siva REDDY - Academia.edu (original) (raw)

Papers by siva REDDY

Research paper thumbnail of Design of an Optimal Auction for Sponsored Search Auction

The 9th IEEE International Conference on E-Commerce Technology and The 4th IEEE International Conference on Enterprise Computing, E-Commerce and E-Services (CEC-EEE 2007), 2007

Page 1. Design of an Optimal Auction for Sponsored Search Auctions Dinesh Garg, Y. Narahari, and ... more Page 1. Design of an Optimal Auction for Sponsored Search Auctions Dinesh Garg, Y. Narahari, and Siva Sankar Reddy Department of Computer Science and Automation Indian Institute of Science, Bangalore - 560 012 dgarg,hari,sankar@csa.iisc.ernet.in Abstract ...

Research paper thumbnail of Outcomes of Pectoralis Major Myocutaneous Flap in Female Patients for Oral Cavity Defect Reconstruction

Journal of Oral and Maxillofacial Surgery, 2014

Although much has been mentioned in the literature worldwide regarding the outcome of pectoralis ... more Although much has been mentioned in the literature worldwide regarding the outcome of pectoralis major myocutaneous flaps (PMMFs), hardly any studies are available that mention the outcome of PMMFs in female patients. It has been presumed that complication rates after PMMF reconstruction in female patients are higher because of the presence of more adipose tissue in the flap. The objective of this study was to analyze our data regarding the outcomes of PMMFs in female patients with oral cancer undergoing reconstruction after tumor ablation. In this retrospective study from January 2008 to May 2012, performed in a single institution in south India, we have analyzed our data on PMMFs in 140 female patients with oral cancer. The operative technique used was essentially the same as that described originally by Ariyan. However, to preserve the deltopectoral flap area, the incision was appropriately modified in a manner as described by Schuller. The mean age of the patients was 52.36 years, with a range from 30 to 76 years. They presented mostly with ulcers or ulceroproliferative lesions. Most of the patients had a history of tobacco and betel nut chewing. All of them underwent composite resection and reconstruction with PMMF under general anesthesia. Of the patients, 30 (21.4%) had complications, comprising infection (8), superficial flap necrosis (11), combined wound infection and superficial flap necrosis (3), total flap failure (2), and orocutaneous fistula (6). PMMF reconstruction is a reliable and cosmetically acceptable method of reconstruction in female patients for oral cavity defects after tumor ablation.

Research paper thumbnail of Removal of Copper (II) by Sodium carboxymethyl cellulose based magnetic nanocomposites

Heavy metal ions pollution is one of the greatest problems causing threat to world environment du... more Heavy metal ions pollution is one of the greatest problems causing threat to world environment due to rapid global industrialization. Metal ions such as Cd, Hg, Cu, Ni and Pb etc., which are commonly associated with pollutants, produce toxicity problems to humans because of their insusceptibility to biological degradation. They can specifically bind to proteins, nucleic acids and small metabolites in living organisms inhibiting their functions. [1,2]. A number of methods have been developed for the removal of these metal ions from waste water [3-5]. Each method has its own draw back in terms of efficiency, cost and complexity. Recently, magnetic separation has become a promising method for environmental purification as it is easily separated from the medium under applied magnetic field [6]. Hence, hydrogels with magnetic properties have become interesting adsorbents for the removal of toxic materials from the aquatic media [7]. Magnetic iron oxides in various forms have been used fo...

Research paper thumbnail of SYNTHESIS AND CHARACTERIZATION OF PECTIN BASED SILVER NANOCOMPOSITE HYDROGELS FOR CONTROLLED RELEASE 5-FLUOROURACIL

In this present contribution we developed a novel silver nanocomposite hydrogels. These are compo... more In this present contribution we developed a novel silver nanocomposite hydrogels. These are composed from poly(acrylamide-co-N-vinylcaprolactam-co-acrylamidoglycolicacid)/ Pectin (PAVA-PN) and were cross-linked with N,N-methylene-bis-acrylamide. These PAVA-PN hydrogels are used as nano reactors to prepare silver nanocomposite hydrogels (SNH). 5-fluorouracil an anticancer drug has been loaded in situ into PAVA-PN hydrogels. Plain as well as drug loaded PAVA-PN hydrogels have been characterized by Fourier transform infrared spectroscopy and scanning electron microscope studies. The above studies has revealed that a molecular level dispersion of the drug in PAVA-PN hydrogels. In vitro release of 5-fluorouracil from the PAVA-PN hydrogels and SNH has been carried out in GIT fluids.

Research paper thumbnail of Synergistic Extraction of Uranium (VI) by Complexation with CYANEX-272 and CYANEX-923, TPBD, TNBD, TOPO in Presence of Nitrate

Abstract- Synergistic extraction of uranium (VI) from nitrate medium by cyanex 272 (HA)2 along wi... more Abstract- Synergistic extraction of uranium (VI) from nitrate medium by cyanex 272 (HA)2 along with cyanex 923, TPBD, TNBD, TOPO and their mixtures in xylene as extractants has been investigated. Analysis of the extraction data by graphical method by taking into account the complexation of the metal ion in the aqueous phase with organic ligands and all plausible complexes extracted into the organic phase is carried out. The metal ion is extracted into xylene as UO2(HA2)2. The results demonstrate that uranyl ion is extracted into xylene as UO2(HA2)2 with cyanex-272 alone and as UO2(HA2).NO3.S (where S = cyanex-923/TOPO )with cyanex-272 and cyanex-923/TOPO, and as UO2(HA2)2.S with cyanex-272 and TPBD/TNBD (where S = TPBD/TNBD). The synergistic systems enhance the extraction efficiency of uranium (VI) marginally.

Research paper thumbnail of Development of Guar Gum Based Semi-IPN Hydrogels for Removal of Toxic Metal Ions

In this paper a novel pH sensitive Guar gam - poly ( acrylamide-co-2-Acrylamido-2-methyl-1-propan... more In this paper a novel pH sensitive Guar gam - poly ( acrylamide-co-2-Acrylamido-2-methyl-1-propanesulphonic acid) ( GG-PAAMPS) hydrogels were prepared by simultaneous freeradical copolymerisation reaction of Guar gam ( GG),acrylicacid(AA) ,acryl amido 2- methyl 1-propane sulphonic acid (AMPS),N,N-methylenebis (acrylamide) (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator in aqueous solution and TEMED as accelerator. In this part westudied swelling properties and characterised with Fourier TransformInfra-red Spectroscopy (FT-IR),Differential scanning calorimetry ( DSC)studies.The swelling parameters were calculated by swelling studies tounderstand the diffusion mechanism.The developed GG-PAAMPS hydrogelscould be used for removal of toxic metal ions.

Research paper thumbnail of Synthesis and Characterisation of Guar Gum-g-Poly(Acrylamidoglycolic acid) by Redox Initiator

Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditi... more Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium persulphate as initiators. The effect initiator, guar gum, and monomer along with reaction time and temperature were studied by determining the grafting parameters: % grafting ratio, % efficiency. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermal analysis. It was observed that the maximum yield occurred at which time of 2h at temperature 60oC. Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium persulphate as initiators. The effect initiator, guar gum, and monomer along with reaction time and temperature were studied by determining the grafting parameters: % grafting ratio, % efficiency. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermal analysis. It was obs...

Research paper thumbnail of Synthesis and Characterization of Sodium Carboxy Methyl Cellulose/Poly (Acrylamide) Magnetic Nano Composite Semi Ipn’s for Removal of Heavy Metal Ions

Sodium carboxy methyl cellulose (NaCMC)/poly(acrylamide) cross linked with N,N-methylene bisacryl... more Sodium carboxy methyl cellulose (NaCMC)/poly(acrylamide) cross linked with N,N-methylene bisacrylamide semi IPN hydrogels were prepared using redox polymerization technique. These hydrogels are used for the preparation of nano composite hydrogels with magnetic properties were further utilized for the removal of toxic metal ions. Semi IPN hydrogels were characterized by Fourier transforms infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). Magnetic properties of hydrogels were characterized by vibration sample magnetometer (VSM). Swelling studies performed in water have been analyzed with the help of an empirical equation to investigate the diffusion mechanism. The sorption behavior with respect to contact time, initial pH, initial metal ion concentration, was investigated to determine the optimum sorption conditions. The adsorption capacities of Cu+2 and Ni+2 on the semi IPN gels and magnetic nano composite semi IPN’s were 0.74, 0....

Research paper thumbnail of Synergistic Extraction of Uranium from Thiocyanate Medium by Complexation with Cyanex-272 and Cyanex-923, TPBD, TNBD, TOPO

The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and... more The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and TNBD in xylene as extractants has been investigated. Analysis of the extraction data by both graphical and theoretical methods by taking into account complexation of the metal ion in the aqueous phase with organic ligands and all plausible complexes extracted into the organic phase. The metal ion is extracted into xylene as UO2(HA2)2. The plot of log D vs pH has a slope of 2. Mixed species of the type UO2(HA2)2.S (where S= TPBD/TNBD) and UO2(HA2)SCN.S (where S = cyanex 923/TOPO) were obtained may be responsible for the synergism.

Research paper thumbnail of Development of Thiourea-Formaldehyde Crosslinked Chitosan Membrane Networks for Separation of Cu (II) and Ni (II) Ions

Bulletin- Korean Chemical Society

Novel chitosan (CS) based membrane networks were developed by solution casting and followed by cr... more Novel chitosan (CS) based membrane networks were developed by solution casting and followed by crosslinking with different crosslinkers such as glutaraldehyde, urea-formaldehyde, and thiourea-formaldehyde. The developed membrane networks were designated as CS-GA, CS-UF and CS-TF. Crosslinking reaction of CS membranes was confirmed by Fourier transform infrared spectroscopy. Membrane rigidity and compactness were studied by the differential scanning calorimetry. The surface morphology of CS membranes was characterized by scanning electron microscopy. The sorption behaviour with respect to contact time, initial pH and initial metal ion concentration were investigated. The maximum adsorption capacity of CS-GA, CS-UF and CS-TF sorbents was found to be 1.03, 1.2 and 1.18 mM/g for Cu2+ and 1.48, 1.55 and 2.18 mM/g for Ni2+ respectively. Swelling experiments have been performed on the membrane networks at 30 oC. Desorption studies were performed in acid media and EDTA and it was found that...

Research paper thumbnail of The Synergistic Extraction of Uranium with Mixtures of Cyanex-272 and Cyanex-923, TPBD, TNBD, TOPO from Thiocyanate Medium

The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and... more The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and TNBD in xylene as extractants has been investigated. Analysis of the extraction data by both graphical and theoretical methods by taking into account complexation of the metal ion in the aqueous phase with organic ligands and all plausible complexes extracted into the organic phase has been done. The metal ion is extracted into xylene as UO2(HA2)2. The plot of log D vs pH has a slope of 2. Mixed species of the type UO2(HA2)2.S (where S= TPBD/TNBD) and UO2(HA2)SCN.S (where S = cyanex 923/TOPO) obtained may be responsible for the synergism.

Research paper thumbnail of Development of Hybrid Hydrogel Networks from Poly(Acrylamide-co-Acrylamido glycolic acid)/Cloisite Sodium for Adsorption of Methylene Blue

Hybrid hydrogel networks synthesized by the simple free radical polymerization of acrylamide, acr... more Hybrid hydrogel networks synthesized by the simple free radical polymerization of acrylamide, acrylamidoglycolic acid and cloisite sodium clay. To synthesize these hybrid hydrogels N,N’-methylenebisacrylamide used as a cross linker and ammonium peroxydisulphate used as an initiator. The structural characterization of this poly(acrylamide-co-acrylamidoglycolic acid/cloisite hybrid hydrogels (PAAGC), were done using Fourier transform infrared spectroscopy. The resulting hybrid networks was used as an adsorbent for studying the effectiveness in the removal of methylene blue (MB), which is having a wide range of use in different fields such as biology and chemistry. The effects of contact time, initial sorbate concentration, pH, and dose of adsorbent were studied to optimize the adsorption capacity. The batch sorption technique employed, revealed a maximum adsorption. Adsorption isotherms and Kinetic models were fitted to know the adsorption mechanism. This Hybrid hydrogels exhibited ex...

Research paper thumbnail of Adsorption Studies of Eu3+ from Aqueous Solutions by Poly(N’-Isopropyl Acrylamide-co-N-Acryloyl-L-Phenylalanine ) Hydrogel Networks

The present work reports the synthesis of Amino acid functionalized hydrogel networks (AFHs). N-a... more The present work reports the synthesis of Amino acid functionalized hydrogel networks (AFHs). N-acryloyl-L-phenylalanine and N’-isopropylacrylamide and were crosslinked by N,N-methylene-bis-acrylamide using redox polymerization technique. The diffusion parameters were calculated by swelling kinetics to understand the diffusion mechanism. Equilibrium swelling experiments have been performed on the AFHs in metal ion solutions. The effect of relevant parameters, such as contact time, initial pH, and initial metal ion concentration were investigated to determine the optimum sorption conditions. Adsorption equilibrium data were better fitted by a Langmuir isotherm. The adsorption capacity of Eu3+ on the AFHs was 0.89 mM/g. Desorption studies were also performed in acid media and EDTA, to observe whether the gels can be utilized as reusable tool for the metal ion removal. Metal ion sorption studies shows that AFHs can be used for removal of Eu3+ ions from aqueous solutions. Adsorption dat...

Research paper thumbnail of Pectin/poly(acrylamide- co -acrylamidoglycolic acid) pH sensitive semi-IPN hydrogels: selective removal of Cu 2+ and Ni 2+ , modeling, and kinetic studies

Desalination and Water Treatment, 2015

Ill Lee (2015):

Research paper thumbnail of Chitosan-poly(aminopropyl/phenylsilsesquioxane) hybrid nanocomposite membranes for antibacterial and drug delivery applications

Polymer International, 2014

ABSTRACT In this paper we fabricated hybrid membranes from chitosan (CS) and poly(aminopropyl/ ph... more ABSTRACT In this paper we fabricated hybrid membranes from chitosan (CS) and poly(aminopropyl/ phenyl silsesquioxane) (PAPSQ) (CSSQ) blends via a sol-gel reaction and solution casting followed by crosslinking with glutaraldehyde. The CSSQ membranes were then used for loading of 5-fluorouracil (5-FU) as an anticancer drug as well as templates for the production of silver nanoparticles (AgNPs). The physicochemical properties of the CSSQ membranes were examined by UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy (SEM). SEM results showed the controllable formation of AgNPs around PAPSQ. CSSQ-Ag nanocomposite membranes exhibited good antibacterial activity towards both Escherichia Coli and Bacilli subtilis, while CSSQ membranes worked as good carriers for controlled release of 5-FU as model drug. The results suggest that both CSSQ and CSSQ-Ag nanocomposite membranes can be potentially applied for biomedical applications such as controlled release carriers as well as an antibacterial wound dressing materials.

Research paper thumbnail of Synthesis, characterization, and metal uptake capacity of a new polyaniline and poly(acrylic acid) grafted sodium alginate/gelatin adsorbent

Desalination and Water Treatment, 2014

The present work reports the development of new (sodium alginate-gelatin (SAG))-g-poly (acrylic a... more The present work reports the development of new (sodium alginate-gelatin (SAG))-g-poly (acrylic acid)/polyaniline (SAPAPN) from sodium alginate/gelatin blend by cross-linking with glutaraldehyde, followed by grafting with poly(acrylic acid) and polyaniline by free radical polymerization using ammonium persulfate. The structure, thermal stability, and morphology of SAPAPN adsorbent was characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, and scanning electron microscopy, and results were consistent with the expected structures. The influence of various experimental conditions like pH, time, and initial feed concentrations on the uptake of metal ions like Cu 2+ , Ni 2+ by SAPAPN adsorbent was tested. It was seen that the adsorption equilibrium data could be fitted to the Langmuir isotherm. Desorption studies were performed in acid media and EDTA, to examine whether the SAPAPN adsorbent can be recycled for the metal ion removal. The results showed that with SAPAPN adsorbent, the maximum metal ion uptake achieved is 0.8386 mMg À1 for Cu 2+ and 2.2026 mMg À1 for Ni 2+ , respectively. Metal ion sorption studies showed that the adsorbent can be used for the removal of hazardous metal ions from aqueous solutions. The copper and nickel uptake achieved suggests the potential use of the adsorbent to extract divalent toxic metals from industrial aqueous streams.

Research paper thumbnail of Design of an Optimal Auction for Sponsored Search Auction

The 9th IEEE International Conference on E-Commerce Technology and The 4th IEEE International Conference on Enterprise Computing, E-Commerce and E-Services (CEC-EEE 2007), 2007

Page 1. Design of an Optimal Auction for Sponsored Search Auctions Dinesh Garg, Y. Narahari, and ... more Page 1. Design of an Optimal Auction for Sponsored Search Auctions Dinesh Garg, Y. Narahari, and Siva Sankar Reddy Department of Computer Science and Automation Indian Institute of Science, Bangalore - 560 012 dgarg,hari,sankar@csa.iisc.ernet.in Abstract ...

Research paper thumbnail of Outcomes of Pectoralis Major Myocutaneous Flap in Female Patients for Oral Cavity Defect Reconstruction

Journal of Oral and Maxillofacial Surgery, 2014

Although much has been mentioned in the literature worldwide regarding the outcome of pectoralis ... more Although much has been mentioned in the literature worldwide regarding the outcome of pectoralis major myocutaneous flaps (PMMFs), hardly any studies are available that mention the outcome of PMMFs in female patients. It has been presumed that complication rates after PMMF reconstruction in female patients are higher because of the presence of more adipose tissue in the flap. The objective of this study was to analyze our data regarding the outcomes of PMMFs in female patients with oral cancer undergoing reconstruction after tumor ablation. In this retrospective study from January 2008 to May 2012, performed in a single institution in south India, we have analyzed our data on PMMFs in 140 female patients with oral cancer. The operative technique used was essentially the same as that described originally by Ariyan. However, to preserve the deltopectoral flap area, the incision was appropriately modified in a manner as described by Schuller. The mean age of the patients was 52.36 years, with a range from 30 to 76 years. They presented mostly with ulcers or ulceroproliferative lesions. Most of the patients had a history of tobacco and betel nut chewing. All of them underwent composite resection and reconstruction with PMMF under general anesthesia. Of the patients, 30 (21.4%) had complications, comprising infection (8), superficial flap necrosis (11), combined wound infection and superficial flap necrosis (3), total flap failure (2), and orocutaneous fistula (6). PMMF reconstruction is a reliable and cosmetically acceptable method of reconstruction in female patients for oral cavity defects after tumor ablation.

Research paper thumbnail of Removal of Copper (II) by Sodium carboxymethyl cellulose based magnetic nanocomposites

Heavy metal ions pollution is one of the greatest problems causing threat to world environment du... more Heavy metal ions pollution is one of the greatest problems causing threat to world environment due to rapid global industrialization. Metal ions such as Cd, Hg, Cu, Ni and Pb etc., which are commonly associated with pollutants, produce toxicity problems to humans because of their insusceptibility to biological degradation. They can specifically bind to proteins, nucleic acids and small metabolites in living organisms inhibiting their functions. [1,2]. A number of methods have been developed for the removal of these metal ions from waste water [3-5]. Each method has its own draw back in terms of efficiency, cost and complexity. Recently, magnetic separation has become a promising method for environmental purification as it is easily separated from the medium under applied magnetic field [6]. Hence, hydrogels with magnetic properties have become interesting adsorbents for the removal of toxic materials from the aquatic media [7]. Magnetic iron oxides in various forms have been used fo...

Research paper thumbnail of SYNTHESIS AND CHARACTERIZATION OF PECTIN BASED SILVER NANOCOMPOSITE HYDROGELS FOR CONTROLLED RELEASE 5-FLUOROURACIL

In this present contribution we developed a novel silver nanocomposite hydrogels. These are compo... more In this present contribution we developed a novel silver nanocomposite hydrogels. These are composed from poly(acrylamide-co-N-vinylcaprolactam-co-acrylamidoglycolicacid)/ Pectin (PAVA-PN) and were cross-linked with N,N-methylene-bis-acrylamide. These PAVA-PN hydrogels are used as nano reactors to prepare silver nanocomposite hydrogels (SNH). 5-fluorouracil an anticancer drug has been loaded in situ into PAVA-PN hydrogels. Plain as well as drug loaded PAVA-PN hydrogels have been characterized by Fourier transform infrared spectroscopy and scanning electron microscope studies. The above studies has revealed that a molecular level dispersion of the drug in PAVA-PN hydrogels. In vitro release of 5-fluorouracil from the PAVA-PN hydrogels and SNH has been carried out in GIT fluids.

Research paper thumbnail of Synergistic Extraction of Uranium (VI) by Complexation with CYANEX-272 and CYANEX-923, TPBD, TNBD, TOPO in Presence of Nitrate

Abstract- Synergistic extraction of uranium (VI) from nitrate medium by cyanex 272 (HA)2 along wi... more Abstract- Synergistic extraction of uranium (VI) from nitrate medium by cyanex 272 (HA)2 along with cyanex 923, TPBD, TNBD, TOPO and their mixtures in xylene as extractants has been investigated. Analysis of the extraction data by graphical method by taking into account the complexation of the metal ion in the aqueous phase with organic ligands and all plausible complexes extracted into the organic phase is carried out. The metal ion is extracted into xylene as UO2(HA2)2. The results demonstrate that uranyl ion is extracted into xylene as UO2(HA2)2 with cyanex-272 alone and as UO2(HA2).NO3.S (where S = cyanex-923/TOPO )with cyanex-272 and cyanex-923/TOPO, and as UO2(HA2)2.S with cyanex-272 and TPBD/TNBD (where S = TPBD/TNBD). The synergistic systems enhance the extraction efficiency of uranium (VI) marginally.

Research paper thumbnail of Development of Guar Gum Based Semi-IPN Hydrogels for Removal of Toxic Metal Ions

In this paper a novel pH sensitive Guar gam - poly ( acrylamide-co-2-Acrylamido-2-methyl-1-propan... more In this paper a novel pH sensitive Guar gam - poly ( acrylamide-co-2-Acrylamido-2-methyl-1-propanesulphonic acid) ( GG-PAAMPS) hydrogels were prepared by simultaneous freeradical copolymerisation reaction of Guar gam ( GG),acrylicacid(AA) ,acryl amido 2- methyl 1-propane sulphonic acid (AMPS),N,N-methylenebis (acrylamide) (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator in aqueous solution and TEMED as accelerator. In this part westudied swelling properties and characterised with Fourier TransformInfra-red Spectroscopy (FT-IR),Differential scanning calorimetry ( DSC)studies.The swelling parameters were calculated by swelling studies tounderstand the diffusion mechanism.The developed GG-PAAMPS hydrogelscould be used for removal of toxic metal ions.

Research paper thumbnail of Synthesis and Characterisation of Guar Gum-g-Poly(Acrylamidoglycolic acid) by Redox Initiator

Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditi... more Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium persulphate as initiators. The effect initiator, guar gum, and monomer along with reaction time and temperature were studied by determining the grafting parameters: % grafting ratio, % efficiency. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermal analysis. It was observed that the maximum yield occurred at which time of 2h at temperature 60oC. Graft copolymer of acrylamidoglycolic acid with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium persulphate as initiators. The effect initiator, guar gum, and monomer along with reaction time and temperature were studied by determining the grafting parameters: % grafting ratio, % efficiency. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermal analysis. It was obs...

Research paper thumbnail of Synthesis and Characterization of Sodium Carboxy Methyl Cellulose/Poly (Acrylamide) Magnetic Nano Composite Semi Ipn’s for Removal of Heavy Metal Ions

Sodium carboxy methyl cellulose (NaCMC)/poly(acrylamide) cross linked with N,N-methylene bisacryl... more Sodium carboxy methyl cellulose (NaCMC)/poly(acrylamide) cross linked with N,N-methylene bisacrylamide semi IPN hydrogels were prepared using redox polymerization technique. These hydrogels are used for the preparation of nano composite hydrogels with magnetic properties were further utilized for the removal of toxic metal ions. Semi IPN hydrogels were characterized by Fourier transforms infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). Magnetic properties of hydrogels were characterized by vibration sample magnetometer (VSM). Swelling studies performed in water have been analyzed with the help of an empirical equation to investigate the diffusion mechanism. The sorption behavior with respect to contact time, initial pH, initial metal ion concentration, was investigated to determine the optimum sorption conditions. The adsorption capacities of Cu+2 and Ni+2 on the semi IPN gels and magnetic nano composite semi IPN’s were 0.74, 0....

Research paper thumbnail of Synergistic Extraction of Uranium from Thiocyanate Medium by Complexation with Cyanex-272 and Cyanex-923, TPBD, TNBD, TOPO

The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and... more The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and TNBD in xylene as extractants has been investigated. Analysis of the extraction data by both graphical and theoretical methods by taking into account complexation of the metal ion in the aqueous phase with organic ligands and all plausible complexes extracted into the organic phase. The metal ion is extracted into xylene as UO2(HA2)2. The plot of log D vs pH has a slope of 2. Mixed species of the type UO2(HA2)2.S (where S= TPBD/TNBD) and UO2(HA2)SCN.S (where S = cyanex 923/TOPO) were obtained may be responsible for the synergism.

Research paper thumbnail of Development of Thiourea-Formaldehyde Crosslinked Chitosan Membrane Networks for Separation of Cu (II) and Ni (II) Ions

Bulletin- Korean Chemical Society

Novel chitosan (CS) based membrane networks were developed by solution casting and followed by cr... more Novel chitosan (CS) based membrane networks were developed by solution casting and followed by crosslinking with different crosslinkers such as glutaraldehyde, urea-formaldehyde, and thiourea-formaldehyde. The developed membrane networks were designated as CS-GA, CS-UF and CS-TF. Crosslinking reaction of CS membranes was confirmed by Fourier transform infrared spectroscopy. Membrane rigidity and compactness were studied by the differential scanning calorimetry. The surface morphology of CS membranes was characterized by scanning electron microscopy. The sorption behaviour with respect to contact time, initial pH and initial metal ion concentration were investigated. The maximum adsorption capacity of CS-GA, CS-UF and CS-TF sorbents was found to be 1.03, 1.2 and 1.18 mM/g for Cu2+ and 1.48, 1.55 and 2.18 mM/g for Ni2+ respectively. Swelling experiments have been performed on the membrane networks at 30 oC. Desorption studies were performed in acid media and EDTA and it was found that...

Research paper thumbnail of The Synergistic Extraction of Uranium with Mixtures of Cyanex-272 and Cyanex-923, TPBD, TNBD, TOPO from Thiocyanate Medium

The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and... more The extraction of uranium (VI) from thiocyanate solutions using Cyanex 272, Cyanex 923, TPBD, and TNBD in xylene as extractants has been investigated. Analysis of the extraction data by both graphical and theoretical methods by taking into account complexation of the metal ion in the aqueous phase with organic ligands and all plausible complexes extracted into the organic phase has been done. The metal ion is extracted into xylene as UO2(HA2)2. The plot of log D vs pH has a slope of 2. Mixed species of the type UO2(HA2)2.S (where S= TPBD/TNBD) and UO2(HA2)SCN.S (where S = cyanex 923/TOPO) obtained may be responsible for the synergism.

Research paper thumbnail of Development of Hybrid Hydrogel Networks from Poly(Acrylamide-co-Acrylamido glycolic acid)/Cloisite Sodium for Adsorption of Methylene Blue

Hybrid hydrogel networks synthesized by the simple free radical polymerization of acrylamide, acr... more Hybrid hydrogel networks synthesized by the simple free radical polymerization of acrylamide, acrylamidoglycolic acid and cloisite sodium clay. To synthesize these hybrid hydrogels N,N’-methylenebisacrylamide used as a cross linker and ammonium peroxydisulphate used as an initiator. The structural characterization of this poly(acrylamide-co-acrylamidoglycolic acid/cloisite hybrid hydrogels (PAAGC), were done using Fourier transform infrared spectroscopy. The resulting hybrid networks was used as an adsorbent for studying the effectiveness in the removal of methylene blue (MB), which is having a wide range of use in different fields such as biology and chemistry. The effects of contact time, initial sorbate concentration, pH, and dose of adsorbent were studied to optimize the adsorption capacity. The batch sorption technique employed, revealed a maximum adsorption. Adsorption isotherms and Kinetic models were fitted to know the adsorption mechanism. This Hybrid hydrogels exhibited ex...

Research paper thumbnail of Adsorption Studies of Eu3+ from Aqueous Solutions by Poly(N’-Isopropyl Acrylamide-co-N-Acryloyl-L-Phenylalanine ) Hydrogel Networks

The present work reports the synthesis of Amino acid functionalized hydrogel networks (AFHs). N-a... more The present work reports the synthesis of Amino acid functionalized hydrogel networks (AFHs). N-acryloyl-L-phenylalanine and N’-isopropylacrylamide and were crosslinked by N,N-methylene-bis-acrylamide using redox polymerization technique. The diffusion parameters were calculated by swelling kinetics to understand the diffusion mechanism. Equilibrium swelling experiments have been performed on the AFHs in metal ion solutions. The effect of relevant parameters, such as contact time, initial pH, and initial metal ion concentration were investigated to determine the optimum sorption conditions. Adsorption equilibrium data were better fitted by a Langmuir isotherm. The adsorption capacity of Eu3+ on the AFHs was 0.89 mM/g. Desorption studies were also performed in acid media and EDTA, to observe whether the gels can be utilized as reusable tool for the metal ion removal. Metal ion sorption studies shows that AFHs can be used for removal of Eu3+ ions from aqueous solutions. Adsorption dat...

Research paper thumbnail of Pectin/poly(acrylamide- co -acrylamidoglycolic acid) pH sensitive semi-IPN hydrogels: selective removal of Cu 2+ and Ni 2+ , modeling, and kinetic studies

Desalination and Water Treatment, 2015

Ill Lee (2015):

Research paper thumbnail of Chitosan-poly(aminopropyl/phenylsilsesquioxane) hybrid nanocomposite membranes for antibacterial and drug delivery applications

Polymer International, 2014

ABSTRACT In this paper we fabricated hybrid membranes from chitosan (CS) and poly(aminopropyl/ ph... more ABSTRACT In this paper we fabricated hybrid membranes from chitosan (CS) and poly(aminopropyl/ phenyl silsesquioxane) (PAPSQ) (CSSQ) blends via a sol-gel reaction and solution casting followed by crosslinking with glutaraldehyde. The CSSQ membranes were then used for loading of 5-fluorouracil (5-FU) as an anticancer drug as well as templates for the production of silver nanoparticles (AgNPs). The physicochemical properties of the CSSQ membranes were examined by UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy (SEM). SEM results showed the controllable formation of AgNPs around PAPSQ. CSSQ-Ag nanocomposite membranes exhibited good antibacterial activity towards both Escherichia Coli and Bacilli subtilis, while CSSQ membranes worked as good carriers for controlled release of 5-FU as model drug. The results suggest that both CSSQ and CSSQ-Ag nanocomposite membranes can be potentially applied for biomedical applications such as controlled release carriers as well as an antibacterial wound dressing materials.

Research paper thumbnail of Synthesis, characterization, and metal uptake capacity of a new polyaniline and poly(acrylic acid) grafted sodium alginate/gelatin adsorbent

Desalination and Water Treatment, 2014

The present work reports the development of new (sodium alginate-gelatin (SAG))-g-poly (acrylic a... more The present work reports the development of new (sodium alginate-gelatin (SAG))-g-poly (acrylic acid)/polyaniline (SAPAPN) from sodium alginate/gelatin blend by cross-linking with glutaraldehyde, followed by grafting with poly(acrylic acid) and polyaniline by free radical polymerization using ammonium persulfate. The structure, thermal stability, and morphology of SAPAPN adsorbent was characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, and scanning electron microscopy, and results were consistent with the expected structures. The influence of various experimental conditions like pH, time, and initial feed concentrations on the uptake of metal ions like Cu 2+ , Ni 2+ by SAPAPN adsorbent was tested. It was seen that the adsorption equilibrium data could be fitted to the Langmuir isotherm. Desorption studies were performed in acid media and EDTA, to examine whether the SAPAPN adsorbent can be recycled for the metal ion removal. The results showed that with SAPAPN adsorbent, the maximum metal ion uptake achieved is 0.8386 mMg À1 for Cu 2+ and 2.2026 mMg À1 for Ni 2+ , respectively. Metal ion sorption studies showed that the adsorbent can be used for the removal of hazardous metal ions from aqueous solutions. The copper and nickel uptake achieved suggests the potential use of the adsorbent to extract divalent toxic metals from industrial aqueous streams.