Response surface methodological approach for the assessment of the photocatalytic degradation of NOM

In this paper, statistics-based experimental design with response surface methodology (RSM) was employed to investigate the effects of operational conditions on the photocatalytic oxidation of humic acid as a model compound of natural organic matter. Considering the vast number of the obtained experimental data, in this study, a correlative approach was employed for the assessment of the photocatalytic degradation efficiency of humic acids (HA) using an empirical method for the optimization of the key parameters such as photocatalyst dose, pH and humic acid concentration. The results of this study revealed that the regression analysis showed a close fit (R-2 > 0.83) between the experimental results and the model predictions. Maximum DOC removal was achieved as 89.3% under the experimental conditions of 30 mg/L humic acid, 2.0 mg/mLTiO(2) and pH = 7. Under acidic conditions (pH = 5), and in the presence of 1.0 mg/mLTiO(2) almost complete removal of UV absorbing centers were attained for 30 mg/L humic acid. Exhaustive decolorization was attained under alkaline conditions (pH = 8), for the photocatalyst loading of 1.5 mg/mLTiO(2) for 18.5 mg/L humic acid. The role of the irradiation period on the removal efficiency of the specified parameters were expressed by the relation between the predicted values attained for irradiation periods (40 min and 60 min) that were presented by the correlation coefficients as R-2 = 0.847, 0.691 and 0.700 for DOC. UV254 and Color(436) respectively. Moreover, model verification was also reported for a selected humic acid substrate and a specified photocatalyst specimen. (C) 2011 Elsevier B.V. All rights reserved

Enhanced ozonation of selected pharmaceutical compounds by sonolysis

In search of new options to achieve removal of pharmaceuticals in the environment, combined ultrasound and ozonation has become a focus of intense investigation for wastewater treatment. In this study, three pharmaceuticals were selected as model compounds for degradation experiments: diclofenac (DCF), sulfamethoxazole (SMX) and carbamazepine (CBZ). Comparison of the degradation rates for both ozonation and combined ultrasound/ozonation treatments was performed on single synthetic solutions as well as on a mixture of the selected pharmaceuticals, under different experimental conditions. For single synthetic solutions, the efficiency removal for ozonation reached 73%, 51% and 59% after 40 min for DCF, SMX and CBZ, respectively. Comparable results were obtained for pharmaceuticals in mixture. However, the combined ultrasound/ozone treatment was found to increase degradation efficiencies for both DCF and SMX single solutions up to 94% and 61%, respectively, whereas lower removal yields, up to 56%, was noted for CBZ. Likewise, when the combined treatment was applied to the mixture, relatively low removal efficiencies was found for CBZ (44%) and 90% degradation yield was achieved for DCF

Application of Fe-doped TiO2 specimens for the solar photocatalytic degradation of humic acid

This study aimed to assess solar photocatalytic activity of Fe-doped TiO2 specimens for the degradation of natural organic matter (NOM) represented by a model humic acid (HA). Fe-doped TiO2 specimens (P-25 and UV-100) were prepared by a wet impregnation method. Humic acid (molecular size < 100 kDa) was characterized by UV-vis and fluorescence spectroscopic parameters and dissolved organic carbon (DOC) content both prior to and following solar photocatalysis. Molecular size fractionation data revealed a shift to lower molecular size fractions i.e.: 30 kDa, 10 kDa and 3 kDa being more pronounced in case of Fe-doped UV-100 in comparison to Fe-doped P-25. Excitation-emission matrix (EEM) fluorescence features of indicated humic molecular size fractions did not illustrate any significant difference related to the formation of new fluorophoric regions but displayed the shift from humic-like fluorophores to fulvic-like fluorophores even in 3 kDa fraction indicating that humic acid followed a photocatalyst type independent pathway via solar photocatalysis. Slower DOC removal rates were attained for Fe-doped TiO2 specimens with respect to bare specimens indicating the importance of substrate properties rather than the inefficiency of visible light activation by metal doping of photocatalyst. (C) 2016 Elsevier B.V. All rights reserved.Research Fund of Bogazici UniversityBogazici University [6729, 6750]The financial support by Research Fund of Bogazici University (Projects No: 6729 and 6750) is gratefully acknowledged

Report on Influence of conflict, gender, and class relations on availability of water in the household

This review essay lays out the conceptual and historical groundwork for the primary research that the WATERSPOUTT social science team will carry out through the project period over four research sites in Ethiopia, Malawi, South Africa and Uganda. We have described it as a report synthesising secondary data on conflict, gender, and class relations in the four case study areas. However, it is emphatically not intended as an exhaustive description of the specificities of the four research sites – the sections that follow will traverse quite unevenly across these regions. The essay will instead offer an overarching reading of how these research sites are situated within wider structures and relationships of power. It will engage the recurrent themes and key debates that have dominated the relevant literatures in the fields of social theory and historical and social studies in order to build a broad foundation of understanding for the empirical research that is to come

Report on Influence of conflict, gender, and class relations on availability of water in the household

This review essay lays out the conceptual and historical groundwork for the primary research that the WATERSPOUTT social science team will carry out through the project period over four research sites in Ethiopia, Malawi, South Africa and Uganda. We have described it as a report synthesising secondary data on conflict, gender, and class relations in the four case study areas. However, it is emphatically not intended as an exhaustive description of the specificities of the four research sites – the sections that follow will traverse quite unevenly across these regions. The essay will instead offer an overarching reading of how these research sites are situated within wider structures and relationships of power. It will engage the recurrent themes and key debates that have dominated the relevant literatures in the fields of social theory and historical and social studies in order to build a broad foundation of understanding for the empirical research that is to come

Report on Influence of conflict, gender, and class relations on availability of water in the household

This review essay lays out the conceptual and historical groundwork for the primary research that the WATERSPOUTT social science team will carry out through the project period over four research sites in Ethiopia, Malawi, South Africa and Uganda. We have described it as a report synthesising secondary data on conflict, gender, and class relations in the four case study areas. However, it is emphatically not intended as an exhaustive description of the specificities of the four research sites – the sections that follow will traverse quite unevenly across these regions. The essay will instead offer an overarching reading of how these research sites are situated within wider structures and relationships of power. It will engage the recurrent themes and key debates that have dominated the relevant literatures in the fields of social theory and historical and social studies in order to build a broad foundation of understanding for the empirical research that is to come