Younes Moussaoui

Ultrasonic activation of Heck type reactions in the presence of Aliquat-336

Without phosphine and base, palladium catalysts such as PdCl(2), Pd(OAc)(2) and PdCl(2)(PhCN)(2) in water/DMF mixtures with Aliquat-336 proved to be excellent catalytic systems for Heck reactions involving several aryl bromides with styrene and acrylic compounds. Yields are remarkably improved under ultrasonic irradiation and the products show a high purity.

Chemical modification of TiO2 by H2PO4−/HPO42− anions using the sol-gel route with controlled precipitation and hydrolysis: enhancing thermal stability

Two titanium phosphate materials (TpP and ThP) have been successfully synthesized by sol-gel route with controlled precipitation and hydrolysis. The TpP material was obtained from the reaction between precipitated titania and phosphate buffer solution H2PO4− /HPO42− (pH = 7.3). The TpP material was prepared through hydrolysis of titanium in the presence of H2PO4−/HPO42. The probable state of the phosphate anions in titania framework and their effect on the anatase-to-rutile transformation were characterized by ICP-AES, DTA-TG, 31P NMR, FT-IR, and Raman analysis HRTEM/SEM. FT-IR and 31P NMR analyses of titanium phosphate TpP calcined at low temperature showed that the phosphate species existed not only as Ti-O-P in the bulk TiO2 but also as amorphous titanium phosphates, including bidentate Ti(HPO4)2 and monodentate Ti(H2PO4)4. Increased calcination temperature only gave an enrichment of bidentate structure on the titania surface. For the TpP material, H2PO4−/HPO42− anions were introduced into the initial solution, before precipitation, what promoted their lattice localization. At high temperatures, all the phosphorus inside the bulk of TiO2 migrated to the surface. The Raman analysis of both samples showed that the bidentate phosphates increased the temperature of the anatase-to-rutile phase transformation to more than 1000 °C with the formation of well crystalline TiP2O7 phase. This phenomenon was more evident for TpP sample.

Detoxification of 4-chlorophenol in TiO2 sunlight system: effect of raw and treated solution on seed germination and plants growth of various sensitive vegetables

The mineralization and detoxification of 4-chlorophenol (4-CP) were studied using a TiO2-paper/sunlight system. The possibility of reusing the photocatalyst was examined to determine the cost effectiveness of the method. Experiments were performed to establish optimum conditions for 4-CP removal. Phytotoxicity of photo-treated and raw 4-CP (100 mg L−1) solutions on seed germination and plant growth were carried out with the aim of water reuse and environment protection. The seeds irrigated with raw 4-CP solution showed lower sprout length while increase in sprout length was observed with the photo-treated solution for tomato (Lycopersicon esculentum), lettuce (Lactuca sativa), onion (Allium cepa), and turnip (Brassica rapa). Plant growth tests with the photo-treated 4-CP solution did not affect the leaf numbers compared to those irrigated with tap water. Photo-treated 4-CP solution can be used for irrigation in agriculture.

Influence of physico-chemical treatment on the subsequent biological process treating paper industry wastewater.

The present paper presents the main results of the biodegradation study of paper industry wastewater through physico-chemical treatment. Indeed, around 60% of chemical oxygen demand (COD) removal can be achieved by electroflocculation treatment. Furthermore, a removal efficiency of the COD of almost 91% has been obtained by biological treatment, with activated amount of sludge for 24 h of culture. Concerning the physico-chemical pre-treatment of the untreated, filtered and electroflocculated rejection effluents, it has been investigated through the degradation curve of COD studies.

Adsorption of ibuprofen sodium salt onto Amberlite resin IRN-78: Kinetics, isotherm and thermodynamic investigations

Amberlite resin IRN-78 was used for the adsorption of Ibuprofen sodium salt (IBP) from liquid phase. The effects of solvent, initial concentration, solution pH, temperature and contact time were investigated. Adsorption studies were carried out in water and in ethanol. It was found that the adsorption capacity was dependent on pH. The optimum pH range was between 6 and 10. The maximum adsorption capacities on the IRN-78 were 1.266 and 0.611 mmol/g for IBP in water and in ethanol, respectively. The equilibrium data of the adsorption of IBP onto IRN-78 fit well to the Langmuir model. The separation factor (RL) values were in the range of 0-1, indicating that the adsorption was favorable. The values of thermodynamic parameters including ΔG0, ΔH0 and ΔS0 demonstrated that the adsorption of IBP onto IRN-78 was spontaneous and endothermic within the temperature range of 288-308 K. The adsorption process was controlled by physical mechanism rather than chemical mechanism.

Baylis–Hillman Reaction Assisted by aliquat-336 and triphenylphosphine Under Ultrasound Radiation

The activation of Baylis–Hillman reaction by aliquat-336 and triphenylphosphine under ultrasound radiation is described. A significant improvement of the yield of Baylis–Hillman reaction was observed. We illustrate the effects of the solvent, the nature of the nucleophilic agent, the phase transfer catalyst and ultrasound, on the Baylis–Hillman reaction efficiency. The reaction examined involves methyl acrylate, which, in the presence of nucleophilic agent, forms a zwitterionic intermediate, which reacts with the aldehyde to subsequently give the product of the reaction. For all the aldehydes tested, it was found that ultrasound radiation in the presence of aliquat-336 could reduce the duration of the Baylis–Hillman reaction and improve the reaction efficiency. This method could be a clean, economical, efficient and safe technology in organic synthesis to prepare Baylis–Hillman adducts.

Nitrophenol Removal from Wastewater onto Prepared Activated Carbon from Opuntia ficus-indica

p-nitrophenol (p-NP) is a common pollutant that serves as a precursor for many pharmaceuticals, pesticides, petrochemicals and other industries.

NaOH-Activated Carbon Prepared from Date Palm Petiole as Adsorbent for Indigo Carmine

The indigo carmine (IC) is an anionic dye usually used in the textile, food, paper and cosmetic industries. It is one of the most common dyes in wastewater discharged from industries (Hu et al. J Environ Manage 166: 512–518, 2016). Discharge of indigo carmine into the environment may cause skin and eye irritations, injury to cornea and conjunctiva, dermatitis and cancer in humans.

Anodic Oxidation of Chlorinated Pesticides on BDD and PbO 2 Electrodes: Kinetics, Influential Factors and Mechanism Determination

In this work, the removal of two pesticides 1, 2- dichlorobenzene and 1, 4- dichlorobenzene by electrolysis using BDD and Pb/PbO2 as anodes is studied. Different operating conditions and factors affecting the treatment process including anode material, applied current density, supporting electrolyte and initial pH value were studied and optimized. Results demonstrate, as expected, that the influence of the anode material used on the degradation of pesticides was very significant in all cases. Infact electrolysis with diamond electrodes can attain the complete depletion of the pesticide and its mineralization faster than with PbO2 anode. Electrolysis experiments strongly improves that the complete degradation of pesticides occurred in the presence of Na2SO4 as conductive electrolyte at current density equals 20 mA cm-2. Acidic pH would accelerate dichlorobenzene degradation, whereas alkaline condition showed negative effects. The disappearance of the pesticides followed a pseudo-first-order kinetics. Reversed-phase chromatography allows detecting Catechol, 2-chlorophenol and Pyrogallol as primary aromatic intermediates of 1,2-DCB and Hydroquinone, Benzoquinone and 4-chlorophenol for 1,4-DCB. Dechlorination of these products gives chloride ions Cl-. Ion-exclusion chromatography reveals the presence of maleic, formic, fumaric, malonic, glyoxylic, acetic and oxalic acid. An oxidation mechanism is proposed in agreement with other works shown in the literature.

Removal of barium and strontium from aqueous solution using zeolite 4A

The adsorption efficiency of Sr(2+) and Ba(2+) from aqueous solutions by zeolite 4A was investigated. Adsorption studies were carried out both in single and binary component systems. The single ion equilibrium adsorption data were fitted to three isotherm models: Langmuir, Freundlich and Dubinin-Radushkevich. The Langmuir model represents the equilibrium data better than the Freundlich model in the studied initial metal concentration (0.3-25 mmol L(-1)) in both the single and binary component systems. The obtained RL (separation factor or Langmuir parameter) values were in the range of 0-1 indicating that Sr(2+) and Ba(2+) sorption were favorable. The obtained mean free energy value for adsorption of Ba(2+) and Sr(2+) was 8.45 kJ mol(-1) and 9.12 kJ mol(-1), respectively, indicating that both ions were uptaken through an ion exchange process. The maximum adsorption capacities (Qmax) were 2.25 mmol g(-1) and 2.34 mmol g(-1) for Ba(2+) and Sr(2+) ions, respectively. Also, the study of the competitive sorption of ions in the binary system showed that zeolite 4A preferentially adsorbs cations in the following order: Ba(2+) < Sr(2+).