Phenolic Compounds Removal from Olive Mill Wastewater Using the Composite of Activated Carbon and Copper-Based Metal-Organic Framework.

As the industry of olive oil continues to grow, the management of olive mill wastewater (OMW) by-products has become an area of great interest. While many strategies for processing OMW have been established, more studies are still required to find an effective adsorbent for total phenolic content uptake. Here, we present a composite of a Cu 1,4-benzene dicarboxylate metal-organic framework (Cu (BDC) MOF) and granular activated carbon (GAC) as an adsorbent for total phenolic content removal from OMW. Experimental results demonstrated that the maximum adsorption capacity was 20 mg/g of total phenolic content (TPC) after 4 h. using 2% wt/wt of GAC/Cu (BDC) MOF composite to OMW at optimum conditions (pH of 4.0 and 25 °C). The adsorption of phenolic content onto the GAC/Cu (BDC) MOF composite was described by the Freundlich adsorption and pseudo-second-order reaction. The adsorption reaction was found to be spontaneous and endothermic at 298 K where ΔS° and ΔH° were found to be 0.105 KJ/mol and 25.7 kJ/mol, respectively. While ΔGº value was -5.74 (kJ/mol). The results of this study provide a potential solution for the local and worldwide olive oil industry.

Photocatalytic Activity of Graphene Oxide/Zinc Oxide Nanocomposites with Embedded Metal Nanoparticles for the Degradation of Organic Dyes.

Nanocomposite materials based on metal nanoparticles and graphene oxide (GO) have gained increasing attention for their wide range of potential applications in various materials science fields. In this study, an efficient photocatalyst based on GO/ZnO nanocomposites with embedded metal nanoparticles was successfully synthesized via a simple one-pot method. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity of the synthesized nanocomposites was tested in the degradation of methylene blue (MB) dyes, as a model of water pollutants. A catalytic activity of 84% was achieved using a nanocomposite with a percentage of 3.125% GO, after 90 min sunlight irradiation. Furthermore, embedded copper and silver nanoparticles were used as dopants to study their effects on the activity of the photocatalyst. The GO-ZnO-Cu nanocomposite showed that the activity toward MB degradation was decreased by 50%, while a significant increase in the activity of MB degradation was achieved by the GO-ZnO-Ag nanocomposite. The removal efficiency of MB by the GO-ZnO-Ag nanocomposite reached 100% after 40 min of sunlight irradiation. Thus, the GO-ZnO-Ag nanocomposite has the potential to be an efficient adaptable photocatalyst for the photodegradation of organic dyes in industrial wastewater.

Ruthenium bis-diimine complexes with a chelating thioether ligand: delineating 1,10-phenanthrolinyl and 2,2'-bipyridyl ligand substituent effects.

Despite the high π-acidity of thioether donors, ruthenium(II) complexes with a bidentate 1,2-bis(phenylthio)ethane (dpte) ligand and two chelating diimine ligands (i.e., Ru(diimine)2(dpte)(2+)) exhibit room-temperature fluid solution emission originating from a lowest MLCT excited state (diimine = 2,2'-bipyridine, 5,5'-dimethyl-2,2'-bipyridine 4,4'-di-tert-butyl-2,2'-bipyridine, 1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 5-chloro-1,10-phenanthroline, 5-bromo-1,10-phenanthroline, 5-nitro-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, and 3,4,7,8-tetramethyl-1,10-phenanthroline). Crystal structures show that the complexes form 2 of the 12 possible conformational/configurational isomers, as well as nonstatistical distributions of geometric isomers; there also are short intramolecular π-π interactions between the diimine ligands and dpte phenyl groups. The photoinduced solvolysis product, [Ru(diimine)2(CH3CN)2](PF6)2, for one complex in acetonitrile also was characterized by single-crystal X-ray diffraction. Variations in the MLCT energies and Ru(III/II) redox couple, E°'(Ru(3+/2+)), can be understood in terms of the influence of the donor properties of the ligands on the mainly metal-based HOMO and mainly diimine ligand-based LUMO. E°'(Ru(3+/2+)) also is quantitatively described using a summative Hammett parameter (σT), as well as using Lever's electrochemical parameters (EL). Recommended parametrizations for substituted 2,2'-bipyridyl and 1,10-phenanthrolinyl ligands were derived from analysis of correlations of E°'(Ru(3+/2+)) for 99 homo- and heteroleptic ruthenium(II) tris-diimine complexes. This analysis reveals that variations in E°'(Ru(3+/2+)) due to substituents at the 4- and 4'-positions of bipyridyl ligands and 4- and 7-positions of phenanthrolinyl ligands are significantly more strongly correlated with σp(+) than either σm or σp. Substituents at the 5- and 6-positions of phenanthrolinyl ligands are best described by σm and have effects comparable to those of substituents at the 3- and 8-positions. Correlations of EL with σT for 1,10-phenanthrolinyl and 2,2'-bipyridyl ligands show similar results, except that σp and σp(+) are almost equally effective in describing the influence of substituents at the 4- and 4'-positions of bipyridyl ligands. MLCT energies and d(5)/d(6)-electron redox couples of the complexes with 5-substituted 1,10-phenanthroline exhibit correlations with values for other d(6)-electron metal complexes that can be rationalized in terms of the relative number of diimine ligands and substituents.

Physicochemical study on microencapsulation of hydroxypropyl-beta-cyclodextrin in dermal preparations.

OBJECTIVE: To investigate the effect of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) concentration on the physicochemical properties of the sunscreen agents, namely oxybenzone (Oxy), octocrylene (Oct), and ethylhexyl-methoxy-cinnamate (Cin), in aqueous solution and cream formulations. METHODS: The inclusion complexes of sunscreen agents with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) in aqueous solution and solid phase were studied by UV-vis spectrophotmetery, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and 13C-NMR techniques. The photodegradation reaction of the sunscreen agents' molecules in lotion was explored using UV-vis spectrophotometry and high-performance liquid chromatography (HPLC). RESULTS: The formation of the inclusion complexes was confirmed experimentally using DSC, SEM, and 13C-NMR. The results of spectrophotometric and HPLC studies have shown that the inclusion complexation with HP-beta-CD has the potential to enhance the photostability of the selected sunscreen agents in lotion. HPLC results indicated that HP-beta-CD has approximately increases the photostability of Oct by six- to eightfold. Moreover, the presence of HP-beta-CD in lotion controlled the isomerization process of Cin to a certain degree, which was found to be a function of the amount of HP-beta-CD added. CONCLUSIONS: It has been demonstrated that the photostability of the tested sunscreen agents has been enhanced upon forming inclusion complexes with HP-beta-CD in lotion. The results of this study demonstrate that HP-beta-CD can be utilized as photostabilizer additive for enhancing the photostability of the sunscreen agents' molecules.

Fluorescence enhancement of carbendazim fungicide in cucurbit[6]uril.

The potential increase in fluorescence of a benzimidazole-type fungicide (carbendazim) due to complexation with cucurbit[6]uril is reported. The fluorescence of the probe carbendazim in aqueous Na2SO4 solution (pH=7.61) at room temperature is found to increase by a maximum factor of approximately 10.0 and blue-shifted up to approximately 11+/-1 nm with the increase in cucurbit[6]uril concentration up to approximately 5 mM. This fluorescence enhancement is the result of formation of a 1:1 guest-host inclusion complex, in which the guest carbendazim is incorporated inside the hydrophobic cavity of the host curbit[6]uril through the amido-ester part. Such mode of inclusion is supported by NMR spectral measurements, in which upon encapsulation, the resonance of the methyl-protons of the amido-ester moiety is shifted significantly to upfield in the (1)H NMR spectrum. Also, to assess the formation of inclusion complex, solid samples prepared by co-evaporation have been studied, using differential scanning calorimetry (DSC). Measurement of the enhancement as a function of cucurbit[6]uril concentrations yielded a value of the equilibrium constant (Ka) of 271+/-10 M(-1) at 25 degrees C. From the temperature dependence of the equilibrium constants, DeltaH and DeltaS values have been negative in sign, indicating the dipole-dipole interactions and the steric factors associated with the formation of this inclusion complex. It might be proposed that the spectral changes due to the inclusion of carbendazim are the result of decrease in the polarity of the surrounded media rather than the loss of carbendazim rotational mobility.