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1.
One‐dimensional MoO3 nanofibers doped with Ce (MoO3 : CeO2) are synthesized by a method combining a sol‐gel process and an electrospinning technique. The resulting MoO3 : CeO2 is characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT‐IR) spectroscopy, and scanning electron microscopy (SEM). The catalytic degradation of rhodamine B and safranin‐T with MoO3 : CeO2 nanofiber catalyst is investigated in a continuous flowing mode using air (O2) as an oxidant. The results show that rhodamine B and safranin‐T are degraded effectively and the removal efficiencies are 98.3%, and 98.5%, respectively. In addition, the organic dyes are totally mineralized to simple inorganic species such as CO3–, Cl– and NO3–. 相似文献
2.
A magnetic‐sulfonic graphene nanocomposite (G‐SO3H/Fe3O4) was synthesized and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction. It was used for removal of three cationic dyes: safranine T (ST), neutral red (NR), victoria blue (VB), and three anionic dyes: methyl orange, brilliant yellow, and alizarin red, from environmental water. The experimental conditions were optimized, including pH, amount of adsorbent, adsorption kinetics, adsorption isotherms, ionic strength, etc. The results show that G‐SO3H/Fe3O4 can adsorb cationic dyes more efficiently and selectively than anionic dyes at pH 6.0. In the first 10 min of adsorption time, more than 93% of the cationic dyes were removed by the sorbent. Adsorption kinetics follow the pseudo‐second‐order kinetic model well. The adsorption isotherm coincided with Langmuir and Freundlich adsorption models. The maximum adsorption capacities of G‐SO3H/Fe3O4 for ST, NR, and VB dyes were 199.3, 216.8, and 200.6 mg g?1. The adsorbed cationic dyes were eluted by using different pH values of ethanol as the solvent. The established method was simple, sensitive, and rapid, and was suitable for the adsorption of cationic dyes in environmental water. 相似文献
3.
K. Machmerth 《洁净——土壤、空气、水》1984,12(5):479-489
A tabular survey is given from literature concerning seven extraction techniques, 14 thin-layer chromatographic detection techniques and 15 spray reagents. From the possibilities represented in this way, a newly composed method is described which can be carried out in any routine laboratory within one hour and has proved successful in situations of average of the drinking water supply. 1 l water is extracted with 25 ml CCl4, the extract is concentrated in the vacuum to 1 ml and chromatographed with n-hexane on a prefabricated foil. Detection is carried out with 10% methanolic molybdophosphoric acid. The detection limit is at 0.5 μg. 相似文献
4.
《Journal of Hydrology》2006,316(1-4):84-97
Dyes are important hydrological tracers. Many different dyes have been proposed as optimal tracers, but none of these dyes can be considered an ideal water tracer. Some dyes are toxic and most sorb to subsurface materials. The objective of this study was to find the molecular structure of an optimal water tracer. We used QSAR to screen a large number of hypothetical molecules, belonging to the class of triarylmethane dyes, in regard to their sorption characteristics to a sandy soil. The QSAR model was based on experimental sorption data obtained from four triarylmethane dyes: C.I. Food Blue 2 (C.I. 42090; Brilliant Blue FCF), C.I. Food Green 3 (C.I. 42053; FD&C Green No. 3), C.I. Acid Blue 7 (C.I. 42080; ORCOacid Blue A 150%), and C.I. Acid Green 9 (C.I. 42100; ORCOacid Fast Green B). Sorption characteristics of the dyes to the sandy soil were expressed with the Langmuir isotherm. Our premise was that dye sorption can be reduced by attachment of sulfonic acid (SO3) groups to the triarylmethane template. About 70 hypothetical dyes were created and QSAR were used to estimate sorption characteristics. The results indicated that both the position and the number of SO3 groups affected dye sorption. Sorption decreased with increasing number of SO3 groups attached to the molecule. Increasing the number of sulfonic acid groups also decreases the toxicity of the compounds. An optimal triarylmethane water tracer contains 4 to 6 SO3 groups. 相似文献
5.
The present paper deals with the determination of LTm values of zolone, rogor, sumithion and abate for Channa gachua by conducting static bioassay experiments. The TLm values for zolone came out to be 0.08275 mg/l, 0.08225 mg/l, 0.0815 mg/l and 0.0810 mg/l; for rogor 5.155 mg/l; 4.955 mg/l, 4.65 mg/l and 4.475 mg/l; for sumithion 12.60 mg/l, 12.50 mg/l, 12.30 mg/l and 12.20 mg/l and for abate 217.25 mg/l, 225.575 mg/l, 221.575 mg/l and 217.25 mg/l for 24, 48, 72 and 96 hours, respectively. Relative susceptibility indicates that this fish is not susceptible to zolone and less to rogor, sumithion and abate, respectively. Present studies also show that increased temperature and pH increase the toxicity of all the biocides, but increased hardness of water decreases the toxicity of biocide solutions. The safe concentrations for zolone, rogor, sumithion and abate came out to be 0.02437 mg/l, 1.3733 mg/l, 3.6907 mg/l and 66.678 mg/l, respectively. 相似文献
6.
Spinel Ferrite Mediated Photo‐Fenton Degradation of Phenolic Analogues: A Detailed Study Employing Two Distinct Inorganic Oxidants 
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下载免费PDF全文 The present work demonstrates the applicability of ferrites as photo‐Fenton catalysts for deterioration of different phenolic derivatives. To analyze optimal reaction conditions, experiments are performed with four magnetic spinel ferrites MFe2O4 (M = Co, Cu, Ni, and Zn) and two inorganic oxidants, i.e., hydrogen peroxide (HP) and potassium peroxymonosulfate (PMS). The reactions are performed using p‐nitrophenol as phenolic probe. CuFe2O4 and CoFe2O4 possessed excellent ability to activate HP and PMS, respectively, among all four synthesized catalysts. A noteworthy aspect of two oxidizing agents is that the concentration of PMS used during the reaction is four times less than HP. Further, the broad pH activity of PMS provides a significant advantage over HP. The optimal reaction conditions, when HP is the oxidant in the photo‐Fenton degradation, are 0.50 g L?1 MFe2O4, pH 2.5, and 8.8 mM HP. Although PMS is active in a wide pH range (2–10), adequate reaction conditions are 0.50 g L?1 MFe2O4, natural pH, and 2.2 mM PMS. The photo‐Fenton activity of ferrites is extended to the degradation of different nitro‐ and chloro‐analogs of phenol (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2,4‐dinitrophenol, 2,4,6‐trinitrophenol, 2‐chlorophenol, 3‐chlorophenol, 4‐chlorophenol, 2,4‐dichlorophenol) with only two ferrites (CuFe2O4 and CoFe2O4). A comparative study is performed with the two oxidants (HP and PMS) with positive results. Finally, stability and reusability of magnetic ferrites as catalysts are also studied to prove their use in phenolic solution treatment. 相似文献
7.
After treatment of the anion exchanger resins from several manufacturers with FeCl3 or CuSO4 their capacity to take up thiocyanate ions increases by the factor 2 … 3. By regeneration with diluted sulphuric acid or hydrochloric acid after precipitation of the ferric or cupric hydroxide a thiocyanate solution of 10 and 15 g/l, respectively, is obtained, which can be reused. The hydroxides dissolved in acid are used for the treatment of the ion exchanger. The process is proposed for the regenerating of wastewaters containing thiocyanate. 相似文献
8.
Rhodamine B and Rhodamine WT are fluorescent dyes commonly used as tracers in hydrological investigations. Since introducing
intensely red substances into rivers raises understandable doubts of ecological nature, the authors aimed at examining the
influence of these dyes on small water fauna using bioindication methods. Quantitative results, calculated with the use of
Bliss-Weber probit statistical method, were achieved by means of standardized ecotoxicological tests containing ready-to-hatch
resting forms of fairy shrimp (Thamnocephalus platyurus). Qualitative studies included observation of water flea crustacean (Daphnia magna) and horned planorbis snail (Planorbis corneus), both typically present in rivers and representative for temperate climate, as well as guppy fish (Poecilla reticulata), paramecium protozoan (Paramaecium caudatum) and the above-mentioned fairy shrimp. The investigation revealed that both dyes in concentrations used for hydrological
purposes are low enough to exert almost no toxic impact on water fauna considered. 相似文献
9.
Waste beer yeast was modified by pyromellitic dianhydride to improve its adsorption capacity for rhodamine B (RhB). Results showed that the adsorption capacity of the modified biomass for RhB was 600 mg g?1, which was about five times than that obtained on the unmodified biomass. Dye loaded modified biomass was regenerated by (1) a common eluent: HNO3 solution and (2) a self‐cleaning eluent: TiO2 hydrosol, while the pH of both systems varied from 1 to 4. Desorption experimental results showed that low desorption rates were obtained in both systems after the first desorption cycle. A large volume of HNO3 solution was needed to obtain high desorption rate, and a concentrated solution of RhB was left, which brought a secondary pollution. As a self‐cleaning eluent, acid TiO2 hydrosol acted both as eluent and photocatalyst. The desorbed RhB could be photodegraded under sunlight irradiation and the same hydrosol could be used in the next desorption cycle without losing its activity, which could economize large volumes of solvent. The results showed an adsorption capacity of the regenerated biosorbent for RhB of 450 mg g?1 by using hydrosol with pH 2 as eluent after four desorption/photodegradation cycles. 相似文献
10.
11.
N. Wasmund 《洁净——土壤、空气、水》1984,12(3):255-272
For the determination of the contents of chlorophyll a and phaeopigment a in sediment samples the method according to LORENZEN with its principle and the error sources is discussed in detail. The acidification required for the determination of the phaeopigments should be carried out on a final concentration of 0.006 mol/l acid. As an extracting agent, such a quantity of acetone has to be added to the sediment sample that a final concentration of 90 % acetone will be obtained with the interstitial water being taken into account. By an extraction done twice 90 % of pigments are extracted. Methanol as an extracting agents is unsuitable for several reasons mentioned. Exposure to light at more than 1 W/m2 results in a high rate of chlorophyll degradation, the same effect being shown by increased temperatures. Between the trichromatic chlorophyll determination according to JEFFREY and HUMPHREY and the determination according to LORENZEN exists the linear relation chl. a (J. and H.)=chl. a (L.)+0.6. phaeo. a (L.). The procedure of the determination of chlorophyll a and phaeopigment a according to LORENZEN is described in a detailed representation. 相似文献
12.
Fluorescent dyes are commonly used as hydrologic tracers in a variety of surface and subsurface environments, including karst aquifers and caves, but the fragile nature of karstic groundwater ecosystems suggests a cautious approach to selecting dyes. This study tested the effects of four fluorescent dye tracers (uranine, eosin, pyranine, sulforhodamine B) on microorganisms from Fort Stanton Cave, New Mexico, United States. Toxicity of the dyes was tested on bacteria isolated from the cave and on a sediment sample collected adjacent to Snowy River in Fort Stanton Cave. The isolates showed minimal inhibition by the four dyes in an agar diffusions assay. Minimum inhibitory concentrations calculated from liquid culture assays of one isolate were 35 g/L for uranine, 3.5 g/L for eosin, 0.1 g/L for pyranine, and 10 mg/L for sulforhodamine B. A 14C-glucose radiotracer experiment showed zero inhibition of overall microbial activity in a sediment sample at all dye concentrations, except at 350 g/L eosin. Thus, there are no cave-specific findings to indicate that Fort Stanton's microbes are especially sensitive to these commonly used dyes. Moreover, a literature survey of mutagenicity tests on these dyes indicates they are safe for environmental use. These results corroborate previous dye toxicity tests and suggest that these four dyes are suitable for use at Fort Stanton Cave in the concentration ranges commonly used for groundwater tracing. While broader testing of dyes with microbes from other caves is advised, the results suggest the dyes may be safe for all karst aquifers. 相似文献
13.
In the present work, experiments have been carried out with a focus to reduce the volume requirement of solvent by mixing with imidazolium based ionic liquids (ILs) for the solvent extraction of phenol, p‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, and pentachlorophenol from aqueous solutions. The effect of aqueous phase pH (2–12), agitation speed (100–450 rpm), solute concentration in feed (2–50 mg/L), temperature (303–333 K), treat ratio (1–11), and 1‐butyl‐3‐methyl imidazolium tetrafluoroborate [Bmim]+[BF4]? volume in tributyl phosphate (TBP; 0–0.7% v/v) on extraction of phenols has been studied and optimized. Parameters like strip phase pH (3–13) and stripping agent concentration (0.001–0.009 N) have also been studied for stripping of phenols from solvent phase. It has been found that 0.5% v/v of ionic liquid [Bmim]+[BF4]? in solvent TBP extracts more than 97.5% of phenol and chlorophenols from aqueous solutions with a treat ratio (aqueous to solvent phase ratio) of 5. Transport mechanism for extraction and stripping of phenol and chlorophenols using ionic liquid [Bmim]+[BF4]? has been discussed. The results show that by appropriate selection of extraction and stripping conditions, it is possible to remove nearly all phenols with a treat ratio of 5. 相似文献
14.
By diluting a boggy water there is produced water with a COD-Mn of 3.4 … 10.6 mg/l O2 which is due only to humic substances. The water is mixed with 2.5 … 12.9 mg/l Cl2 at pH-values of 5.2 … 8.5 and incubated for 24 h at 20°C. CHCl3 concentrations of 38 … 480 μg/l were found by the subsequent gas-chromatographic determination. The production of chloroform can be calculated by means of a quadratic polynomial in dependence on COD-Mn, chlorine concentration and pH-value. 相似文献
15.
The standardised growth curve (SGC) technique has the potential to save instrument time for equivalent dose (De) determination when applying single-aliquot regenerative-dose (SAR) protocol during optically stimulated luminescence (OSL) measurements. In this study, we test the applicability of two commonly used SGC procedures for OSL signals of quartz grains from aqueous deposits of the Yangtze Delta in China, which have been reported for weak luminescence signals and suffering from partial bleaching. Multiple silt-sized and sand-sized fractions of quartz samples from eight cores are used to construct SGCs by test dose standardisation (TD-SGC) and least-squares normalisation (LS-SGC), respectively. Three strategies, i.e. region-specific (SGCR), region with core-specific (SGCR + C) and core-specific (SGCC), are adopted to categorise these normalised data into different SGC datasets. The large variability of dose response signals is substantially reduced by the SGC procedures for most of these datasets. Hence, common SGCs for a variety of samples from the Yangtze Delta can be established, irrespective of their distinctive particle sizes and luminescence characteristics. The De values are then estimated using both TD-SGC and LS-SGC procedures for samples from a specific core. Comparing to the full SAR protocol, the TD-SGC procedure roughly gives reproducible De estimates lower than ∼100 Gy while the LS-SGC procedure derives generally consistent De estimates of up to ∼230 Gy. Although LS-SGCC and LS-SGCR + C procedures replicate the most consistent De values, the LS-SGCR procedure performs better in efficiency with a slightly less accuracy. In addition to careful comparison of LS-SGC and full SAR procedures, we suggest that a synchronous ratio derived by the chosen regenerative dose and its response signal for re-normalisation can be used to predict the LS-SGC De reliability on samples from similar sedimentary environments. 相似文献
16.
The method is based on the determination of the number of the nonmotile sperms and/or the lethally damaged sperms with the aid of the fluorescent dye primuline. Incubation takes place at a suspension density of 10.000/mm3… 38.000/mm3, at 40°C or 46 °C for 15… 60 min. During the test with sublimate the loss of motility amounts to 55% at 4 mg/l Hg2+, the LC50 is 7.3 mg/l Hg2+. Phenyl-mercuric acetate causes the total loss of motility with 20 mg/l, the LC50 is above 168 mg/l (equivalent to 100 mg/l Hg2+). The LC50 of sodiumpentadecylmonosulphonate and dodecylpyridinchloride are 11.6 and 15.8 mg/l, resp. Filtrates of blooming of cyanophyceae on Baltic, having been digested by repeated freezing and thawing, with 1.5… 6.4 g/l dry matter showed motility losses of 30… 100 % for Nodularia spumigena, whereas no significant effect was produced by a filtrate of Microcystis aeruginosa with 28.2 g/l dry matter as well as water-blooming of Nodularia spumigena from the Small Jasmund Bodden. 相似文献
17.
The adsorption of three cationic dyes (rhodamine B, RB; crystal violet, CV; and malachite green, MG) onto termite feces, a low‐cost adsorbent, was investigated. The adsorbent was characterized by IR spectroscopy, point of zero charge measurement, and the Boehm titration method. The adsorption follows the pseudo‐second‐order kinetic model and the Langmuir–Freundlich isotherm with maximum adsorption capacities of 95.53 mg g?1 (RB), 75.71 mg g?1 (CV), and 44.78 mg g?1 (MG). The study of thermodynamics showed that the adsorption is a spontaneous and endothermic process. This works suggest that termite feces can be used as a new low‐cost adsorbent for cationic dye removal. 相似文献
18.
Competitive solid phase enzyme immunoassays using polyclonal antibodies were developed for the detection of the phenoxycaboxylic acids MCPB [4-(4-chloro-2-methylphenoxy)butyric acid], Mecoprop [2-(4-chloro-2-methylphenoxy)propionic acid], and 2,4-D [(2,4-dichloro-phenoxy)acetic acid] in drinking water and ground water. The carrier protein for the immunization was bovine serum albumin, horseradish peroxidase conjugates were employed as enzyme tracer. For the three antisera, the optimization of detection limits and test sensitivities was our first consideration. For the mecoprop and 2,4-D antisera, the strongest influences were the pH value and the ionic strength, as much as the use of enzyme tracers with lower affinities. The MCPB antiserum reacted with 2,4-DB[4-(2,4-dichlorophenoxy)butyric acid] with equal specificity, either could be detected at 0.02 μg/L (80% B/B0), middle of the test (50 B/B0) lying at 0.1 μg/L. The detection limit with mecoprop antiserum was optimized to 0.02 μg/L, the prescribed limit for drinking water of 0.1 μg/L ling at 60 % B/B0. The strongest cross-reactivity was found for mecoprop methyl ester. MCPB. 2,4-DB, and dichloroprop have crossreactivities of 50%, 6.7%, and 6.3%, respectively. The 2,4-D antiserum reacts less sensitively with 2,4-D, the detection limit being 0.4 μg/L. The 2,4-D isooctyl ester and 2,4-D methyl ester demonstrate as cross-reacting compounds high cross-reactivites of 3630% and 2230%. The cross-reactions of the compounds 2,4-DB, MCPB, and MCPA [(4-chloro-2-methylphenoxy)acetic acid] lie at 52%, 69%, and 41%. 100 ground water tests were spiked within laboratory. All positive samples were correctly identified. Falsely negative results did not appear. 相似文献
19.
The total organic carbon (TOC) is calculated by subtracting the inorganic carbon (IC) from the total carbon (TC). For TC determination, the carbon in a sample is completely converted to CO2 by decomposition/combustion in an oxygen stream. To determine IC, inorganic carbon (carbonate) is liberated by adding acid and by heating in an oxygen stream. In both cases, CO2 is quantified by infrared spectrometry. To gain reliable and reproducable results for sludge, sediment and suspended solids, at least the following conditions have to be met: particle size has to be smaller than 200 μm; weightout has to be selected in such a way, that the signal area is not below and the signal maximum is not above specific instrument dependent parameters; combustion/decomposition has to be complete (TC: ≥ 1300 °C, no soot) and rules for analytical quality assurance must be followed. The TC quantification of calcium carbonate is used for system calibration. Daily working procedures include calibration checks by mean control charts for TC determination of calcium carbonate and IC determination of sodium carbonate as well as for control sediment TC and IC quantifications. 相似文献
20.
In batch experiments with exposure for 24 to 96 h Macrobrachium naso and M. dayanum were exposed to solutions of the sodium salt of 2,4-dichlorophenoxy acetic acid. The LC50,96h are 2.397 g/l for Macrobrachium naso and 2.275 g/l for M. dayanum. No mortality was observed in solutions of 2.1 and 1.85 g/l. The differences in toxicity are not dependent on the size of the organisms, but they are species-specific. 相似文献