Heterogeneous Fenton-like degradation of Rhodamine 6G in water using CuFeZSM-5 zeolite catalyst prepared by hydrothermal synthesis

In this study, heterogeneous Fenton-like degradation of reactive azo dye Rhodamine 6G in water was investigated over a CuFeZSM-5 zeolite catalyst prepared by hydrothermal synthesis. At initial pH of 3.4, a color removal of 100% was achieved after a reaction time of 45 min. TOC elimination was measured to be 51.8% after 2 h of oxidation. Initial decolorization rate was described by an equation of -r(A0) = 4.56 x 10(2) e(-24.83/RT)C(R6G,0)C(0.35)(H2O2,0) where R is in kJ/mol. The leaching of iron and copper cations from zeolite structure into the solution during oxidation was dependent on pH strongly. The regulation of pH from 6.5 (dye solution pH) to 3.4, increased leaching for iron from 0.7 to 0.8 mg/dm3 and for copper from 1.4 to 2.1 mg/dm3. The copper was totally leached from the catalyst during the process at pH 3.4.

Sonolytic degradation of acetic acid in aqueous solutions

In this work, ultrasonic degradation of acetic acid, which is one of the most resistant carboxylic acids to oxidize, was investigated. The effects of parameters such as ultrasonic power, initial concentration, addition of NaCl or several oxides were studied on the degradation of acetic acid. Acetic acid was sonicated indirectly using an ultrasonic bath with 40 kHz. It was observed that degradation degree increased with decreasing power and initial concentration and with increasing NaCl concentration. Initial degradation degree was enhanced with addition of zeolite and SiO(2).

Ultrasonic degradation of oxalic acid in aqueous solutions

This paper describes the ultrasonic degradation of oxalic acid. The effects of ultrasonic power, H(2)O(2), NaCl, external gases on the degradation of oxalic acid were investigated. Reactor flask containing oxalic acid was immersed in the ultrasonic bath with water as the coupling fluid. Representative samples withdrawn were analysed by volumetric titration. Degradation degree of oxalic acid increased with increasing ultrasonic power. It was observed that H(2)O(2) has negative contribution on the degradation of oxalic acid and there was an optimum concentration of NaCl for enhancing the degradation degree of oxalic acid. Although bubbling nitrogen gave higher degradation than that for bubbling air, both gases (for 20 min before sonication and during sonication together) could not help to enhance the degradation of oxalic acid when compared with the degradation without gas passage.

Direct sonication of acetic acid in aqueous solutions

Sonochemical oxidation has a promising future in the area of waste water treatment as one of the advanced oxidation methods. In this study, direct ultrasonic degradation of acetic acid was investigated in low powers (0.1-0.4 W) and in a frequency range of 30-100 kHz. An ultrasonic transducer was used for sonication. The results showed that there was an optimum frequency at 60 kHz for direct sonication of acetic acid and degradation rate increased up to a power of 0.2 W and then it decreased. Sonochemistry is associated with the bubble of cavitation which depends on the sound pressure field and nature of molecule. Therefore, the frequency and intensity have to be optimized for the minimization of energy requirement during waste water treatment with ultrasound.

Cytogenetic study in 102 infertile men

Chromosomal anomalies may be a reason for male infertility. To find out whether this is true mitotic chromosome studies were performed on 41 males with azoospermia and 61 males with oligozoospermia. A constitutional chromosomal abnormality was diagnosed in 14 (34.1%) azoospermic patients and in 2 (3.3%) oligozoospermic patients. The 47,XXY karyotype was the commonest in the azoospermic group. An overall incidence of 15.7% abnormality indicates that routine chromosome analysis of infertile men should be considered.

Preservation of Cheese and Plain Yogurt by Low-dose Irradiation

Irradiation preservation of Turkish kashar cheese and plain yogurt was studied using very low doses of Co-60 radiation. No side effects were observed below 0.15 Mrad. The number of bacteria killed was directly related to total dose up to 0.02 Mrad, then the effectiveness of the dose decreased. Coating cheese samples with a sorbic acid solution helped in reducing the number of bacteria by about 10-12% in irradiated samples. The shelf-life of irradiated samples stored at refrigerator temperature was almost the same as that of ones coated with sorbic acid but stored at room temperature. Mold formation in irradiated samples took three to four times longer than in nonirradiated ones. With plain yogurt the effect of total dose seemed to be the same as in cheese. Irradiation increased the shelf-life of yogurt three- to four-fold. Preservation by irradiation combined with refrigeration increased the shelf-life about five-fold.