Biennial Report 2005-2007 - Saha Institute of Nuclear Physics

Biophysical Sciences 2316.1.10.11 Effect of accumulation of arsenic by an alkaloid extracted from fruits ofPiper nigrum (Family: Piperaceae)Plant bio-molecules are frequently being used as a replacement of synthetic reagents for preconcentrationand extraction of metal ions. We studied the efficacy of piperine and black pepper toremove As(III) or As(V) from aqueous solution. Salts of sodium arsenate (Na 2 HAsO 4 , 7H 2 O) andsodium arsenite (NaAsO 2 ) were irradiated by thermal neutron at CIRUS reactor, BARC, Mumbaito produce 76 AsO 4 −3 and 76 AsO 2 − . These irradiated salts were subsequently used for accumulationstudies of two arsenic species. Both black pepper and piperine showed no accumulation for any ofthe species of arsenic. This data is definitely a valuable addition to Green Chemistry experiments.Kalpita Ghosh, Susanta LahiriCSD6.1.10.12 Speciation dependent study of 51 Cr(VI) and 51 Cr(III) using an AqueousBiphasic SystemThe speciation study of neutron activated Cr(III) and Cr(VI) was carried out using a polyethyleneglycol (PEG) based aqueous biphasic extraction system (ABS). The best condition of extractionand separation of Cr(VI) from Cr(III) in the PEG rich phase was achieved with 2M Na 2 SO 4 andPEG #4000 (50% w/w) solution. The relatively soft anion Cr 2 O 7 −2 partitions quantitatively tothe PEG rich phase in ABS. Hard metal cations as Cr(III) with relatively large magnitudes of∆G hyd report to the salt rich phase. The chromium(III) can also be quantitatively extracted bythe PEG rich phase when complexed with dithizone.Susanta Lahiri, Kamalika RoyCSD6.1.10.13 Aqueous Biphasic Extraction of As(III) and As(V)Aqueous biphasic system (ABS) is formed when a water soluble polymer [e.g., polyethylene glycol,PEG] is mixed with water structuring salts [e.g., Na 2 SO 4 , K 2 CO 3 , NaOH]. Arsenic may remainas As(III), As(V) and some organoarsenic compounds. Sodium arsenate (Na 2 HAsO 4 , 7H 2 O) andsodium arsenite (NaAsO 2 ) salts were irradiated with thermal neutrons, to produce 76 As (1.087 d)salts. It was found that 90% of As(V) salt and 50% of As(III) salt could be extracted in the PEGphase from salt rich phase containing 2M Na 2 SO 4 or Na 2 SO 3 in an acidic medium. The methodoffers an environmentally benign extraction system of highly toxic As(V) from aqueous solutions.Susanta Lahiri, Kamalika RoyCSD6.1.10.14 Studies on bioaccumulation of 152 Eu, 137 Cs, 60 Co by different algal generaWe have studied the bioaccumulation of a mixture of long lived radionuclides 152 Eu, 137 Cs and60 Co by five algal genera, viz.: Lyngbya and Phormidium from cyanophyceae; Rhizoclonium andChaetomorpha from chlorophyceae and Catenella from rhodophyceae. Eu-152 accumulation washigh for all the five algal genera after 7 days of exposure. No accumulation of 137 Cs was found by