Showing papers on "Distilled water published in 2008"

Growth of tomato (Lycopersicon esculentum) in response to salicylic acid under water stress

Abstract: Plants of Lycopersicon esculentum L. cv. K-25 were subjected to water stress by withholding water for 10 days at 20 (WS I) and 30 (WS II) days after sowing (DAS). Seedlings were sprayed with double distilled water (DDW) or 10−5M salicylic acid (SA) at 45 DAS. The water stress at earlier stage of growth (20 day stage) was more inhibitory as compared to the later stage (30 day stage). The plants exposed to water stress exhibited a significant (p<0.05) decline in photosynthetic parameters, membrane stability index (MSI), leaf water potential, activity of nitrate reductase (NR), carbonic anhydrase (CA), chlorophyll and relative water content (RWC). A follow-up treatment with SA protected against the stress generated by water and significantly improved the above parameters. However, proline content and antioxidant enzymes increased under drought as well as under SA treatments.

Stress corrosion cracking of rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) compared with AZ80

Abstract: Stress corrosion cracking (SCC) of the high-performance rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) was studied using slow strain rate test (SSRT) method in air, distilled water and 0.5 wt.% NaCl solution. For comparison, the well-known AZ80 alloy was also studied. All alloys were susceptible to SCC in 0.5 wt.% NaCl solution and distilled water to some extent. AZ80 had similar SCC susceptibility in distilled water and 0.5 wt.% NaCl solution. ZE41, QE22 and EV31A had higher susceptibility to SCC in 0.5 wt.% NaCl solution than in distilled water. EV31A had the highest resistance to SCC compared to AZ80, ZE41 and QE22 in both distilled water and 0.5 wt.% NaCl solution. The fractography was consistent with (i) largely transgranular SCC (TGSCC) in distilled water for AZ80, ZE41 and QE22 and also for AZ80 in 0.5 wt.% NaCl solution, and (ii) a significant component of intergranular SCC (IGSCC) in 0.5 wt.% NaCl solution for QE22, ZE41 and EV31A. The TGSCC fracture path in AZ80, ZE41 and QE22 is consistent with a mechanism involving hydrogen. In each case, the IGSCC appeared to be associated with the second-phase particles along grain boundaries. For IGSCC of EV31A and QE22, the fractography was consistent with micro-galvanic acceleration of the corrosion of α-magnesium by the second-phase particles, whereas it appeared that the second-phase particles had corroded itself in the case of ZE41 in 0.5 wt.% NaCl solution. The study suggests that rare-earth elements in magnesium alloys can improve SCC resistance significantly as observed in the case of EV31A. However, the SCC resistance also depends on the other critical alloying elements such as zinc (in ZE41) and silver (in QE22) and the microstructure.

Adsorption kinetics for arsenic removal from aqueous solutions by untreated powdered eggshell

Abstract: The batch removal of arsenic from aqueous solution using low-cost adsorbent (powdered eggshell) under the influences of initial arsenic ion concentrations (0.50 to 1.50 mg/L), pH (3.2 to 11.5) and particle size of eggshells (63 to 150 μm) were investigated. Eggshells were collected from Obafemi Awolowo University, Ile-Ife, washed with distilled water, air dried, ground into powder and sieved into different sieve sizes using British standard sieve. Powdered eggshells were stored in a desiccator for use. Adsorption isotherms and dynamics of arsenic onto PES were studied. The study revealed that there was a slight reduction in the rate of adsorption of arsenic ion onto the larger particle size, but adsorption capacity and parameters were unaffected. Powdered eggshell with particle size of 63 μm removed up to 99.6% of the 1.5 mg/L of arsenic ion in synthetic water within the first 6 hours but decreased to 98.4% and 97.4% when the powdered eggshell particle sizes were increased to 75 and 150 μm respectively. The pH optimum for arsenic removal was 7.2. The adsorption isotherms and adsorption dynamic kinetic studied through the use of graphical method revealed that Freundlich, activated sludge adsorption and pseudo second-order kinetic models correlate significantly with the experimental data with correlation coefficient of not less than 0.964.

The Adequacy of Pressure Plate Apparatus for Determining Soil Water Retention

Abstract: This study evaluated the accuracy of pressure plate apparatus for measuring soil water retention at -0.5 and -1.5 MPa matric potential. Samples from 35 contrasting Australian soils were wetted with distilled water and drained on pressure plate apparatus at -0.5 and -1.5 MPa. The soil matric potential of each sample was then determined using a thermocouple psychrometer, and water content was measured. Water content at exactly -0.5 and -1.5 MPa matric potential was determined independently by interpolating between replicates of matric potential-water content data measured using a thermocouple psychrometer. Water content of the soil samples at apparent equilibrium on pressure plates was compared with these "target" water contents. The 35 samples on pressure plates at -1.5 MPa equilibrated, on average, to 0.3% (w/w) wetter than the target water content, with mean matric potential of -1.10 MPa. Fifteen samples were significantly wetter than the target values. Soil samples on pressure plates at -0.5 MPa equilibrated, on average, to 0.2% (w/w) wetter than the target water content, attaining a mean matric potential of-0.48 MPa. Mean error in water content at -1.5 MPa on pressure plates was reduced from >0.5 to <0.1% (w/w) in a subset of 10 samples prone to dispersion by wetting with 0.01 mol L -1 CaCl 2 . Water contents of samples equilibrated on pressure plates at -1.5 MPa were good estimates of "true" -1.5 MPa water content for the nonswelling soils tested, provided CaCl 2 was used to minimize dispersion. Vapor equilibrium measurement methods are recommended for swelling soils.

To what extent are pesticides removed from surface water during coagulation-flocculation?

Abstract: Laboratory for Applied Physical Chemistry and Environmental Technology, Department of ChemicalEngineering, K. U. Leuven W. de Croylaan 46, B-3001 Leuven, Belgium; Department of SanitaryEngineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft,Netherlands; Department of Environmental Engineering, Division of Water Supply and Sanitation, HanoiUniversity of Civil Engineering, Hanoi, Viet Nam Abstract: The occurrence of pesticides in drinking water sources is of concern for drinking water productioncompanies as well as for the end users. However, it is still unclear which pesticides are removed, and towhat extent, in widely used treatment methods such as coagulation-flocculation. Pesticides possibly interactwith colloidal particles by adsorption on the flocs during coagulation-flocculation. In this study, removal offour pesticides (aldrin, dieldrin, atrazine, bentazon) was observed during jar test experiments in distilled andsurface water (Dijle river, Belgium), using aluminium sulphate as a coagulant in different amounts rangingfrom no coagulant to high doses (300 mg/L). Without aiming at an accurate description of the removalprocess, the purpose of this study was to evaluate how much of the pesticides can be removed by changingthe concentration, the dosage, the water matrix and the properties of the pesticides. The results show that theremoval is usually low. The efficiency was worse when the matrix was distilled water than for Dijle riverwater, which is consistent with the idea that the removal of micropollutants only occurs through adsorptionon the available organic material, and not on inorganic coagulants. Sorption on the natural material availablein the Dijle river water seemed to be the main mechanism controlling the removal of micropollutants withcoagulation/flocculation, rather than the amount of coagulant added. The hydrophobicity of the compoundswas found to be a major factor in determining the removal efficiency with coagulation-flocculation; the mosthydrophobic compound had the highest removal efficiency. Nevertheless, the removal was below 50%under all the tested circumstances. The results of this study prove that pesticide removal in conventionalwater treatment plants depends on physico-chemical interactions, but is insufficient even with extreme dosesof alum. © 2008 The Authors. Journal compilation © 2008 CIWEM. Author Keywords: Coagulation-flocculation; Drinking water production; Hydrophobic pesticides; Pesticides Index Keywords: Adsorption; Agricultural chemicals; Chemicals removal (water treatment); Chlorinecompounds; Coagulation; Concentration (process); Flocculation; Hydrophobicity; Insecticides; Matrixalgebra; Offshore oil well production; Pesticides; Potable water; Removal; Rivers; Sorption; Spraying;Sulfate minerals; Water recycling; Water treatment; Water treatment plants; Coagulation-flocculation;Drinking water production; Hydrophobic pesticides; Dewatering; aldrin; aluminum sulfate; atrazine;bentazon; dieldrin; organic matter; pesticide; river water; surface water; coagulation; concentration(composition); drinking water; efficiency measurement; flocculation; hydrophobicity; pesticide;physicochemical property; removal experiment; water treatment; adsorption; article; Belgium; chemicalanalysis; chemical structure; concentration response; controlled study; flocculation; hydrophobicity; priorityjournal; waste component removal; waste water management; waste water treatment plant; water analysis;

Experimental Data and Predictions of Dissociation Conditions for Ethane and Propane Simple Hydrates in the Presence of Distilled Water and Methane, Ethane, Propane, and Carbon Dioxide Simple Hydrates in the Presence of Ethanol Aqueous Solutions

Abstract: Experimental gas hydrate dissociation data for ethane + distilled water, propane + distilled water, methane + 0.05 and 0.1 mass fraction ethanol aqueous solution, ethane + 0.05 and 0.1 mass fraction ethanol aqueous solution, propane + 0.05 and 0.1 mass fraction ethanol aqueous solution, and carbon dioxide + 0.05 and 0.1 mass fraction ethanol aqueous solution systems are reported herein. The new experimental data have been measured using an isochoric method. All the experimental data are compared with the predictions of a general correlation and a thermodynamic model. The agreements between the experimental and predicted data are generally found to be acceptable. The hydrate dissociation data for ethane + distilled water and propane + distilled water systems are also compared with some experimental data reported in the literature, and acceptable agreements between the data indicate the reliability of the experimental technique used in this study.

Inorganic arsenic speciation in various water samples with GFAAS using coprecipitation

Abstract: A simple, economic and sensitive method for selective determination of As(III) and As(V) in water samples is described. The method is based on selective coprecipitation of As(III) with Ce(IV) hydroxide in presence of an ammonia/ammonium buffer at pH 9. The coprecipitant was collected on a 0.45 µm membrane filter, dissolved with 0.5 mL of conc. nitric acid and the solution was completed to 2 or 5 mL with distilled water. As(III) in the final solutions was determined by graphite furnace atomic absorption spectrometry (GFAAS). Under the working condition, As(V) was not coprecipitated. Total inorganic arsenic was determined after the reduction of As(V) to As(III) with NaI. The concentration of As(V) was calculated by the difference of the concentrations obtained by the above determinations. Both the determination of arsenic with GF-AAS in presence of cerium and the coprecipitation of arsenic with Ce(IV) hydroxide were optimised. The suitability of the method for determining inorganic arsenic species was check...

Effect of Inorganic Salt Solutions on the Consistency Limits of Two Clays

Abstract: Due to its low permeability, a clay liner is the main material used in solid waste disposal landfills. It is exposed there to various chemical, biological, and physical events, and the clay liner is affected by the resulting leachate. For this reason, when attempting to define the geotechnical characteristics of clay liners, the use of distilled water or tap water is far from being representative of the in-situ conditions. In this study, the effects of 4 different salt solutions on the consistency limits of clays were experimentally investigated. The salt solutions used as leachate compounds were ammonium chloride (NH4Cl), potassium chloride (KCl), copper(II) sulfate (CuSO4), and iron(II) sulfate (FeSO4). Consistency limit tests were conducted on low plasticity (CL-class) and high plasticity (CH-class) commercial clays using both distilled water and these salt solutions. The experimental results indicated that the liquid limit increased when the salt concentration for the CL clay was increased. Moreover, the liquid limit was found to decrease when the salt concentration for the CH clay was increased. The plastic limit of the CL clay increased as the salt concentration increased to a certain value. However, the plastic limit of CH clay decreased at low salt concentrations and increased at high salt concentrations. In addition, the test results indicated that salt solutions at high concentrations changed the soil class of clays. In other words, for the conditions investigated, CL and CH class clays were transformed into low plasticity silt (ML) and high plasticity silt (MH) class soils, respectively, according to the Unified Soil Classification System (USCS).

Effect of Water Cationic Content on flocculation, flocs resistance and reflocculation capacity of PCC induced by polyelectrolytes

Abstract: In papermaking, mill water closure may result in a significant increase of inorganic salts in the white water. The effect of these contaminants on the performance of retention aids was evaluated, in this study, through flocculation of Precipitated Calcium Carbonate with three very high molecular weight cationic polyacrylamides of medium charge density and with different degrees of branching. Furthermore, flocs resistance and reflocculation capacity was also investigated when different types of shear forces were applied. Tests were carried out in distilled water and in industrial water containing a high concentration of cationic compounds. The flocculation, deflocculation, and reflocculation processes were monitored by evaluating particle size distribution using a light diffraction spectroscopy technique. Additionally to the effect of the cationic content of the medium, the influence of the flocculant dosage and degree of polymer branching were also studied. The effect of these parameters on the flocs stru...

Corrosion of AZ91 in 1N NaCl and the Mechanism of Magnesium Corrosion

Abstract: A study of the NDE of the magnesium alloy AZ91 in order to provide a test of the unipositive Mg ion mechanism for the corrosion of magnesium was reported. The electrolyte, made with analytic grade reagents and distilled water, was 1 N NaCl solution, the pH was adjusted to pH 11 with NaOH. The evolved hydrogen was collected during the experiment, and the concentration of Mg in the solution was measured. The results demonstrated that the volume of evolved hydrogen increased with increasing applied current density. The electrolyte was analyzed at the end of each experiment. It was observed that the concentration of Mg ions increased with increasing applied current density. The experimental results agreed with the standard excepted model of Mg, corrosion involving the unipositive Mg ion.

Development of chloride binding capacity in cement pastes and influence of the pH of hydration products

Abstract: This study deals with the chloride binding capacity of cementitious materials. The binding capacities of ordinary Portland cement (OPC), 30% pulverized fuel ash (PFA), 60% ground granulated blast furnace slag (GGBS), and 10% silica fume (SF) pastes were monitored for 150 d using the water extraction method and the pH of the suspension (ground sample in distilled water) was simultaneously measured at 150 d. Results show that the binding capacity always increased with time, irrespective of binder, and the order of binding capacity with binders was 60% GGBS > 30% PFA > OPC > 10% SF. The pH of suspensions increased with time up to about 10 d, presumably due to a leaching out of alkalis, and then kept a certain value that was dependent on binder type. It was also found that an increase in the concentration of hydroxyl ions, derived from the pH of the suspension, resulted in a decrease in the mole ratio of free chloride to hydroxyl ions, reflecting the lower risk of steel corrosion.

Chemical, microbial and physical evaluation of commercial bottled waters in greater Houston area of Texas

Abstract: Due to the increased demand and consumption of bottled water in the United States, there has been a growing concern about the quality of this product. Retail outlets sell local as well as imported bottled water to consumers. Three bottles for each of 35 different brands of bottled water were randomly collected from local grocery stores in the greater Houston area. Out of the 35 different brands, 16 were designated as spring water, 11 were purified and/or fortified tap water, 5 were carbonated water and 3 were distilled water. Chemical, microbial and physical properties of all samples were evaluated including pH, conductivity, bacteria counts, anion concentration, trace metal concentration, heavy metal and volatile organics concentration were determined in all samples. Inductively coupled plasma/mass spectrometry (ICPMS) was used for elemental analysis, gas chromatography with electron capture detector (GCECD) as well as gas chromatography mass spectrometry (GCMS) were used for analysis of volatile organics, ion chromatography (IC) and selective ion electrodes were used for the analysis of anions. Bacterial identification was performed using the Biolog software (Biolog, Inc., Hayward, Ca, USA). The results obtained were compared with guidelines of drinking water recommended by the International Bottled Water Association (IBWA), United States Food and Drug Administration (FDA), United States Environmental Protection Agency (EPA) and the World Health Organization (WHO) drinking water standard. The majority of the analyzed chemicals were below their respective drinking water standards for maximum admissible concentrations (MAC). Volatile organic chemicals were found to be below detection limits. Four of the 35 brands of the bottled water samples analyzed were found to be contaminated with bacteria.

Surfactant-Enhanced Removal of Cu (II) and Zn (II) from a Contaminated Sandy Soil

Abstract: Batch tests were conducted to know the effectiveness of using surfactants only and surfactants with a complexing agent to remove Cu (II) and Zn (II) from an artificially contaminated sandy soil. SDS (sodium dodecyl sulfate), AOT (alpha-olefin sulfonate) and Tx-100 (Triton X-100) were the surfactants selected as the washing liquids. Complexing agent EDTA (ethylenediaminetetraacetic acid) was also selected for washing the soil. To avoid external factors from interfering with the cleaning process, artificial soil formed by a mixture of clean sand and bentonite was used to form contaminated soil samples. The amount of organic matter present was insignificant. Compared to extraction by distilled water, tests indicated that a six-fold increase in copper extraction occurred due to the presence of surfactants and/or the complexing agent EDTA. Compared to extraction by distilled water, zinc extraction by surfactants and or the complexing agent EDTA was nearly 1.2 to 1.3 times more. Effects of competition as well as interference associated with the adsorption and desorption of these metals are also very briefly reported.

Salt-and pH-Resisting Collagen-based Highly Porous Hydrogel

Abstract: A novel approach was developed to prepare a highly porous hydrogel with superior salt- and pH-resisting properties. According to this method, synthetic comonomers, i.e. acrylic acid (AA) and 2-acrylaufido-2-methylpropanesulfonic acid (AMPS), were polymerized and crosslinked in the presence of hydrolyzed collagen as a natural backbone. The characterizations of hydrogels were investigated by swelling experiment, Fourier transform infrared (FT-IR) spectroscopy, acid-base titration and thermogravimetric analysis (TGA). Morphology of the samples was examined by scanning electron microscopy (SEM). Experimental results indicate that the hydrogel has an absorbency of 360 and 73-82 g/g for distilled water and saline solutions, respectively. Water absorbency slightly changes from pH 3 to 8 and interestingly is more than of that in distilled water (∼ 500 g/g). The hydrogel thus prepared was showing a better salt- and pH-resistance compared to collagen-g-PAA hydrogel due to the introduction of the AMPS segment and therefore is a suitable candidate for horticulture and tissue engineering applications.

Emulsifying behavior of an exopolysaccharide produced by Enterobacter cloacae

Abstract: A major concern for industrial production of microbial emulsifiers is expensive substrates. The aim of this work was to produce a microbial exopolysaccharide (EPS) using sea broth. Seawater, seawater + distilled water and nutrient broth were inoculated with Enterobacter cloacea and incubated in a rotary shaker at 37°C for 80 h. The microorganism produced different amount of exopolysaccharide in different ratios of distilled water and seawater but there was no any production in the nutrient broth. The best result was obtained in the sea water broth without addition of distilled water. Stability of emulsions formed with corn oil and toluene was studied at different concentration of EPS (15 - 75) and in the presence of sodium chloride (5 – 40 mg ml-1). The exopolysaccharide efficiently emulsified corn oil and toluene with water and salty solutions. There was a linear correlation between the concentration of EPS 71a and emulsification indices. The presents of salt up to 40 mg/ml did not show remarkable decrease in emulsion indices. This result suggests that the produced exopolysaccharide has a good potential to be used in the food industry.

CHARACTERIZATION OF LAYERED DOUBLE HYDROXIDE Mg-Al-CO3 PREPARED BY RE-HYDRATION OF Mg-Al MIXED OXIDE

Abstract: Emanation thermal analysis, differential thermal analysis, thermogravimetry, X-ray diffraction, scanning electron microscopy (SEM) and surface area and porosity determination from nitrogen adsorption/desorption measurements were used to characterize the Mg-Al-CO3 LDH compound with the Mg:Al ratio 3:1 prepared by re-hydration of the Mg-Al mixed oxide. The mixed oxide was obtained after heating of the intial Mg-Al-CO3 LDH compound in air at 500°C for 2 h. The samples were re-hydrated by two ways namely in a distilled water at 20°C for 5 days or by moistening at 60°C in air with RH 80% during 10 days, respectively. The characteristics of the re-hydrated LDH samples were compared with the initial Mg-Al-CO3 compound. The influence of the re-hydration conditions on the microstructure, surface morphology and thermal stability of the regenerated Mg-Al-CO3 LDHs samples is discussed. It was demonstrated that the re-generation of the layered structure by the hydration of the mixed oxide in water or in air,...

Cattle freezing seminal fluid dilution and method for producing the same

Abstract: The invention discloses a frozen bovine semen diluent, and the consumption amounts of all the raw materials in 100ml of the diluent are: 0.8 to 1.2g of fructose, 1.4 to 1.6g of sodium citrate, 2.3 to 2.6g of TRIS, 7.5 to 9.5g of low-density lipoprotein, 5 to 8ml of glycerol, 0.085 to 0.12 million IU of penicillin and the rest is distilled water. The preparation method is that: the fructose, the sodium citrate and the TRIS are dissolved in the distilled water to be prepared into a base liquid; penicillin G sodium and the low-density lipoprotein are added in the base liquid to prepare a I liquid; the glycerol is added in the I liquid to prepare a II liquid; then the pH value is adjusted to 6 to 7.5, then a filtration and a sterilization are carried out, and the liquid is cooled until reaching the room temperature and then arranged in a refrigerator of 2 - 5 DEG C for standby. The frozen bovine semen diluent of the invention has good and reliable effect, which can provide high-quality and excellent straw frozen semen for bovine artificial insemination and have very broad market application prospect.

Study of the degradation of the herbicide clomazone in distilled and in irrigated rice field waters using HPLC-DAD and GC-MS

Abstract: This study evaluated the degradation of the herbicide clomazone in distilled water and from irrigated rice fields, through UV irradiation and under natural conditions. After a solid phase extraction (SPE) as preconcentration step, the remained concentration of clomazone was determined by high performance liquid chromatography with diode array detection (HPLC-DAD) and the identification of the degradation products was achieved by gas chromatography-mass spectrometry (GC-MS). Under UV irradiation, the clomazone was degraded faster in distilled water than in surface water. In irrigated rice water, under sunlight irradiation, clomazone presented a half-life time average of 3.2 days in three consecutive harvests, and after application the concentration in water remained higher than 0.1 μg L-1 for 20 days. Several by-products, like 2-chlorobenzaldehyde and 2-chlorobenzene methanol, were identified by GC-MS, which evidenced that the concentration of intermediates at the begining increase and then they also undergo degradation.

Preparation, Swelling, and Slow-Release Characteristics of Superabsorbent Composite Containing Sodium Humate

Abstract: A series of multifunctional poly(acrylic acid-co-acrylamide)/Ca−montmorillonite/sodium humate superabsorbent composites with slow-release sodium humate were prepared by graft copolymerization reaction with partially neutralized acrylic acid (AA), acrylamide (AM), Ca−montmorillonite (Ca−MMT), and sodium humate (SH) in aqueous solution. The effects of SH and Ca−MMT contents on water absorbency were studied, and the highest water absorbency was obtained when the SH-to-MMT ratio was 3:2 (total amount of SH and Ca−MMT in the feed was fixed at 50 wt %). The swelling kinetics in distilled water and swelling behaviors in various pH solutions for the developed composites were systematically investigated. A two-stage release characteristic of SH in distilled water was observed, and the differences before and after SH release were characterized by FTIR, XRD, SEM, and TGA. With increasing SH and Ca−MMT contents, water absorbency differed, suggesting that SH was mainly chemically bonded with the polymer matrix, wherea...