Noureddine Barka

Zn–Al layered double hydroxides intercalated with carbonate, nitrate, chloride and sulphate ions: Synthesis, characterisation and dye removal properties

Abstract In this work, Zn–Al layered double hydroxides intercalated with carbonate, nitrate, chloride and sulphate ions were synthesised via a co-precipitation method at a constant solution pH. The as-synthesised samples were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and simultaneous thermogravimetric/differential thermal analysis (TGA-DTA). The XRD patterns showed that Zn-Al-SO4 had the greatest interlayer spacing, followed by Zn-Al-Cl, Zn-Al-NO3 and Zn-Al-CO3. The FTIR spectra clearly confirmed the presence of intercalated anions in the structure of the LDHs. Batch experiments for methyl orange (MO) adsorption onto synthesised samples were investigated under various conditions such as contact time, initial dye concentration and solution pH. The experimental results show that pH is the most influencing factor. The effective pH range for the MO removal was found to be 3.5–4.5. The kinetics data can be described accurately by a pseudo-second-order kinetic model instead of a pseudo-first-order model. The equilibrium data were analysed using the Langmuir, Freundlich and Dubinin–Radushkevich models. The results showed that the Langmuir and Dubinin–Radushkevich isotherm models fit well to the experimental data. The Zn-Al-LDH samples exhibited exceptional Langmuir maximum adsorption capacities of 2758, 2455, 2270 and 1684 mg/g for Zn-Al-SO4, Zn-Al-Cl, Zn-Al-NO3 and Zn-Al-CO3, respectively.

Kinetics and equilibrium of cadmium removal from aqueous solutions by sorption onto synthesized hydroxyapatite

Abstract Calcium hydroxyapatite (Ca10(PO4)6(OH)2, Hap) was synthesized by a simple and rapid co-precipitation method. The samples were characterized by X-ray diffraction analysis, FT-IR spectral analysis, and transmission electron microscopy coupled energy-dispersive X-ray analysis (transmission electron microscope-energy dispersive X-ray spectrometer). The synthesized Hap was used as an adsorbent for the cadmium ion removal from aqueous solutions in batch mode. The influence of contact time and initial concentration of metal ion was studied and discussed. The equilibrium uptake increases with an increase in the initial cadmium concentration in solution. Adsorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir, Freundlich, Toth, and Tempkin isotherm equations. The best fit was obtained by the Toth model with high correlation coefficients (r 2 > 0.99). The Langmuir model also yielded a good fit to experimental data ...

Potential capability of natural biosorbents: Diplotaxis harra and Glebionis coronaria L. on the removal efficiency of dyes from aqueous solutions

AbstractThis study focuses on the use of natural biomaterials as a good alternative for dyes’ removal from aqueous solutions. For this purpose, two local abundant plants Diplotaxis harra (D. harra) and Glebionis coronaria L. (G. coronaria) were chosen for the biosorption of methylene blue (MB) as a reference dye molecule due to its potential risk toward the environment and ecosystems, and malachite green (MG) representative of textile dyes. Biosorption experiments were carried out in batch mode as a function of solution pH, biosorbent dosage, contact time, initial dye concentration, and temperature. The experimental results show that the process is very rapid and the biosorption yield increases with an increase in the biosorbent dosage. Maximum biosorption capacity occurred at basic pH medium. The temperature doesn’t have much influence on the biosorption yield. Kinetic data were analyzed using pseudo-first and pseudo-second kinetic orders. Equilibrium data were correlated to Langmuir, Freundlich, Temkin,...

Modeling of photocatalytic mineralization of phthalic acid in TiO2 suspension using response surface methodology (RSM)

ABSTRACTThe optimization of operational parameters for enhanced phthalic acid photocatalytic mineralization by TiO2/UV system was conducted using factorial experimental design and analysis. Response surface methodology (RSM) was adopted to investigate the optimum value of the selected factors for achieving maximum photocatalytic mineralization. The main factors studied were the initial concentration of phthalic acid, TiO2 dosage, volume of the solution, and agitation speed. The parameters coded as X1, X2, X3, and X4, consecutively, and were investigated at two levels (−1 and + 1). The effects of individual variables and their interaction effects for dependent variables, namely, the quantity of CO2 formed after 60 min of irradiation were determined. Experimental results showed that TiO2 dosage had significant influence on the photocatalytic mineralization. The optimum quantity of CO2 formed after 60 min of irradiation was 0.08513 mmol, when the operational parameters were phthalic acid concentration of 1 m...

M-Al-SO4 layered double hydroxides (M=Zn, Mg or Ni): synthesis, characterization and textile dyes removal efficiency

AbstractMg–Al, Zn–Al, and Ni–Al layered double hydroxides (LDH) materials with molar ratio (M2+/Al3+) of 3 were synthesized via co-precipitation method. The as-synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and simultaneous thermogravimetric–differential thermal analysis (TGA/DTA). XRD analyses showed that Zn–Al-SO4 had the greatest lattices parameters followed by Mg–Al-SO4 and Ni–Al-SO4. FTIR confirmed clearly the presence of sulfate anions in the structure of LDHs with the presence of carbonate impurity in the interlayer. TGA/DTA analysis indicates a better thermal stability of Zn–Al-SO4 vs. Ni–Al-SO4 and Mg–Al-SO4. The capability of the materials for textile dye removal was investigated using methyl orange (MO) as a model dye and an industrial textile effluent. Experimental results showed that pH is the most affecting factor in dye removal. The effective pH range for dye removal was between 3.5 a...

Optimization of Coagulation/Flocculation Process for Landfill Leachate Treatment Using Box–Behnken Design

Being categorized as high strength wastewater, landfill leachate is a complex mixture of organic and inorganic matters many of which are toxic and harmful. The composition of leachate depends on landfill age, percolation, precipitation and type of solid waste (Narayanasamy et al. in Environ Sci Technol 33(2):482–489, 2014; Kochany and Lipczynska-Kochany in J Hazard Mater 166(1):248–254, 2009).