Abdelmoula Kheribech

Bio: Abdelmoula Kheribech is an academic researcher. The author has contributed to research in topics: Freundlich equation & Adsorption. The author has an hindex of 2, co-authored 5 publications receiving 7 citations.

Removal of Methylene Blue from Water by Polyacrylonitrile Co Sodium Methallylsulfonate Copolymer (AN69) and Polysulfone (PSf) Synthetic Membranes

Abstract: Polyacrylonitrile-co-sodium methallylsulfonate copolymer (AN69) and polysulfone (PSf) synthetic membranes were prepared and used for the removal of methylene blue (MB) from water. Atomic Force Microscopy (AFM), Ionic exchange capacity (IEC), and Swelling ratio (Sr) were employed to determine the membrane characteristics. pH, membrane composition and initial dye concentration were used for the evaluation of the efficiency of MB adsorption on AN69/PSf membranes. Isotherms and kinetic models were applied to determine the adsorption mechanism and to calculate the values of adsorption parameters. The various methods reveal that with the increase of PSf percentage, the membrane surface becomes rougher and the average values of ionic exchange capacity and the swelling ratio reach 0.6 meq/g and 7%, respectively. The adsorption of MB is more efficient at higher pH (92%) and the maximum adsorption capacity reaches 75.75 mg/g. The mechanism of adsorption is perfectly fitted by pseudo-second order (R2 = 0.984) whereas the isotherm adsorption follows better the Freundlich isotherm (n = 1.49 and R2 = 0.96).

Synthesis of polyacrylonitrile-co-sodium methallyl sulfonate copolymer (AN69) and polyacrylic acid (PAA) membranes for the removal of methylene blue from water

Abstract: The scope of this work is focused on the removal of methylene blue (MB) from aqueous solution by adsorption (bach method) on polyacrylonitrile-co-sodium methallyl sulfonate copolymer (AN69) and polyacrylic acid (PAA) synthetic membranes which were prepared specifically for this purpose. Investigations have covered membrane properties and the determination of adsorption parameters. The immobilization of PAA chains into AN69 matrix was revealed by FTIR analysis, whereas the presence of small superficial microcavities was demonstrated by AFM scanning. Otherwise, the increase in PAA fraction (0 to 10%), in membrane composition, induces an increase in swelling ratio (12–22%) and ionic exchange capacity (0.8–1.2 meq/g). Moreover, the equilibrium adsorption capacity improves with the increase in alkalinity of initial adsorbate solution (pH = 2–11) and with the concentration (C = 20–80 mg/L). The results of kinetic adsorption show that the mechanism of adsorption is perfectly fitted by pseudo-second order (R2 = 0.999) and the isotherm adsorption follows the Freundlich isotherm (R2 = 0.98). From the different applied adsorption models, it was found that the maximum Langmuir adsorption capacity Qm was 116 mg/g and the Freundlich index of adsorption n was 2.2.

Removal of heavy metals from synthetic solution by electrocoagulation

Abstract: The objective of this work concerns the optimization of the operating conditions for the removal of heavy metals from synthetic solution by Electrocoagulation (EC). To reach this purpose, we prepared a synthetic wastewater containing certain heavy metals (Ni, Cu, Zn, Fe and Pb) to study the influence of various parameters (conductivity, pH, time of electrolysis, current density and the initial concentration of the metal) on the rate of removal of these metals. The results show that this rate of removal can reach 99.9 % in the following optimal conditions: pH included between 6 and 8 and a density of the current of 1~1.5A / dm 2 . This study shows that it is possible to remove metals in aqueous solution by the technique of electrocoagulation.

Elimination of fluoride ions from aqueous solutions with unmodified bentonite clay in batch reactor

Abstract: T presence of excess fluoride ions in wastewater generated by different industrial activities has been acknowledged as a major environmental problem worldwide. Groundwater is one the important sources of drinking water. The discharge of industrial wastewater containing such as pollutant into the surface water would lead to groundwater pollution. The consumption of this latter can be considered as the major path of human exposure. Various technologies have been reported in the literature for fluoride removal from wastewaters to conquer the hazardous impacts generated by fluoride ions on the environment and human health. In this study, the fluoride removal from wastewaters was carried out by adsorption on local available bentonite clay obtained from the Northern part of Morocco using batch equilibrium experiments. The main aim of this study was on the one hand, the evaluation of the adsorption potential of the unmodified bentonite clay for waste water defluoridation, and on the other hand, the identification of the mechanism involved in the fluoride adsorption process. The compositional, structural and textural characteristics of the natural bentonite clay were determined using accurate physicochemical and mineralogical characterizations. The contents of fluoride ions in wastewater were determined by the potentiometric method with a fluoridespecific ion electrode connected to a digital ion analyzer. Batch adsorption experiments were conducted at room temperature to optimize various operational parameters such as contact time, initial fluoride concentration, adsorbent dose and initial pH solution. It was observed that 30 min of contact time between the adsorbent and aqueous solution containing fluoride ions was sufficient for attaining equilibrium. The maximum wastewater defluoridation (52.2%) was obtained under acidic conditions (pH=2), and for 5 mg L-1 and 2 g L-1 of initial fluoride concentration and adsorbent dose, respectively. The experimental data followed pseudo-second-order and fitted well into Freundlich adsorption, indicating multilayer adsorption with heterogeneous energetic distribution of active sites and with interaction between adsorbed molecules.

Heavy metal ions removal from wastewater using electrocoagulation processes: A comprehensive review

Abstract: A vast number of publications have investigated the application of electrocoagulation (EC) process in heavy metal ions removal from wastewaters. Most of these studies were simple lab-scale using synthetic wastewater with the absence of holistic and systematic approach to consider the process complexity. This comprehensive review considers the fundamental aspects of EC processes such as mechanisms, kinetic models, and isotherm models used by different researchers. Furthermore, the impact of the main design and process operational parameters on the removal efficiency is discussed and analyzed. Many concluding remarks and perspectives are stated to give insights for possible future investigations.

Bioinspired approaches to toughen calcium phosphate-based ceramics for bone repair.

Abstract: To respond to the increasing need for bone repair strategies, various types of biomaterials have been developed. Among those, calcium phosphate (CaP) ceramics are promising since they possess a chemical composition similar to that of bones. To be suitable for implants, CaP ceramics need to fulfill a number of biological and mechanical requirements. Fatigue resistance and toughness are two key mechanical properties that are still challenging to obtain in CaP ceramics. This paper thus reviews and discusses current progress in the processing of CaP ceramics with bioinspired microstructures for load-bearing applications. First, methods to obtain CaP ceramics with bioinspired structure at individual lengthscales, namely nano-, micro-, and macroscale are discussed. Then, approaches to attain synergistic contribution of all lengthscales through complex and biomimetic hierarchical structures are reviewed. The processing methods and their design capabilities are presented and the mechanical properties of the materials they can produce are analyzed. Their limitations and challenges are finally discussed to suggest new directions for the fabrication of biomimetic bone implants with satisfactory properties. The paper could help biomedical researchers, materials scientists and engineers join forces to create the next generation of bone implants.

Inorganic Materials for Regenerative Medicine

Abstract: Methods that are used in regenerative medicine rely on the inherent ability of living organisms to regenerate their tissue. If the size (volume) of a defect exceeds some critical level, regeneration can be initiated and maintained using resorbable porous scaffolds made of natural, artificial, or synthetic materials capable of temporary defect compensation. When modified with pharmaceutical products and specific proteins or cells, such porous scaffolds are referred to as tissue engineering constructs. Inorganic resorbable materials are most frequently used for bone tissue defect repair. Natural bone is a composite having a polymer (collagen) matrix filled with calcium phosphate nanocrystals in the form of insoluble calcium hydroxyapatite. For this reason, calcium phosphate-based materials are leaders of medical inorganic materials research. To date, resorbable biocompatible materials based on tricalcium phosphate, calcium pyrophosphate, brushite, monetite, and octacalcium phosphate have been developed. Calcium hydroxyapatite is known as an inorganic ion exchanger. Because of this, the composition of bone tissue includes, in addition to phosphate and calcium ions, carbonate, silicate, and sulfate ions, as well as sodium, potassium, magnesium, iron, strontium, zinc and some other metal ions. The fact that bone tissue contains anions substituting for orthophosphate ions or hydroxide ions in the calcium hydroxyapatite of bone tissue prompted researchers to produce resorbable materials based on calcium sulfates, calcium carbonate, and calcium phosphates in which orthophosphate ions are replaced by anions mentioned above. Cation substitutions in calcium hydroxyapatite of bone tissue and the chemical composition of the medium of an organism allow one to produce and use resorbable materials for bone implants consisting of cation-substituted calcium phosphates and calcium–biocompatible cation double phosphates, such as sodium-substituted tricalcium phosphate, potassium-substituted tricalcium phosphate, sodium rhenanite, potassium rhenanite, and calcium magnesium double pyrophosphate. The resorption of an inorganic material intended for use as a pharmaceutical product can be controlled via designing a preset phase composition. The above-mentioned biocompatible resorbable phases can be used in various combinations in already existing composite materials or composites under development. The microstructure of a biocompatible resorbable inorganic material can be formed as a result of various physicochemical processes. The phase composition and microstructure of a ceramic material are determined by solid-state and liquid-phase sintering processes, as well as by heterogeneous chemical reactions during firing. The phase composition and microstructure of cement stone are formed as a result of chemical binding reactions initiated by the addition of water or aqueous solutions. Amorphous materials can be prepared via melting of starting reagents or sol–gel processing. The osteoconductivity of a biocompatible resorbable inorganic material is an important property necessary for body fluids and bone cells to be able to penetrate into the implant material. Macroporosity, which determines the osteoconductivity of a resorbable inorganic material, can be produced using various technological approaches. 3D printing methods make it possible to obtain materials with tailored phase composition and microstructure and permeable macroporosity of preset architecture. A large surface area of a porous inorganic material is thought to be a factor of controlling the resorption rate. This review summarizes information about existing biocompatible resorbable inorganic materials for regenerative medicine and considers physicochemical principles of the preparation of such materials with the use of synthetic starting powders and natural materials.

Removal of trivalent chromium ions from aqueous solutions by Sodium polyacrylate beads

Abstract: In the present study, the performance of sodium polyacrylate beads on the removal of trivalent chromium Cr (III) from aqueous solutions was evaluated using several techniques such as Fourier Transformed Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX), Inductively Coupled Plasma (ICP) and Atomic Adsorption Spectroscopy (AAS). On one hand, the characterization of dry PANa beads was carried out through FTIR and the surface morphology was analyzed by SEM and EDAX methods in order to show the loading of heavy metal on PANa beads. On the other hand, the effect of contact time, initial pH solution, initial Cr(III) concentration, adsorbent mass and temperature on the adsorption capacity of PANa was studied. All results have shown that the adsorption equilibrium was reached at about 60 minutes with an adsorption efficiency close to 90 %. Also, the study of the reliability of PANa beads was effectuated using 0.01 M nitric acid solution through six cycles of adsorption/desorption which were determined in order to study the reliability of PANa over time and to test their efficiency in industrial applications. Finally, the obtained thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicate that the adsorption process is spontaneous and endothermic.

Green Production of Zero-Valent Iron (ZVI) Using Tea-Leaf Extracts for Fenton Degradation of Mixed Rhodamine B and Methyl Orange Dyes

Abstract: The danger from the content of dyes produced by textile-industry waste can cause environmental degradation when not appropriately treated. However, existing waste-treatment methods have not been effective in degrading dyes in textile waste. Zero-valent iron (ZVI), which has been widely used for wastewater treatment, needs to be developed to acquire effective green production. Tea (Camellia sinensis) leaves contain many polyphenolic compounds used as natural reducing agents. Therefore, this study aims to synthesize ZVI using biological reducing agents from tea-leaf extract and apply the Fenton method to degrade the color mixture of rhodamine B and methyl orange. The results show that the highest polyphenols were obtained from tea extract by heating to 90 °C for 80 min. Furthermore, PSA results show that ZVI had a homogeneous size of iron and tea extract at a volume ratio of 1:3. The SEM-EDS results show that all samples had agglomerated particles. The ZVI 1:1 showed the best results, with a 100% decrease in the color intensity of the dye mixture for 60 min of reaction and a degradation percentage of 100% and 66.47% for rhodamine B and methyl orange from LC-MS analysis, respectively. Finally, the decrease in COD value by ZVI was 92.11%, higher than the 47.36% decrease obtained using Fe(II).