Removal of odorant dimethyl disulfide under alkaline and neutral conditions in biotrickling filters

2012 ◽  
Vol 66 (8) ◽  
pp. 1641-1646 ◽  
Author(s):  
L. Arellano-García ◽  
A. González-Sánchez ◽  
H. Van Langenhove ◽  
A. Kumar ◽  
S. Revah
Keyword(s):  
Main Product ◽  
Dimethyl Disulfide ◽  
Continuous Treatment ◽  
Batch Experiments ◽  
Reduced Sulfur Compounds ◽  
Biotrickling Filters ◽  
Bacterial Consortia ◽  
Low Concentrations ◽  
Alkaline Conditions ◽  
Neutral Conditions

The aim of this paper was to evaluate the performance of biotrickling filters (BTFs) for treating low concentrations of dimethyl disulfide (DMDS), using different bacterial consortia adapted to consume reduced sulfur compounds under alkaline (pH ≈ 10) or neutral (pH ≈ 7) conditions. Solubility experiments indicated that the partition of DMDS in neutral and alkaline mineral media was similar to the value with distilled water. Respirometric assays showed that oxygen consumption was around ten times faster in the neutrophilic as compared with the alkaliphilic consortium. Batch experiments demonstrated that sulfate was the main product of the DMDS degradation. Two laboratory-scale BTFs were implemented for the continuous treatment of DMDS in both neutral and alkaline conditions. Elimination capacities of up to 17 and 24 gDMDS m−3 h−1 were achieved for the alkaliphilic and neutrophilic reactors with 100% removal efficiency after an initial adaptation and biomass build-up.

scholarly journals Formulation of More Efficacious Curcumin Delivery Systems Using Colloid Science: Enhanced Solubility, Stability, and Bioavailability

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2791 ◽  
Author(s):  
Bingjing Zheng ◽  
David Julian McClements
Keyword(s):  
Water Solubility ◽  
Biological Activities ◽  
Anticancer Activities ◽  
Potential Health ◽  
Colloid Science ◽  
Enhanced Solubility ◽  
Alkaline Conditions ◽  
Low Toxicity ◽  
Neutral Conditions ◽  
Bioactive Constituent

Curcumin is a bioactive constituent isolated from turmeric that has historically been used as a seasoning, pigment, and herbal medicine in food. Recently, it has become one of the most commonly studied nutraceuticals in the pharmaceutical, supplement, and food areas because of its myriad of potential health benefits. For instance, it is claimed to exhibit antioxidant, anti-inflammatory, antimicrobial, antiparasite, and anticancer activities when ingested as a drug, supplement, or food. Toxicity studies suggest that it is safe to consume, even at relatively high levels. Its broad-spectrum biological activities and low toxicity have meant that it has been widely explored as a nutraceutical ingredient for application in functional foods. However, there are several hurdles that formulators must overcome when incorporating curcumin into commercial products, such as its low water solubility (especially under acidic and neutral conditions), chemical instability (especially under neutral and alkaline conditions), rapid metabolism by enzymes in the human body, and limited bioavailability. As a result, only a small fraction of ingested curcumin is actually absorbed into the bloodstream. These hurdles can be at least partially overcome by using encapsulation technologies, which involve trapping the curcumin within small particles. Some of the most commonly used edible microparticles or nanoparticles utilized for this purpose are micelles, liposomes, emulsions, solid lipid particles, and biopolymer particles. Each of these encapsulation technologies has its own benefits and limitations for particular product applications and it is important to select the most appropriate one.

Influence of Nitrilotriacetate on the Elimination of Metal Ions by Coprecipitation with Ferric Hydroxide

1987 ◽  
Vol 19 (5-6) ◽  
pp. 1013-1019 ◽  
Author(s):  
F. H. Frimmel ◽  
J. Geywitz
Keyword(s):  
Conditional Distribution ◽  
Ferric Hydroxide ◽  
Distribution Coefficients ◽  
Metal Species ◽  
Batch Experiments ◽  
Reaction Conditions ◽  
Low Concentrations ◽  
Zinc Cadmium ◽  
Copper Zinc ◽  
Cadmium And Lead

The elimination of dissolved copper, zinc, cadmium and lead by coprecipitation with iron(III) hydroxide was investigated. The reaction conditions of the batch experiments were adopted from water treatment. Conditional distribution coefficients show the order Cd < Zn < Cu < Pb for increasing interaction of the metals with the ferric hydroxide. The presence of nitrilotriacetate (NTA) decreases the efficiency of the metal elimination. NTA is also able to remobilize metals from the metal enriched precipitation. There is a significant effect, even at low concentrations of a few µmol/l. Remobilization of Cu, Zn and Cd increases, remobilization of Pb decreases with reaction time. The “ageing” of the precipitation plays an important role for the yield of the reactions. From a broad application of NTA in detergents an increase of the concentration of dissolved metal species has to be expected.

Hydrothermal Synthesis of Nanostructured TiO2 Particles and Characterization of Their Photocatalytic Antimicrobial Activity

2008 ◽  
Vol 8 (2) ◽  
pp. 878-886 ◽  
Author(s):  
Beril K. Erdural ◽  
Alp Yurum ◽  
Ufuk Bakir ◽  
Gurkan Karakas
Keyword(s):  
Sol Gel ◽  
Time Lag ◽  
Alkaline Treatment ◽  
Antimicrobial Activities ◽  
Distilled Water ◽  
Bacterial Inactivation ◽  
Sem Images ◽  
Alkaline Conditions ◽  
Aqueous Conditions ◽  
Neutral Conditions

Nanostructured titania particles were synthesized by using hydrothermal processing and the photocatalytic antimicrobial activities were characterized. Both sol–gel synthesized and commercial TiO2 (anatase) samples were processed with two step hydrothermal treatments, under alkaline and neutral conditions. Scanning Electron Microscope (SEM) images showed that alkaline treatment yields nanofibers and lamellar structured particles from the commercial anatase and sol–gel synthesized samples respectively. Further treatment of nanofibers and nanostructured lamellar particles with distilled water results with crystal growth and the formation of nano structured bipyramidal crystalline particles. The photocatalytic antimicrobial activities of the samples were determined against Escherichia coli under irradiation. It was observed that the samples treated under alkaline conditions have improved activity than the original anatase samples. Limited activity and resulting time lag in bacterial inactivation were observed for hydrothermally treated samples with distilled water. However, a post treatment comprising the UV irradiation in aqueous conditions enhanced the photocatalytic activity.

scholarly journals Cholesterol 7α-hydroxylase in rat liver microsomal preparations

1972 ◽  
Vol 128 (1) ◽  
pp. 1-9 ◽  
Author(s):  
K. A. Mitropoulos ◽  
S. Balasubramaniam
Keyword(s):  
Fatty Acids ◽  
Molecular Oxygen ◽  
Rat Liver ◽  
Main Product ◽  
Subcellular Fractions ◽  
Native Protein ◽  
Low Concentrations ◽  
Rat Livers ◽  
Double Isotope

Subcellular fractions containing microsomes prepared from rat livers homogenized in the absence of EDTA catalysed the oxidation of cholesterol to 7α-hydroxycholesterol, 7-oxocholesterol, 7β-hydroxycholesterol and 5α-cholestane-3β,5,6β-triol. These reactions required native protein, molecular oxygen and NADPH. It is suggested that these compounds are formed by a peroxidation analogous to the peroxidation of fatty acids catalysed by liver microsomal preparations. Incubations of [4-14C]cholesterol with microsomal preparations from rat liver homogenized in the presence of EDTA gave 7α-hydroxy[14C]cholesterol as the main product. This reaction required molecular oxygen and NADPH, and was inhibited by CO. The mass of 7α-hydroxycholesterol formed during the incubation was measured by a double-isotope-derivative dilution procedure. This procedure was used to assay the activity of cholesterol 7α-hydroxylase and to measure low concentrations of endogenous 7α-hydroxycholesterol in liver.

scholarly journals Enhanced effects of reducing agent on oxalate chelated Fe(II) catalyzed percarbonate system for benzene degradation

2021 ◽  
Author(s):  
Xiaori Fu ◽  
Xinyan Wei ◽  
Wei Zhang ◽  
Wupeng Yan ◽  
Peng Wei ◽  
...  
Keyword(s):  
Hydroxylamine Hydrochloride ◽  
Reducing Agent ◽  
Sodium Ascorbate ◽  
High Concentration ◽  
H2o2 Decomposition ◽  
Benzene Degradation ◽  
Benzene Removal ◽  
Alkaline Conditions ◽  
Negative Effect ◽  
Neutral Conditions

Abstract The addition of hydroxylamine hydrochloride (HAH), ascorbic acid (ASC), sodium ascorbate (SAS) to the OA-Fe(II)/SPC system could promote the generation of HO• by accelerating Fe(II)/Fe(III) recycles and H2O2 decomposition. The enhancement of HAH on HO• generation surpasses ASC and SAS in the OA-Fe(II)/SPC system. The generation of O2•− was also enhanced by HAH, ASC and SAS, and more significant promotion of O2•− generation was observed with ASC and SAS addition. More effective benzene removal was achieved in an OA-Fe(II)/SPC system with suitable HAH, ASC and SAS addition, compared to the parent system. Excessive HAH, ASC or SAS had a negative effect on benzene removal. Results of scavenger tests showed that HO• is indeed the dominant free radical for benzene removal in every system, but the addition of HAH, ASC and SAS increased the contribution of O2•− to benzene degradation. HAH, ASC and SAS enhanced OA-Fe(II)/SPC systems could be well utilized to acidic and neutral conditions, while HCO3−, high concentration of HA and alkaline conditions were not favorable to benzene removal. Moreover, the addition of HAH, ASC and SAS are conducive to benzene removal in actual groundwater, and HAH was the optimal reducing agent for the enhancement of the OA-Fe(II)/SPC system.

scholarly journals Aerobic Methanol Oxidation over Unsupported Nanoporous Gold: The Influence of an Added Base

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 416 ◽  
Author(s):  
Anastasia Lackmann ◽  
Christoph Mahr ◽  
Andreas Rosenauer ◽  
Marcus Bäumer ◽  
Arne Wittstock
Keyword(s):  
Catalyst Surface ◽  
Aerobic Oxidation ◽  
Intermediate Formation ◽  
Active Oxygen ◽  
Nanoporous Gold ◽  
Oxidation Of Methanol ◽  
Alkaline Conditions ◽  
Activation Of Oxygen ◽  
Neutral Conditions ◽  
Effective Segregation

We studied the aerobic oxidation of methanol over nanoporous gold catalysts under neutral and alkaline conditions. We find that under neutral conditions the catalyst has an activation period of about 10 h while upon addition of a base the catalyst becomes active right away. After this activation period, however, the activity of the catalyst is in both cases similar. Moreover, the selectivity was not affected by the base. We tested different bases and found the largest effect when adding OH−. The cation, however, does not play a role. We conclude that it is OH−, which is impacting the reaction and propose a mechanism for the suppression of the activation period. While the catalytic cycle, i.e., the reaction of methanol on the catalyst surface seems unaffected, the transient adsorption of OH− onto the surface can facilitate the activation of molecular oxygen by donating electrons to the surface. Due to the intermediate formation of oxidic Ag species, an effective segregation of surface-near Ag can be induced, which increases the abundance of Ag being essential for the activation of oxygen at the surface. In this way, a more efficient pathway for the generation of active oxygen is opened, allowing the reaction to set in faster.

Removal of Copper from Vineyard Soil by Washing with Biosurfactant

2014 ◽  
Vol 1065-1069 ◽  
pp. 3091-3095
Author(s):  
Da Zhao ◽  
Yue Zhao ◽  
Shi Bo Tao
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Ph Value ◽  
Batch Experiments ◽  
Liquid Ratio ◽  
Washing Process ◽  
Vineyard Soil ◽  
Alkaline Conditions ◽  
Solid Liquid ◽  
Fermentation Solution

The washing process in batch experiments was conducted to investigate the performance of fermentation solution on removal copper(Cu) from vineyard soil. The effects of solid-liquid ratio, pH value and contact time on the removal capacities of Cu by fermentation solution had been studied. The results showed that the optimum solid-liquid ratio was 1:10 for soil treatment. The fermentation solution showed a better removal efficiency of Cu in alkaline conditions, getting the highest removal efficiency of 34.3%. In addition, with the increase of contact time, higher removal efficiency was obtained.

Metabolism of arginine, proline, and ornithine in tissues of the squid, Illex illecebrosus

1983 ◽  
Vol 61 (8) ◽  
pp. 1835-1846 ◽  
Author(s):  
Thomas P. Mommsen ◽  
Peter W. Hochachka ◽  
Christopher J. French
Keyword(s):  
Digestive Gland ◽  
Main Product ◽  
Arginine Metabolism ◽  
Low Concentrations ◽  
Tissue Homogenates

Interconversions of arginine, ornithine, and proline were studied in the squid Illex illecebrosus, by supplying tissue homogenates from kidney, digestive gland, heart, brain, gill, middle and outer mantle with 14C-labelled substrates. Production of 14CO2 and distribution of label in various intermediates were measured for each tissue. Activities of enzymes catalysing the interconversions were also assessed. 14CO2 production was highest in middle and outer mantle with arginine as substrate, in kidney with ornithine, and in heart with proline. Urease was absent from all tissues. All tissues utilised arginine at reasonable rates, the highest being observed in middle and outer mantle and digestive gland. In heart, γ-guanidinobutyrate was the main product of arginine metabolism. In all other tissues, ornithine was the first product. Kidney utilised ornithine at the fastest rate, while proline was utilised and oxidised best by heart and brain. The results suggest that the capacity of all tissues to metabolise arginine rapidly is a means for maintaining low concentrations of this compound. In some tissues (brain, kidney) the products of arginine metabolism may be fully oxidised in situ whereas in others (digestive gland, gill) produced ornithine may be exported for utilisation elsewhere.

scholarly journals Stability of Cu-Sulfides in Submarine Tailing Disposals: A Case Study from Repparfjorden, Northern Norway

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 169 ◽  
Author(s):  
Yulia Mun ◽  
Sabina Strmić Palinkaš ◽  
Matthias Forwick ◽  
Juho Junttila ◽  
Kristine Bondo Pedersen ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Mine Tailings ◽  
Benthic Fauna ◽  
Residual Fraction ◽  
Northern Norway ◽  
Fine Grained ◽  
Low Concentrations ◽  
Ore Mineralization ◽  
Alkaline Conditions ◽  
Tectonic Window

Mine tailings that were produced during the exploitation of the Ulveryggen siliciclastic sediment-hosted Cu deposit in northern Norway were disposed into the inner part of Repparfjorden from 1972 to 1978/1979. This study focuses on the mineralogy and geochemistry of the submarine mine tailings and underlying natural marine sediments from the inner part of Repparfjorden, as well as on the primary Ulveryggen ore. The ore mineralization from the neighboring Nussir carbonate sediment-hosted Cu deposit was studied too, due to the forthcoming mining of both deposits. Bornite and chalcopyrite are the major Cu-sulfides, and are characterized by low concentrations of potentially toxic elements including Cd, Hg, and As. The tailing material occupies the uppermost 9 cm of Repparfjorden sediments. It is characterized by predomination of a silty component with elevated Cu (up to 747.7 ppm), Ni (up to 87 ppm), and Cr (up to 417 ppm) concentrations. The high Cu concentration is related to the deposition of mine tailings. In contrast, Ni and Cr concentrations are close to those in naturally occurring stream sediments from the feeding river, Repparfjordelva, reflecting the compatibility of these elements with hosting mafic volcanics, which are widely spread in the Repparfjord Tectonic Window. Copper in the uppermost part of the sediments is bound to the acid-soluble fraction while Ni and Cr are bound to the residual fraction. Artificial placement of large masses of fine-grained material, i.e., smothering, resulted in a diminished biological activity and/or physical distortion of mostly benthic fauna, which was reflected in total organic carbon (TOC) values as low as 0.15% in the uppermost strata. Sulfide minerals are found both in natural marine sediments and in the mine tailings. They are generally well-preserved with an exception for chalcopyrite from the uppermost part of the submarine tailing, which shows signs of incipient weathering. Thermodynamic modeling confirmed that redox potential and pH are important factors in the weathering of sulfides. Available ligands contribute to the Cu speciation. In near-neutral to slightly alkaline conditions a presence of carbonates can lead to the mobilization of Cu in form of CuCO3 complexes.

scholarly journals Flow Rate and Interference Studies for Copper Binding to a Silica-Immobilized Humin Polymer Matrix: Column and Batch Experiments

2005 ◽  
Vol 3 (1-2) ◽  
pp. 1-14 ◽  
Author(s):  
Jorge L. Gardea-Torresdey ◽  
Carolina Contreras ◽  
Guadalupe de la Rosa ◽  
Jose R. Peralta-Videa
Keyword(s):  
Binding Capacity ◽  
Silica Matrix ◽  
The Other ◽  
Contaminated Water ◽  
Copper Binding ◽  
Batch Experiments ◽  
Column Studies ◽  
Flow Rates ◽  
Low Concentrations ◽  
Interference Studies

Batch and column experiments were performed to determine the Cu(II) binding capacity of silica-immobilized humin biomass. For column studies, 500 bed volumes of a 0.1 mM Cu(II) solution were passed through humin packed columns at the flow rates of 1, 1.5, 2, and 3 mL/min. The biopolymer showed an average Cu binding capacity of 12 ± 1.5 mg/g and a Cu recovery of about 96.5 % ± 1.5. The breakthrough points for Cu(II) alone were approximately 420, 390, 385, and 300 bed volumes for the flow rates of 1, 1.5, 2 and 3 mL/min, respectively. The interference studies demonstrated that at low concentrations, the hard cations Ca(II) and Mg(II) did not seem to represent a major interference on Cu(II) binding to the humin biopolymer. The selectivity showed by this biopolymer was Cu(II)>Ca(II)>Mg(II). On the other hand, batch experiments showed that Ca(II) + Mg(II) at 100mM each reduced the Cu(II) binding to 73 %. However, 1000 mM concentrations of Ca(II) and Mg(II), separately and in mixture, reduced the Cu(II) binding to 47 %, 44 % and 31 %, respectively. The results of this study showed that immobilized humin in a silica matrix could represent an inexpensive bio-source for Cu removal from contaminated water, even in the presence of low concentrations of the hard cations Ca(II) and Mg(II).

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