Environmental Science and Pollution Research, Jan 7, 2021
Pharmaceuticals and personal care products (PPCPs) do not have standard regulations for discharge... more Pharmaceuticals and personal care products (PPCPs) do not have standard regulations for discharge in the environment and are categorized as contaminants of emerging concern as they pose potential threats to ecology as well as humans even at low concentrations. Conventional treatment processes generally employed in the wastewater treatment plants are not adequately engineered for effective removal of PPCPs. Identifying cost-effective tertiary treatment is therefore, important for complete removal of PPCPs from wastewater prior to discharge or reuse. Present study demonstrates adsorption using granular-activated carbon (GAC) as a possible tertiary treatment for simultaneous removal of five PPCPs from aqueous media. Adsorbent was characterized in terms of morphology, surface area, surface charge distribution, and presence of functional groups. Performance of GAC was investigated for sorption of three hydrophilic (ciprofloxacin, acetaminophen, and caffeine) and two hydrophobic (benzophenone and irgasan) PPCPs from aqueous solution varying the process parameters (initial concentration, adsorbent dose, pH, agitation time). Langmuir isotherm model (correlation coefficients (R2): 0.993 to 0.998) appeared to fit the isotherm data better than Temkin isotherm model for these adsorbates. Adsorption efficiencies of these compounds (8.26 to 20.40 mg g−1) were in accordance with their log Kow values. While the adsorption kinetics was best explained in terms of a pseudo-second-order kinetic model, the data suggested that adsorption mechanism was mainly governed by the intraparticle diffusion. The role of physical factors like molecular volume, molecular size, and area of targeted PPCPs were investigated through computational studies which in turn can help predicting their uptake onto GAC.
Journal Of The Chinese Advanced Materials Society, Dec 3, 2014
The present work describes a solid-phase extraction (SPE) procedure using the molecularly imprint... more The present work describes a solid-phase extraction (SPE) procedure using the molecularly imprinted polymers (MIPs) in order to obtain a cleaner extract and high recovery from a highly complex and aqueous herbal matrix. MIPs with a similar composition of precursors were synthesized by bulk (MIPB), precipitation (MIPP) and reverse microemulsion polymerization (MIPR) methods, and the resulting MIPs were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The MIPs were used as sorbent in SPE procedure to study their imprinting performance in the aqueous conditions. The molecularly imprinted solid-phase extraction (MISPE) procedure for selective extraction of gallic acid (GA) from the herbal extract was performed. MIPR have shown the superior performance with the 86% extraction of GA. It was observed that the morphology of the MIPs can be enhanced using various polymerization methods for improved SPE application.
ABSTRACT Molecularly imprinted polymers (MIPs) are the materials mimicking the function of biolog... more ABSTRACT Molecularly imprinted polymers (MIPs) are the materials mimicking the function of biological receptors and offer many possibilities for the development of novel composite materials. A computational approach was used to study the influence of porogen on the stability of template-monomer complex for rational design of MIPs. The effect of porogenic solvent was computed through polarizable continuum model, followed by the comparison of the binding energies (G) of the template-monomer complexes in different porogens. MIPs were prepared for Gallic acid by thermal polymerization method, using acrylamide as functional monomer and ethylene glycol dimethacrylate as crosslinker in the presence of three different porogens, to validate the results of computational approach. The MIPs were characterized by the FT-IR, SEM, Brunauer-Emmett-Teller surface area characterization techniques and swelling analysis to study the influence of porogen on the morphology of MIPs. The performance of prepared MIPs was evaluated by batch binding experiments, Langmuir-Freundlich isotherm model and selectivity experiments. MIP prepared in THF showed the highest binding capacity and selectivity with an imprinting factor of 7.74. The results of quantum chemical computational analysis were in good accordance with the experimental results.
Environmental Science and Pollution Research, Mar 29, 2022
The major reason behind the spread of antibiotic resistance genes (ARGs) is persistent selective ... more The major reason behind the spread of antibiotic resistance genes (ARGs) is persistent selective pressure in the environment encountered by bacteria. Genome plasticity plays a crucial role in dissemination of antibiotic resistance among bacterial pathogens. Mobile genetic elements harboring ARGs are reported to dodge bacterial immune system and mediate horizontal gene transfer (HGT) under selective pressure. Residual antibiotic pollutants develop selective pressures that force the bacteria to lose their defense mechanisms (CRISPR-cas) and acquire resistance. The present study targets the ESKAPE organisms (namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) causing various nosocomial infections and emerging multidrug-resistant species. The role of CRISPR-cas systems in inhibition of HGT in prokaryotes and its loss due to presence of various stressors in the environment is also focused in the study. IncF and IncH plasmids were identified in all strains of E. faecalis and K. pneumoniae, carrying Beta-lactam and fluoroquinolone resistance genes, whereas sal3, phiCTX, and SEN34 prophages harbored aminoglycoside resistance genes (aadA, aac). Various MGEs present in selected environmental niches that aid the bacterial genome plasticity and transfer of ARGs contributing to its spread are also identified.
Abstract The widespread use and presence of pharmaceuticals and personal care products (PPCPs) in... more Abstract The widespread use and presence of pharmaceuticals and personal care products (PPCPs) in aquatic environment throughout the world and their potential biological activity suggest that understanding how these compounds can influence aquatic ecosystem functions is an important research direction. PPCPs are widely studied and the number of papers published in SCI journals is >1500 in 2017 itself and >7000 since 2012 ( https://scholar.google.co.in ). The present chapter discusses the classification and possible environmental sources of PPCPs. It also details the fate, pathways, persistence, and ecotoxicological profile of these compounds focusing on aquatic environment. The efficiency and limitations of the existing conventional/advanced water/wastewater treatment systems in the removal of these compounds are also overviewed to understand the aquatic environmental pathway of PPCPs. The chapter describes the steps toward directives and regulations and the key strategy adopted for the basis of concern.
Carbonate is a common pollutant in water and wastewater. A study to understand its influence on t... more Carbonate is a common pollutant in water and wastewater. A study to understand its influence on the photodegradation rates is necessary especially when TiO2/UV technique is emerging as an advanced technology for pollution abatement. In the present investigation, we report surface modification of titanium dioxide using carbonate ions, characterization of carbonate modified titanium dioxide (CMT) and photocatalytic application of carbonate modified TiO2. Titanium dioxide from two different sources namely BDH, Mumbai and Degussa AG, Germany was used as photocatalyst. The CMT catalysts were characterized using potentiometry, FT-IR and XPS. Approximately, 18.9 mg CO3/g CMT(BDH) and 8.13 mg CO3/g CMT(Degussa) was found loaded as determined by potentiometry. The C 1s and O 1s binding energies observed at 289.2 and 531.3 eV, respectively were attributed to surface carbonate species. The adsorption and photodegradation of Acid Blue I dye examined using neat TiO2as well as CMT catalysts revealed that carbonate inhibits catalytic activity for color and Chemical Oxygen Demand (COD) removal. The photo degradation rate constant (k, s-1) decreases gradually with increasing concentration of carbonate. Thus, in the absence of carbonatekdyeis 5.45 × 10-4s-1(R2= 0.97) andkCODis 3.50 × 10-5s-1(R2= 0.97). At 100 mg/L CO32-,kdyeis 0.16 × 10-4s-1(R2= 0.96) andkCODis 2.66 × 10-5s-1(R2= 0.98). In addition, the carbonate spiking studies revealed the onset of inhibition soon after the addition of carbonate into reacting suspensions of TiO2. The results suggest that carbonate inhibits catalytic activity through formation of strong surface complex under suitable pH by displacing OH2+and OH groups from TiO2surface. This results not only in fewer (OH)surfacegroups available for h+trapping for oxidation into OH radicals but also in non-availability of adsorption sites for the dye molecules. A pretreatment to remove carbonate from (waste) water appears necessary prior to application of TiO2/UV technique
Molecularly imprinted polymers (MIPs) have been demonstrated to be a promising class of biomimeti... more Molecularly imprinted polymers (MIPs) have been demonstrated to be a promising class of biomimetic materials that can be tailored to meet specific end use recognition requirements. Molecular imprinting is achieved by the interaction, either covalent or non-covalent between complementary groups in a template molecule and functional monomer units through polymerization. MIPs have been widely employed for divers applications such as chiral separation, chemical sensing, catalysis, drug screening, chromatographic separations and solid phase extraction. During respiration and metabolism, human body produce free radicals as by products, which can damage genetic material, lipids and proteins leading to several fatal diseases such as Cancer, Cardio-vascular disease, Alzheimer’s disease, Immune dysfunction etc. Antioxidants define a family of natural or synthetic nutrients in food, which acts as free radical scavengers. They are present in complex matrix such as herbs, fruit pulp in small concentration, either combined or in free form. Although several techniques have been developed for their detection, (e.g. HPLC, Thin layer chromatography, Capillary gas chromatography, Supercritical fluid chromatography), to achieve highly specific and sensitive analysis, high affinity, stable and specific recognition agents are needed. In this review, special attention is paid to the MIPs based analytical methods for antioxidants, focusing on solid phase extraction, chromatographic and non chromatographic separations and sensing approaches as well as on novel approaches for the discovery of new imprinted materials for antioxidants.
Environmental Science and Pollution Research, Jan 7, 2021
Pharmaceuticals and personal care products (PPCPs) do not have standard regulations for discharge... more Pharmaceuticals and personal care products (PPCPs) do not have standard regulations for discharge in the environment and are categorized as contaminants of emerging concern as they pose potential threats to ecology as well as humans even at low concentrations. Conventional treatment processes generally employed in the wastewater treatment plants are not adequately engineered for effective removal of PPCPs. Identifying cost-effective tertiary treatment is therefore, important for complete removal of PPCPs from wastewater prior to discharge or reuse. Present study demonstrates adsorption using granular-activated carbon (GAC) as a possible tertiary treatment for simultaneous removal of five PPCPs from aqueous media. Adsorbent was characterized in terms of morphology, surface area, surface charge distribution, and presence of functional groups. Performance of GAC was investigated for sorption of three hydrophilic (ciprofloxacin, acetaminophen, and caffeine) and two hydrophobic (benzophenone and irgasan) PPCPs from aqueous solution varying the process parameters (initial concentration, adsorbent dose, pH, agitation time). Langmuir isotherm model (correlation coefficients (R2): 0.993 to 0.998) appeared to fit the isotherm data better than Temkin isotherm model for these adsorbates. Adsorption efficiencies of these compounds (8.26 to 20.40 mg g−1) were in accordance with their log Kow values. While the adsorption kinetics was best explained in terms of a pseudo-second-order kinetic model, the data suggested that adsorption mechanism was mainly governed by the intraparticle diffusion. The role of physical factors like molecular volume, molecular size, and area of targeted PPCPs were investigated through computational studies which in turn can help predicting their uptake onto GAC.
Journal Of The Chinese Advanced Materials Society, Dec 3, 2014
The present work describes a solid-phase extraction (SPE) procedure using the molecularly imprint... more The present work describes a solid-phase extraction (SPE) procedure using the molecularly imprinted polymers (MIPs) in order to obtain a cleaner extract and high recovery from a highly complex and aqueous herbal matrix. MIPs with a similar composition of precursors were synthesized by bulk (MIPB), precipitation (MIPP) and reverse microemulsion polymerization (MIPR) methods, and the resulting MIPs were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The MIPs were used as sorbent in SPE procedure to study their imprinting performance in the aqueous conditions. The molecularly imprinted solid-phase extraction (MISPE) procedure for selective extraction of gallic acid (GA) from the herbal extract was performed. MIPR have shown the superior performance with the 86% extraction of GA. It was observed that the morphology of the MIPs can be enhanced using various polymerization methods for improved SPE application.
ABSTRACT Molecularly imprinted polymers (MIPs) are the materials mimicking the function of biolog... more ABSTRACT Molecularly imprinted polymers (MIPs) are the materials mimicking the function of biological receptors and offer many possibilities for the development of novel composite materials. A computational approach was used to study the influence of porogen on the stability of template-monomer complex for rational design of MIPs. The effect of porogenic solvent was computed through polarizable continuum model, followed by the comparison of the binding energies (G) of the template-monomer complexes in different porogens. MIPs were prepared for Gallic acid by thermal polymerization method, using acrylamide as functional monomer and ethylene glycol dimethacrylate as crosslinker in the presence of three different porogens, to validate the results of computational approach. The MIPs were characterized by the FT-IR, SEM, Brunauer-Emmett-Teller surface area characterization techniques and swelling analysis to study the influence of porogen on the morphology of MIPs. The performance of prepared MIPs was evaluated by batch binding experiments, Langmuir-Freundlich isotherm model and selectivity experiments. MIP prepared in THF showed the highest binding capacity and selectivity with an imprinting factor of 7.74. The results of quantum chemical computational analysis were in good accordance with the experimental results.
Environmental Science and Pollution Research, Mar 29, 2022
The major reason behind the spread of antibiotic resistance genes (ARGs) is persistent selective ... more The major reason behind the spread of antibiotic resistance genes (ARGs) is persistent selective pressure in the environment encountered by bacteria. Genome plasticity plays a crucial role in dissemination of antibiotic resistance among bacterial pathogens. Mobile genetic elements harboring ARGs are reported to dodge bacterial immune system and mediate horizontal gene transfer (HGT) under selective pressure. Residual antibiotic pollutants develop selective pressures that force the bacteria to lose their defense mechanisms (CRISPR-cas) and acquire resistance. The present study targets the ESKAPE organisms (namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) causing various nosocomial infections and emerging multidrug-resistant species. The role of CRISPR-cas systems in inhibition of HGT in prokaryotes and its loss due to presence of various stressors in the environment is also focused in the study. IncF and IncH plasmids were identified in all strains of E. faecalis and K. pneumoniae, carrying Beta-lactam and fluoroquinolone resistance genes, whereas sal3, phiCTX, and SEN34 prophages harbored aminoglycoside resistance genes (aadA, aac). Various MGEs present in selected environmental niches that aid the bacterial genome plasticity and transfer of ARGs contributing to its spread are also identified.
Abstract The widespread use and presence of pharmaceuticals and personal care products (PPCPs) in... more Abstract The widespread use and presence of pharmaceuticals and personal care products (PPCPs) in aquatic environment throughout the world and their potential biological activity suggest that understanding how these compounds can influence aquatic ecosystem functions is an important research direction. PPCPs are widely studied and the number of papers published in SCI journals is >1500 in 2017 itself and >7000 since 2012 ( https://scholar.google.co.in ). The present chapter discusses the classification and possible environmental sources of PPCPs. It also details the fate, pathways, persistence, and ecotoxicological profile of these compounds focusing on aquatic environment. The efficiency and limitations of the existing conventional/advanced water/wastewater treatment systems in the removal of these compounds are also overviewed to understand the aquatic environmental pathway of PPCPs. The chapter describes the steps toward directives and regulations and the key strategy adopted for the basis of concern.
Carbonate is a common pollutant in water and wastewater. A study to understand its influence on t... more Carbonate is a common pollutant in water and wastewater. A study to understand its influence on the photodegradation rates is necessary especially when TiO2/UV technique is emerging as an advanced technology for pollution abatement. In the present investigation, we report surface modification of titanium dioxide using carbonate ions, characterization of carbonate modified titanium dioxide (CMT) and photocatalytic application of carbonate modified TiO2. Titanium dioxide from two different sources namely BDH, Mumbai and Degussa AG, Germany was used as photocatalyst. The CMT catalysts were characterized using potentiometry, FT-IR and XPS. Approximately, 18.9 mg CO3/g CMT(BDH) and 8.13 mg CO3/g CMT(Degussa) was found loaded as determined by potentiometry. The C 1s and O 1s binding energies observed at 289.2 and 531.3 eV, respectively were attributed to surface carbonate species. The adsorption and photodegradation of Acid Blue I dye examined using neat TiO2as well as CMT catalysts revealed that carbonate inhibits catalytic activity for color and Chemical Oxygen Demand (COD) removal. The photo degradation rate constant (k, s-1) decreases gradually with increasing concentration of carbonate. Thus, in the absence of carbonatekdyeis 5.45 × 10-4s-1(R2= 0.97) andkCODis 3.50 × 10-5s-1(R2= 0.97). At 100 mg/L CO32-,kdyeis 0.16 × 10-4s-1(R2= 0.96) andkCODis 2.66 × 10-5s-1(R2= 0.98). In addition, the carbonate spiking studies revealed the onset of inhibition soon after the addition of carbonate into reacting suspensions of TiO2. The results suggest that carbonate inhibits catalytic activity through formation of strong surface complex under suitable pH by displacing OH2+and OH groups from TiO2surface. This results not only in fewer (OH)surfacegroups available for h+trapping for oxidation into OH radicals but also in non-availability of adsorption sites for the dye molecules. A pretreatment to remove carbonate from (waste) water appears necessary prior to application of TiO2/UV technique
Molecularly imprinted polymers (MIPs) have been demonstrated to be a promising class of biomimeti... more Molecularly imprinted polymers (MIPs) have been demonstrated to be a promising class of biomimetic materials that can be tailored to meet specific end use recognition requirements. Molecular imprinting is achieved by the interaction, either covalent or non-covalent between complementary groups in a template molecule and functional monomer units through polymerization. MIPs have been widely employed for divers applications such as chiral separation, chemical sensing, catalysis, drug screening, chromatographic separations and solid phase extraction. During respiration and metabolism, human body produce free radicals as by products, which can damage genetic material, lipids and proteins leading to several fatal diseases such as Cancer, Cardio-vascular disease, Alzheimer’s disease, Immune dysfunction etc. Antioxidants define a family of natural or synthetic nutrients in food, which acts as free radical scavengers. They are present in complex matrix such as herbs, fruit pulp in small concentration, either combined or in free form. Although several techniques have been developed for their detection, (e.g. HPLC, Thin layer chromatography, Capillary gas chromatography, Supercritical fluid chromatography), to achieve highly specific and sensitive analysis, high affinity, stable and specific recognition agents are needed. In this review, special attention is paid to the MIPs based analytical methods for antioxidants, focusing on solid phase extraction, chromatographic and non chromatographic separations and sensing approaches as well as on novel approaches for the discovery of new imprinted materials for antioxidants.
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