Chloride Concentration Ratio Research Articles

Biopolymeric Composite Columns for Improving Water Quality in a Freshwater Stream Receiving Wastewater Treatment Plant Effluents

Inefficiently treated wastewater, which contains a high concentration of pollutants, is hazardous when it is mixed with the clean water of rivers and lakes. Nitrate in particular is a major global problem that leads to eutrophication and poses a threat to both aquatic ecosystems and human health. To address this issue, this work assessed the efficiency of polymeric cryogel (PC) and biopolymer (EPS)-blended composites (EPS@PC) in removing nitrates. Tests were also conducted to quantify the decrease in phosphate, chloride ions, and chemical oxygen demand (COD) in real water samples taken from the Ankara stream, which receives effluents from both urban (UWTP) and industrial (IWTP) wastewater treatment plants. Five different columns with varying adsorptive properties were prepared, some of which were combined with iron. The EPS-@PC-C5 column demonstrated the highest adsorption ratio for nitrate removal compared to the other tested columns. The EPS@PC-C5 achieved a high removal efficiency of 126.38 mg nitrate/g and showed COD reduction ranging from 60.2 to 94.1%. The removal ratio of chloride concentration varied between 56.0 and 75.7%, while the removal of phosphates ranged from 87 to 99%. Columns composed of EPS (EPS@PC) with both negatively and positively charged ligands are dependable and suitable options for water remediation.Graphical

Manipulating the monomers supply of interfacial polymerization towards the ultrathin polyamide composite membrane for CO2 capture

Preparing polyamide (PA) composite membranes with high gas separation performance requires rational control for the interfacial polymerization (IP) process. In this study, the monomer supply of piperazine (PIP) and trimesoyl chloride (TMC) in the IP process was precisely manipulated to generate an ultrathin PA film on the polydimethylsiloxane (PDMS) gutter layer for CO2 separation. Concretely, the PIP supply was regulated from the homogeneous, slow, and excess mode to the inhomogeneous, fast, and small mode by constructing a sodium dodecyl sulfate (SDS) array at the phase interface; subsequently, the TMC supply was increased by elevating the TMC concentration. Therefore, the amine-to-acid chloride concentration ratio in the reaction zone was optimized and, as a consequence, the IP reaction rate was significantly increased. As a result, the thickness of the PA film was reduced from ∼92 nm to ∼37 nm through the optimization of SDS and TMC concentrations, and accordingly, the CO2 permeance was increased from 501 GPU to 1498 GPU under 0.1 MPa without sacrificing selectivity. Moreover, the membrane preparation efficiency was greatly improved with an IP reaction time of less than 30 s. The insights provided could promote the industrial application of interfacial polymerization in the scale-up preparation of high-performance CO2 separation membranes.

The Susceptibility of Copper to Pitting Corrosion in Borate-Buffered Aqueous Solutions Containing Chloride and Sulfide

The formation of sulfide and oxide films on copper (Cu) was studied in chloride solutions with and without added borate and sulfide. Electrochemical experiments demonstrated that Cu sulfide (Cu2S) films formed at considerably lower potentials than oxides (Cu2O/CuO) films. The growth of Cu2S was controlled by a combination of sulfide transport to the reacting Cu surface and the competition between SH− and Cl− ions for adsorption sites on the Cu surface. Scanning electron microscopy on focused ion-beam cut cross sections demonstrated that the films were porous and not passive. At more positive potentials, Raman spectroscopy and X-ray photoelectron spectroscopy demonstrated that the formation of oxide films, likely with the formation of a passive oxide film, dominated over anodic dissolution of Cu as CuI chloride complexes when the borate to chloride concentration ratio was sufficiently high. If pitting is to occur on Cu, it will require oxide not sulfide film growth.

Preparation and Characterization of Activated Carbon from Sesame Seed Shells by Microwave and Conventional Heating with Zinc Chloride Activation

ABSTRACTThe preparation of activated carbon from sesame shells as raw precursor was investigated in the study by sequentially applying microwave and conventional heating methods assisted by zinc chloride activation. The optimizisation of experimental parameters including microwave power, microwave treatment time, conventional activation time, conventional activation temperature and zinc chloride concentration ratio for the microwave and conventional heating method was performed. The characterization of the prepared activated carbon was done by thermogravimetric and differential thermal measurements, infrared spectroscopy, scanning electron microscopy and specific surface area analyses. The maximum surface area of 1254 m2/g for the prepared activated carbon was obtained at a microwave power of 750 W, a microwave treatment time of 20 min, an activation time of 45 min, an activation temperature of 500°C and zinc chloride concentration ratio of 1:1. Methylene blue and iodine adsorption capacities for the prepared activated carbon were 103 and 1199 mg/g, respectively.

Influences of chloride immersion on zeta potential and chloride concentration index of cement-based materials

This paper measured the zeta potential and chloride concentration index of hardened cement paste, which was defined as the ratio of chloride concentration in the expressed pore solution to that in soaking solution. A model was proposed to explain the relationship of zeta potential and concentration index of hardened cement pastes immersed in chloride solution. The results showed that with the increase of chloride concentration in soaking solution, both the chloride concentration index and zeta potential of hardened cement paste gradually decreased. The addition of slag influenced the chloride concentration index and zeta potential. The relationship between chloride concentration index, chloride concentration in soaking solution and slag replacement level, as studied by the Gouy-Chapman model was well correlated with the measured results.

Identification of corrosion mechanisms on 13% Cr martensitic stainless steel in thiosulphate containing chloride solution by acoustic emission technique

The use of brine containing thiosulphate solution to simulate the sour gas environment was recently evaluated in the scientific literature to overcome the problems related to H2S use for laboratory testing of corrosion-resistant alloy (CRA) for Oil and Gas industry. However, corrosion attacks on stainless steel alloys are strongly influenced by thiosulphate to chloride concentration ratio. The identification of a reliable non destructive monitoring technique that can allow to distinguish between the different corrosion mechanisms is a big issue and it is the main aim of the present paper. Corrosion behaviour under tensile load of 13% Cr martensitic stainless steel in a modified NACE TM0177 standard solution at room temperature in presence of thiosulphate ions at different concentration (from 10-3 to 10-1 M) was evaluated by acoustic emission technique. By microstructural observations and a bivariate analysis it was possible to evidence how some acoustic emission patterns can clearly identify specific corrosion mechanisms.

Effects of Process Variables on Size of Chitosan-Alginate Capsules through Extrusion-Dripping Method

The objective of this study was to investigate the effects of process variables on size of chitosan-alginate capsules produced through extrusion-dripping method. Chitosan-calcium chloride solution was extruded into sodium alginate to form chitosan-alginate capsules which have a defined inner core and membrane. The results showed that sodium alginate concentration, chitosan concentration, chitosan to calcium chloride concentration ratio, needle diameter, gelation time have significant effect on the diameter and membrane thickness of chitosan-alginate capsules. Under the tested condition, chitosan-alginate capsules with diameter in a range of 3.4 mm to 4.5 mm were produced. The membrane thickness of the capsules increased when the curing time increased from 5 min to 60 min. As the concentration of sodium alginate (0.3-0.9 %w/v) and chitosan (0.4-1.0 %w/v) increased, the diameter of the chitosan-alginate capsules increased. The diameter of chitosan-alginate capsules increased with decreasing the chitosan to calcium chloride concentration ratio (1:0.5-1:1.5).

A GIS-based vulnerability assessment of brine contamination to aquatic resources from oil and gas development in eastern Sheridan County, Montana

Water (brine) co-produced with oil in the Williston Basin is some of the most saline in the nation. The Prairie Pothole Region (PPR), characterized by glacial sediments and numerous wetlands, covers the northern and eastern portion of the Williston Basin. Sheridan County, Montana, lies within the PPR and has a documented history of brine contamination. Surface water and shallow groundwater in the PPR are saline and sulfate dominated while the deeper brines are much more saline and chloride dominated. A Contamination Index (CI), defined as the ratio of chloride concentration to specific conductance in a water sample, was developed by the Montana Bureau of Mines and Geology to delineate the magnitude of brine contamination in Sheridan County. Values >0.035 indicate contamination.Recently, the U.S. Geological Survey completed a county level geographic information system (GIS)-based vulnerability assessment of brine contamination to aquatic resources in the PPR of the Williston Basin based on the age and density of oil wells, number of wetlands, and stream length per county. To validate and better define this assessment, a similar approach was applied in eastern Sheridan County at a greater level of detail (the 2.59km2 Public Land Survey System section grid) and included surficial geology. Vulnerability assessment scores were calculated for the 780 modeled sections and these scores were divided into ten equal interval bins representing similar probabilities of contamination. Two surface water and two groundwater samples were collected from the section with the greatest acreage of Federal land in each bin. Nineteen of the forty water samples, and at least one water sample from seven of the ten selected sections, had CI values indicating contamination. Additionally, CI values generally increased with increasing vulnerability assessment score, with a stronger correlation for groundwater samples (R2=0.78) than surface water samples (R2=0.53).

Effects of Steady‐State Assumption on Hydraulic Conductivity and Recharge Estimates in a Surficial Aquifer System

AbstractThe ability of a calibrated flow model to predict the behavior of a surficial aquifer system is governed by the quality of the hydraulic conductivity and recharge estimates used. Reasonable lateral and vertical hydraulic conductivities can be estimated by steady‐state simulations driven by effective recharge rates that approximate the net effects of evapotranspiration, and water released from storage during periods of recession. Results from a hypothetical, transient, cross‐sectional model indicated that most of the water was contributed uniformly from storage from five to 25 days after a recharge event. Results also showed that a steady‐state, snapshot calibration approach can be used on aquifers in a humid climate with diffusivities between 20 and 500 m2/d. Most estimates of the lateral and vertical hydraulic conductivities of the hypothetical aquifer system were within 30% of the actual values. Estimates of hydraulic conductivity from the transient cases were similar to those from the snapshot calibration cases. The long‐term recharge rate could be identified by calibrating to multiple synoptic surveys that were sampled over the range of drier to wetter conditions. The effective recharge rates estimated for the driest and wettest conditions bracketed the long‐term recharge rate. Results suggested that the effective recharge rate estimated for the synoptic survey with the lowest water level root‐mean‐square (RMS) error was the best estimate of the long‐term recharge rate. A field application of the snapshot calibration approach simulated the surficial aquifer system beneath Cecil Field Naval Air Station well and provided reasonable estimates of the long‐term recharge rate (0.4 mm/d) relative to the range of recharge rates that were independently estimated by the chloride concentration ratio method (0.2 to 0.6 mm/d).

Micropuncture Study of the Superficial Nephron of <i>Cercopithecus aethiops</i>

Clearance and micropuncture experiments were performed on male Cercopithecus monkeys weighing between 2 and 4 kg to evaluate the function of the superficial nephron. The mean glomerular filtration rate was 4.47 +/- 0.32 ml/min. The fraction of filtered sodium, potassium, calcium, magnesium, and phosphate remaining at the end of the accessible proximal tubule were 54 +/- 3, 64 +/- 4, 70 +/- 3, 79 +/- 5, and 39 +/- 5%, respectively. The concentration of magnesium and calcium in the tubule fluid rose significantly along the length of the proximal tubule. The tubule fluid bicarbonate concentration was measured by determination of total CO2 with microcalorimetry. The tubule fluid to blood bicarbonate ratio fell to 0.48 +/- 0.06 at the late proximal tubule collection site, as the tubule fluid to ultrafiltrable chloride concentration ratio rose to 1.08 +/- 0.02. Thus, bicarbonate is reabsorbed in preference to chloride in the superficial proximal tubule of the monkey, to provide a potential driving force for water and salt absorption. By the time the tubular fluid reached the distal tubule sampling site, most of the filtered sodium potassium, calcium, magnesium, and chloride was reabsorbed, suggesting the loop of Henle as a major site of ion reabsorption. Segments beyond the distal tubule collection site reabsorbed little of the delivered ions. These studies indicate that the function of the superficial nephron resembles that of species previously studied, except that calcium reabsorption is demonstrably diminished in the proximal convoluted tubule relative to other mammals.

Maleic acid-induced reabsorptive dysfunction in the proximal and distal nephron.

Micropuncture and clearance studies were performed to assess reabsorptive function in the proximal and distal nephron of rats with experimental Fanconi's syndrome induced by maleic acid. Anesthetized rats were studied by free-flow micropuncture of the late proximal tubule 90-120 min after continuous intravenous administration of maleic acid, 100 mg X kg-1 X h-1. Compared with control rats, the reabsorption of sodium and phosphate was significantly reduced (P less than 0.001 and less than 0.02, respectively). Tubular fluid-to-ultrafiltrate (TF/UF) chloride concentration ratio was 1.00 +/- 0.02 compared with 1.16 +/- 0.03 (P less than 0.01) in controls, suggesting a nearly total inhibition of proximal bicarbonate reabsorption. Whole kidney fractional excretions of sodium and chloride were increased significantly (P less than 0.02) but could not be explained by enhanced delivery of these solutes out of the late proximal tubule. To assess whether distal nephron reabsorption of sodium and chloride were inhibited by maleic acid, clearance studies were performed during water diuresis in awake rats. During maleic acid administration, 200 mg X kg-1 X h-1, urine flow rate (P less than 0.02) and the fractional excretions of sodium and chloride (P less than 0.001) increased significantly, but fractional free water clearance decreased from 7.16 +/- 0.42 to 4.03 +/- 0.68% (P less than 0.001). In acetazolamide-treated control rats but not in maleic acid-treated rats with similar bicarbonaturia, the magnitude of fractional free water clearance closely approximated the simultaneously measured fractional distal delivery of chloride. These studies suggest that maleic acid inhibits reabsorption at a distal nephron site or sites as well as in the proximal tubule.

In vivo proximal tubular fluid-to-plasma chloride concentration gradient in the rabbit.

It has been reported that the concentration of chloride in the proximal tubule is greater than that in plasma in several mammalian species. Much of the theory concerning fluid and electrolyte reabsorption in the proximal tubule is based on data taken from in vitro isolated proximal tubules of the rabbit nephron. This study measured in vivo the rabbit proximal tubule fluid-to-ultrafiltrate chloride concentration ratio [(TF/UF)Cl] and its relationship to proximal tubule length as estimated by the tubule fluid-to-plasma inulin concentration ratio [(TF/P)In]. From six rabbits, 19 random proximal tubules were micropunctured and analyzed for inulin and chloride concentrations, the latter being measured by microelectrometric titration. Plasma ultrafiltrate was determined by correcting plasma chloride concentration for protein concentration. The average single nephron filtration rate was 20.2 +/- 0.8 nl/min. The (TF/UF)Cl ratio was 1.10 +/- 0.03, which was significantly different from unity. Furthermore, regression analysis yielded no significant correlation between the (TF/UF(Cl and (TF/P)In ratio. This study demonstrates that a tubule lumen-to-plasma chloride concentration gradient exists in the in vivo proximal tubule of the rabbit that is apparently established early and is not correlated with proximal tubule length.

Tubular handling of bicarbonate and chloride in the dog.

Bicarbonate reabsorption was assessed in the superficial proximal and distal tubule of the hydropenic dog. Tubule fluid bicarbonate concentration was measured by determination of total CO2 with microcalorimetry. Total CO2 declined from 21 to 14 mM along the proximal tubule, which reabsorbed 56% of the filtered bicarbonate prior to the late proximal sampling site. Absolute bicarbonate reabsorption was 124 pmol . min-1 . mm tubule length-1. Concurrent water reabsorption was 34% of the glomerular filtration rate. Tubule fluid-to-ultrafilterable chloride concentration ratio rose to 1.10 as the tubule fluid-to-blood bicarbonate ratio fell to 0.69 at the late proximal collection site. The total CO2 in distal tubule fluid was 6 mM, indicating that 94% of the filtered bicarbonate was reabsorbed prior to the distal tubule. It is concluded that bicarbonate is reabsorbed in preference to chloride in the superficial proximal tubule of the dog, which, like that of the rat, may provide a potential driving force for water and salt reabsorption.

Excessive drinking (polydipsia) in a galápagos mockingbird ( Nesomimus)

1. 1. A species of Galápagos mockingbird Nesomimus parvulus on a diet of insects, goat meat and bread drank between 14 and 30 per cent of its body weight/day in distilled water. As the NaCl concentration of the drinking water was increased to 300 mM, the amount drunk increased. Lesser amounts of 400 and 500 mM NaCl were drunk. The maximum cloacal fluid to plasma chloride concentration ratio was 3·2–3·6. 2. 2. Another Galápagos mockingbird species, Nesomimus macdonaldi, on the same diet drank 52 to 89 per cent of its body weight/day in distilled water, an excessive consumption of water. As the salinity of the drinking water was increased in 100 mM steps, the amount drunk remained constant until a precipitous decline occurred on 400 mM NaCl. The maximum cloacal fluid to plasma chloride concentration ratio was estimated as 3·4–4.·1. On a dry diet (chicken mash), drinking varied between 54 and 119 per cent body weight/day. This species feeds partly in the intertidal zone on marine invertebrates and probably has no access to fresh water for long periods of time. The cause of the pronounced polydipsia observed and its relevance to adaptation of this species to arid conditions deserve futher study.

CLINICAL OBSERVATION OF DIABETES INSIPIDUS (Ist REPORT)

Water and electrolyte metabolism was studied in 25 cases with diabetes insipidus, and the following results were obtained:(1) Daily urinary volume in most of the cases (88%) did not exceed eight liters.(2) In the dilution and concentration test, their dilution capacity was not impaired, however, the urinary output per unit of hour was rather uniform, which was indicative of primary polyuria. On the contrary, there were variable degrees of severe impairment of their concentrating capacity.(3) Renal blood flow (RBF), renal plasma flow (RPF), glomerular filtration rate (GFR) and filtration fraction (FF) were not significantly different from those of normal subjects, whereas tubular reabsorption rate (TRR) was materially reduced (10 cases).(4) There was somewhat increased excretion rate of PSP (5 cases).(5) Serum antidiuretic substance (ADS) was at the lower range of that of normal in 6 out of 7 cases. There was also no daily or diurnal variation of ADS, and no decrease was observed following the water load by mouth.(6) By intravenous infusion of hypertonic saline solution, there was a slight decrease in urinary output in one of 4 cases, whereas there was a slight or moderate increase in urinary output in the rest of the cases without elevation of urinary and plasma chloride concentration ratio.(7) By intravenous administration of 0.8 to 2.0mg of nicotine, there was a slight decrease in urinary output in one of 3 cases, whereas no decrease in the rest of the cases.(8) There was no demonstrable change in serum electrolyte concentration (11 cases); there was, however, a marked increase in K/Ca as a result of increased serum potassium concentration following posterior pituitary transplantation.(9) Daily urinary output significantly decreased after posterior pituiatry transplantation, which was accompanied by increase in serum ADS, abolition of urinary dilution capacity and prolongation of time required for disappearance of the elevation produced by intradermally injected salt solution by method of McClure and Aldrich (2 cases). A slight decrease in RPF with increase in GFR, resulting in increase of FF, and elevation of TRR were observed following the transplantation (1 case).