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... formation of PVA/polyvinylpyridine (PVA-g-PVP) and polyethylene glycol and dex-tran sulfate-silica sol composite which was used for hydrogen peroxide or ... starting carbon and the silicate, Ormosils or other inorganic oxides such as... more
... formation of PVA/polyvinylpyridine (PVA-g-PVP) and polyethylene glycol and dex-tran sulfate-silica sol composite which was used for hydrogen peroxide or ... starting carbon and the silicate, Ormosils or other inorganic oxides such as titanium, zirconium and ruthenium ...
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Engineering nanoparticles (ENPs) are an integral part of consumer products. Released to the atmosphere or disposed to sewage, ENPs quickly penetrate to surface and ground water sources. An absence of a dedicated ENP-retaining water... more
Engineering nanoparticles (ENPs) are an integral part of consumer products. Released to the atmosphere or disposed to sewage, ENPs quickly penetrate to surface and ground water sources. An absence of a dedicated ENP-retaining water treatment strategy imposes a potential health threat on drinking water consumers. The threat is met by gearing up an upgrade of treatment systems towards membrane filtration that provides a better barrier to ENP penetration at higher energy costs. The current study compares the energy demand of granular and membrane filtrations, with the retention efficiency of inorganic and organic ENPs. Dedicated experiments with gold and silver nanoparticles, dyed viruses, proteins, polysaccharides, and plasmid DNA showed that the energy demand increases from slow to river bank to rapid sand filtration, and to membrane ultrafiltration (UF). The UF alone consumes on average two times more energy than the entire coagulation–flocculation–sedimentation–sand filtration tray...
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Polymer membranes are often used in water treatment industry, as a reliable economic solution for purification of surface water streams. Among a variety of membrane processes the ultrafiltration (UF) membranes combine high pathogen... more
Polymer membranes are often used in water treatment industry, as a reliable economic solution for purification of surface water streams. Among a variety of membrane processes the ultrafiltration (UF) membranes combine high pathogen removal ability with minimal energy consumption. Since the membranes are considered to be chemically and mechanically stable, in-place cleaning is routinely performed with strong oxidizing agents, such as hypochlorite. The results of the current study, however, clearly indicate that the mechanical strength of UF membranes deteriorates upon hypochlorite cleaning. Values of ultimate tensile strength, ultimate elongation and Young's modulus decreased as the dose (concentration · contact time) of hypochlorite was increased, with the decreases being more marked for cellulose acetate membranes than for polyethersulfone membranes. Scanning probe microscopy showed membrane aging in response to hypochlorite treatment. The aging was related to gradual chain br...
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Pilot-scale experiments were conducted to investigate the removal of C. parvum by contact granular filtration. The experiments indicated efficient transport of C. parvum oocysts and limitations posed by attachment conditions. The required... more
Pilot-scale experiments were conducted to investigate the removal of C. parvum by contact granular filtration. The experiments indicated efficient transport of C. parvum oocysts and limitations posed by attachment conditions. The required 99% oocyst removal was achieved during the operable period. Insufficient 95% removal was attributed to a reduced amount of accumulated material at ripening stage. Coagulation, filter depth and run time were found to be important in the removal of C. parvum oocysts.
BACKGROUND: Flocculation, adsorption and ultrafiltration, alone and in combination, were tested for tertiary treatment of Beer Sheva (southern Israel) municipal wastewater. The focus was on the adsorption of soluble organics with powdered... more
BACKGROUND: Flocculation, adsorption and ultrafiltration, alone and in combination, were tested for tertiary treatment of Beer Sheva (southern Israel) municipal wastewater. The focus was on the adsorption of soluble organics with powdered activated carbon (PAC) and with organoclays.
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Pesticides, personal care products, industrial chemicals often pollute surface- and groundwater sources. With trace concentrations and low molecular weights, these micropollutants (MPs) easily penetrate through treatment systems and... more
Pesticides, personal care products, industrial chemicals often pollute surface- and groundwater sources. With trace concentrations and low molecular weights, these micropollutants (MPs) easily penetrate through treatment systems and impose a real health threat on drinking water consumers. The absence of a dedicated MP-retaining treatment technology at water treatment plants results in a constant consumption of MP-contaminated water. Advanced oxidation processes, and in particular the Fenton reaction, can successfully degrade MPs if other, larger, fractions of organics are retained. Here, we suggest a novel combined two-stage retention–degradation approach. Ceramic membranes retain large organics such as bovine serum albumin (BSA). Fenton processes disintegrate nonretained MPs such as methylene blue (MB) and bisphenol A (BPA) that penetrate through the membrane. The efficiency of the suggested approach is high. Single-layered ultrafiltration membrane retains more than 96% BSA and deg...
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The direct oxidative dehydrogenation of lactates with molecular oxygen is a "greener" alternative for producing pyruvates. Here we report a one-pot synthesis of mesoporous vanadia-titania (VTN), acting as highly efficient and... more
The direct oxidative dehydrogenation of lactates with molecular oxygen is a "greener" alternative for producing pyruvates. Here we report a one-pot synthesis of mesoporous vanadia-titania (VTN), acting as highly efficient and recyclable catalysts for the conversion of ethyl lactate to ethyl pyruvate. These VTN materials feature high surface areas, large pore volumes, and high densities of isolated vanadium species, which can expose the active sites and facilitate the mass transport. In comparison to homogeneous vanadium complexes and VO /TiO prepared by impregnation, the meso-VTN catalysts showed superior activity, selectivity, and stability in the aerobic oxidation of ethyl lactate to ethyl pyruvate. We also studied the effect of various vanadium precursors, which revealed that the vanadium-induced phase transition of meso-VTN from anatase to rutile depends strongly on the vanadium precursor. NHVO was found to be the optimal vanadium precursor, forming more monomeric vana...
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Pilot-scale experiments were conducted to investigate the removal of C. parvum by contact granular filtration. The experiments indicated efficient transport of C. parvum oocysts and limitations posed by attachment conditions. The required... more
Pilot-scale experiments were conducted to investigate the removal of C. parvum by contact granular filtration. The experiments indicated efficient transport of C. parvum oocysts and limitations posed by attachment conditions. The required 99% oocyst removal was achieved during the operable period. Insufficient 95% removal was attributed to a reduced amount of accumulated material at ripening stage. Coagulation, filter depth and run time were found to be important in the removal of C. parvum oocysts.
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The chemical and technological aspects for the retention of humic acid (HA) by combining coagulation and ultrafiltration (UF) are discussed in this paper. Coagulation was performed with polyaluminium chloride (PACl) in three operating... more
The chemical and technological aspects for the retention of humic acid (HA) by combining coagulation and ultrafiltration (UF) are discussed in this paper. Coagulation was performed with polyaluminium chloride (PACl) in three operating modes: in-line 30 s coagulation, coagulation with 25 min flocculation, and coagulation/flocculation with 3 h sedimentation. UF capillaries with a molecular weight cut-off (MWCO) of about 200 kDa, made of polyethersulfone (PES), were operated in inside-out mode with constant positive pressure. The applied experimental scheme posed additional demands to the HA-PACl flocs, limiting their size and density. The optimal floc was achieved at low [AlT]/DOC mass-to-mass ratio of 0.4. The obtained flocs were big enough to provide sufficient retention of HA by UF, small enough to minimize clogging, and with moderate density to minimize fouling. The optimal floc provided a highest 70% HA retention with minimal fouling. Combining coagulation with flocculation we we...
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Research Interests: Engineering, Biochemistry, Earth Sciences, Analytical Chemistry, Organic Chemistry, and 69 morePhysical Chemistry, Technology, Kinetics, Mass Spectrometry, Phospholipids, Lithium, Molecular Microbiology, Biological Sciences, Lipids, Cell Differentiation, Brain, Humans, Hyperglycemia, Insulin, Liver, Phosphatidate Phosphatase, Fatty acids, Copper, Escherichia coli, Borates, Pancreas, Animals, Male, Physical sciences, Membrane Fusion, Peptides, Nitrogen, Membrane Lipids, Cyclic peptides, Rat Brain, Nickel, Insulinoma, Glycosylation, Microcystins, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Cattle, Electrons, Amino Acids, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Molecules, Rats, Myocardium, Fourier transform infrared spectroscopy, Time Factors, Fourier transform ion cyclotron resonance, Tritium, Age Factors, Arginine, Exocytosis, Agricultural and Food Chemistry, Protein Conformation, Analytical Biochemistry, Sensitivity and Specificity, Subcellular Fractions, Recombinant Proteins, Protein Binding, Hydrolysis, Aorta, Hydrogen-Ion Concentration, Diglycerides, Drug Induced Liver Injury, Ions, Histidine, Oxalic acid, Arachidonic Acid, Biochemistry and cell biology, islets of Langerhans, and Serum albumin(Physical Chemistry, Technology, Kinetics, Mass Spectrometry, Phospholipids, Lithium, Molecular Microbiology, Biological Sciences, Lipids, Cell Differentiation, Brain, Humans, Hyperglycemia, Insulin, Liver, Phosphatidate Phosphatase, Fatty acids, Copper, Escherichia coli, Borates, Pancreas, Animals, Male, Physical sciences, Membrane Fusion, Peptides, Nitrogen, Membrane Lipids, Cyclic peptides, Rat Brain, Nickel, Insulinoma, Glycosylation, Microcystins, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Cattle, Electrons, Amino Acids, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Molecules, Rats, Myocardium, Fourier transform infrared spectroscopy, Time Factors, Fourier transform ion cyclotron resonance, Tritium, Age Factors, Arginine, Exocytosis, Agricultural and Food Chemistry, Protein Conformation, Analytical Biochemistry, Sensitivity and Specificity, Subcellular Fractions, Recombinant Proteins, Protein Binding, Hydrolysis, Aorta, Hydrogen-Ion Concentration, Diglycerides, Drug Induced Liver Injury, Ions, Histidine, Oxalic acid, Arachidonic Acid, Biochemistry and cell biology, islets of Langerhans, and Serum albumin)
(Physical Chemistry, Technology, Kinetics, Mass Spectrometry, Phospholipids, Lithium, Molecular Microbiology, Biological Sciences, Lipids, Cell Differentiation, Brain, Humans, Hyperglycemia, Insulin, Liver, Phosphatidate Phosphatase, Fatty acids, Copper, Escherichia coli, Borates, Pancreas, Animals, Male, Physical sciences, Membrane Fusion, Peptides, Nitrogen, Membrane Lipids, Cyclic peptides, Rat Brain, Nickel, Insulinoma, Glycosylation, Microcystins, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Cattle, Electrons, Amino Acids, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Molecules, Rats, Myocardium, Fourier transform infrared spectroscopy, Time Factors, Fourier transform ion cyclotron resonance, Tritium, Age Factors, Arginine, Exocytosis, Agricultural and Food Chemistry, Protein Conformation, Analytical Biochemistry, Sensitivity and Specificity, Subcellular Fractions, Recombinant Proteins, Protein Binding, Hydrolysis, Aorta, Hydrogen-Ion Concentration, Diglycerides, Drug Induced Liver Injury, Ions, Histidine, Oxalic acid, Arachidonic Acid, Biochemistry and cell biology, islets of Langerhans, and Serum albumin)
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ABSTRACT Surfactant cleaning of ultrafiltration membranes is essentially a sequence of three stages. The micelles, formed when the dose of nonionic surfactant exceeds the critical micelle concentration, transport to the membrane surface,... more
ABSTRACT Surfactant cleaning of ultrafiltration membranes is essentially a sequence of three stages. The micelles, formed when the dose of nonionic surfactant exceeds the critical micelle concentration, transport to the membrane surface, partially disassemble, and bind to proteins. The binding first results in protein dislocation but then continues to surfactant occupation of the membrane surface including the sites released by the proteins. The membrane surface gradually becomes more hydrophilic and ripe for the adsorption of micelles that now build a cake layer. The developed cake is responsible for an increased protein retention and severe fouling.The surfactant cleaning time needs to be optimized to maximize the protein solubilization and to prevent the growth of a micelle cake. Circulation of a cleaning solution accelerates the surfactant transport to the membrane surface but facilitates micelle pore blocking. The induced internal fouling can counteract the benefits of reduced cleaning times due to circulation. Water flow can disassemble the external cake and wash away surfactant monomers, but will barely release clogged pores.
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Pilot-scale experiments were conducted to investigate removal of Cryptosporidium parvum by contact granular filtration. The research demonstrated enhanced removal of Cryptosporidium parvum in the presence of kaolin particles. This is... more
Pilot-scale experiments were conducted to investigate removal of Cryptosporidium parvum by contact granular filtration. The research demonstrated enhanced removal of Cryptosporidium parvum in the presence of kaolin particles. This is believed to be due electrostatic ...
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ABSTRACT Notwithstanding the food-for-fuel debate, turning waste cooking oil and fat (WCO) into a valuable product is a classic example of green chemistry. We demonstrate that sulfated zirconia and lanthanum-supported sulfated zirconia... more
ABSTRACT Notwithstanding the food-for-fuel debate, turning waste cooking oil and fat (WCO) into a valuable product is a classic example of green chemistry. We demonstrate that sulfated zirconia and lanthanum-supported sulfated zirconia are good catalysts for the esterification of WCO free fatty acids (FFAs) with glycerol, giving high-value monoglycerides. Various catalysts were first screened using palmitic acid as a model FFA. Subsequently, six 10-kg batches of actual WCO were collected from commercial cookeries over a period of 28 weeks, pre-treated in a purpose-built decanter and esterified with industrial grade glycerol using heterogeneous catalysis. Good yield and turnovers were obtained. The pre-treatment stage and the catalytic esterification experiments are described and discussed.
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ABSTRACT In-line coagulation with aluminum or iron salts and ultrafiltration (UF) or microfiltration (MF) membranes is a valuable treatment option. The efficiency of the treatment is often evaluated by the achieved separation degree. That... more
ABSTRACT In-line coagulation with aluminum or iron salts and ultrafiltration (UF) or microfiltration (MF) membranes is a valuable treatment option. The efficiency of the treatment is often evaluated by the achieved separation degree. That separation-oriented approach implies the coagulation with doses that are prohibitively high for many operations including the tertiary effluent treatment. The main purpose of the advanced wastewater treatment however is the retention of microorganisms and suspended solids, and that goal can be achieved even without coagulants. Thus the in-line coagulation can pursue the prevention or minimization of the irreversible fouling as an ultimate goal not related to the maximal separation of organic and inorganic impurities. Pilot experiments at conventional activated sludge (CAS) municipal wastewater treatment plant confirmed that the addition of 1 mg/L Fe3+ prevents the irreversible fouling as efficiently as the addition of 5 and 10 mg/L Fe3+. The economic impact of the suggested alteration is significant. Estimated operational expenses (OPEX) of a filtration at 60 LMH with 45 min cycles and 1 chemical – enhanced backwash per day is around 2 cents (€)/m3, almost a half of an OPEX of the separation-oriented treatment. Intermittent in-line coagulation down to first 2.5 min of 30 and 45 min filtration cycles is another cost-effective method to successfully depress the fouling. The success is explained by two-stage kinetics of a cake formation. At ripening stage, a layer of flocks restricted by a membrane gradually covers its surface and forms an initial dynamic cake. At operable stage, the cake entraps fresh solutes and prevents their contact with a membrane surface even without a coagulant. A superposition of two approaches reduces the consumption of ferric chloride coagulant by 94%.