Mallikarjuna Nadagouda | United States Environmental Protection Agency (original) (raw)
Papers by Mallikarjuna Nadagouda
Membrane Processes for the Separation of Potential Emerging Pollutants -Review Article
European Polymer Journal, 1998
ÐEight novel polyurea-imides were prepared by a three-step reaction procedure. First, the ureylen... more ÐEight novel polyurea-imides were prepared by a three-step reaction procedure. First, the ureylene linkage chain-extended diamines (UCD) were synthesized by the reaction of 1 mol 2,4-diisocyanato toluene with 2 mol of a diamine in the presence of pyridine below 58C; the condensation polymerization then took place between UCD and 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) or pyromellitic dianhydride (PMDA), forming polyurea-amic acids (PUA). The polyurea-imides (PUI) were ®nally obtained by imidizing the resulting PUA thermally. UCD were characterized by elemental analysis, IR, 1 r-NMR and TG-DTA; PUA were investigated by IR, 1 r-NMR and TG-DTA; and PUI by interfacial tension in addition to IR and TG-DTA. The results of the interfacial tension of the PUI indicate that, not only the choice of diamines and dianhydrides with dierent structures, but also, the introduction of ureylene linkage into polyimides are eective approaches to the modi®cation of polyimide's interface. However, the thermal stability of the PUI is generally decreased in comparison with the corresponding homopolyimides due to the introduction of the ureylene linkage in the backbone.
Chemical Engineering Journal, 2018
Phosphorus is an essential and limited nutrient that is supplied by a depleting resource, mineral... more Phosphorus is an essential and limited nutrient that is supplied by a depleting resource, mineral phosphate rock. Eutrophication is occurring in many water bodies which provides an opportunity to recover this nutrient from the water. One method of recovery is through adsorption; this study focused on fabricating a porous and granular adsorptive material for the removal and recovery of phosphate. Magnesium carbonate was combined with cellulose in varying weight ratios (0, 5, 10, 15, 20%) to synthesize pellets, which were then calcined to increase internal surface area. Physiochemical properties such as surface area, surface morphology, elemental composition, and crystal structure of the materials were characterized using Brunauer, Emmett, and Teller (BET) surface area analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The pellet proved to be uniform in composition and an increase in BET surface area correlated with an increase in cellulose content until pellet stability was lost. Phosphate adsorption using the pellets was studied via batch kinetics and sorption isotherms. The pseudo-second-order kinetics model fits best suggesting that the adsorption occurring was chemisorption. The isotherm model that fit best was the Langmuir isotherm, which showed that the maximum equilibrium adsorption capacity increased with an increase in cellulose content between 10% and 20%. The average adsorption capacity achieved in the triplicate isotherm study was 96.4 mg g-1 for pellets synthesized with 15% cellulose. Overall, using cellulose and subsequent calcination created an additional internal surface area for adsorption of phosphate and suggested that granular materials can be modified for efficient removal and recovery of phosphate from water.
Following a pH reduction in their drinking water over a span of more than 20 years, the City of N... more Following a pH reduction in their drinking water over a span of more than 20 years, the City of Newark, New Jersey, has struggled with elevated lead (Pb) release from Pb service lines and domestic plumbing in the zone fed by the Pequannock Water Treatment Plant. In response, Newark initiated orthophosphate addition and provided faucet-mounted point-of-use (POU) filters and pitcher filters certified for Pb and particulate reduction under NSF/ANSI Standards 53 and 42 to residential homes in that zone. Water chemistry analysis and size fractionation sampling were
Environmental Science: Nano, 2021
Magnetite and graphene have been combined in a heterojunction which results in efficient activati... more Magnetite and graphene have been combined in a heterojunction which results in efficient activation of inorganic peroxides for the removal of antibiotics from water via a non-radical pathway (electron-mediated transfer) and easily recoverable after use.
ACS Omega, 2021
A variety of methods, including chemical precipitation, biological phosphorus elimination, and ad... more A variety of methods, including chemical precipitation, biological phosphorus elimination, and adsorption, have been described to effectively eliminate phosphorus (P) in the form of phosphate (PO 4 3−) from wastewater sources. Adsorption is a simple and easy method. It shows excellent removal performance, cost effectiveness, and the substantial option of adsorbent materials. Therefore, it has been recognized as a practical, environmentally friendly, and reliable treatment method for eliminating P. Nanocomposites have been deployed to remove P from wastewater via adsorption. Nanocomposites offer low-temperature alteration, high specific surface area, adjustable surface chemistry, pore size, many adsorption sites, and rapid intraparticle diffusion distances. In this Mini-Review, we have aimed to summarize the last eight years of progress in P removal using graphene-based composites via adsorption. Ultimately, future perspectives have been presented to boost the progress of this encouraging field.
Membranes, 2022
Municipal wastewater has been identified as a potential source of natural phosphorus (P) that is ... more Municipal wastewater has been identified as a potential source of natural phosphorus (P) that is projected to become depleted in a few decades based on current exploitation rates. This paper focuses on combining a bench-scale anaerobic/anoxic/aerobic membrane bioreactor (MBR) and magnesium carbonate (MgCO3)-based pellets to effectively recover P from municipal wastewater. Ethanol was introduced into the anoxic zone of the MBR system as an external carbon source to improve P release via the enhanced biological phosphorus removal (EBPR) mechanism, making it available for adsorption by the continuous-flow MgCO3 pellet column. An increase in the concentration of P in the MBR effluent led to an increase in the P adsorption capacity of the MgCO3 pellets. As a result, the anaerobic/anoxic/aerobic MBR system, combined with a MgCO3 pellet column and ethanol, achieved 91.6% P recovery from municipal wastewater, resulting in a maximum P adsorption capacity of 12.8 mg P/g MgCO3 through the cont...
Journal of Environmental Management, 2020
Phosphate is one of the most costly and complex environmental pollutants that leads to eutrophica... more Phosphate is one of the most costly and complex environmental pollutants that leads to eutrophication, which decreases water quality and access to clean water. Among different adsorbents, biochar is one of the promising adsorbents for phosphate removal as well as heavy metal removal from an aqueous solution. In this study, biochar was impregnated with nano zinc oxide in the presence of glycine betaine. The Zinc Oxide Betaine-Modified Biochar Nanocomposites (ZnOBBNC) proved to be an excellent adsorbent for the removal of phosphate, exhibiting a maximum adsorption capacity of phosphate (265.5 mg. g-1) and fast adsorption kinetics (~100% removal at 15 min at 10 mg. L-1 phosphate and 3 g. L-1 nanocomposite dosage) in phosphate solution. The synthesis of these benign ZnOBBNC involves a process that is eco-friendly and economically feasible. From material characterization, we found that the ZnOBBNC has ~20-30 nm particle size, high surface area (100.01 m2. g-1), microporous (25.79 Å) structures, and 7.64% zinc content. The influence of pH (2-10), coexisting anions (Cl-, CO32-, NO3- and SO43-), initial phosphate concentration (10-500 mg. L-1), and ZnOBBNC dosage (0.5-5 g. L-1) were investigated in batch experiments. From the adsorption isotherms data, the adsorption of phosphate using ZnOBBNC followed Langmuir isotherm (R2 = 0.9616), confirming the mono-layered adsorption mechanism. The kinetic studies showed that the phosphate adsorption using ZnOBBNC followed the pseudo-second-order model (R2 = 1.0000), confirming the chemisorption adsorption mechanism with inner-sphere complexion. Our results demonstrated ZnOBBNC as a suitable, competitive candidate for phosphate removal from both mock lab-prepared and real field-collected wastewater samples when compared to commercial nanocomposites.
Water, 2018
Various compositions of barium carbonate (BaCO3) loaded polycaprolactone (PCL) composites were pr... more Various compositions of barium carbonate (BaCO3) loaded polycaprolactone (PCL) composites were prepared, including 2.5/97.5, 10/90, 30/70, 50/50 and 90/10 (PCL/BaCO3), via re-precipitation technique. Small-scale column tests were conducted to study the efficiency of sulfate removal using the PCL/BaCO3 composites. The composites before and after their use to remove sulfate were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and thermogravimetric analysis (TGA). As PCL is a biodegradable polymer, these composites are environmentally friendly and have several advantages over barium sulfate precipitation in overcoming clogging issues in filters or resins due to collection of natural organic matter (NOM). The media used in this study exhibited high capacity and was able to remove more than 90% sulfate from synthetic sulfate containing w...
Electrochimica Acta, 2017
Highlights 3D graphene-based biosensors can detect MC-LR with remarkable sensitivity. Good li... more Highlights 3D graphene-based biosensors can detect MC-LR with remarkable sensitivity. Good linear correlation between electron-transfer resistance and MC-LR concentration.
Polymer News, 2005
ABSTRACT The Center of Excellence in Polymer Science (CEPS) was established in the year 2002 with... more ABSTRACT The Center of Excellence in Polymer Science (CEPS) was established in the year 2002 with the massive financial support from University Grants Commission, New Delhi. The center has created new infrastructure to carry out research in the areas of Membrane Science, Drug Delivery, and Molecular Modeling. The experimental and computational facilities at CEPS were inaugurated on December 17, 2004 at 10:30 AM by lighting the lamps by Professor Alan G. MacDiarmid, James Von Ehr Distinguished Chair in Science and Technology, Professor of Chemistry and Physics, University of Texas (UTD) at Dallas and Nobel Laureate in Chemistry, year 2000. Professor Sanjeev K. Manohar, UTD and Professor Padmakar V. Kulkarni, University of Texas Southwestern Medical Center (UTSWMC), Dallas were also present.
Polymer News, 2005
... Nadagouda N. Mallikarjuna a , Sanjeev K. Manohar a & Tejraj M. Aminabhavi b pages 6-13. .... more ... Nadagouda N. Mallikarjuna a , Sanjeev K. Manohar a & Tejraj M. Aminabhavi b pages 6-13. ... A novel gas-phase purification method for a CNT was developed by Zimmerman et al. [4747. Zimmerman, JL, Bradley, RK, Huffman, CB, Hauge, RH and Margrave, JL 2000. Chem. ...
Environmental Toxicology and Chemistry, 2010
Relatively little is known about the behavior and toxicity of nanoparticles in the environment. O... more Relatively little is known about the behavior and toxicity of nanoparticles in the environment. Objectives of work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of a commonly used bioassay for testing AgNPs, and determining the advantages and disadvantages of multiple characterization techniques for AgNPs in simple aquatic systems. Daphnia magna were exposed to a silver nitrate solution and AgNPs suspensions including commercially available AgNPs (uncoated and coated), and laboratory-synthesized AgNPs (coated with coffee or citrate). The nanoparticle suspensions were analyzed for silver concentration (microwave acid digestions), size (dynamic light scattering and electron microscopy), shape (electron microscopy), surface charge (zeta potentiometer), and chemical speciation (X-ray absorption spectroscopy, X-ray diffraction). Toxicities of filtered (100 nm) versus unfiltered suspensions were compared. Additionally, effects from addition of food were examined. Stock suspensions were prepared by adding AgNPs to moderately hard reconstituted water, which were then diluted and used straight or after filtration with 100-nm filters. All nanoparticle exposure suspensions, at every time interval, were digested via microwave digester and analyzed by inductively coupled argon plasma-optical emission spectroscopy or graphite furnaceatomic absorption spectroscopy. Dose-response curves were generated and median lethal concentration (LC50) values calculated. The LC50 values for the unfiltered particles were (in mg/L): 1.1 AE 0.1-AgNO 3 ; 1.0 AE 0.1-coffee coated; 1.1 AE 0.2-citrate coated; 16.7 AE 2.4 Sigma Aldrich Ag-nanoparticles (SA) uncoated; 31.5 AE 8.1 SA coated. LC50 values for the filtered particles were (in mg/L): 0.7 AE 0.1-AgNO 3 ; 1.4 AE 0.1-SA uncoated; 4.4 AE 1.4-SA coated. The LC50 resulting from the addition of food was 176.4 AE 25.5-SA coated. Recommendations presented in this study include AgNP handling methods, effects from sample preparation, and advantages/ disadvantages of different nanoparticle characterization techniques.
Catalysis Communications, 2013
ABSTRACT Preferential oxidation of target chemicals of concern has been a challenging issue in Ti... more ABSTRACT Preferential oxidation of target chemicals of concern has been a challenging issue in TiO2 photocatalysis, considering typical source water contains low concentrations of highly toxic substances along with high concentrations of less toxic naturally abundant organic matter (NOM). This study demonstrates simply controlling the porous structure of TiO2 can suppress the access of large size NOM to the TiO2 and thus improve the selective oxidation of small size target contaminants. Ibuprofen as a target contaminant was successfully decomposed even in the presence of humic acid as competing NOM. Selectivity enhancement mechanism was proposed, based on size exclusion principle.
Journal of Controlled Release, 2005
Alzheimer's disease (AD) is the most common cause of dementia among the elderly, affecting 5% of ... more Alzheimer's disease (AD) is the most common cause of dementia among the elderly, affecting 5% of Americans over age 65, and 20% over age 80. An excess of senile plaques (h-amyloid protein) and neurofibrillary tangles (tau protein), ventricular enlargement, and cortical atrophy characterizes it. Unfortunately, targeted drug delivery to the central nervous system (CNS), for the therapeutic advancement of neurodegenerative disorders such as Alzheimer's, is complicated by restrictive mechanisms imposed at the blood-brain barrier (BBB). Opsonization by plasma proteins in the systemic circulation is an additional impediment to cerebral drug delivery. This review gives an account of the BBB and discusses the literature on biodegradable polymeric nanoparticles (NPs) with appropriate surface modifications that can deliver drugs of interest beyond the BBB for diagnostic and therapeutic applications in neurological disorders, such as AD. The physicochemical properties of the NPs at different surfactant concentrations, stabilizers, and amyloid-affinity agents could influence the transport mechanism.
ChemCatChem
Copper doped‐TiO2 (P25) nanomaterials have been intensively studied as promising catalysts for H2... more Copper doped‐TiO2 (P25) nanomaterials have been intensively studied as promising catalysts for H2 production by photo‐reforming of selected organic compounds. However, the role of copper oxidation states on the improvement of photocatalytic activity is still debated. In this work, CuOx‐impregnated P25‐TiO2 catalysts were used for photocatalytic production of hydrogen from methanol. Copper species/oxidation states both in the as‐prepared catalysts and after the photocatalytic process were investigated. To this purpose, H2 production rates were correlated to physico‐chemical properties of the samples, both before and after photocatalytic process, by means of Raman, X‐Ray Diffraction, Electron Paramagnetic Resonance spectroscopy, X‐Ray Photoelectron Spectroscopy, Temperature‐Programmed Reduction and High Resolution Transmission Electron Microscope techniques. Results revealed the presence of both Cu2O and CuO deposits on the samples surface after calcination. Notably, under near‐UV irradiation, the fraction of highly dispersed CuO particles undergo a partial dissolution process, followed by reduction to metallic copper Cu(s) by photogenerated electrons, boosting H2 production rate. Our findings indicate that both Cu2O and Cu(s) act as co‐catalysts for H2 generation, yet by different mechanisms. Overall this study, provides the basis to enhance catalytic performance of red‐ox active systems through UV‐irradiation approach.
... Daniel M. Neumark J. Phys. Chem. ... Daniel M. Neumark is currently Professor of Chemistry at... more ... Daniel M. Neumark J. Phys. Chem. ... Daniel M. Neumark is currently Professor of Chemistry at the University of California, Berkeley and has been Director of the Chemical Sciences Division at Lawrence Berkeley National Laboratory since 2000. ...
Magnetic manganese ferrites were created in the laboratory using a novel combustion method in ord... more Magnetic manganese ferrites were created in the laboratory using a novel combustion method in order to blend the catalytic properties of manganese (Mn) with the magnetic and structural properties of ferrites. The developed synthesis method involved mixing Mn and iron (Fe) nitrate (NO3) salts with polyvinyl alcohol (PVA) followed by calcination. The resulting synthesis method is a scaleable and a simplified synthesis pathway. Preparation studies varying the Mn:Fe stoichiometric ratio and PVA content during synthesis revealed that PVA content above 1:1.5 NO3:PVA is required to form manganese ferrites. XRD, SEM-EDS, carbon content, and BET surface area analysis confirmed that the developed method yielded manganese ferrites of the form Mn2.5Fe0.5O4, MnFe2O4, and Mn0.5Fe2.5O4. The manganese ferrites were then used to remove methylene blue dye from an aqueous solution as a proof-of-concept study to demonstrate their reactivity and use as a treatment technology.
Membrane Processes for the Separation of Potential Emerging Pollutants -Review Article
European Polymer Journal, 1998
ÐEight novel polyurea-imides were prepared by a three-step reaction procedure. First, the ureylen... more ÐEight novel polyurea-imides were prepared by a three-step reaction procedure. First, the ureylene linkage chain-extended diamines (UCD) were synthesized by the reaction of 1 mol 2,4-diisocyanato toluene with 2 mol of a diamine in the presence of pyridine below 58C; the condensation polymerization then took place between UCD and 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) or pyromellitic dianhydride (PMDA), forming polyurea-amic acids (PUA). The polyurea-imides (PUI) were ®nally obtained by imidizing the resulting PUA thermally. UCD were characterized by elemental analysis, IR, 1 r-NMR and TG-DTA; PUA were investigated by IR, 1 r-NMR and TG-DTA; and PUI by interfacial tension in addition to IR and TG-DTA. The results of the interfacial tension of the PUI indicate that, not only the choice of diamines and dianhydrides with dierent structures, but also, the introduction of ureylene linkage into polyimides are eective approaches to the modi®cation of polyimide's interface. However, the thermal stability of the PUI is generally decreased in comparison with the corresponding homopolyimides due to the introduction of the ureylene linkage in the backbone.
Chemical Engineering Journal, 2018
Phosphorus is an essential and limited nutrient that is supplied by a depleting resource, mineral... more Phosphorus is an essential and limited nutrient that is supplied by a depleting resource, mineral phosphate rock. Eutrophication is occurring in many water bodies which provides an opportunity to recover this nutrient from the water. One method of recovery is through adsorption; this study focused on fabricating a porous and granular adsorptive material for the removal and recovery of phosphate. Magnesium carbonate was combined with cellulose in varying weight ratios (0, 5, 10, 15, 20%) to synthesize pellets, which were then calcined to increase internal surface area. Physiochemical properties such as surface area, surface morphology, elemental composition, and crystal structure of the materials were characterized using Brunauer, Emmett, and Teller (BET) surface area analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The pellet proved to be uniform in composition and an increase in BET surface area correlated with an increase in cellulose content until pellet stability was lost. Phosphate adsorption using the pellets was studied via batch kinetics and sorption isotherms. The pseudo-second-order kinetics model fits best suggesting that the adsorption occurring was chemisorption. The isotherm model that fit best was the Langmuir isotherm, which showed that the maximum equilibrium adsorption capacity increased with an increase in cellulose content between 10% and 20%. The average adsorption capacity achieved in the triplicate isotherm study was 96.4 mg g-1 for pellets synthesized with 15% cellulose. Overall, using cellulose and subsequent calcination created an additional internal surface area for adsorption of phosphate and suggested that granular materials can be modified for efficient removal and recovery of phosphate from water.
Following a pH reduction in their drinking water over a span of more than 20 years, the City of N... more Following a pH reduction in their drinking water over a span of more than 20 years, the City of Newark, New Jersey, has struggled with elevated lead (Pb) release from Pb service lines and domestic plumbing in the zone fed by the Pequannock Water Treatment Plant. In response, Newark initiated orthophosphate addition and provided faucet-mounted point-of-use (POU) filters and pitcher filters certified for Pb and particulate reduction under NSF/ANSI Standards 53 and 42 to residential homes in that zone. Water chemistry analysis and size fractionation sampling were
Environmental Science: Nano, 2021
Magnetite and graphene have been combined in a heterojunction which results in efficient activati... more Magnetite and graphene have been combined in a heterojunction which results in efficient activation of inorganic peroxides for the removal of antibiotics from water via a non-radical pathway (electron-mediated transfer) and easily recoverable after use.
ACS Omega, 2021
A variety of methods, including chemical precipitation, biological phosphorus elimination, and ad... more A variety of methods, including chemical precipitation, biological phosphorus elimination, and adsorption, have been described to effectively eliminate phosphorus (P) in the form of phosphate (PO 4 3−) from wastewater sources. Adsorption is a simple and easy method. It shows excellent removal performance, cost effectiveness, and the substantial option of adsorbent materials. Therefore, it has been recognized as a practical, environmentally friendly, and reliable treatment method for eliminating P. Nanocomposites have been deployed to remove P from wastewater via adsorption. Nanocomposites offer low-temperature alteration, high specific surface area, adjustable surface chemistry, pore size, many adsorption sites, and rapid intraparticle diffusion distances. In this Mini-Review, we have aimed to summarize the last eight years of progress in P removal using graphene-based composites via adsorption. Ultimately, future perspectives have been presented to boost the progress of this encouraging field.
Membranes, 2022
Municipal wastewater has been identified as a potential source of natural phosphorus (P) that is ... more Municipal wastewater has been identified as a potential source of natural phosphorus (P) that is projected to become depleted in a few decades based on current exploitation rates. This paper focuses on combining a bench-scale anaerobic/anoxic/aerobic membrane bioreactor (MBR) and magnesium carbonate (MgCO3)-based pellets to effectively recover P from municipal wastewater. Ethanol was introduced into the anoxic zone of the MBR system as an external carbon source to improve P release via the enhanced biological phosphorus removal (EBPR) mechanism, making it available for adsorption by the continuous-flow MgCO3 pellet column. An increase in the concentration of P in the MBR effluent led to an increase in the P adsorption capacity of the MgCO3 pellets. As a result, the anaerobic/anoxic/aerobic MBR system, combined with a MgCO3 pellet column and ethanol, achieved 91.6% P recovery from municipal wastewater, resulting in a maximum P adsorption capacity of 12.8 mg P/g MgCO3 through the cont...
Journal of Environmental Management, 2020
Phosphate is one of the most costly and complex environmental pollutants that leads to eutrophica... more Phosphate is one of the most costly and complex environmental pollutants that leads to eutrophication, which decreases water quality and access to clean water. Among different adsorbents, biochar is one of the promising adsorbents for phosphate removal as well as heavy metal removal from an aqueous solution. In this study, biochar was impregnated with nano zinc oxide in the presence of glycine betaine. The Zinc Oxide Betaine-Modified Biochar Nanocomposites (ZnOBBNC) proved to be an excellent adsorbent for the removal of phosphate, exhibiting a maximum adsorption capacity of phosphate (265.5 mg. g-1) and fast adsorption kinetics (~100% removal at 15 min at 10 mg. L-1 phosphate and 3 g. L-1 nanocomposite dosage) in phosphate solution. The synthesis of these benign ZnOBBNC involves a process that is eco-friendly and economically feasible. From material characterization, we found that the ZnOBBNC has ~20-30 nm particle size, high surface area (100.01 m2. g-1), microporous (25.79 Å) structures, and 7.64% zinc content. The influence of pH (2-10), coexisting anions (Cl-, CO32-, NO3- and SO43-), initial phosphate concentration (10-500 mg. L-1), and ZnOBBNC dosage (0.5-5 g. L-1) were investigated in batch experiments. From the adsorption isotherms data, the adsorption of phosphate using ZnOBBNC followed Langmuir isotherm (R2 = 0.9616), confirming the mono-layered adsorption mechanism. The kinetic studies showed that the phosphate adsorption using ZnOBBNC followed the pseudo-second-order model (R2 = 1.0000), confirming the chemisorption adsorption mechanism with inner-sphere complexion. Our results demonstrated ZnOBBNC as a suitable, competitive candidate for phosphate removal from both mock lab-prepared and real field-collected wastewater samples when compared to commercial nanocomposites.
Water, 2018
Various compositions of barium carbonate (BaCO3) loaded polycaprolactone (PCL) composites were pr... more Various compositions of barium carbonate (BaCO3) loaded polycaprolactone (PCL) composites were prepared, including 2.5/97.5, 10/90, 30/70, 50/50 and 90/10 (PCL/BaCO3), via re-precipitation technique. Small-scale column tests were conducted to study the efficiency of sulfate removal using the PCL/BaCO3 composites. The composites before and after their use to remove sulfate were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and thermogravimetric analysis (TGA). As PCL is a biodegradable polymer, these composites are environmentally friendly and have several advantages over barium sulfate precipitation in overcoming clogging issues in filters or resins due to collection of natural organic matter (NOM). The media used in this study exhibited high capacity and was able to remove more than 90% sulfate from synthetic sulfate containing w...
Electrochimica Acta, 2017
Highlights 3D graphene-based biosensors can detect MC-LR with remarkable sensitivity. Good li... more Highlights 3D graphene-based biosensors can detect MC-LR with remarkable sensitivity. Good linear correlation between electron-transfer resistance and MC-LR concentration.
Polymer News, 2005
ABSTRACT The Center of Excellence in Polymer Science (CEPS) was established in the year 2002 with... more ABSTRACT The Center of Excellence in Polymer Science (CEPS) was established in the year 2002 with the massive financial support from University Grants Commission, New Delhi. The center has created new infrastructure to carry out research in the areas of Membrane Science, Drug Delivery, and Molecular Modeling. The experimental and computational facilities at CEPS were inaugurated on December 17, 2004 at 10:30 AM by lighting the lamps by Professor Alan G. MacDiarmid, James Von Ehr Distinguished Chair in Science and Technology, Professor of Chemistry and Physics, University of Texas (UTD) at Dallas and Nobel Laureate in Chemistry, year 2000. Professor Sanjeev K. Manohar, UTD and Professor Padmakar V. Kulkarni, University of Texas Southwestern Medical Center (UTSWMC), Dallas were also present.
Polymer News, 2005
... Nadagouda N. Mallikarjuna a , Sanjeev K. Manohar a & Tejraj M. Aminabhavi b pages 6-13. .... more ... Nadagouda N. Mallikarjuna a , Sanjeev K. Manohar a & Tejraj M. Aminabhavi b pages 6-13. ... A novel gas-phase purification method for a CNT was developed by Zimmerman et al. [4747. Zimmerman, JL, Bradley, RK, Huffman, CB, Hauge, RH and Margrave, JL 2000. Chem. ...
Environmental Toxicology and Chemistry, 2010
Relatively little is known about the behavior and toxicity of nanoparticles in the environment. O... more Relatively little is known about the behavior and toxicity of nanoparticles in the environment. Objectives of work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of a commonly used bioassay for testing AgNPs, and determining the advantages and disadvantages of multiple characterization techniques for AgNPs in simple aquatic systems. Daphnia magna were exposed to a silver nitrate solution and AgNPs suspensions including commercially available AgNPs (uncoated and coated), and laboratory-synthesized AgNPs (coated with coffee or citrate). The nanoparticle suspensions were analyzed for silver concentration (microwave acid digestions), size (dynamic light scattering and electron microscopy), shape (electron microscopy), surface charge (zeta potentiometer), and chemical speciation (X-ray absorption spectroscopy, X-ray diffraction). Toxicities of filtered (100 nm) versus unfiltered suspensions were compared. Additionally, effects from addition of food were examined. Stock suspensions were prepared by adding AgNPs to moderately hard reconstituted water, which were then diluted and used straight or after filtration with 100-nm filters. All nanoparticle exposure suspensions, at every time interval, were digested via microwave digester and analyzed by inductively coupled argon plasma-optical emission spectroscopy or graphite furnaceatomic absorption spectroscopy. Dose-response curves were generated and median lethal concentration (LC50) values calculated. The LC50 values for the unfiltered particles were (in mg/L): 1.1 AE 0.1-AgNO 3 ; 1.0 AE 0.1-coffee coated; 1.1 AE 0.2-citrate coated; 16.7 AE 2.4 Sigma Aldrich Ag-nanoparticles (SA) uncoated; 31.5 AE 8.1 SA coated. LC50 values for the filtered particles were (in mg/L): 0.7 AE 0.1-AgNO 3 ; 1.4 AE 0.1-SA uncoated; 4.4 AE 1.4-SA coated. The LC50 resulting from the addition of food was 176.4 AE 25.5-SA coated. Recommendations presented in this study include AgNP handling methods, effects from sample preparation, and advantages/ disadvantages of different nanoparticle characterization techniques.
Catalysis Communications, 2013
ABSTRACT Preferential oxidation of target chemicals of concern has been a challenging issue in Ti... more ABSTRACT Preferential oxidation of target chemicals of concern has been a challenging issue in TiO2 photocatalysis, considering typical source water contains low concentrations of highly toxic substances along with high concentrations of less toxic naturally abundant organic matter (NOM). This study demonstrates simply controlling the porous structure of TiO2 can suppress the access of large size NOM to the TiO2 and thus improve the selective oxidation of small size target contaminants. Ibuprofen as a target contaminant was successfully decomposed even in the presence of humic acid as competing NOM. Selectivity enhancement mechanism was proposed, based on size exclusion principle.
Journal of Controlled Release, 2005
Alzheimer's disease (AD) is the most common cause of dementia among the elderly, affecting 5% of ... more Alzheimer's disease (AD) is the most common cause of dementia among the elderly, affecting 5% of Americans over age 65, and 20% over age 80. An excess of senile plaques (h-amyloid protein) and neurofibrillary tangles (tau protein), ventricular enlargement, and cortical atrophy characterizes it. Unfortunately, targeted drug delivery to the central nervous system (CNS), for the therapeutic advancement of neurodegenerative disorders such as Alzheimer's, is complicated by restrictive mechanisms imposed at the blood-brain barrier (BBB). Opsonization by plasma proteins in the systemic circulation is an additional impediment to cerebral drug delivery. This review gives an account of the BBB and discusses the literature on biodegradable polymeric nanoparticles (NPs) with appropriate surface modifications that can deliver drugs of interest beyond the BBB for diagnostic and therapeutic applications in neurological disorders, such as AD. The physicochemical properties of the NPs at different surfactant concentrations, stabilizers, and amyloid-affinity agents could influence the transport mechanism.
ChemCatChem
Copper doped‐TiO2 (P25) nanomaterials have been intensively studied as promising catalysts for H2... more Copper doped‐TiO2 (P25) nanomaterials have been intensively studied as promising catalysts for H2 production by photo‐reforming of selected organic compounds. However, the role of copper oxidation states on the improvement of photocatalytic activity is still debated. In this work, CuOx‐impregnated P25‐TiO2 catalysts were used for photocatalytic production of hydrogen from methanol. Copper species/oxidation states both in the as‐prepared catalysts and after the photocatalytic process were investigated. To this purpose, H2 production rates were correlated to physico‐chemical properties of the samples, both before and after photocatalytic process, by means of Raman, X‐Ray Diffraction, Electron Paramagnetic Resonance spectroscopy, X‐Ray Photoelectron Spectroscopy, Temperature‐Programmed Reduction and High Resolution Transmission Electron Microscope techniques. Results revealed the presence of both Cu2O and CuO deposits on the samples surface after calcination. Notably, under near‐UV irradiation, the fraction of highly dispersed CuO particles undergo a partial dissolution process, followed by reduction to metallic copper Cu(s) by photogenerated electrons, boosting H2 production rate. Our findings indicate that both Cu2O and Cu(s) act as co‐catalysts for H2 generation, yet by different mechanisms. Overall this study, provides the basis to enhance catalytic performance of red‐ox active systems through UV‐irradiation approach.
... Daniel M. Neumark J. Phys. Chem. ... Daniel M. Neumark is currently Professor of Chemistry at... more ... Daniel M. Neumark J. Phys. Chem. ... Daniel M. Neumark is currently Professor of Chemistry at the University of California, Berkeley and has been Director of the Chemical Sciences Division at Lawrence Berkeley National Laboratory since 2000. ...
Magnetic manganese ferrites were created in the laboratory using a novel combustion method in ord... more Magnetic manganese ferrites were created in the laboratory using a novel combustion method in order to blend the catalytic properties of manganese (Mn) with the magnetic and structural properties of ferrites. The developed synthesis method involved mixing Mn and iron (Fe) nitrate (NO3) salts with polyvinyl alcohol (PVA) followed by calcination. The resulting synthesis method is a scaleable and a simplified synthesis pathway. Preparation studies varying the Mn:Fe stoichiometric ratio and PVA content during synthesis revealed that PVA content above 1:1.5 NO3:PVA is required to form manganese ferrites. XRD, SEM-EDS, carbon content, and BET surface area analysis confirmed that the developed method yielded manganese ferrites of the form Mn2.5Fe0.5O4, MnFe2O4, and Mn0.5Fe2.5O4. The manganese ferrites were then used to remove methylene blue dye from an aqueous solution as a proof-of-concept study to demonstrate their reactivity and use as a treatment technology.