Papers by Srinivasa Popuri
Desalination and Water Treatment, 2016
AbstractThe present study describes the development of novel sodium alginate–gelatin (SAG) blend ... more AbstractThe present study describes the development of novel sodium alginate–gelatin (SAG) blend membranes for the removal of copper(II) and nickel(II) ions from aqueous solutions through sorption. The SAG blend membranes were chemically crosslinked by various crosslinkers, such as glutaraldehyde (GA), urea-formaldehyde (UF) and thiourea-formaldehyde (TF) in order to enhance the strength of the membranes and reduce their swelling behaviour in presence of water. The resulting membranes were extensively characterized by FTIR, SEM and DSC to study various structural aspects of the membranes. Equilibrium swelling experiments were performed on SAG membranes in metal ion solutions at 30°C. The effect of contact time, initial pH and initial metal ion concentration on the sorption behaviour of the membranes was investigated. The adsorption capacities of copper(II) and nickel(II) on the SAG (SAG-GA/UF/TF) membranes as obtained from Langmuir adsorption isotherm were found to be 0.4284, 0.5307, 0.6847 mM/g and 1.756...
Journal of Material Cycles and Waste Management, 2016
An integrated process flow sheet for the recovery of yttrium and europium from waste cathode-ray ... more An integrated process flow sheet for the recovery of yttrium and europium from waste cathode-ray tube (CRT) phosphors was developed. This flow sheet is based on a sequence of roasting, leaching with organic acids and precipitation steps. Zinc was efficiently removed from the roasted CRT phosphors by leaching with acetic acid, giving access to the rare earth content. Yttrium and europium were quantitatively leached from the residue by a 1 mol L À1 methanesulphonic acid (MSA) solution. Precipitation with oxalic acid gave a mixed Y/Eu oxalate of high purity (>99 wt%). Co-precipitation of zinc was less than 2 wt%.
a b s t r a c t A new biosorbent was developed by coating chitosan, a naturally and abundantly av... more a b s t r a c t A new biosorbent was developed by coating chitosan, a naturally and abundantly available biopolymer, on to polyvinyl chloride (PVC) beads. The biosorbent was characterized by FTIR spectra, porosity and surface area analyses. Equilibrium and column flow adsorption characteristics of copper(II) and nickel(II) ions on the biosorbent were studied. The effect of pH, agitation time, concentration of adsorbate and amount of adsorbent on the extent of adsorption was investigated. The experimental data were fitted to Langmuir and Freundlich adsorption isotherms. The data were analyzed on the basis of Lagergren pseudo first order, pseudo-second order and Weber-Morris intraparticle diffusion models. The maximum monolayer adsorption capacity of chitosan coated PVC sorbent as obtained from Langmuir adsorption isotherm was found to be 87.9 mg g À1 for Cu(II) and 120.5 mg g À1 for Ni(II) ions, respectively. In addition, breakthrough curves were obtained from column flow experiments...
Environmental science and pollution research international, 2017
Microbial fuel cells (MFCs) are emerging technology for wastewater treatment by chemical oxygen d... more Microbial fuel cells (MFCs) are emerging technology for wastewater treatment by chemical oxygen demand (COD) reduction and simultaneous bioelectricity production. Fabrication of an effective proton exchange membrane (PEM) is a vital component for MFC performance. In this work, green chitosan-based (CS) PEMs were fabricated with graphene oxide (GO) as filler material (CS-GO) and cross-linked with phosphoric acid (CS-GO-P(24)) or sulfuric acid (CS-GO-S(24)) to determine their effect on PEM properties. Interrogation of the physicochemical, thermal, and mechanical properties of the cross-linked CS-GO PEMs demonstrated that ionic cross-linking based on the incorporation of PO4(3-) groups in the CS-GO mixed-matrix composites, when compared with sulfuric acid cross-linking commonly used in proton exchange membrane fuel cell (PEMFC) studies, generated additional density of ionic cluster domains, rendered enhanced sorption properties, and augmented the thermal and mechanical stability of the...
Powder Metallurgy and Metal Ceramics, 2016
The Taguchi robust design method is implemented for the optimization of experimental conditions i... more The Taguchi robust design method is implemented for the optimization of experimental conditions in the synthesis of high-purity ultrafine copper powder (HUCP) in mass-production by the chemical reduction method. A reducing agent, reaction temperature, reducing agent weight, and a stirring rate are chosen as the major optimization factors and the conversion rate, particle size, and reaction time are chosen as the desired targets. It is established that the reducing agent and the reaction temperature are the most significant factors that affect the desired targets. Among the selected or designed factors, the optimal conditions for producing the HUCP are: NaH2PO2 · H2O as the reducing agent (level 2), temperature 70°C (level 3), a reducing agent weight of 8.14 kg (level 3), and a stirring rate 300 rpm (level 2). The study results for the three desired targets are in agreement with the prediction made by the Taguchi method. Furthermore, the pure (impurity <0.06%) facecentered cubic structure of the HUCP with 1.51 μm average particle size is extensively characterized and determined by inductively coupled plasma–optical emission spectrometer (ICP–OES), laser particle-size analyzer (DLS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. This surfactant-free facility method is suitable for the synthesis of highpurity ultrafine copper powder by mass-production method.
Http Dx Doi Org 10 1080 19443994 2013 826779, 2014
Carbohydrate polymers, Jan 20, 2016
The effects of plasticization and cross-linking on the performance of chitosan as promising proto... more The effects of plasticization and cross-linking on the performance of chitosan as promising proton exchange membranes (PEMs) for bioelectricity generation in microbial fuel cells (MFCs) were investigated. The physico-chemical properties of chitosan (CS), sorbitol-chitosan (S-CS), phosphorylated-chitosan (CS-P) and phosphorylated-sorbitol-chitosan (S-CS-P) membranes were investigated by FESEM-EDS, FTIR-ATR, XRD, TGA, tensile strength and sorption studies. The performance of the fabricated PEMs was assessed by power density and cation exchange capacity (CEC). Maximum power densities achieved were 130.03, 20.76, 94.59 and 7.42mW/m(2) for CS-P, S-CS-P, S-CS and CS membranes respectively. Phosphorylation of the CS membranes increased CEC and tensile strength, attributed to an increase in bonded amide and phosphate ionic surface groups. Further, 49.07% COD removal from municipal wastewater was achieved with CS-P membranes. Thus, through chemical modifications, the physico-chemical and mec...
International Biodeterioration & Biodegradation, 2014
Desalination and Water Treatment, 2015
Desalination, 2011
... a Department of Biological & Chemical Sciences, The University of the West Indies, Cave H... more ... a Department of Biological & Chemical Sciences, The University of the West Indies, Cave Hill Campus, St. Michael, 11000, Barbados. b College of Sustainable Environment, Chia Nan University of Pharmacy and Science, 60, Erh-Jen Road, Sec. 1, Jen-Te, Tainan 71710, Taiwan ...
Desalination and Water Treatment, 2016
The present study describes the development of novel sodium alginate–gelatin (SAG) blend membrane... more The present study describes the development of novel sodium alginate–gelatin (SAG) blend membranes for the removal of copper(II) and nickel(II) ions from aqueous solutions through sorption. The SAG blend membranes were chemically crosslinked by various crosslinkers, such as glutaraldehyde (GA), urea-formaldehyde (UF) and thiourea-formaldehyde (TF) in order to enhance the strength of the membranes and reduce their swelling behaviour in presence of water. The resulting membranes were extensively characterized by FTIR, SEM and DSC to study various structural aspects of the membranes. Equilibrium swelling experiments were performed on SAG membranes in metal ion solutions at 30°C. The effect of contact time, initial pH and initial metal ion concentration on the sorption behaviour of the membranes was investigated. The adsorption capacities of copper(II) and nickel(II) on the SAG (SAG-GA/UF/TF) membranes as obtained from Langmuir adsorption isotherm were found to be 0.4284, 0.5307, 0.6847 mM/g and 1.7567, 3.3329, 4.1 mM/g, respectively.
Environmental engineering and management journal
Indian journal of environmental health
Studies on removal of Ni2+ by adsorption on flyash and acid treated flyash have been carried out ... more Studies on removal of Ni2+ by adsorption on flyash and acid treated flyash have been carried out at room temperature (30+/-1 degrees C). The adsorption isotherm of Ni2+ on flyash and acid treated flyash was obtained in a batch reactor. Various parameters such as pH, initial concentration of adsorbate and adsorbent dose were studied. The experimental adsorption data fitted reasonably well to Langmuir, Freundlich and Redlich - Peterson isotherms for both the adsorbents. The adsorption follows Lagergren first order kinetic model. The monolayer adsorption model are found to be 41.7 and 62.9 mg/g respectively. Acid treated flyash has been observed to have greater adsorptive capacity than flyash in natural form.
Polish Journal of Chemical Technology, 2015
ABSTRACT
Biosorption of chromium (VI) on prawn pond biomass Sphaeroplea algae in natural and acid treated ... more Biosorption of chromium (VI) on prawn pond biomass Sphaeroplea algae in natural and acid treated forms has been studied by using batch technique. The equilibrium biosorption level is a function of solution pH, agitation time, initial metal ion concentration and adsorbent ...
Journal of Material Cycles and Waste Management, 2015
ABSTRACT
International Biodeterioration & Biodegradation, 2014
ABSTRACT Chitosan Nanoparticles were used as a novel material for the separation of Europium from... more ABSTRACT Chitosan Nanoparticles were used as a novel material for the separation of Europium from aqueous solutions.•The biosorption of Europium onto crab shell particles and chitosan nanoparticles was evaluated.•Various operational conditions were studied and chitosan nanoparticles proved to be a more effective sorbent for Europium.•Kinetics was Pseudo-second order and Weber–Morris models confirmed that intraparticle diffusion was the rate-limiting step.•The data was fitted to the Langmuir, Freundlich and Temkin isotherms to best describe the mechanism of Eu sorption.
International Biodeterioration & Biodegradation, 2015
ABSTRACT Taiwan is one of the leading manufacturers of florescent lamps worldwide, which has subs... more ABSTRACT Taiwan is one of the leading manufacturers of florescent lamps worldwide, which has subsequently contributed to the Europium containing waste generation. This study investigated the use of natural, ecofriendly and biodegradable materials, such as Arthrobacter sp., chitosan powder and chitosan beads to remove the rare-earth europium ion from aqueous solutions. Initial studies were conducted in batch mode where the function of time, pH and metal ion concentration on Europium(III) ion adsorption were investigated. The kinetic data was fitted to Lagergren pseudo-first order, pseudo-second order, Weber–Morris and the particle-controlled diffusion models. It was deduced that adsorption kinetics followed the pseudo-second order model. The experimental data was also fitted to isotherms of Langmuir, Freundlich and Temkin in order to investigate the sorption mechanism. The maximum monolayer adsorption capacities of the Arthrobacter sp., chitosan powder and chitosan beads were determined to be 9.53, 48.3 and 18.4 mg g−1 respectively. Thus, this method could be used for the removal of Europium(III) ion from industrial effluent to prevent soil contamination in agricultural soils, as Arthrobacter sp. exist in soils. Characterization and ligand complexation behavior were investigated by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy analysis (SEM).
Toxicological & Environmental Chemistry, 2007
... DOI: 10.1080/02772240601156650 J. Ajitha Priya a , P. Srinivasa Rao b , Y. Vijaya a , A. Subb... more ... DOI: 10.1080/02772240601156650 J. Ajitha Priya a , P. Srinivasa Rao b , Y. Vijaya a , A. Subba Reddy a &amp; Professor A. Krishnaiah a * pages 421-442. Available online: 01 Aug 2011. ...
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Papers by Srinivasa Popuri