The study is about the degradation of a widely used anti-inflammatory drug-diclofenac (DCF) by high frequency ultrasound to select the operating conditions and to improve the process efficiency by the addition of iron species. The initial concentration, pH and frequency of operation that rendered maximum degradation of the drug were 30 μM, 3.0 and 861 kHz, respectively. The efficacy (EF) of each additive was expressed by a "yield factor" defined as the change in DCF concentration in 1-h sonication per unit mass of Fe in the reactor. Estimated values of EF were 41.54, 1.65 and 0.02 μM mg(-1), respectively for non-reactive iron superoxide nanoparticles (NPI), reactive divalent iron (DVI) and reactive zero-valent iron (ZVI). The remarkably high yield in presence of NPI was attributed to the synergy of nanotechnology and ultrasound; i.e. combined effects of massive surface area, excess cavitation nuclei, enhanced mass transfer and continuous cleaning of the metal surface. Total mineralization after 90 min sonication of DCF in the presence of 8.9 mM ZVI, 0.01 mM DVI and 0.001 mM NPI were 22%, 43% and 30%, respectively. Although DVI provided a larger degree of mineralization, the efficiency of NPI was still higher owing to its 10-fold lower effective dose.

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The degradation of anti‐inflammatory and antipyretic drug (Ibuprofen; IBP) has been described in this study by using photocatalytic‐based advanced oxidation processes. The catalysts (TiO2 and ZnO) were activated by irradiation of artificial UV lamp and solar rays for the generation of highly oxidizing species which resulted in the degradation of IBP to intermediates and finally to carbon dioxide and water. In solar reactor, quartz and borosilicate tubes were installed for absorption of required ultraviolet rays and curved chrome plates were used to reflect and concentrate rays on the tubes containing feed mixture. The liquid chromatography, Total organic carbon (TOC), and Chemical oxygen demand (COD) tests were employed to determine the degradation rates and demineralization of solution samples. At catalyst dosing of 1–1.5 g/L, TiO2‐based experiments showed high degradation rate under acidic conditions. Similarly, for ZnO catalyst, 1 g/L dozing rate was found to be effective under neutral conditions (pH = 7.0). UV lamp‐based photocatalysis had higher degradation rate as compared to that of solar reactor. Moreover, better absorption of solar rays by quartz tubes resulted in higher degradation than that in borosilicate tubes. For UV lamp photocatalysis, the TOC and COD reduction was higher. With improved catalyst doping and better solar reactor design, solar‐based IBP degradation could be more promising than UV‐based catalysis. Practitioner points TiO2 and ZnO were employed to generate oxidizing agents for comparative photocatalytic degradation. Degradation rate of Ibuprofen with TiO2 was much higher compared to ZnO. Quartz material was found more effective as radiation absorbing material than borosilicate glass for solar photo catalysis. Influence of catalyst loading (TiO2 and ZnO) and pH conditions on degradation rate and mineralization of IBP was examined. IBP is a carcinogenic and endocrine disrupting drug so its degradation in water can protect ecological and human life.

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Buyukcekmece Lake located north of the Marmara Sea coast of Turkey is the third largest water resources among the six main reservoirs of a megacity Istanbul, providing 17% water demand. This study aims to investigate the water quality changes in Buyukcekmece Lake and to classify it in accordance to Turkish Water Pollution Control Regulation for inland surface waters, and assess the impacts of the land-use practices, population density, and settlement in the Buyukcekmece watershed. Physical, chemical, and biological quality of Büyükçekmece Lake has been investigated between December 2007 and June 2008 by collecting samples from the Lake and four streams that feed Büyükçekmece Lake. Land use profile maps of the water basin were created by using ARC-GIS to ensure the quality of drinking water. It was determined that the water quality of Büyükçekmece Lake was still of overall second class, implying that it can be used as a safe drinking water resource following a conventional water treatment scheme; however, it is moving toward the third class. Remarkable portion of the pollution in water basin was attributed to domestic wastewater discharges. Agricultural areas that occupy more than half of the water basin have also adversely affected the water quality.

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