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Acorn pericarps of the Algerian holm oak (Quercus ilex) constitute a largely underexploited forestry co-product. In the aim of valorization, adsorption efficiencies of crude, parietal, and lignocellulosic fractions of acorn pericarps were evaluated towards lead, cadmium, nickel, and copper ions. The results were modeled using Langmuir and Freundlich isotherms. The best results were obtained with the lignocellulosic fraction towards lead and cadmium with qmax values of 370.37 and 303.03 mg.g−1, respectively. On the contrary, crude and parietal fractions showed the highest capacities for nickel and copper, with qmax values of 200 and 303.03 mg.g−1, respectively. This work thus provides the first trial of acorn pericarps of oaks growing in northwest Algeria as an efficient biosorbent for the removal of metallic cations from aqueous solutions, whose adsorption capacities surpass most of the previously described biosorbents. [ABSTRACT FROM AUTHOR]

This report focusses on the modification of physical structure and chemical properties of a bentonite clay from the Hammam Boughrara region of the Maghnia district in western Algeria to maximize its adsorption capacity. The purified bentonite clay (called B) was modified, either by acid activation with 1M sulfuric acid (B-Act), or by intercalation with the cationic surfactant cetytrimethyl ammonium bromide (CTAB), applying a cation exchange capacity (CEC) of 100% (called B-CTAB). Modification of B was also introduced by combining these two steps consecutively, i.e., at first acid activation of B, followed by intercalation with CTAB (B-Act-CTAB). The B-Act-CTAB was obtained by H2SO4 (1M) acid activation, followed by co-adsorption of CTAB with 100% and 300% of the CEC of B-Act as precursor. In particular, a strong increase of surface area and pore volume of the modified bentonites was observed for B-Act (469.83 m²/g and 0.401 cm3g−1), B-Act-CTAB100 (267.72 m²/g and 0.316 cm3 g−1) and B-Act-CTAB300 (111.15 m²/g and 0.171 cm3g−1), compared to B (31.79 m²/g and 0.074 cm3 g−1) and B-CTAB (3.79 m²/g and 0.034 cm3 g−1), respectively. The bentonite-based adsorbents were then used to evaluate the removal efficiency of an organic molecule, the azo dye Orange G (OG), as a model for a Persistent Organic Pollutant. Freundlich, Langmuir and Sips (Langmuir–Freundlich) models were applied to analyze equilibrium isotherms, showing a good correlation between experimental data and the Freundlich model. A good agreement was obtained between experimentally obtained kinetic adsorption data and the pseudo-second-order model, allowing to evaluate rate constants. B-Act-CTAB300 can be applied as a low-cost material for removal of azo dyes, since its adsorption capacity towards OG (102.80 mg/g) exceeds largely that of B-CTAB (31.49 mg/g) and B-Act-CTAB100 (12.77 mg/g). [ABSTRACT FROM AUTHOR]

With the significantly increasing pharmaceutical and antibiotics industry in Algeria, the elimination of biomass is of utmost importance since the latter represents a large part of waste from the manufacturing process. In this work, the elimination of hexavalent chromium Cr (VI) and Congo red dye is part of the Pleurotus mutilus biomass recovery process. Thus, biosorption has been studied in a discontinuous system. Optimal conditions were estimated by variations in contact time, temperature, initial pollutant concentrations, and simultaneous removal of both pollutants. The greatest uptake capacities achieved were 36.68 mg/g of and 15.08 mg/g of Cr(VI). The initial concentrations of both pollutants being equal to 50 mg/l, for a duration time of 180 min and a temperature of 300 K. Based on the values of the coefficient of determination R2, χ2, and ARE, the isothermal equilibrium data were better represented by Freundlich, Temkin, and Dubinin-Radushkevich models. The kinetic biosorption of the two pollutants was well described using the pseudo-first-order model. The biosorption process is controlled by external mass transfer. The physical process in nature of Cr(VI) and (CR) biosorption has been justified based on the values obtained of ΔG° and ΔH°. Globally, this work demonstrates the considerable potential of Pleurotus mutilus for the elimination of anionic pollutants. Research results indicate that this biomass, a waste material, first destined for incineration, was recovered without any treatment. Due to its low cost, it could serve as an inexpensive source for recovering heavy metals and dyes from dilute contaminated water. [ABSTRACT FROM AUTHOR]

Sorghum stems will be considered in this work as an alternative for the adsorption of cyanides in aqueous solution. It is an abundant material in southern Algeria, and it does not require any specific pretreatment. Therefore, it is a much cheaper adsorbent than the adsorbents usually used for cyanide adsorption, such as activated carbon. In this work, a complete study will be presented that includes the physicochemical characterization of prepared sorghum stem particles (SSPs) and the kinetic and thermodynamic adsorption studies. The pseudo-second-order kinetic model best described the experimental data with a high coefficient of determination and that the Langmuir isotherm model fitted better than the Freundlich and Temkin models. The Langmuir maximum adsorption capacity (qm) was 76.92 mg/g at 293 K. The thermodynamic study showed that the adsorption of cyanides on SSPs was endothermic and spontaneous and that it was chemisorption. The comparison with the usual adsorbents tested by other authors showed that SSP could be an interesting candidate due to its high adsorption capacity and easy preparation. [ABSTRACT FROM AUTHOR]

In this study, date waste, very abundant agricultural waste in southern Algeria, was evaluated for its ability to eliminate Congo Red (RC) dye from an aqueous solution. The adsorption tests were carried out at various initial concentrations of dye (7-20 mg / L), quantities of waste (1-7g), pH of the solution (2,5-12) and temperature (30-70 ° C) . The results obtained showed that the concentration of RC contained in the aqueous solution decreased with time. The quantities of RC adsorbed at equilibrium by the waste were verified by contribution to Langmuir and Freundlich isotherms. The results indicate that the Langmuir equation provides a good correlation of the experimental data. The experimental data from the kinetic biosorption study at different initial concentrations showed that the pseudo-second-order model is the most suitable for describing the adsorption of RC on the date waste. [ABSTRACT FROM AUTHOR]

This study is based on synthesis and characterization of three different clays (Sodic-bentonite noted 𝑁𝑎 − 𝐵𝑡, Dialyl Dimethyl Ammonium Chloride-bentonite noted 𝐷𝐷𝑀𝐴 − 𝐵𝑡 and bentonite intercalated by Hexadecyl Trimethyl Ammonium Bromide or 𝐻𝐷𝑇𝑀𝐴 − 𝐵𝑡. These three clay complexes were characterized by both 𝑋𝑟𝑎𝑦 diffraction (𝑋𝑅𝐷) and Fluorescence (𝑋𝑅𝐹)Scanning Electron Microscopy (𝑆𝐸𝑀), Fourier transform infrared spectroscopy (𝐹𝑇𝐼𝑅), textural measurements (𝐵𝐸𝑇 specific surface areas and porosities) and the cationic exchange capacity (𝐶𝐸𝐶). Corresponding obtained results confirm the good intercalation of the 𝑁𝑎 − 𝐵𝑡 by the two used surfactants at low concentrations (0.006𝑀 for 𝐻𝐷𝑇𝑀𝐴𝐵 and 0.007𝑀for 𝐷𝐷𝑀𝐴+). Obtained results give basal spacing values around 14.5 and 18.5𝐴, respectively for verified two aims firstly: The originality of this research, secondly for minimized the production cost of the adsorbents. Adsorption kinetic study of phosphate ions (𝑃𝑂4 3−) on these three matrices was carried out using kinetic models of pseudo-first, pseudo-second-order and intraparticular diffusion. Results obtained at the studied conditions (room temperature 𝑇 = 25𝑜𝐶), (acidic medium 𝑝𝐻 = 5.7) show clearly the good validity of the pseudosecond-order model which gives a better correlation coefficient both, for 𝐷𝐷𝑀𝐴 − 𝐵𝑡 (𝑅2 = 0.995) and 𝐻𝐷𝑇𝑀𝐴 − 𝐵𝑡 (𝑅2 = 0.999) compared to that obtained by 𝑁𝑎 − 𝐵𝑡 (𝑅2 = 0.990)The aim of this present study was to evaluate the feasibility of using chicken eggshells as low-cost biosorbentfor nickel(II) ions adsorption from aqueous solutions. In order to clarify the adsorption process, batch experiments were performed to study the effect of operating parameters such asbiosorbent dose (1-10 g/L), initial concentration of nickel ions (10-50 mg/L), contact time (5-120 min) and temperature (20-50 °C). To describe the adsorption equilibrium, the experimental data were analyzed by the Langmuir, Freundlich and Temkin isotherm models. The Freundlich model showed better representation of data (R2> 0.999). The maximum adsorption capacity Adsorption isotherms give adsorbed amounts of about 33 and 63 𝑚𝑔. 𝑔−1 onto 𝐷𝐷𝑀𝐴 − 𝐵𝑡 𝐻𝐷𝐷𝑀𝐴 − 𝐵𝑡 complexes, respectively, and 14 𝑚𝑔. 𝑔−1for 𝑁𝑎 − 𝐵𝑡 as reference adsorbent. These results indicated the adsorption of phosphate anions (𝑃𝑂4 3−) by the two prepared Algerian modified organo clays through interactions by the chemisorptions on the surface sites of each used modified clay complexes. [ABSTRACT FROM AUTHOR]

The present study consists of comparing the retention of paracetamol dispersed in aqueous solutions by two different natural adsorbents commonly found in Algeria, namely olive stones (OS) and date pits (DP). Comparative study was carried out using adsorption parameters such as contact time, temperature and initial concentration of paracetamol. The kinetic study revealed that adsorption on both adsorbents follow the pseudo-second-order equation but the values of adsorption capacity, qe, and the rate constant, k2, are found to be 37.12 mg g-1 and 0.0128 g mg-1 min-1, respectively, for OS, which are significantly higher than those obtained for DP which are 29.74 mg g-1 and 0.0032 mg g-1 min-1, respectively, on the other hand, data of equilibrium has been well adjusted by the Langmuir isothermal model. The adsorption of paracetamol on these adsorbents is exothermic and spontaneous with ΔS° = -71.0 J mol-1 K-1 and ΔH° = -30.4 kJ mol-1 for OS and ΔS° = -10.2 J mol-1 K-1 and ΔH° = -6.1 kJ mol-1 for DP. The results indicate that the OS was more efficient with a removal percentage greater than 98% compared with the DP which is about 78%, these results are similar to those found by scanning electron microscopy in the OS which represent porous structure with a number of pores larger than those observed for DP and even the X-ray fluorescence analysis shows that the surface nature of OS contains a significant percentage of calcium contrary to DP which has a higher percentage in potassium. [ABSTRACT FROM AUTHOR]

Adsorption of several chemical contaminants onto clay minerals is the most recommended technique applied in the wastewater treatment field, owing to its low economic cost, efficiency, and low power consumption. In this context, natural bentonite particles with 80-μm diameter were investigated for the ammonium adsorption in aqueous solution using an incubator that kept the constant temperature and stirring speed at 200 RPM. The study of different experimental parameters effect on the adsorption process revealed that the raw bentonite have adsorbed approximately 53.36 % of the initial ammonium concentration at pH 7 and temperature of 30 °C. This percentage has been improved by increasing the adsorbent dosage in solution, which could reach up to 81.2 % at 40 g/L of bentonite with an initial ammonium concentration of 10 mg-NH /L. Moreover, experimental data modeling allowed us to conclude that the adsorption isotherm obeys to both models of Langmuir and Freundlich. [ABSTRACT FROM AUTHOR]

Low-cost-activated carbon derived from dates stones of Phoenix dactylifera L. has been used to replace the current high-cost methods of cadmium removal from aqueous solutions and waste waters. Effect of some operating parameters such as pH, contact time, initial metal concentration, and solution temperature was examined. Adsorption of cadmium ions was found to increase with increasing pH to reach a maximum removal rate of 4.29 mg/g at pH= 8 (C0 = 50 mg/l). Adsorption data are found to follow the Freundlich model. [ABSTRACT FROM AUTHOR]

Abstract: In this study, cedar cone (CC), a forest waste, available in large quantity in Algeria, is proposed as novel material for the removal of basic dye Rhodamine B (RhB) from aqueous solutions. The effect of operating parameters such as the sorbent dose, initial dye concentration, stirring speed and solution temperature on the sorption kinetics of RhB was studied. The removal of RhB by sorbent increased with an increase in sorbent dose and initial concentration. Kinetic models, the pseudo-first and pseudo-second order rate equations were applied. The obtained results show that the sorption of RhB by CC was best described by the pseudo- second order kinetic model. Sorption equilibrium isotherms of RhB at different temperatures was determined and correlated with common isotherm equations such as Langmuir and Freundlich models. The results indicate that the Langmuir model fits the data better. The thermodynamic study of Rhb sorption by CC reveals that the sorption process is spontaneous(ΔG°<0) and endothermic (ΔH°>0).The low and positive value of ΔS° indicates that affinity of Rbh molecules to the sorbent surface. [Copyright &y& Elsevier]

In this work, low-cost and readily available limestone was converted into nanolimestone chitosan and mixed with alginate powder and precipitate to form a triple nanocomposite, namely limestone—chitosan–alginate (NLS/Cs/Alg.), which was used as an adsorbent for the removal of brilliant green (BG) and Congo red (CR) dyes in aqueous solutions. The adsorption studies were conducted under varying parameters, including contact time, temperature, concentration, and pH. The NLS/Cs/Alg. was characterized by SEM, FTIR, BET, and TEM techniques. The SEM images revealed that the NLS/Cs/Alg. surface structure had interconnected pores, which could easily trap the pollutants. The BET analysis established the surface area to be 20.45 m2/g. The recorded maximum experimental adsorption capacities were 2250 and 2020 mg/g for CR and BG, respectively. The adsorption processes had a good fit to the kinetic pseudo second order, which suggests that the removal mechanism was controlled by physical adsorption. The CR and BG equilibrium data had a good fit for the Freundlich isotherm, suggesting that adsorption processes occurred on the heterogeneous surface with a multilayer formation on the NLS/Cs/Alg. at equilibrium. The enthalpy change (ΔH0) was 37.7 KJ mol−1 for CR and 8.71 KJ mol−1 for BG, while the entropy change (ΔS0) was 89.1 J K−1 mol−1 for CR and 79.1 J K−1 mol−1 BG, indicating that the adsorption process was endothermic and spontaneous in nature. [ABSTRACT FROM AUTHOR]