Indian Institute of Technology Guwahati

About: Indian Institute of Technology Guwahati is a education organization based out in Guwahati, Assam, India. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 6933 authors who have published 17102 publications receiving 257351 citations.

Rapid removal of Auramine-O and Methylene blue by ZnS:Cu nanoparticles loaded on activated carbon: A response surface methodology approach

Abstract: The focus of this research is on the rapid ultrasound-assisted removal of Methylene blue (MB) and Auramine-O (AO) dyes from aqueous solutions using ZnS:Cu nanoparticles loaded on activated carbon (ZnS:Cu-NP-AC) as a low cost and environmental friendly adsorbent. The adsorbent was characterized by FE-SEM, FTIR and XRD. The effect of variables such as adsorbent dosage, sonication time, initial concentration of MB, and initial concentration of AO on the removal percentages of MB and AO dyes were simultaneously investigated by central composite design (CCD) under response surface methodology (RSM) while pH was optimized separately. It was shown that the adsorption of AO and MB follows the pseudo-second-order rate equation, while the Langmuir model explains equilibrium data. A small amount of the adsorbent was able to remove more than 99.5% of both dyes rapidly with high adsorption capacity in single component system (106.9 mg/g for MB, and 94.2 mg/g for AO) and in binary-component system (51.7 mg/g for MB, and 38.1 mg/g for AO). It is worth to note that the optimum adsorption of MB and AO dyes occurred at neutral pH, which is an advantage of our work.

Mechanistic Approach to Enhancement of the Yield of a Sonochemical Reaction

Abstract: In this study, a mechanistic approach has been taken to enhance yield of a sonochemical reaction. Formation of highly reactive free radicals due to the transient collapse of cavitation bubbles is the primary mechanism of a sonochemical reaction. A physical (reduction in dissolved gas concentration) and a chemical (increasing the reactant concentration) technique is used for enhancing yield of a sonochemical reaction using those techniques, which influence the phenomenon of radical formation by the cavitation bubbles. A bubble dynamics model is used for explaining the sonochemical phenomena. In a degassed medium, the ultrasound wave undergoes lesser attenuation; moreover, equilibrium size of a bubble shrinks due to rectified diffusion. Because of this, a bubble undergoes more violent collapse, resulting in greater production of radicals that give higher yield. On the other hand, increasing the initial reactant concentration shows an adverse effect on the sonochemical yield. This is ascribed to reduction in water vapor flux in the bubble due to reduction of vapor pressure of the medium. This study, therefore, demonstrates as how macroscopic manifestation (the sonochemical yield) of the microscopic phenomena (transient collapse of cavitation bubble) is a complicated function of several physical processes. The results of this study shed light on the complex and multifaceted physical mechanism of a sonochemical reaction, which may be useful in maximization of yield of other sonochemical systems. 2007 American Institute of Chemical Engineers AIChE J, 53: 1132–1143, 2007

Is curcumin bioavailability a problem in humans: lessons from clinical trials.

Abstract: Introduction: Since ancient times, turmeric has been used in several folklore remedies against various ailments. The principal component of turmeric is curcumin and its efficacy has been advocated ...