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Author: search.filters.author.Aksil, TounsiaSubject: search.filters.subject.Kinetics

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    Thermodynamic and kinetics studies on adsorption of Indigo Carmine from aqueous solution by activated carbon
    (Elsevier, 2019) Harrache, Zahia; Abbas, Moussa; Aksil, Tounsia; Trarib, Mohamed
    The kinetic and equilibrium parameters of the quantitative adsorption for Indigo Carmine (IC) removed by commercial activated carbon (AC) were studied by UV–visible absorption spectroscopy. AC with a high specific surface area (1250.320 m2/g) was characterized by the Brunauer–Emmett–Teller (BET) method and point of zero charge (pzc). The effect of the initial dye concentration (10–60 mg/L), contact time (0–90 min), pH (1−12), agitation speed (0–600 rpm), adsorbent dose (1–10 g/L) and temperature (298–323 K) were determined to find the optimal conditions for a maximum adsorption. The adsorption mechanism of Indigo Carmine onto AC was studied using the first pseudo order, second pseudo order and Elovich kinetics models. The adsorptions kinetic were found to follow a pseudo second order kinetic model with a determination coefficient (R2) of 0.999. To get an idea on the adsorption mechanism, we applied the Webber-Morris diffusion model. The equilibrium adsorption data for Indigo Carmine on AC were analyzed by the Langmuir, Freundlich, Elovich, Dubinin and Temkin models. The results indicate that the Langmuir model provides the best correlation at 25 °C (qmax = 79.49 mg/g) and Dubinin at 40 °C (qmax = 298.34 mg/g). The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters such as free energy (ΔG° = −0.071 to −1.050 kJ/mol), enthalpy (ΔH° = 28.11 kJ/mol), entropy (ΔS° = 0.093 kJ/mol·K) and activation energy (Ea) of 51.06 kJ/mol of adsorption. The negative ΔG° and positive ΔH° values indicate that the overall adsorption is spontaneous and endothermic.
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    Performance of mixed mesoporous silica Si (Mes)-perovskite (P) to remove hydroxybenzene in aqueous solution-effect of parameters influencing the adsorption efficiency
    (Balaban Publishers – Desalination Publications, 2020) Abbas, Moussa; Aksil, Tounsia; Trari, Mohamed
    * Corresponding author.1944-3994/1944-3986 © 2020 Desalination Publications. All rights reserved.Desalination and Water Treatmentwww.deswater.comdoi: 10.5004/dwt.2020.26157202 (2020) 306–316OctoberPerformance of mixed mesoporous silica Si(Mes)-perovskite (P) to remove hydroxybenzene in aqueous solution — effect of parameters influencing the adsorption efficiencyMoussa Abbasa,*, Tounsia Aksila, Mohamed TraribaLaboratory of Soft Technologies and Biodiversity, Faculty of Sciences, University M’hamed Bougara, Boumerdes 35000, Algeria, Tel. +213 552408419; Fax: +213 21 24 80 08; emails: moussaiap@gmail.com (M. Abbas), tounsiaiap@gmail.com (T. Aksil) bLaboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry (USTHB), BP 32-16111 Algiers, Algeria, email: mtrari@usthb.dz (M. Trari)Received 1 December 2019; Accepted 25 May 2020abstractMesopores are materials with pore diameters between 2 and 50 nm, are used in several fields such as catalysis, chromatography, adsorption, etc. This study focuses on the potential use of mesoporous Si(Mes) and perovskite (P) as adsorbents, their ability to remove hydroxybenzene from aqueous solutions and the possibilities of elimination of a certain class of phenolic compounds, whose chem-ical structures of which contain functions capable of interacting on the surface of the supports. The adsorbent was characterized by Brunauer–Emmett–Teller, Fourier-transform infrared spectros-copy and X-ray diffraction methods. Batch adsorption experiments were undertaken to assess the effect of physical parameters on the hydroxybenzene removal efficiency. It has been observed that under optimized conditions (pH 4; adsorbent dose 1 g L–1; agitation speed 200 rpm; contact time 90 min); up qmax of 4.210 g of hydroxybenzene/g adsorbent at 25°C were removed from the solution. The adsorption by the adsorbent follows a pseudo-second-order kinetic model with a determina-tion coefficient (R2) of 0.999; which relies on the assumption that the physisorption may be the rate-limiting step. The adsorption at different temperatures has been used for the determination of thermodynamic parameters, the negative free energy (ΔG°) and positive enthalpy (ΔH°) indicate that the overall adsorption is spontaneous and endothermic, while the negative value (ΔS°) states clearly that the randomness increases at the solid-solution interface during the phenol adsorption onto Si(Mes)-(P), indicating that some structural exchange may occur among the active sites of the adsorbent and the ions
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    Adsorption in simple batch experiments of Coomassie blue G-250 by apricot stone activated carbon—Kinetics and isotherms modelling
    (Taylor & Francis, 2015) Abbas, Moussa; Cherfi, Abdelhamid; Kaddour, Samia; Aksil, Tounsia
    The preparation of an activated carbon from apricot stones (ASAC) with H3PO4 activation and its ability to remove the Coomassie blue (CB) from aqueous solutions are reported in this study. The spectroscopy method is used to get information on interactions between the functional groups of the adsorbent and the CB. Batch adsorption experiments were first undertaken to assess the effect of various parameters on the removal efficiency of CB. It was observed that under optimized conditions up to 98.022 mg/g could be removed from solution at 50°C. The equilibrium experimental data were analysed using Langmuir and Freundlich isotherm equations. An error-based statistic study showed that the isotherm data are well described by the Freundlich model. The suitability of the kinetic models for the adsorption of CB onto ASAC was also investigated. It was found that the adsorption kinetics of the dye obeyed pseudo-second-order kinetic model. The evaluation of thermodynamics parameters such as activation energy of adsorption (Ea: 66.161 kJ/mol) predicted the chemisorption nature of the sorption process. The negative Gibbs free energy (−ΔG° = 15.21–19.27 kJ/mol) and negative enthalpy change (ΔH° = −55.088 kJ/mol) indicated, respectively, the spontaneous and exothermic nature of the reaction