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The current global population is nearly 6 billion; due to this rapid population growth, there is a need to produce food in a more efficient, safe, and sustainable way, and it should be safe from the adverse effects of pathogenic organisms. A large proportion of population living in developing countries face daily food shortages as a result of environmental impacts or some other reasons like political instability, etc., while in the developed countries, food is surplus. For developing countries, the objective is to develop drought- and pest-resistant crops, with maximized yield. In developed countries, the food industry depends on consumer’s demand for fresher and healthier foodstuffs. The present chapter describes the use of nanoparticles in food science.

Department of Chemistry, PAHER University, Udaipur-313 003, Rajasthan, India bDepartment of Chemistry, J. R. N. Rajasthan Vidyapeeth (Deemed to be University), Udaipur-313 001, Rajasthan, India E-mail: rakshit_ameta@yahoo.in Manuscript received online 16 January 2019, revised 10 February 2019, accepted 12 February 2019 Water pollution is a serious issue all over the world because water is contaminated by various pollutants, out of which dyes are most common and hazardous because of their complex structures making them stable, non-degradable and hazardous. Azure A is such a dye. Composite of rGO/CuS was prepared by mechanochemical method and further characterized by XRD, FTIR and EDAX techniques. This composite was used to degrade azure A photocatalytically. This composite showed better photocatalytic property as compared to pure CuS. Optimum conditions for maximum dye degradation were observed as: pH = 6.5, [Azure A] = 3.4×10–5 M, amount of composite = 0.06 g and light intensity = 50.0 mW cm–2 .

USE OF ZINC FERRITE AS A PHOTOCATALYST FOR DEGRADATION OF TOLUIDINE BLUE PRIYA PARSOYA and SURESH C. AMETA Department of Chemistry, PAHER University, UDAIPUR – 313003 (Raj.) INDIA ABSTRACT The photocatalytic activity of ZnFe2O4 was investigated by carrying out the photocatalytic degradation of toluidine blue dye under visible light. ZnFe2O4 was synthesized by precipitation method. The dye solution was exposed to a 200 W tungsten lamp. The degradation rate of the dye was observed by measuring its absorbance at regular time intervals at 630 nm. Effect of various parameters like pH, concentration of dye, amount of semiconductor and intensity of light on rate of degradation was observed. The optimum rate was observed at pH = 9.5; toluidine blue = 2.10 x 10−5 M; zinc ferrite = 0.06 g and light intensity = 60.0 mWcm−2. The rate constant for a typical run was observed as 2.67 x 10−4 sec−1. A tentative mechanism has been proposed for the photocatalytic degradation of toluidine blue in presence of zinc ferrite involving superoxide anion radical as the active oxidizing species. Key words: Ternary oxide, Photocatalyst, Toluidine blue, Zinc ferrite

The photocatalytic degradation of methylene blue dye under visible light has been investigated using chromium modified titanium dioxide supported on zeolite (Cr-TiO2/zeolite). The photocatalyst was prepared by sol-gel method and characterized by X-ray diffraction and SEM. The rate of photodegradation of dye was monitored spectrophotometrically. The effect of pH, dye concentration, amount of photocatalyst and intensity of light on the rate of photocatalytic reaction was observed. The results showed that the use of Cr-doped TiO2 increased the rate of photocatalytic degradation of methylene blue as compared to untreated TiO2. The photocatalytic mechanism of Cr-TiO2 catalyst has been tentatively discussed. Keywords: Methylene blue, zeolite, chromium, photocatalytic degradation

Solar Energy and Photochemistry Laboratory, Department of Chemistry, University College of Science, M. L. Sukhadia University, Udaipur-313 002, Rajasthan, India E-mail : ameta_sc@yahoo.com, vaishnave.prahlad@gmail.com Department of Chemistry, M.P. Government P.G. College, Chittorgarh-312 001, Rajasthan, India Manuscript received 06 May 2010, revised 19 May 2010, accepted 27 July 2010 The oxidation using sono-photo-Fenton has been found to be a promising treatment for the effective decolorization and degradation of dye. The degradation of methylene blue was investigated using photo-Fenton and sono-photo-Fenton processes. The effect of different variables like the concentration of ferric ion, concentration of dye, pH, hydrogen peroxide, light Intensity etc. on the reaction rate has been observed and optimal conditions determined. The methylene blue dye degradation was found to depend on these variables. The progress of dye degradation was observed spectrophotometrically. The sono-photo-Fenton reaction showed higher degradation rate of the dye as compared to photo-Fenton process. The results showed that the dye was completely oxidized and degraded Into CO2 and H2O. A suitable tentative mechanism for degradation of methylene blue by sono-photo-Fenton's reaction has been proposed.

Department of Chemistry, University College of Science, M. L. Sukhadia University, Udaipur-313 001, Rajasthan, India E-mail : ameta_sc@yahoo.com Manuscript received 5 October 2005, revised 27 November 2006, accepted 27 November 2006 Acetic acid has been used for acetylation of seven aromatic amines and two phenols under microwave exposure. The time taken for these reactions ranges from 18-25 min with reasonability good yields (65-77%).

Photochemistry Laboratory, Department of Chemistry, M. L. Sukhadia University, Udaipur-313 002, Rajasthan, India E-mail: ameta_sc@yahoo.com Manuscript received 18 August 2005, revised 10 April 2006, accepted 6 June 2006 Photooxidation of \(o\)-phenylenediamine by singlet oxygen has been carried out. After completion of photooxidation reaction, product was isolated and characterized by physical, chemical and spectral data. Effect of various factors like triplet energy of sensitizer,life time of singlet oxygen, light intensity and singlet oxygen scavengers on the yield of photoproduct was also observed. A tentative mechanism has been proposed involving singlet oxygen as an oxidizing species.

Department of Chemistry, Photochemistry and Solar Energy Laboratory, M. L. Sukhadia University, Udaipur-313 002, Rajasthan, India Department of Chemistry, Geetanjali Institute of Technical Studies, Dabok, Udaipur-313 022, Rajasthan, India E-mail : ali_yasmin2002@rediffmail.com Manuscript received 25 February 2005, revised 30 May 2005, accepted 30 August 2005 The photocatalytic degradation of resorcinol over titanium dioxide using photo-Fenton's and other related reagents was investigated. The effect of various parameters; such as pH, concentration of resorcinol, amount of semiconductor, amount of H2O2, concentration of ferric ions, light intensity, effect of other ions, etc. were observed. The photocatalytic degradation of resorcinol follows pseudo-first order kinetics. A tentative mechanism has been proposed for the photocatalytic degradation of resorcinol using photo Fenton's reagent.

Photochemistry Laboratory, Department of Chemistry, University College of Science, M. L. Sukhadia University, Udaipur-313 002, India E-mail : ameta_sc@yahoo.com Fax : 91-294-2423191 Manuscript received 10 March 2005, revised 8 June 2005, accepted 21 June 2005 A comparative study of photocatalytic bleaching of azure-B over Sb2S3 powder was carried out in the presence and absence of sodium bicarbonate/carbonate. The photocatalytic bleaching was observed to be more efficient in the presence of bicarbonate/carbonate ions. The effect of various parameters has been studied and a tentative mechanism for the photocatalytic bleaching has been proposed.

Photochemistry Laboratory, Department of Chemistry, M. L. Sukhadia University, Udaipur-313 002, India E-mail: ameta_sc@yahoo.com Fax : 91-294-2423191 Manuscript received 10 May 2002, accepted 5 February 2003 The photocatalytic bleaching of methylene blue over CdS powder was carried out in the presence and absence of sodium bicarbonate/carbonate. A comparison was made between the rate of photobleaching of methylene blue with and without bicarbonate or carbonate ions. It was observed that the photobleaching was more efficient in the presence of bicarbonate or carbonate ions. The effects of various parameters have been observed and a tentative mechanism for the photobleaching has been proposed.&nbsp

Photochemistry and Solar Energy Laboratory, Department of Chemistry, M. L. Sukhadia University, Udaipur-313 002, India E-mail: ameta_sc@yahoo.com Manuscript received 11 September 2002 Photocatalysis : a promising technology for wastewater treatment.

Department of Chemistry, University College of Science, Sukhadia University, Udaipur-313 002, India Green chemistry: the chemistry of new millenium

Department of Chemistry, College of Science, Sukhadia University, Udaipur-313 001, India Department of Chemistry, M. L. V. P.G. College, Bhilwara-311 001, India Manuscript received 12 April 2000, revised 1 December 2000, accepted 8 December 2000 The most important but the least understood part of the oxygen cycle is the nature and interaction of oxygen with many chemical and biological systems in nature. Therefore, there is a need to understand the mechanism of oxygen involvement in such systems. Present review describes the various aspects of singlet oxygen, a high energy state of ground state oxygen. These aspects include electronic structure, generation, detection, quenching, various reactions etc.

President, Indian Chemical Society Recent trends in chemical sciences

Department of Chemistry, College of Science, Sukhadia University, Udaipur-313 001, India Manuscript received 29 July 1999, accepted 11 November 1999 The photocatalytic degradation of sodium lauryl sulfate (SLS) over TiO2 has been carried out. The effects of various pa­rameters such as pH, variation of pH with time, concentration of surfactant, amount of semiconductor, effect of pal title size, light intensity, etc. have been observed and a tentative mechanism has been proposed.