Mohamed El-Hadi Samar

Pillared clays as catalysts for methyl parathion removal by advanced oxidation processes

A natural bentonite from Mostaganem in Algeria was modified by intercalation with polyoxocationic solutions (Al·Fe, Al·Co, Al·Cu, Al·Fe·Cu or Al·Fe·La). The modification of the bentonite occurred via pillaring by ionic exchange with these solutions. The addition of these solutions led to the formation of pillared clays with important catalytic properties in environmental impact reactions. The structural and textural properties of materials calcined at 500 °C were determined by several techniques: X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and N2 adsorption–desorption analysis. The pillared clays were then used as a Fenton-type heterogeneous catalyst for the heterogeneous sono-Fenton process for the oxidation of methyl parathion in water. The catalytic tests revealed the activity of the introduced iron species and the promoter effect of lanthanide or copper on the catalytic activity of these species. The sono-Fenton method showed promising results for the degradation of methyl parathion when compared with the Fenton method. Therefore, the sono-Fenton method can be a viable alternative technology to the existing methods for treating methyl parathion in wastewater.

Effects of operator parameters, anions and cations on the degradation of AY99 in an aqueous solution using Fenton’s reagent. Optimization and kinetics study

In the present work, the decolourization of azo dye Acid Yellow 99 (AY99) in an aqueous solution by Fenton oxidation process was investigated. The results indicated that the initial pH, the nature of the acid to adjust pH, the temperature and the initial concentrations of the Fenton’s reagent FeSO4 of H2O2 and of the AY99 played an important role on the dye decolourization. It was found that under optimum conditions, which have been determined to be pH = 3, [H2O2]0 = 1.8 mmol/L, [Fe2+]0 = 0.09 mmol/L, [AY]0 = 0.06 mmol/L and T = 30°C, efficiency of degradation obtained after 40 min of reaction was about 95%. The decolourization of AY99 by the Fenton process followed the second-order reaction kinetics. The empirical kinetic equation for AY99 decolourization under the conditions of 0.03 to 0.15 mmol/L of Fe2+, 0.9 to 1.8 mmol/L of H2O2, 0.03 to 0.15 mmol/L of Acid Yellow and pH = 3 was found to follow the relation:K = 6.39 × 107 [AY] −2.8[H2O2]2.29[FeSO4]0.837 exp (−7021.3/T).The decolourization efficiency Ef (in percent) was 88.36%, 87.93%, 85.98% and 39.61% in the presence of H2SO4, HNO3, HCl and H3PO4 acids, respectively. We can deduce that H2SO4, HNO3 and HCl acids lead almost to the same efficiency (Ef), but in the presence of H3PO4, it is too low:Ef (H2SO4) ~ Ef (HNO3) > Ef (HCl) > > Ef (H3PO4).Effects of additives such as inorganic salts (sodium chloride, calcium chloride, sodium sulphate and calcium sulphate) and cations (sodium sulphate, calcium sulphate, copper sulphate, manganese sulphate and magnesium sulphate) on the efficiency (Ef) and on the rate constant (k2) of AY99 degradation were also studied under optimum conditions.Ef (Na2SO4) > Ef (CaSO4) > Ef (NaCl) > Ef (CaCl2)k2 (CaCl2) < k2 (NaCl) < k2 (CaSO4) < k2 (Na2SO4)Ef (ZnSO4) > Ef (MgSO4) > Ef (Na2SO4) > Ef (CaSO4) > Ef (CuSO4) > Ef (MnSO4)k2 (Na2SO4) < k2 (MnSO4) < k2 (CuSO4) < k2 (CaSO4) < k2 (ZnSO4) < k2 (MgSO4).The presence of anions and cations in the aqueous solution decreases the decolourization efficiency and the rate constant of the degradation of AY99. This inhibition may be due to a complexation and a radical scavenging.

A method of making an aqueous dispersion of polyaniline and inhibiting corrosion in cooling water

Abstract The present study provides a process for the dispersion of polyaniline after its synthesis, to improve the solubility of the polyaniline in an aqueous medium in the presence of nonionic surfactant (fatty alcohol ethoxylate). The surfactant selected based on their chemical composition and their Hydrophile-Lipophile-Balance and the induced steric hindrance effect. The dispersion process was developed, and the polyaniline dispersion was characterized by the electrical conductivity and in the macroscopic phase boundary. The polyaniline dispersions have been studied for their possible use in such fields as a corrosion inhibitor. In our case, the corrosion inhibitor was employed in industrial cooling water, which contains hardness and operating at temperature of 41°C and pH of 8.7. The weight-loss and corrosion polarization resistance (corrater system) methods were carried out to study the corrosion of carbon steel. Inhibition efficiencies of nearly 80% have been observed even at as low concentration o...

Recovery of 4-chlorophenol from an aqueous solution by ELM: stability of the membrane, modeling, and optimization of the extraction using experimental designs

AbstractAn emulsified liquid membrane has been developed for the extraction of the 4-chlorophenol (4-CP) from an aqueous effluent. The membrane used was an emulsion of water in oil (W/O), the internal phase was an alkaline solution (NaOH), and the organic phase was a mixture of a surfactant (SPAN 80) and an extractant (TBP) dissolved in an organic solvent (heptane). The only limitation of this technique was the stability of the membrane (swelling, cohesion, and rupture). To optimize the different parameters that have a direct influence on the stability of the membrane, experiments were conducted using a fractional factorial design of Plackett–Burman. The obtained results showed the behavior of the emulsified membrane under different operating conditions. Among the different factors studied, the concentrations of SPAN 80 of TBP and the stirring velocity appeared to be the most important parameters. Indeed, a high yield above 99% almost a total elimination of 4-CP was achieved under optimized operating cond...

Phenol photodegradation process assisted with Wells–Dawson heteropolyacids

AbstractThis work aims to investigate the catalytic properties of the heteropolyacids (HPAs) within photocatalytic process. Photocatalytic degradation of phenol in aqueous solution was performed using Wells–Dawson HPAs as catalysts under UV-illuminated condition at 254 nm. The effects of various parameters such as, concentration of catalyst, initial pH, and initial phenol concentration on the performance of photocatalytic process have been investigated to obtain the efficient and durable catalysts and determine the better reaction conditions. The kinetics and the efficiency of phenol degradation were determined by various analytical techniques, such as HPLC and TOC. The results show that the photocatalytic degradation efficiency increases with decreasing pH and the optimum pH is 2 for both catalysts. The photodegradation follows pseudo-first-order kinetics with rate constants k = 8.56 × 10−2 and 9.94 × 10−2 min−1 for iron- and vanadium-substituted HPAs, respectively.

Kinetics study and neural network modeling of degradation of Naphtol Blue Black by electro-Fenton process: effects of anions, metal ions, and organic compound

AbstractIn the present work, the degradation of azo dye Naphtol Blue Black (NBB) in aqueous solution by electro-Fenton process was investigated. The results indicated that the degradation of NBB by electro-Fenton process followed the second-order reaction kinetics. The experimental results were also modeled by artificial neural network (ANN) with mean squared error of 10−5. This model was developed in Matlab using a feed forward back propagation network; multi-layered perceptron. The input variables to the feed-forward neural network were as follows: initial Fe3+ concentration, initial pH, concentration of Na2SO4, temperature, applied current, and initial dye concentration. The degradation efficiency and rate constant were chosen as the experimental responses or output variables. The findings indicated that ANN provided reasonable predictive performance (R2 > 0.99). Effects of additives such as anions, metal ions, and organic compound on the efficiency and on the rate constant of NBB degradation were also...