Multicomponent Modelling Kinetics and Simultaneous Thermal Analysis of Apricot Kernel Shell Pyrolysis

Apricot kernel shells are naturally available source of biomass with potential for conversion to clean energy through a thermo-chemical process such as pyrolysis. To facilitate further process development, an advanced mathematical model which represents the process kinetics is developed and validated on the thermal decomposition studies using simultaneous thermal analysis, over a temperature range of 30-900 degrees C, at four heating rates of 5, 10, 15 and 20 degrees C min(-1), under argon atmosphere. Model-free analysis and numerically developed methods were utilized for determination of effective activation energies, pre-exponential factors and the fractional contribution. A novel approach is introduced in order to determine actual pseudo-components of studied biomass that are included in its composition. The comparative study of the obtained kinetic results was also presented. The results obtained strongly indicated that the pseudo-component reaction modelling method could be employed to predict the experimental devolatilization rate and biomass composition with a high likelihood of success

Synthesis, characterization and application of activated carbon materials obtained from the fruit of plane tree

Predmet ove teze, u širem smislu, je bila sinteza, karakterizacija i primena aktivnih ugljeničnih materijala dobijenih od ploda platana. Poznato je da postupci sinteze utiču na mikrostrukturu i svojstva materijala. Ugljenični materijali mogu biti napravljeni sa širokim spektrom struktura, kompozicija i svojstava, u zavisnosti od prirode organskih prekursora i procesnih parametra. Bilo koji materijal koji sadrži ugljenik može se koristiti za proizvodnju ugljeničnih materijala. Zbog toga, biomasa kao prirodna mešavina ugljovodonika, dostupna u velikom obimu odličan je preduslov. Isto tako, to je ekološki obnovljivi resurs. Postoje značajne ekonomske i tehničke prednosti u korišćenju biomase. Za prevođenje biomase (ploda platana) u ugljenični materijal korišćena je hidrotermalna sinteza na niskim temperaturama kao i piroliza na višim temperaturama. Ugljenični materijal je izložen metodama aktiviranja kao što su fizička (CO2) i hemijska (H3PO4) aktivacija u pokušaju da se dobije aktivni ugljenični materijal sa visokim stepenom adsorpcije za određenu primenu. Adsorpcija na aktivnom uglju ima primenu u prehrambenoj, farmaceutskoj, hemijskoj, automobilskoj, nuklearnoj industriji, itd. Primeri za to su razni filteri, adsorbenti, nosači katalizatora, baterije, kao elektrodni materijal u elektrohemiji i raznim drugim različitim granama industrije. 6 Ugljenični materijali se uveliko intenzivno proučavaju kao elektrodni materijali za elektrohemijske kondenzatore usled njihove visoke specifične površine, dobre električne provodljivosti i niske cene. Istraživači, različitim mnogobrojnim istraživanjima pokušavaju da sintetišu različite forme ugljeničnih materijala sa razvijenom specifičnom površinom i razvijenom poroznošću u cilju što boljeg skladištenja nаеleketrisanja. Karakterizacijom datih materijala u pogledu vrednosti specifične površine, veličine i raspodele pora, prisustva i raspodele površinskih grupa, stepena uređenosti i čistoće, pokušava da se ustanovi koji su ključni parametari za najefikasnije skladištenje energije ugljeničnog kondenzatora. Sintetisani su mikroporozni i mezoporozni ugljenični materijali dobijeni od ploda platana sa različitim, visokim specifičnim površinama na različitim temperaturama...In general terms, the subject of this thesis, was the synthesis, characterization and application of active carbon materials obtained from the plane tree fruit. It is known that synthetic methods influence the microstructure and properties of the material. Carbon materials can be obtained with a wide range of structures, compositions and properties, depending on the nature of organic precursors and process parameters. Any carbon-containing material can be used for the production of carbon materials. Therefore, biomass as a natural mixture of hydrocarbons, available on a large scale, is a great prerequisite. Likewise, it is an ecological renewable resource. There are significant economic and technical advantages in the use of biomass. Hydrothermal synthesis at low temperatures, as well as pyrolysis at higher temperatures, was used to convert biomass (plane tree fruit) into carbon material. Carbon material is exposed to activation methods such as physical (CO2) and chemical (H3PO4) activation in an attempt to obtain an active carbon material with a high degree of adsorption for a particular application. Adsorption on activated carbon has application in food, pharmaceutical, chemical, automotive, nuclear industry, etc. Examples are various filters, adsorbents, catalyst carriers, batteries, electrode materials in electrochemistry and various other industries. 9 Carbon materials are extensively studied as electrode materials for electrochemical condensers due to their high specific surface area, good electrical conductivity and low price. Researchers, by various numerous studies, are trying to synthesize different forms of carbon materials with a developed specific surface and developed porosity in order to improve storage of electrical charge. By specifying the given materials in terms of the value of the specific surface area, size and distribution of pores, the presence and distribution of surface groups, the degree of orderliness and purity, an attempt is made to determine the key parameters for the most efficient energy storage of the carbon capacitor. Microporous and mesoporous carbon materials derived from the plane tree fruit with different, high specific surfaces, were synthesized at different temperatures..

Properties of Self-compacting Concrete Produced with Biomass Wood Ash

The demand of the contemporary society for renewable energy sources lead to the increase of the bio-power plants. Accordingly, the amount of ash generated by burning the biomass is increased, and its disposal becomes a large environmental problem. The paper presents the research of potential use of biomass wood ash as a partial replacement for coal fly ash (10%, 20%, 30% and 40% of mass) in production of self-compacting concrete (SCC). The effects of biomass wood ash on the properties of SCC in fresh and hardened states have been examined, as well as on the properties of durability. Test results indicated that the biomass wood ash slightly reduces the flowability and passing ability of SCC, while its addition enhances the viscosity of SCC and significantly prevents segregation and bleeding. SCCs with the contents of biomass wood ash up to 20% have approximately same mechanical strength as the reference mixture. Biomass wood ash has no negative effect on the resistance of concrete to the action of water under pressure, but a decrease of freeze/thaw resistance with de-icing salt is detected as its contents increases. The addition of biomass wood ash into SCC increases the drying shrinkage in the initial period of drying (up to 14 days), and it is decreased in a later phase

Multicomponent Modelling Kinetics and Simultaneous Thermal Analysis of Apricot Kernel Shell Pyrolysis

Apricot kernel shells are naturally available source of biomass with potential for conversion to clean energy through a thermo-chemical process such as pyrolysis. To facilitate further process development, an advanced mathematical model which represents the process kinetics is developed and validated on the thermal decomposition studies using simultaneous thermal analysis, over a temperature range of 30-900 °C, at four heating rates of 5, 10, 15 and 20 °C min−1, under argon atmosphere. Model-free analysis and numerically developed methods were utilized for determination of effective activation energies, pre-exponential factors and the fractional contribution. A novel approach is introduced in order to determine actual pseudo-components of studied biomass that are included in its composition. The comparative study of the obtained kinetic results was also presented. The results obtained strongly indicated that the pseudo-component reaction modelling method could be employed to predict the experimental devolatilization rate and biomass composition with a high likelihood of success

Uklanjanje olova i kadmijuma iz vodenog rastvora koristeći okrakalcijum-fosfat kao adsorbent

Octacalcium phosphate (OCP) is a material from the calcium phos-phate 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 pre-cipitation 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 %

Investigation of Co0.9Ho0.1MoO4 Nanopowders Obtained by Glycine Nitrate Procedure

Nanometric size Co0.9Ho0.1MoO4 powder particles were obtained by applying glycine nitrate procedure (GNP). Powder properties have been studied by DTA, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, Spectroscopy, Field emission scanning electron microscopy (FESEM), and nitrogen adsorption method. The photocatalytic activity of acquiring Co0.9Ho0.1MoO4 nanopowders was estimated by the photocatalytic degradation of crystal violet in an aqueous solution. We present a simple and effective method for controlling the composition and morphology of Co0.9Ho0.1MoO4, as well as a possible new approach in inorganic synthesis methodology. During photocatalytic testing, the studied nanoparticle powder indicated a potentially promising solution in photocatalytic processes toward green chemistry and sustainable development

Thermo-chemical conversion of cigarette butt filters waste through pyrolysis process using thermal analysis techniques

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 thermo-physical 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 crystal-linity causes the reduction of hydroxyl groups, leading to less organized chains, and whereby decreasing of inter-molecular interactions through hydrogen bond-ing. Based on the examination of thermophysical characteristics of the tested ma-terial, 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 poros-ity. Furthermore, it was inferred that magnitude drops of thermal conductivity, κ, after Tg depends on the material fibrillatio

Influence of 24-Epibrassinolide on the Energetic Parameters and Early Stages of Growth and Development in Seedlings of Two Maize (Zea mays L.) Genotypes

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

Cigarette Butt as a Carbon Source and Its Potential Application in the Preservation of Environmental Protection

Cigarette butts (CBs) are the most common type of litter on earth, with an estimated 5.5 trillion discarded annually. Apart from being unsightly, CBs pose a serious threat to living organisms and ecosystem health when discarded in the environment because they are toxic to microbes, insects, fish and mammals. In spite of the CB toxic hazard, no studies have addressed the effects of environmental conditions on CB decomposition rate. Numerous proposals have been made to prevent or mitigate cigarette butt pollution, but none has been effective; unsurprisingly, several studies have reported that CBs are the most common item retrieved by clean-up activities in public areas such as beaches and parks. The aim of this study was to collect a certain quantity of CBs, to examine the raw CB, their composition and properties, and then translate them into carbon material as a source of carbon, and as such material also examine the properties and its potential application, and therefore contribute to the preservation of the environment. Physicochemical properties of raw and carbonized CBs were studied by using element analysis, XRD (x-ray diffraction), Fourier-transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (SEM), X-ray fluorescence (XRF) analysis.10th International Symposium Forest and Sustainable Development : October 14-15, Romania, 2022

Mineralogical Characterization of Raw Clay from Rujište (Serbia) Used in Traditional Pottery Manufacture

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