Mahjoub Jabli

New chitosan microspheres supported [bis(2-methylallyl)(1,5-cyclooctadienne)ruthenium(II)] as efficient catalysts for colour degradation in the presence of hydrogen peroxide

This paper concerns the immobilisation of either [bis(2-methylallyl)(1,5-cyclooctadienne)ruthenium(II)] (I) or ruthenium chloride (RuCl3) (II) on chitosan microspheres (catalyst I and catalyst II, respectively). These heterogenised catalysts were used for the oxidative degradation of two acid dyes, i.e. [Calmagite (Calma) and Acid Blue 25 (AB25)] in aqueous solution at pH 7.0 in the presence of hydrogen peroxide (H2O2). Prepared solid supports were characterised by Fourier transform infrared (FTIR) spectral study, thermogravimetry (TG), differential thermogravimetry (DTG) and differential scanning calorimetry (DSC) analyses. The efficiency of decolourisation was justified using UV–visible spectroscopic analysis. The factors affecting dye degradation were studied. Some tests for Calma decolourisation achieved up to 100% colour removal using catalyst I. The pseudo first-order equation was shown to fit degradation kinetics in most cases. However, for some cases, it was necessary to use a reversible equation. The energetic parameters were determined and the activation energy (E a) was found to be low, between 11 and 36 kJ mol−1, confirming that these catalysts were very efficient for the degradation of anionic dyes using H2O2. The interpretation of the equilibrium sorption data complies well with the Freundlich adsorption model. The combination of adsorption process and catalytic oxidation made the new developed catalyst systems to achieve a simple and efficient water treatment.

Dimethyl diallyl ammonium chloride and diallylamin Co-polymer modified bio-film derived from palm dates for the adsorption of dyes

For the first time, co-polymer of dimethyl diallyl ammonium chloride and diallylamin (PDDACD) was used to modify the films derived from the waste of palm date fruits, which were then investigated by the purification of colored aqueous solutions. The physico-chemical characteristics were identified using data color, FT-IR spectroscopy, and SEM features. The modified films were evaluated as adsorbents of Methylene Blue (MB), Direct Yellow 50 (DY50), Reactive Blue 198 (RB198) and Naphtol Blue Black (NBB). High retention capacities were achieved in the following order: The equilibrium da DY50 (14 mg g−1) < RB198 (16 mg g−1) < NBB (63.9 mg g−1) < MB (150 mg g−1). The kinetic modeling of the data revealed that the adsorption data follows the pseudo second order model. It was fitted to the Langmuir, Freundlich, Temkin, and Dubinin-Redushkevich equations, and the data best fit the Freundlich model indicating that the adsorption might occur in the heterogeneous adsorption sites. These results reveal that PDDACD modified films are valuable materials for the treatment of industrial wastewater. Moreover, the as-prepared adsorbent is economically viable and easily controllable for pollutant adsorption.

A comparative study on the performance of dye removal, from aqueous suspension, using (2-hydroxypropyl)-β-cyclodextrin-CS, PVP-PVA-CS, PVA-CS, PVP-CS and plain CS microspheres

This paper reports the results of the study on the performance of the removal of Cibacron Brilliant Yellow 3G-P and Calmagite, from aqueous solution, using either prepared 2-hydroxypropyl-β-cyclodextrin-chitosan [HPβCD-CS], poly(vinylalcohol)-polyvinylpyrrolidone-chitosan [PVA-PVP-CS], Poly(vinylalcohol)-chitosan [PVA-CS], polyvinylpyrrolidone-chitosan [PVP-CS] or plain chitosan microspheres [CS]. Modified CS molecules were analysed using FT-IR and TG-DTA techniques. Adsorption experiments were carried out and compared through varying mass ratio, contact time, initial dye concentration and temperature. Among the five studied adsorbents, the highest adsorption capacity was reached using HPβCD-CS. Kinetic equations were applied and the first-order model was shown to fit the adsorption phenomenon. The applicability of Langmuir, Freundlich, Temkin and Dubinin–Radushkevich equations was tested and the Langmuir isotherm exhibited the best fit with the experimental data. Data gleaned from both modelling and thermodynamic results indicate that the adsorption follows a physical and exothermic process.

Synthesis and Characterization of a New Racemic Helically Chiral Ru(II) Complex and Its Catalytic Degradation of Eriochrome Blue Black B

Abstract A new helically chiral ruthenium complex of fused aromatic rings was prepared in a one stepsequence and fully characterized. The new complex was used as an heterogeneous catalyst for the degradation of Eriochrome Blue Black B (one of the azoic dyes) in aqueous medium in the presence of hydrogen peroxide. Using a fixed dose of H2O2, experiments revealed that the dye degradation was affected by the reaction temperature and the initial dye concentration. The energetic parameters were also determined, and the activation energy (E a) was found to be low (31 kJ mol−1), confirming that the prepared catalyst was very efficient for the degradation of anionic dyes using H2O2. The complex exhibited excellent catalytic activity and has the advantage of easy separation from the reaction medium. In addition, the ruthenium helical complex–H2O2 system could remain with good catalytic activity after five cycles. GRAPHICAL ABSTRACT

New Helically Chiral Metallated Complexes: Characterization and Catalytic Activity

Abstract New helically chiral and air-stable Pd(II) and Ru(II) complexes were prepared in good yields and fully characterized. The optical properties of these new complexes were investigated, showing interesting behavior. The Ru complex was used as heterogeneous catalyst for the decoloration of calmagite (one of the azoic dyes) solutions at pH 6.5 in the presence of hydrogen peroxide (H2O2). Experiments revealed that the decoloration process was affected by the H2O2 dose, the reaction temperature, and the initial dye concentration. The energetic parameters were also determined and the activation energy, E a, was found to be low, confirming that the prepared catalyst was very efficient for color removal. The new ruthenium complex exhibited excellent catalytic activity and has the advantage of easy separation from the reaction medium. It could remain with good catalytic activity after five cycles. GRAPHICAL ABSTRACT

Removal of a wide range of dyes using 4-methyl-2-(naphthalen-2-yl)-N-propylpentanamide-functionalized ethoxy-silica and raw silica

Abstract The present research offers a comparative study on the character of the performance of dye removal using either functionalized silica or raw silica gel as adsorbents. First, these supports were characterized in terms of FT-IR and SEM analyses. Then, four different dye solutions were checked for the adsorption phenomenon: Eriochrome Black B (an acid dye), Methylene Blue (a basic dye), Direct Yellow 50 (a direct dye), and Reactive Blue 49 (a reactive dye). Experimental data revealed a dependence on the experimental conditions. Functionalized silica presented a higher removal of dyes than the raw silica. Among the four studied dyes, the highest capacity removal was achieved with Eriochrome Blue Black B (140 mg g−1) using functionalized silica as adsorbent. This value was reduced to 55 mg g−1 for raw silica. Further, kinetic and thermodynamic investigations of Eriochrome were discussed. Results gleaned from this study suggest that the functionalized silica could be considered as an efficient candidate to treat colored waters.

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

Summary The present paper describes the synthesis of new palladium–oxazoline complexes in one step with good to high yields (68–95%). The oxazolines were prepared from enantiomerically pure α-aminoalcohols. The structures of the synthesized palladium complexes were confirmed by NMR, FTIR, TOFMS, UV–visible spectroscopic analysis and X–ray diffraction. The optical properties of the complexes were evaluated by the determination of the gap energy values (E g) ranging between 2.34 and 3.21 eV. Their catalytic activities were tested for the degradation of Eriochrome Blue Black B (a model of azo dyes) in the presence of an ecological oxidant (H2O2). The efficiency of the decolorization has been confirmed via UV–visible spectroscopic analysis and the factors affecting the degradation phenomenon have been studied. The removal of the Eriochrome reached high yields. We have found that the complex 9 promoted 84% of color elimination within 5 min (C 0 = 30 mg/L, T = 22 °C, pH 7, H2O2 = 0.5 mL) and the energetic parameters have been also determined.

Physico-chemical characteristics of a seed fiber arised from Pergularia Tomentosa L.

In the present paper, we analyze a seed fiber arising from Pergularia tomentosa L. (PTL). It was, primarily, characterized using different techniques. The morphology of the fibers was observed via Scanning Electron Microscopy (SEM). They are also checked in term of decomposition behavior through TGA/DTG instrument. The cristallinity index was determined using XRD and it was about 52 %. The chemical composition in terms of moisture percent, ash, waxes and fats, lignin, hemicellulose and cellulose were, respectively 8.5 %, 2.74 %, 1.88 %, 8.6 %, 16 % and 43.8 %. The contact angle value was measured and the evolution of drop profile was captured with video-camera using GBX Tensiometer Surfaces Sciences Studies. Further, fibers were dyed with Methylene Blue, Direct Red 79, Sumifix supra yellow 3RF and Reactive Blue 198. Color coordinates (ΔL*, Δa*, Δb*, ΔC* and ΔH*) of the samples were so measured. All obtained data were compared to cotton fibers and some other cellulosic fibers. The Results revealed that, based on such properties, PTLF could be a competitive fiber in many applications field (textile weaving, composites, etc).

Tetrakis(ethyl-4(4-butyryl)oxyphenyl)porphyrinato zinc complexes with 4,4′-bpyridin: synthesis, characterization, and its catalytic degradation of Calmagite

This work reports on the synthesis and characterization of a new porphyrins complex:[Zn(TEBOP)(4,4′-bpy)](4,4′-bipyridine)(5,10,15,20-(tetraethyl-4(4-butyryl)oxyphenyl)porphyrinato)zinc(II) (3). Single crystal X-ray diffraction, photophysical and electrochemical characteristics were studied. The prepared complex, penta-coordinated zinc(II) porphyrin derivatives shows moderate ruffling distortion and the zinc atom is nearly planar with the porphyrin core. Tolyl and ethyl-4(4-butyryl)oxyphenyl) moieties at the meso positions present a bathochromic shift of the absorption bands, and a notable increase in the absorption coefficient of the Q(0,0) and Q(0,1) bands was observed with a higher fluorescence quantum yield and lifetime compared with the free base porphyrin. The electrochemical investigation shows a reversible reduction of the synthesized complexes. The catalytic power and the adsorption properties of the prepared complexes were studied for Calmagite degradation, an azoic organic dye. The results reveal that the studied compounds could be used as catalysts for the decolourisation of dyes in the presence of H2O2.

Preparation, characterization and evaluation of the catalytic power of an hybrid compound [H3PMo12O40-chitosan] for the azoic-colored solutions

Abstract Inorganic–organic hybrid structures have become novel alternatives for many applications as they combine the advantages of both systems. In this current study, a hybrid compound [H3PMo12O40-chitosan] was prepared using a wet impregnation method with different proportions (0-100 wt. %, considering the polymer as the main component). The chemical structure and the morphology of the synthesized compounds were studied using FT-IR and SEM. Their catalytic powers were evaluated for Naphtol Blue Black and Eriochrome Blue Black B. Experimental data revealed that the decolorization phenomenon depends on the structure of the dye it-self, the pH value, the initial dye concentration, the time contact, the oxidant dose and the temperature. Kinetic data, well described using the first order model, allowed us to establish the thermodynamic parameters. The calculated low values of Ea (7.48 and 8.14 KJ. mol-1) proved the efficiency of the prepared catalyst. Eriochrome Blue Black B could be decomposed more rapidly than Naphtol Blue Black. As example, after a period of 30 min of reaction, the target removals were, respectively, 70% and 15% for mono and bi-azoic dyes. The reuse of the catalyst is carried out and it was found to be recyclable more than three consecutives cycles.