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Shikha Goyal ¹, Usha Malagi ¹, Rama Naik ¹

Affiliations
1 Department of Food Science and Nutrition, College of Rural Home Science, University of Agricultural Sciences, Dharwad, Karnataka - 580005, IN

Abstract

Perimenopause is the time around menopause during which menstrual cycle and endocrine changes are occurring but 12 months of amenorrhea has not yet occurred. At this stage the amount and number of days of flow decreases, skipping one or more months during several years before complete cessation.

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Pankaj ¹, Shikha Goyal ¹

Affiliations
1 Department of Chemistry, Dayalbagh Educational Institute, Agra-282005, IN

Abstract

Degradation of an azo dye, Reactive Red 141 (C₅₂H₂₆C₁₂N₁₄Na₈O₂₆S₈) in the aqueous solution has been carried out with ultrasound (US) and in combination with rare earth ions (La³⁺ and Pr³⁺). Both horn and tank type of sonicating devices, operating at 20 kHz and 250 W, were used for the degradation. A comparative study of continuous and pulsed mode of ultrasound induction has also been undertaken. Operational parameter, such as, initial dye concentration, pH and the presence of rare earth ions on the degradation of dye have been found to affect the degradation process . The degradation rate increased with increasing rare earth concentration, decreasing pH and initial dye concentration. The kinetic data fitted well with pseudo-first order kinetic model. The rate constant for the degradation process with US+RE was three times compared to US alone. The efficiency of various processes for the degradation of RR 141 dye was found to be in the order: US+La>US+Pr>US.

Keywords

Degradation, Ultrasound, RR 141, Rare Earth Ions, Kinetics.

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Pankaj ¹, Shikha Goyal ¹, Prem Kishore Patnala ¹

Affiliations
1 Department of Chemistry, Dayalbagh Educational Institute, Agra-282005, U.P., IN

Abstract

Adsorption study of three textile dyes[Acid Red 114 (AR 114), Reactive Blue 21 (RB 21) and Basic Violet 16 (BV 16)] of different classes has been carried out on TiO₂ alone and in combination with rare earth ion [Ce⁴⁺], in the aqueous solutions, in the presence and absence of ultrasound. The complete removal of AR 114 and RB 21 were achieved in 5 minutes of sonication in the presence of rare earths while BV 16 was decolourised to only 21% even after 50 min. The experimental data was analysed using different adsorption isotherms, kinetics and adsorption mechanism. The isotherm data fitted very well with Langmuir model and the adsorption followed pseudo-second order kinetics. The presence of Ce⁴⁺ ions enhanced adsorption of anionic dyes on TiO₂ surface but decreased for basic dye. A mechanism of adsorption and the degradation of dyes have been proposed.

Keywords

Adsorption, Ultrasound, AR 114, RB 21, BV 16, TiO₂, Rare Earth.

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