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The United States Environmental Protection Agency (EPA) classified the phenylurea herbicide Diuron (C9H10Cl2N2O) as possibly carcinogenic to humans. This research is focused on the adsorbent performances of a Algerian sodium Montmorillonite (Mont-Na), for the removal of Diuron in aqueous solutions. The material is characterised before and after processing using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), specific surface area (SBET) and thermal analysis (TGA/DTA). The tests were firstly realised at 25°C and pH = 6.3. Until 61 hours of experiment, no removal was obtained in this case. After that, the experiments were carried out on Mont-Na at high temperature and medium pH (T = 45°C, pH = 6.3) and then at ambient temperature and basic pH (T = 25°C, pH = 11). The removal was increased from 74% to 91%, respectively. The equilibrium is reached after 5 hours and the adsorption capacity is between 0.74 mg/g at 45°C and 0.91 mg/g at pH = 11. The kinetic modelling shows that the pseudo-first order describes the experimental data of the Diuron adsorption on Mont-Na and the equilibrium data are modelled perfectly by applying the Elovich model. The thermodynamic quantities indicate that the adsorption process on Mont-Na at pH = 6.3 is spontaneous (ΔG < 0) and endothermic (ΔH = 31.80 kJ.mol−1). In conclusion, under the operating conditions used, local Mont-Na proved to be an excellent material for the adsorption of Diuron in aqueous solutions. That could be very promising for sewage treatment. [ABSTRACT FROM AUTHOR]

In this study, low-cost biomaterial hydroxyapatite (N-Hap) prepared from bovine bones was tested for its potential to sorb copper [Cu.sup.2+] and [Fe.sup.3+] from aqueous solution and was compared with commercial hydroxyapatite (C-Hap). The structural characterization of N-Hap and C-Hap were carried out by Fourier transform infrared (FTIR) analysis, textural analysis (BET), morphology, and elemental analysis via scanning electron microscopy (SEM-EDX). The results obtained show that SEM images confirmed the formation of porous N-Hap with various morphologies and the average particle size ranges from 50 to 100 nm and the CaP ratio is 1.657. The presence of functional groups on N-Hap surface was confirmed by FTIR analysis. The specific surface areas of N-Hap and C-Hap are found to be 46.87 and 40.98 [m.sup.2]/g, respectively. Adsorption of two metals [Cu.sup.2+] and [Fe.sup.3+] was fast, with equilibrium attained within 30 min. Copper ions exhibited the greatest adsorption on both adsorbents because of their size and pH conditions. Metallic ion removal efficiency was favored at a slightly acidic solution pH and low temperature. The equilibrium and kinetic data were found to fit well the Langmuir model and the pseudo second order model with intraparticle diffusion. Thermodynamic parameters ([DELTA][H.sub.ads] < 0 and [DELTA][G.sub.ads] < 0) involved the exothermic, spontaneous, and physical adsorption process. The adsorption interaction of [Cu.sup.2+] and [Fe.sup.3+] with Hap surface was investigated by theoretical density functional theory (DFT) calculations. Therefore, the porous hydroxyapatite N-Hap displays potential as a new biocompatible adsorbent, and its use seems to be an interesting solution for the treatment of industrial wastewater. Key words: porous hydroxyapatite, thermal synthesis, metallic ions, adsorption study, mechanism. Dans cette etude, nous avons essaye de preparer un biomateriau (l'hydroxyapatite N-Hap) a partir d'os de bovins, et le tester pour son potentiel d'adsorption du cuivre Cu (II) et Fe fer (III) dans une solution aqueuse, par rapport a l'hydroxyapatite commerciale (C-Hap). Les caracteristiques structurales des materiaux obtenus ont ete realisees par l'analyse infrarouge par transformee de Fourier (IRTF), l'analyse texturale (BET), l'analyse morphologique et elementaire par microscopie electronique a balayage (SEM-EDX). Les resultats obtenus montrent que les images MEB confirment la formation de morphologies diverses de materiau poreux (N-Hap) et que la taille moyenne des particules varie de 50 a 100 nm ainsi que le rapport CaP est de 1657. La presence des groupes fonctionnels sur la surface de N-Hap a ete confirmee par analyse infrarouge par transformation de Fourier (IRTF). Les surfaces specifiques de BET des materiaux N-Hap et C-Hap sont 46,87 et 40,98 [m.sup.2]/g respectivement. Adsorption de deux metaux [Cu.sup.2+] et [Fe.sup.3+] a ete rapide a l'equilibre est atteinte en 30 min. Le cuivre a presente la plus grande adsorption sur les deux adsorbants en raison de leur taille et de leurs conditions de pH. L'efficacite d'elimination des ions metalliques a ete favorisee a pH de solution legerement acide et a basse temperature. Les resultats d'equilibre et cinetiques s'averent bien correspondre au modele de Langmuir et au modele de pseudo-second ordre avec diffusion intraparticulaire. Les parametres thermodynamiques ([DELTA][H.sub.ads] < 0 et [DELTA][G.sub.ads] < 0) ont implique que le processus d'adsorption exothermique, spontanee et physique. L'interaction d'adsorption de [Cu.sup.2+] et [Fe.sup.3+] avec la surface de Hap a ete etudiee par des calculs de la theorie de la fonctionnelle de la densite (DFT). Par consequent, l'hydroxyapatite poreuse (N-Hap) presente un potentiel en tant que nouvel adsorbant biocompatible et son utilisation semble être une solution interessante pour le traitement des eaux usees industrielles. Mots-cles: hydroxyapatite poreuse, synthese thermique, ions metalliques, etude de l'adsorption, mecanisme., Introduction Nowadays, the use of effective techniques to clean up contaminated sites has become indispensable. One of them, adsorption, has many advantages; (1) it is economically viable to develop and [...]

The oil and carbohydrates contained in the Moringa oleifera seeds (MO) are two parameters that inhibit its coagulant potential. Oil extraction and protein purification are therefore necessary to improve its performance. The extraction process to recover the maximum oil yield was carried out using the solvent chloroform: ethanol C: E in a ratio (3:1). At a temperature of 100°C, the yield was higher than 44%. Purification was carried out by salting-in the protein with 1 M NaCl combined with ethanol precipitation and heat treatment. Analysis of the protein powder by the Kjeldahl method revealed 92% pure protein and 14% nitrogen; energy dispersive X-ray (EDX) analysis revealed high percentages of carbon (45%) and oxygen (39%). Scanning electron microscopy (SEM) showed a porous surface, and X-ray diffraction identified a crystalline phase of protein. The isoelectric point of Moringa oleifera protein (MOP) is in the range of pH 6.5–7.5 and its zeta potential varies between −19 mv and + 25.49 mV. It indicates a lower level of dispersion stability, implying a high capacity for protein agglomeration and flocculation. By reducing the zeta potential of water from −16 mv to −1.18 mv after treatment without modifying its pH, the Moringa protein has proven its ability to destabilise organic colloids. Moringa protein as a coagulat aid is effective for high turbidity wastewater with removal up to 86.78% and DOC removal up to 56.52%. The study reveals that coagulation with Moringa protein is a cost-effective alternative since it reduces the quantity of coagulant and time required for wastewater treatment. [ABSTRACT FROM AUTHOR]

This work studies the removal of o-cresol from wastewater by using ozonation followed by adsorption onto sodium natural bentonite (Na-Bent). The degradation of o-cresol was followed by UV-Vis. During ozonation, 2-methylbenzoquinone (2-mBQ) and 2-methylhydroquinone (2-mHQ) were identified as two of the main by-products, while the pH decrease suggested the breakage of aromatic compounds into smaller organic acids. After 30 min treatment, the o-cresol degradation for 250–62.5 mg/L solutions was found between 64–85%, respectively. Next, the wastewater containing persistent o-cresol and by-products was contacted with Na-Bent adsorbent. The solutions and physicochemical properties of Na-Bent were analysed, before and after adsorption, by UV-Vis, FTIR, XRD and N2 adsorption-desorption. Moreover, equilibrium and kinetic experiments were carried out to study the adsorptive properties of the Na-Bent. While sole ozonation or adsorption failed on the remediation of o-cresol solutions, the obtained results show that the contact of ozonated solutions with Na-Bent led to almost total removal of the o-cresol initial concentrations (between 96% and 99%). This excellent performance is assigned to the high volume of interlayer micropores and the suitable surface chemistry of this natural adsorbent. [ABSTRACT FROM AUTHOR]

The treatment of used vegetable oil (UVO) with seven different adsorbents and through two different procedures (stirring and gravity filtration) was explored. Important differences in terms of density, turbidity, electrical resistance, free fatty acids (FFAs) content and relative fatty acid distribution were observed. Different outcomes were shown depending both on the adsorbent and on the procedure. Lower values of density and FFAs were registered for oils treated by gravity filtration with portland (respectively 0.6% and 0.81 g/ml) and celite (respectively 0.7% and 0.72 g/ml). Considering the undesired leaching from the powder to the oil, related to the turbidity, the celite resulted more suitable for the oil recycling (241 Nephelometric Turbidity Unit (NTU) for portland vs 184 NTU for celite). In addition, Fourier-transform infrared spectroscopy combined with multivariate analysis allowed to determine a chemical fingerprint relative characteristic of vegetable oils recycled by gravity or by adsorption by stirring. [ABSTRACT FROM AUTHOR]

In this study, solid olive wastes were suggested as adsorbents for olive mill wastewater (OMWW) clean‐up. These solid olive wastes underwent thermal treatment by two‐step process: carbonization at 300°C and 400°C, then physical activation at 800°C and 1000°C. Characterizations were determined by FTIR, TGA/DTA, and N2 Adsorption‐Desorption techniques. The efficiency of these new bio‐adsorbents was verified on OMWW. Adsorption kinetics experiments were realized at room temperature and diluted OMWW (1/100 v/v). Evaluation of obtained activated carbons (ash, iodine value, and moisture) shows a good activity and stability in weight according to the thermogravimetric analysis. Moreover, the textural results of BET surface area showed a high area for activated carbons prepared from olive stones at 300°C/800°C (SBET = 208 ± 0.3 m2/g) and olive flesh at 400°C/1000°C (SBET = 77 ± 0.8 m2/g). The adsorption rates of OMWW were 91% after 120 min and 95.3% after 60 min contact time at pH = 2.0, respectively. At the end, the pH increased to neutral value. Thus, these bio‐adsorbents from solid waste of olive industry can be efficient adsorbents for their liquid effluent clean‐up. [ABSTRACT FROM AUTHOR]

Diuron is categorized as a probable human carcinogen by the United States Environmental Protection Agency (EPA). This work is aimed to determine the optimal conditions for the catalytic degradation of Diuron in an aqueous solution with H2O2 using Algerian sodium Montmorillonite (Mont‐Na) as the catalyst. The material is characterized before and after the experiment using X‐ray diffraction, Fourier transform infrared (FTIR) spectroscopy, specific surface area (SBET), elemental analysis, and thermal analysis (TGA/DTA). The surface charge is determined by measuring the point of zero charge. Tests with H2O2 without Mont‐Na provide a 32% conversion rate after 8 h. However, a mixture of 1 g Mont‐Na and H2O2 increases the conversion rate to 91% after 180 min at 25 °C and pH 6.3. The Diuron disappearance is evidenced by high‐performance liquid chromatography using a UV–vis detector (HPLC/UV–vis). Specifically, 3,4‐dichloroaniline (DCA) is the only by‐product. At the basic pH values 9 and 11, a conversion rate of 72.5% is achieved with a lower contact time of 150 min. A change in temperature toward higher values results in a decrease in the degradation rate. Overall, Algerian sodium Montmorillonite is used successfully for the heterogeneous catalytic degradation of Diuron from polluted water. [ABSTRACT FROM AUTHOR]

Cresols are phenolic pollutants found in industrial wastewaters. Their efficient removal is an important environmental concern. The isotherms and kinetics of the adsorption of an aqueous solution of o-Cresol, on a local Algerian Montmorillonite clay mineral (sodium clay (SC)) were determined experimentally. Various parameters influencing the adsorption were optimized, mainly the effect of the contact time, initial concentration and pH of the solution were studied. The experimental results obtained show that the equilibrium of sorption is reached within 15 min with a percentage of 99.507%. Indeed, the adsorbent dose is 15 mg with o-Cresol concentration of 62 mg/L,T = 25°C and pH 6.31 for the better adsorption. Results deducted from the adsorption isotherms also showed that the retention is predictable from these isotherms in agreement with the Langmuir model. Pseudo-second-order model describes the o-Cresol adsorption behavior with an intraparticle diffusion. In addition, the adsorption heat is around −31 kJ/K mol, which are in the limit between physical and chemical adsorption. The use of adsorptive properties of SC for the treatment of industrial wastewater seems to be an interesting solution. [ABSTRACT FROM PUBLISHER]