization stages. The pre-carbonization stage (devolatilization) of the precursor material (cellulose acetate filter, r-CAcF) was analyzed by micro-scale experiments under non-isothermal conditions using TG-DTG-DTA and DSC techniques. The results of a detailed kinetic study showed that the decomposition of r-CAcF takes place via complex mechanisms, including consecutive reaction steps and two single-step reactions. Consecutive stages include the α-transition referred to as a cellulose polymorphic transformation (cellulose I → II) through crystallization mechanism changes, where a more thermodynamically ordered system was obtained. It was found that the transformation rate of cellulose I → II ('cellulose regeneration') is strongly affected by the presence of alkali metals and the deacetylation process. Two single-step reactions showed significant overlapping behavior, which involves a nucleation-controlled scission mechanism (producing levoglucosan, gaseous products, and abundant radicals) and hydrolytic decomposition of cellulose by catalytic cleavage of glycosidic bonds with the presence of an acidic catalyst. A macro-scale experiment showed that the operating temperature and heating rate had the most notable effects on the total surface area of the manufactured carbon. A substantial degree of mesoporosity with a median pore radius of 3.1695 nm was identified. The presence of macroporosity on the carbon surface and acidic surface functional groups was observed. [ABSTRACT FROM AUTHOR]

Brassinosteroids (BRs) are a class of plant hormones that play important roles in regulating various physiological and developmental processes in plants. One of the most effective BRs involved in modulating crop growth is 24-epibrassinolide (24-EBL). The effects of different concentrations of 24-EBL on various biochemical and biophysical parameters critical to early growth stages and seedling development were investigated using two maize hybrids, 'ZP 434' (a new-generation hybrid) and 'ZP 704' (an older-generation hybrid). The evaluation of results is based on measurements of germination percentage, morphometric parameters, redox status, comparative analysis of thermodynamic parameters (such as Gibbs free energy, enthalpy, entropy), and the concentration of specific sugars in different parts of maize seedlings. The results indicate that the germination and initial growth of maize seedlings are influenced by the flow of crucial sugars from the remaining seed (as a source of nutrients) towards the plumule and radicle (as sink organs). Furthermore, alterations in Gibbs free energy play a significant role in these sugar transfers within the maize seedlings. The seed germination was most affected by the highest concentrations of 24-EBL, showing inhibitory effects, whereas lower and moderate concentrations of exogenously added 24-EBL exhibited a beneficial influence on the initial phases of seedling growth. The mentioned approach gives new insights into source–sink relationships and can be used as a quantitative measure of the germination energy, which until now has been a qualitative criterion in seed science. [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]

There is an increased research interest in methods for transparent wood production and its use. Wood transparency could be achieved by its delignification followed by an impregnation process with polymers having proper optical properties. However, delignification processes are mainly time consuming and not environmentally friendly. The possibility of treating mahogany wood (Swietenia macrophylla King) with 20% hydrogen peroxide for 70, 100, 135, and 170 min at 103 °C is presented in this research. According to the treatment duration, lignin content decreased 40 to 94% relative to its initial content in the control samples, whilst the cell structure remained intact. Due to the light scatter effect, caused mainly by wood tissue structure, the direct optical transmittance of treated samples in the visible light spectrum (400 to 800 nm) was less than 40%. Simultaneously, the total optical transmittance of samples treated for 100 and 135 min reached values between 70 to 80% with high values of the haze at approximately 30 and 60%. Optical transmittance in the visible spectrum area of the samples treated for 170 min was from 45 to 80% and the haze from 25 to 45%. [ABSTRACT FROM AUTHOR]

The aim of this study is to explain the consequences of the occurrence of enthalpy–entropy compensation (EEC) and isoequilibrium relationship during slow pyrolysis of cigarette butt filters (CBFs), consisting cellulose acetate (AC) as the main component. By using model-free and model-based kinetic methods and thermodynamic calculations, the complete reaction mechanism and extrathermodynamic issues about investigated process are completely resolved. It was established that compensation phenomenon where isoequilibrium temperature occurs is a consequence of formation of low-entropy molecular structure (cellulose II) and breaking of hydrogen bonds. Consequently, it was concluded that mechanisms which include a formation of low-entropy molecular structure and H-bonds breakage enter the changes in both enthalpy and entropy, which compensate each other. For the cellulose II generation, it was necessary to invest energy which represents use up energy. This “wasted” energy turns into work for creation of cellulose II molecular structures, whereby additional energy was provided from “local” decomposition reactions (which were identified in the established process mechanism) that arise from pyrolysis of starting material. Therefore, it was concluded that for “local reactions”, a negative ΔS° value was identified, but for the global process, the entropy change retained a positive value. Considering thermodynamic effects manifested through compensation temperature found below glass transition temperature (Tg) in the undercooling conditions, it was concluded that small amounts of plasticizers affect reduction of free volume in the glassy state. Obtained results indicated a decrease in β-relaxation mode of cellulose acetate by an abatement of the polymer free volume.Graphical abstract: The aim of this study is to explain the consequences of the occurrence of enthalpy–entropy compensation (EEC) and isoequilibrium relationship during slow pyrolysis of cigarette butt filters (CBFs), consisting cellulose acetate (AC) as the main component. By using model-free and model-based kinetic methods and thermodynamic calculations, the complete reaction mechanism and extrathermodynamic issues about investigated process are completely resolved. It was established that compensation phenomenon where isoequilibrium temperature occurs is a consequence of formation of low-entropy molecular structure (cellulose II) and breaking of hydrogen bonds. Consequently, it was concluded that mechanisms which include a formation of low-entropy molecular structure and H-bonds breakage enter the changes in both enthalpy and entropy, which compensate each other. For the cellulose II generation, it was necessary to invest energy which represents use up energy. This “wasted” energy turns into work for creation of cellulose II molecular structures, whereby additional energy was provided from “local” decomposition reactions (which were identified in the established process mechanism) that arise from pyrolysis of starting material. Therefore, it was concluded that for “local reactions”, a negative ΔS° value was identified, but for the global process, the entropy change retained a positive value. Considering thermodynamic effects manifested through compensation temperature found below glass transition temperature (Tg) in the undercooling conditions, it was concluded that small amounts of plasticizers affect reduction of free volume in the glassy state. Obtained results indicated a decrease in β-relaxation mode of cellulose acetate by an abatement of the polymer free volume. [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]

In order to clarify relationship between apricot kernel shell biomass slow pyrolysis mechanism and its main constituents (viz. hemicelluloses, cellulose and lignin), the reactivity effects of main constituents on pyrolysis characteristics were determined by the non-isothermal simultaneous thermal analysis. It was found that four-step (parallel) reaction model is suitable for studying the slow pyrolysis process, within the semi-global model which excludes the strong interaction between biomass constituents (pseudo-components). The application of the proposed model was allowed by the results obtained from KAS iterative isoconversional (model-free) approach. The valorization of the model was confirmed by the process optimization. The complex (cumulative) apricot kernel shell pyrolysis rate curves at different heating rates are successfully resolved into the individual decomposition rate curves (arising from thermal conversion of hemicelluloses, cellulose, and primary/secondary lignin fragments) by four-parameter Fraser–Suzuki function. Besides hemicelluloses and cellulose pyrolyses, the proposed model distinguishes primary and secondary lignin reactions, which enhance the gaseous products releasing (primarily CO and CO2 gases) and charification of the solid residue (increased the bio-char yield). [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]

In the presented paper, activated carbons were prepared from fructose and glucose, and activating agents (KOH, NaOH, LiOH) by hydrothermal treatment (HTC) treatment. After preparation, samples were characterized in details. Different techniques were used: x-ray powder diffraction analysis, Raman spectral analysis, elemental analysis, and determination of textural and morphological properties. Obtained results showed dependence of investigated properties and the nature of precursors (glucose or fructose) as well as the type of hydroxides used as activating agents. After characterization, samples were tested as materials for heavy metals (Pb2+, Cd2+ and Zn2+) and methylene blue removal. Also, adsorption experiments were performed on wastewaters taken from tailings of the lead and zinc mine and kinetic of the methylene blue removal was studied. The factors which distinguished the KOH activated samples were high yield (~14%), content of organic carbon (63–74%), porosity and specific surface area (SBET ~700–1360 m2/g), a low degree of the crystal phase, indications that potassium ions may be included in heavy metals removal, good removal of the heavy metal ions (~47–59 mg/g for Pb2+, ~21–27 mg/g for Cd2+ and ~6–10 mg/g for Zn2+) and fast (~10–30 min) and good methylene blue (~60–200 mg/g) removal. [ABSTRACT FROM AUTHOR]