Korišćenje otpadnih koštica šljive kao izvora ulja i katalizatora za proizvodnju biodizela

Possibilities of using waste plum stones in biodiesel production were investigated. The plum kernels were used as a source to obtain oil by the Soxhlet extraction method, while the whole plum stones, the plum stone shells that remained after the crashing, and the plum kernel cake that remained after the oil extraction, were burned off to obtain ashes. The collected ashes were characterized by elemental composition, porosity, and base strength and tested for catalytic activity in transesterification of esterified plum kernel oil. Dominant elements were potassium, calcium, and magnesium at different contents in the three obtained ashes. The most active catalyst was the plum stone shell ash, so the effect of temperature (40, 50, and 60°C) on the reaction rate was investigated. The reaction rate constant increased with the reaction temperature with the activation energy value of 58.8 kJ mol-1. In addition, the plum stone shell ash can be reused as a catalyst after recalcination.U ovom radu istraživana je mogućnost korišćenja otpadnih koštica šljive u proizvodnji biodizela. Jezgra šljive su iskorišćena kao sirovina za dobijanje ulja primenom Soxhlet-ove metode ekstrakcije. Cele koštice, ljuske koštica šljive i pogača dobijena nakon ekstrakcije ulja iz jezgra šljive spaljeni su da bi se dobio pepeo, koji je korišćen kao katalizator. Dobijene tri vrste sakupljenog pepela su najpre okarakterisane u pogledu hemijskog sastava, poroznosti i baznosti, a zatim je testirana katalitička aktivnost u transesterifikaciji esterifikovanog ulja koštica šljive. Dominantni elementi u pepelu, kao što su kalijum, kalcijum i magnezijum, imali su različit sadržaj u sve tri vrste pepela. Najveću katalitičku aktivnost pokazao je pepeo koštica šljive, zbog čega je dalje istraživan uticaj temperature (40, 50 i 60 °C) na brzinu reakcije katalizovane ovim pepelom. Konstanta brzine reakcije povećavala se sa porastom temperature reakcije, a vrednost energije aktivacije je 58,8 kJ mol-1 . Pored toga, pepeo koštica šljive može se ponovo koristiti kao katalizator nakon rekalcinacije

Adsorption of nicotine from aqueous solutions on montmorillonite and acid – modified montmorillonite

Montmorillonite (Mt) and acid modified montmorillonite (MtA) were tested as nicotine adsorbents. The samples were characterized using FT-IR spectroscopy and low temperature nitrogen physisorption. Nicotine adsorption was performed with respect to contact time, pH and initial nicotine concentration. The kinetics of adsorption obeyed the pseudo-second-order kinetics. The optimal pH values for nicotine adsorption were 6 and 9 for Mt and MtA, respectively. The isotherms related to adsorption on Mt at pH = 6 and 9 as well as for MtA at pH=6 were best fitted with Sips isotherm model, while adsorption onto MtA at pH=9 obeyed Langmuir isotherm model.Монморијонит (Mt) и кисело модификован монморијонит (MtA) су испитани као адсорбенси никотина. Узорци су окарактерисани FT-IR спектроскопијом и нискотемпературном физисорпцијом азота. Адсорпција никотина испитивана је у зависности од времена контакта, pH и почетне концентрације никотина. Псеудодруги ред добро описује кинетику адсорпције. Оптимална pH вредност за адсорпцију никотина на Mt је 6 док је за MtA 9. Сипсов модел најбоље описује адсорпцију никотина на Mt на pH = 6 и 9 као и на MtA на pH = 6, док се aдсорпција на MtA на pH = 9 одвија по Лангмировом моделу

Supplementary data for the article: Ilić, I.; Milutinović-Nikolić, A.; Mojović, Z.; Vuković, Z.; Vulić, P.; Gržetić, I.; Banković, P.; Jović-Jovičić, N. Oxidative Degradation of Aromatic N-Compounds Using Cobalt Containing Montmorillonite-Based Catalysts. Applied Clay Science 2020, 193, 105668. https://doi.org/10.1016/j.clay.2020.105668

Supplementary material for: [https://doi.org/10.1016/j.clay.2020.105668]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4045

Thermodynamic and kinetic study of nicotine adsorption on acid-modified smectite

Kinetic and thermodynamic parameters of nicotine adsorption onto acid-activated standard Wyoming clay were investigated to obtain the optimum conditions for adsorption. The nicotine adsorptions were performed in a batch system, using 0.75 mM solution of nicotine, the mass of adsorbent of 25 mg at native pH=9.26, in temperature range from 25°C – 60 °C. The pseudo-first (PFO) and pseudo-second kinetics (PSO) models in both linear and nonlinear forms were apied for experimental data in the temperature range 25 °C – 60 °C. Error analysis parameters such as correlation coefficient (R2) and 2 (chi-square) have been used to determine the best kinetics interpretations of adsorption data. The analyzed parameters suggested that nicotine adsorption can be best described by tested models in the following order: non-linear PSO = linear PSO >non-linear PFO>linear PFO. The Weber-Morris intraparticle diffusion model was applied in order to predict the rate-limiting step. The calculated values for Cid were in the range 0.452 mmol g-1 to 0.484 mmol g-1, indicating effective role of the boundary layer on the adsorption rate. Thermodynamic study revealed that nicotine adsorption i\ \] Q K\  ¡G°=-18.93 kJ mol-1) physisorpton process with calculated value of enthalpy change of 4.99 kJ mol-1 and activation energy of 21.95 kJ mol-1

White Mustard (Sinapis alba L.) Oil in Biodiesel Production: A Review

White mustard (Sinapis alba L.) seed oil is used for cooking, food preservation, body and hair revitalization, biodiesel production, and as a diesel fuel additive and alternative biofuel. This review focuses on biodiesel production from white mustard seed oil as a feedstock. The review starts by outlining the botany and cultivation of white mustard plants, seed harvest, drying and storage, and seed oil composition and properties. This is followed by white mustard seed pretreatments (shelling, preheating, and grinding) and processing techniques for oil recovery (pressing, solvent extraction, and steam distillation) from whole seeds, ground seed or kernels, and press cake. Novel technologies, such as aqueous, enzyme-assisted aqueous, supercritical CO2, and ultrasound-assisted solvent extraction, are also discussed. The main part of the review considers biodiesel production from white mustard seed oil, including fuel properties and performance. The economic, environmental, social, and human health risk/toxicological impacts of white mustard-based biodiesel production and use are also discussed

The removal of nicotine from aqueous solution by adsorption onto montmorillonite

Wastewaters polluted with nicotine have been classified as toxic and hazardous by European Union Regulations. Using montmorillonite as nicotine adsorbent has several advantage to other methods and/or adsorbents since montmorillonite is an efficient adsorbent and at the same time natural, widely available at relatively low cost. In this work montmorillonite (SWy-2 purchased from The Source Clays Repository - The Clay Minerals Society) was used for nicotine adsorption experiments. UV-Vis spectroscopy (λmax=261 nm) was used for measuring the nicotine concentration and adsorption was carried out at pH=9.26. The estimated equilibrium time was 60 min. The adsorption obeyed the pseudo-second-order-kinetics. The adsorption isotherms were obtained for initial concentration range of nicotine from 1×10-4 to 2×10-3 mol dm-3 and temperature range was between from 25 and 55 ºC. The obtained isotherms were fitted with Langmuir, Freundlich and Sips’ models. For all investigated temperatures the results were best described with Sips’ model indicating that adsorption occurred on heterogeneous surface with defined number of active sites. The Gibbs free energy (DG) values calculated for the experimental data suggested that adsorption of nicotine onto montmorillonite was spontaneous, while the value of DH=19.0 kJ mol-1 was associated with endothermic process. The result obtained for maximum adsorption capacity of SWy-2 in this study (Qmax=0.275 mmol g-1) is comparable with data referred in literature, while at optimal pH=6 the Qmax of 0.713 mmol g-1 was achieved. The obtained results suggest that montmorillonite can be regarded as promising adsorbent for nicotine removal from aqueous solutions

Kinetics of adsorption of nicotine by natural and acid-activate montmorillonite

The adsorption of nicotine from aqueous solutions was performed on natural and acid-activated Wyoming montmorillonite. The adsorption experiments showed that acid-activation increases adsorption capacity of montmorillonites toward nicotine molecules. The pseudo-first and pseudosecond order kinetics models were tested. The nicotine adsorption was well represented by the pseudo-second-order kinetics model for both montmorillonite samples

Cobalt impregnated smectites (raw and acid activated) as catalysts in organic dye oxidation process in the presence of peroxymonosulfate generated radicals

Smectite based Co catalysts were prepared using the wetness impregnation method and applied as activators of potassium peroxymonosulfate as the source of sulfate radicals and tested in the degradation of Acid Orange 10 (AO10) in aqueous solution. Starting smectite clay (Bogovina, Serbia) was submitted to acid activation which resulted in enhanced textural properties [1]. The starting smectite (S) and acid activated (SA) were impregnated with predefined amounts of Co(NO3)2 which corresponded to 1.0 or 0.5 times the value of CEC. The impregnation process was followed by calcination at 450 °C during 6 h. The obtained catalysts were denoted according to the type of activation and Co2+ loading as: 1.0Co/S, 0.5Co/S, 1.0Co/SA and 0.5Co/SA. The chemical and phase composition of the catalysts were determined using XRF and XRD method, respectively. Textural properties were monitored using the low temperature N2 physisorption method. Potassium peroxymonosulfate (Oxone® i.e. 2KHSO5∙KHSO4∙K2SO4) was used as the source of sulfate radicals generated by cobalt incorporated into smectite structure of Co/S and Co/SA. The influence of cobalt content and acid modification on the efficiency of the decolorization of dye solutions was investigated. The decolorization of AO10 was monitored using UV–Vis spectrophotometry at lambda_max=478 nm. All catalyst efficiently decolorized investigated dye within 4 h. The decrease of absorbance at the characteristic wavelength was tested with different kinetic models and the exponential equation showed the best fit indicating the first order kinetics for investigated catalytic systems. The increase of cobalt content had higher impact on decolorization rate than the development of porous structure achieved by acid activation

Gas holdup in a gassed reciprocating plate column with rashig rings placed in interplate spaces

The gas holdup is studies in a gassed reciprocating plate column with the addition of the Rashig rings placed in each interplate space. The gas holdup generally increases with increasing the vibration speed, the superficial gas velocity, and the solids concentration in the range of operating conditions applied. Independently of the solids concentration, the gas holdup is correlated with the power consumption and the superficial gas velocity. The Rashig rings are shown to have more effective dispersion action than the polypropylene spheres under the same other operating conditions