Degradation of high level m-cresol by zinc oxide as photocatalyst

In this study, the high concentration of m-cresol as a sample of organic pollutants was degraded in the presence of zinc oxide and UV irradiation during 6 h at laboratory scales. The amount of photocatalyst, pH and m-cresol concentration were considered as effective factors on the photodegradation. The demineralization of m-cresol was measured by UV–Vis spectrophotometry while the total organic carbon-analyzer was used to determine the mineralization. The ultrahigh performance LC was used to identify probable intermediates. The results showed optimum condition at pH 7–9, which is the natural pH of industrial wastewater. Moreover, 100% of m-cresol was removed after 5 h of irradiation time, which is quite significant. The detected intermediates were 3,5-hydroxytoluene, 2,5-hydroxy-benzaldehyde, and 3-hydroxy-benzaldehyde after 3 h of reaction time. Reusability of the photocatalyst showed insignificant reduction in the photo-catalytic performance. In conclusion, this investigation indicated high potential of zinc oxide suspension to remove high level concentration of m-cresol under UV irradiation

Enhanced photodegradation of o-cresol in aqueous Mn(1%)-doped ZnO suspensions

The effective removal of o-cresol is currently both an environmental and economic challenge. ZnO is not only an efficient photocatalyst but is also cost effective, as its photoabsorption can extend from the ultraviolet (UV) to the visible range thereby allowing the use of inexpensive visible light sources, such as sunlight. The principal objective of the present work is to investigate the visible light-driven removal of o-cresol from aqueous solution in the presence of 1.0 wt% Mn-doped ZnO. To measure the efficiency of photodegradation, the variables studied included the amount of photocatalyst, concentration of o-cresol, pH and irradiation time. The concentration of o-cresol and residual organic carbon was monitored using a UV-visible spectrophotometer, ultra high-pressure liquid chromatography and a total organic carbon analyser. The optimum conditions under which the photodegradation of o-cresol was most favourable corresponded to 1.5 g/l ZnO, 35 ppm o-cresol and pH 9. The ZnO-1wt%Mn photoprocess has demonstrated reusability for more than three times, which warrants its scale-up from laboratory- to in industrial-scale application

A conductometric study of complexation reaction between meso-octamethylcalix[4]pyrrole with titanium cation in acetonitrile-ethanol binary mixtures.

The equilibrium constants and thermodynamic parameters for complexation process between titanium (III) cation and meso-octamethylcalix[4]pyrrole were determined by conductivity measurements in acetonitrile–ethanol (AN–EtOH) binary mixture at different temperatures. The conductance data show that the stoichiometry of the (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex in all binary mixed solvents is 1:1[I:M]. The stability of the formed complex is sensitive to the solvent composition and a non-linear behavior was observed for changes of log Kf of this complex versus the composition of the binary mixed solvents. The values of thermodynamic parameters (Hc and Sc) for formation of (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex were obtained from temperature dependence of the stability constant using van’t Hoff plots. The obtained results show that the formed complex is enthalpy destabilized, but entropy stabilized and a non-monotonic behavior was observed for variations of standard enthalpy and entropy changes versus the composition of the binary mixed solvents

A conductometric study of complexation reaction between meso-octamethylcalix[4]pyrrole with titanium cation in acetonitrile-ethanol binary mixtures.

The equilibrium constants and thermodynamic parameters for complexation process between titanium (III) cation and meso-octamethylcalix[4]pyrrole were determined by conductivity measurements in acetonitrile–ethanol (AN–EtOH) binary mixture at different temperatures. The conductance data show that the stoichiometry of the (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex in all binary mixed solvents is 1:1[I:M]. The stability of the formed complex is sensitive to the solvent composition and a non-linear behavior was observed for changes of log Kf of this complex versus the composition of the binary mixed solvents. The values of thermodynamic parameters (Hc and Sc) for formation of (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex were obtained from temperature dependence of the stability constant using van’t Hoff plots. The obtained results show that the formed complex is enthalpy destabilized, but entropy stabilized and a non-monotonic behavior was observed for variations of standard enthalpy and entropy changes versus the composition of the binary mixed solvents

Microfluidic paper-based analytical devices (µPADs) for fast and ultrasensitive sensing of biomarkers and monitoring of diseases

Through the development of analytical techniques, microscaled devices have displayed attractive advantages, including ultrasensitive detection and analysis, cost-effectiveness, portability, process integrity, multi-process functionality, and in-situ analysis. In the last decade, a new generation of analytical devices has emerged based on the cellulose materials – so-called microfluidic paper-based analytical devices (µPADs) – a field that will change the face of the diagnosis of different diseases and sensing of a wide range of biological/chemical/biochemical phenomena. The main aim of the current editorial is to highlight the importance of the µPADs in the research and development of diagnostic devices and pharmaceuticals

Antifungal properties of phenyl fatty hydroxamic acids and their copper complexes synthesized based on canola and palm kernel oils

Phenyl fatty hydroxamic acids (PFHAs) were synthesized by phenyl hydroxylaminolysis of canola or palm kernel oils using lipozyme TL IM as catalyst. Copper complexes of phenyl fatty hydroxamic acids (copper phenyl fatty hydroxamate (Cu-PFHs)) acids were prepared by stirring the phenyl fatty hydroxamic acids which were dissolved in hexane and copper(II) nitrate solution. The antifungal properties of phenyl fatty hydroxamic acids and its copper(II) complex Cu-PFHs based on canola and palm kernel oils were separately investigated against Candida parapsilosis, Candida albicans and Aspergillus fumigatus by the disc diffusion method using Mueller-Hinton agar. The results showed that antifungal activity of Cu-PFHs is higher than phenyl fatty hydroxamic acids do and also the activity of phenyl fatty hydroxamic acids and Cu-PFHs increase while their concentrations increase. The antifungal activity of phenyl fatty hydroxamic acids and Cu-PFHs are significantly higher than nystatin while use against the A. fumigatus, C. parapsilosis and C. albicans and also are significantly higher than ketoconazole while use against the A. fumigatus

Photodegradation of m-cresol by zinc oxide under visible-light irradiation.

The photodegradation of m-cresol was carried out under visible light (46% sunlight) by ZnO as photocatalyst. To measure the efficiency of photodegradation, the different variables studied included amount of photocatalyst, concentration of m-cresol and pH. The maximum amount of photocatalyst and concentration of m-cresol was 1.5 g/L and 25 ppm respectively. The photodegradation was favorable in the pH 6-9 range. The detected intermediates were 2-methyl-1,4-benzodiol, 2-methyl-para-benzoquinone, 3,5-dihydroxytoluene and 2,5-dihydroxy-benzaldehyde. TOC studies show that 78% of total organic carbon is removed from solution during irradiation time. This study indicates the great potential of ZnO to remove aqueous m-cresol under visible-light irradiation which is part of sunlight

Photodegradation of m-cresol by zinc oxide under visible-light irradiation.

The photodegradation of m-cresol was carried out under visible light (46% sunlight) by ZnO as photocatalyst. To measure the efficiency of photodegradation, the different variables studied included amount of photocatalyst, concentration of m-cresol and pH. The maximum amount of photocatalyst and concentration of m-cresol was 1.5 g/L and 25 ppm respectively. The photodegradation was favorable in the pH 6-9 range. The detected intermediates were 2-methyl-1,4-benzodiol, 2-methyl-para-benzoquinone, 3,5-dihydroxytoluene and 2,5-dihydroxy-benzaldehyde. TOC studies show that 78% of total organic carbon is removed from solution during irradiation time. This study indicates the great potential of ZnO to remove aqueous m-cresol under visible-light irradiation which is part of sunlight

Photodegradation of p-cresol by zinc oxide under visible light

The degradation of p-cresol was carried out under visible light (46% sunlight) by zinc oxide as photocatalyst. To measure the efficiency of photodegradation, the different variables studied included amount of photocatalyst, concentration of p-cresol and pH. The maximum amount of photocatalyst and removed p-cresol was 1.5g/L and 25ppm respectively. The photodegradation was favorable in the pH 7-9 range. In optimum condition, total organic carbon (TOC) studies show that 94% of total organic carbon is removed from solution during irradiation time. As a result zinc oxide can remove p-cresol from wastewater under visible light irradiation, and being more economic than UV light could be applied on an industrial scale

Comparison of estimation capabilities of the artificial neural network with the wavelet neural network in lipase-catalyzed synthesis of triethanolamine-based esterquats cationic surfactant

In this study, estimation capabilities of the artificial neural network (ANN) and the wavelet neural network (WNN) based on genetic algorithm were investigated in a synthesis process. An enzymatic reaction catalyzed by Novozym 435 was selected as the model synthesis process. The conversion of enzymatic reaction was investigated as a response of five independent variables; enzyme amount, reaction time, reaction temperature, substrates molar ratio and agitation speed in conjunction with an experimental design. After training of the artificial neurons in ANN and WNN, using the data of 30 experimental points, the products were used for estimation of the response of the 18 experimental points. Estimated responses were compared with the experimentally determined responses and prediction capabilities of ANN and WNN were determined. Performance assessment indicated that the WNN model possessed superior predictive ability than the ANN model, since a very close agreement between the experimental and the predicted values was obtained