Hydrochemical and stable isotopic assessment of groundwater quality and its variations in rice-growing areas in East China

Agricultural activities are frequently associated with water contamination. Thus, the development of efficient strategies for groundwater protection in agricultural areas requires an assessment of the contaminants. Given this perspective, groundwater quality monitoring is carried out in a rice-growing area in Hangjiahu Plain, East China. Thirty-two piezometers are installed to measure physico-chemical parameters such as major ions, field-measured parameters (pH, electrical conductivity (EC), dissolved oxygen, and temperature), and δ¹⁵N isotopic ratios and their variations in space and time. The groundwater shows a variable chemical composition, e.g. EC ranged from 760 to 2,300 μS cm^?1. Most groundwater is weakly acidic, and is characterized as Ca²⁺ + Na⁺? HCO₃ ^? + SO₄ ^2? + Cl^? type. The results demonstrate NH₄ ⁺ coming from agricultural activities and SO₄ ^2? deriving from natural chemical inputs are the major contaminants in the groundwater at the study area. Correlations among NO₃ ^?, NH₄ ⁺ and K⁺ suggest that these ions come from the same source of fertilizer and indicate a significant degree of nitrification in the study area. The highly positive correlations among the variables of HCO₃ ^?, SO₄ ^2?, and Mg²⁺ indicated that these ions were derived from the same source of natural chemical inputs. Nitrate isotopic composition suggests that nitrate in groundwater originates from chemical fertilizers, manure, and soil organic matter.     

Effects of electrolytes on the reduction of 2,4‐dinitrotoluene by zero‐valent iron

BACKGROUND: Dinitrotoluenes (DNTs) are environmentally persistent, making the remediation of contaminated streams and groundwater difficult. Zero‐valent iron (Fe⁰) can be used as an electron source for the reduction of recalcitrant DNTs in waste‐water and thus enhance their biodegradability. However, little is known about the qualitative effects of major anions and cations present in waste‐water on the reduction of DNTs by Fe⁰. RESULTS: The presence of Na₂SO₄ and NaCl at levels between 0.25 and 2 mmol L^?1 was observed to enhance the reactivity of Fe⁰ towards 2,4‐DNT. The positive effect of K₂SO₄ is stronger than that of Na₂SO₄ at the same level (1 mmol L^?1). Varying (NH₄)₂SO₄ from 0.1 to 1.0 mmol L^?1 improved the efficiency of 2,4‐DNT degradation by Fe⁰. The effects of varying NaNO₃ and NaNO₂ from 0 mmol L^?1 to 4.7 mmol L^?1 and 0 mmol L^?1 to 5.8 mmol L^?1, respectively, were also investigated. Both NaNO₃ and NaNO₂ at low concentration improved the efficiency of 2,4‐DNT degradation by Fe⁰, however, at high concentration, inhibiting effects appeared. CONCLUSION: SO₄^2?, Cl^?, Na⁺, K⁺ and NH₄⁺ notably enhanced 2,4‐DNT reduction by Fe⁰ at the tested concentrations. The positive effect of K⁺, Cl^? was relatively stronger than that of Na⁺ and sulfate (SO₄^2?). However, the effect of NH₄⁺ was relatively weaker at concentrations greater than 1.0 mmol L^?1. The presence of low concentrations of NO₃^? and NO₂^? promoted 2,4‐DNT reduction by Fe⁰ and inhibited the reaction. The results suggest that 2,4‐DNT reduction by Fe⁰ can be controlled by the ions composition of the waste‐water. Copyright © 2010 Society of Chemical Industry     

Ortho-experiment study on formation of potassium sulfate from the system of K+, Ca2+, NH4+ ‖ Cl−, SO42− in H2O

An ortho-experiment design and the analysis method of mathematical statistics are adopted to study the conversion of gypsum and potassium chloride to potassium sulfate in the system of K⁺, Ca²⁺, NH₄⁺ ‖ Cl^?, SO₄^2? in H₂O. Optimal reaction parameters and engineering mean are acquired to attain a conversion yield of potassium chloride of 94.52%.     

How the Influence of Different Salts on Interfacial Properties of Surfactant–Oil–Water Systems at Optimum Formulation Matches the Hofmeister Series Ranking

In this work, we present the effects of salts on sodium dodecyl benzene sulfonate micellization and on the interfacial performance of a sodium dodecyl benzene sulfonate–heptane–brine system at optimum formulation, i.e., hydrophilic–lipophilic deviation (HLD) = 0. In order to do that, interfacial tension and dilational interfacial rheology properties of surfactant–heptane–water systems at optimum formulation are measured using an interfacial spinning drop tensiometer with an oscillating velocity, which can accurately measure interfacial rheology properties at both low and ultralow interfacial tensions. The brines used contain one of the following salts: MgCl₂, CaCl₂, NaCl, NH₄Cl, NaNO₃, CH₃COONa, or Na₂SO₄. We performed a one-dimensional salinity scan with each of these salts to achieve an optimum formulation. In relation to the Hofmeister series, we found that, at optimum formulation, systems with chaotropic ions (NH₄⁺, NO₃⁻) present interfaces with ultralow interfacial tensions, very low dilational modulus, and a low phase angle, whereas kosmotropic ions (Mg²⁺, Ca²⁺, SO₄⁻²) generate high interfacial tension and high rigidity monolayers. Intermediate ions in the Hofmeister series (Na⁺, CH₃COO⁻, Cl⁻) present interfaces with intermediate properties. Furthermore, according to the Hofmeister series, interfaces can be respectively ordered from higher to lower rigidity for surfactant counterions Mg²⁺ > Ca²⁺ > Na⁺ > NH₄⁺ and coions SO₄²⁻ > CH₃COO^– > Cl⁻ > NO₃⁻, which correspond to a salting-out (highest rigidity) and salting-in (lowest rigidity) effect. We observed that counterions have a more significant effect on surfactant–oil–water system properties than those that act as coions.     

Electrokinetic Properties of Vermiculite and Expanded Vermiculite: Effects of pH,Clay Concentration and Mono- and Multivalent Electrolytes

Abstract

In this study, the zeta potential values of vermiculite and expanded vermiculite were measured to determine the effect of pH, clay concentration, and various mono- and multivalent electrolytes including NaCl, KCl, NH₄Cl, NaNO₃, NaClO₄, Na₂SO₄, Na₂CO₃, Na₃PO₄·12H₂O, MgCl₂·6H₂O, CaCl₂·2H₂O, BaCl₂, SrCl₂·6H₂O, CuCl₂·2H₂O, CoCl₂·6H₂O, NiCl₂, AlCl₃, and CrCl₃·6H₂O on the electrokinetic properties of vermiculite samples. It was found that generally the measured zeta potential values of expanded vermiculite for the studied systems were slightly more negative than that of vermiculite. The pH profiles of vermiculite and expanded vermiculite at acidic, natural, and basic pH values were obtained to determine the effect of time on the pH values of clay suspensions. The zeta potential measurements showed that the surface charge of clay particles was negative in water. The isoelectric point of vermiculite and expanded vermiculite were determined as pH 2.30 and 2.57, respectively. Divalent cations (Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺), heavy metal ions (Cu²⁺, Ni²⁺, and Co²⁺) and trivalent cations (Al³⁺ and Cr³⁺) were potential determining ions for vermiculite and expanded vermiculite particles. Moreover, divalent and trivalent cations caused the change of surface charge from negative to positive. On the other hand, monovalent cations (Na⁺, K⁺ and NH₄ ⁺), monovalent anions (Cl^?, NO₃ ^?, and ClO₄ ^?) and multivalent anions (SO₄ ^2?, CO₃ ^2?, and PO₄ ^3?) acted as indifferent ions for these clay particles.     

A study of Ga3+ Reduction in the drop mercury electrode

A kinetic study is carried out of the Ga^3? + 3e → Ga electrode reaction in relation to the existing ionic species in the media used: LiClO₄, NaCl, KBr, NaNO₃, Na₂SO₄ and NH₄OH. It is found that the predominant species in equilibrium at the electrode have a coordination index of 6 ligands for the SO^?₄, the Cl^? and NO^?₃ ions, 5 for Br^? and 4 for NH₃. It is also noted that Ga³⁺ does not form complex compounds with ClO^?4 ions. The specific rate constant of electrode reaction in the equilibrium potential, k_O calculated by Koutecky's method, is in all cases between 2·10^?5 and 1·10^?8 cm s^?1, and the transfer coefficient, α, is about 0·15.By microcoulometric methods it is confirmed that the number of electrons in the electron transfer is three.A study is also made of interaction of the Ga³⁺ reduction wave, which in a 0·1 M LiClO₄ medium presents a half wave potential (E_{$\text{1}\text{2}$}) of ?1·270 V with reference to sce, with the H⁺ wave. It is concluded that the optimum pH of study is between 2·7 and 3·1. The ionic intensity of the medium is also taken into account.     

A chromotropic acid modified SBA-15 as a highly sensitive fluorescent probe for determination of Fe<Superscript>3+</Superscript> and I<Superscript>−</Superscript> ions in water

A novel organic–inorganic hybrid nanomaterial (SBA-15-CA) was prepared by covalent immobilization of chromotropic acid onto the surface of mesoporous silica material SBA-15. Different techniques such as XRD, TEM, FT-IR, N₂ adsorption–desorption and TGA analyses were employed to characterize the grafting process. The data showed that the organic moiety (0.41 mmol g^?1) was successfully grafted to the SBA-15 and the primary hexagonally ordered mesoporous structure of SBA-15 was preserved after the grafting procedure. SBA-15-CA has been realized as a highly sensitive and selective fluorescent probe towards Fe³⁺ and I^? ions in aqueous media. SBA-15-CA exhibited a remarkable fluorescent quenching in the presence of Fe³⁺ ion over other competitive cations including Na⁺, Mg²⁺, Al³⁺, K⁺, Ca²⁺, Cr³⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺ as well as I^? ion among a series of anions including F^?, Cl^?, Br^?, CO₃^2?, HCO₃^?, CN^?, NO₃^?, NO₂^?, SCN^?, SO₄^2?, H₂PO₄^?, HPO₄^2?, and CH₃COO^?. A good linear response was observed between the concentration of the quenchers (Fe³⁺ and I^? ions) and fluorescence intensity of SBA-15-CA with detection limits of 1.5?×?10^?7 M for Fe³⁺ and 0.2?×?10^?7 M for I^?. Moreover, the effects of various pH values on the sensing ability of SBA-15-CA were investigated. Finally, the proposed method was successfully utilized for the determination of Fe³⁺ and I^? ions in river water, well water and tap water samples.     

Pitting of zinc in leclanche and related electrolytesII. Mode of growth of pits and rate of propagation

The nucleation and growth of pits on battery zinc alloy electrodes in commercial (standard) Leclanché and related electrolytes has been studied quantitatively using both potentiodynamic and potentiostatic techniques. Pit numbers, volumes, surface areas and distributions have been determined by optical microscopy. The effect on pitting kinetics of pH, NH⁺₄ ions and various anions: Br^?, Cl^?, ClO^?₄ and SO^2?₄, has also been investigated. A theory is provided which acts as a basis for interpreting the observed time dependence of the pitting current density at constant potential and deviations of the real system from the idealized model are discussed.     

Studies on integration of ion exchange and nanofiltration for water desalination

This work addresses an integrated treatment to produce drinking water involving the ion exchange (IEX) and nanofiltration processes. In the first stage, the experimental procedure consisted of evaluating the IEX equilibrium and the dynamics of fixed-bed saturation/regenerations, for the system Cl^?/SO₄², using an anionic resin, Purolite A850, in the form sulphate. A mathematical model which considers axial dispersion for the liquid phase and linear driving force for intraparticle mass transfer predicted well the breakthrough curves of Cl^? and SO₄^2?. In the second stage, the selective separation of Cl^?, Na⁺ and SO₄^2? ions through a flat membrane nanofiltration TS80 was assessed.     

The effect of some soluble inorganic admixtures on the early hydration of portland cement

The effects of the soluble chlorides, bromides, nitrates, sulphates and acetates of Ca²⁺, Mg²⁺, Li⁺, Na⁺ and Zn²⁺ as well as the corresponding mineral acids on the early hydration of neat Portland cement pastes have been studied. Both the cations and anions are ranked according to their general effectiveness as accelerators of the hydration of the Ca₃SiO₅ phase: Ca²⁺>Mg²⁺>Li⁺>Na⁺>H₂O>Zn²⁺ and OH^? >Cl^?>Br^? >NO₃^?SO₄²～H₂O > CH₃CO₂^?.     

Influence of Some Hofmeister Anions on the Krafft Temperature and Micelle Formation of Cetylpyridinium Bromide in Aqueous Solution

In this work, the effect of some Hofmeister anions on the Krafft temperature (T_K) and micelle formation of cetylpyridinium bromide (CPB) have been studied. The results show that more chaotropic anions increase, while the less chaotropic ones lower the T_K of the surfactant. More chaotropic I^? and SCN^? form contact ion pairs with the cetylpyridinium ion and reduce the electrostatic repulsion between the CPB molecules. As a result, these ions show salting‐out behavior, with a consequent increase in the T_K. In contrast, less chaotropic Cl^? and NO₃^? increase the activity of free water molecules and enhance hydration of CPB molecules, showing a decrease in the T_K. A rather unusual behavior was observed in the case of SO₄^2? and F^?. These strong kosmotropes shift from their usual position in the Hofmeister series and behave like moderate chaotropes, lowering the T_K of the surfactant. Because of the high charge density and the strong tendency for hydration these ions preferentially remain in the bulk. Rather than forming contact ion pairs, these ions stay away from the CPB molecules, decreasing the T_K of the surfactant. In term of decreasing the T_K, the ions follow the order NO₃^? > SO₄^2? > Cl^? > F^? > Br^? > SCN^? > I^?. The critical micelle concentration (CMC) of the surfactant decreases significantly in the presence of these ions due to the screening of the micelle surface charge by the excess counterions. The decreasing trend of the CMC in the presence of the salts follows the order SCN^? > I^? > SO₄^2? > NO₃^? > Br^? > Cl^? > F^?.     

Effects of anions on the photocatalytic and photoelectrocatalytic degradation of reactive dye in a packed‐bed reactor

The effects of various anions, Cl^?, ClO₄^?, SO₄^2?, NO₃^?, HCO₃^?, H₂PO₄^? and C₂O₄^2?, on the photocatalytic and photoelectrocatalytic degradation of reactive Brilliant Orange K‐R have been investigated in a packed‐bed photoelectrocatalytic reactor. It was found that the nature and concentrations of these inorganic anions significantly affected the photocatalytic and photoelectrocatalytic degradation performance of the reactive dye. The results indicated that the external electric field was successfully applied to improve the photocatalytic efficiency of reactive Brilliant Orange K‐R in the presence of Cl^?, especially at higher concentrations, while other inorganic anions displayed more or less negative effects on the degradation of the dye. The strongest inhibition effect on photocatalytic and photoelectrocatalytic degradation of the dye was observed in the presence of HCO₃^? ions. Copyright © 2004 Society of Chemical Industry     

Source Identification of Size-Segregated Aerosol in Münster,Germany, by Factor Analysis

Sources of size-segregated PM ₁₀ , as collected with a five stage Berner type impactor during six intensive measurement campaigns between January 2006 and August 2007 in Münster, NW Germany, were studied by applying factor analysis. PM samples were collected twice a day, each with a sampling duration of 5 to 7.5 hours. Samples were analyzed for water soluble ions, Ca²⁺, Cl^?, Mg²⁺, Na⁺, NH⁺ ₄ , NO^? ₃ , SO^2? ₄, and elemental and organic carbon. Positive matrix factorization (PMF) was used for source apportionment where each size class accounted for a single variable. Five factors were identified of which at least four could be found during each season. Traffic, ammonium nitrate, and long distance transport showed a weekly cycle, whereas the factor representing power generation and industrial products seemed to be relatively stable through the week. Sea salt particles were independent of the day of week. The five factors do not only have a similar composition, but also a similar size distribution, throughout all seasons of the year. Particles from long-distance transport were identified in the accumulation mode while PM originating from power generation were characterized by a larger diameter. Sea salt aerosol consisted mainly of coarse particles, ammonium nitrate is mainly found in the largest size fraction. Even without a detailed chemical trace elements analysis, precise PM source apportionment was accomplished.     

Separation performance of a nanofiltration membrane influenced by species and concentration of ions

Nanofiltration (NF), which has been largely developed over the past decade, is a promising technology for the treatment of organic and inorganic pollutants in surface and ground waters. The ESNA 1 membrane from the Nitto Denko Corporation of Japan is made of aromatic polyamide, which provides salt rejection from 50% to 90%. In this paper permeation experiments of aqueous solutions of five chlorides (NH₄Cl, NaCl, KCl, MgCl₂ and CaCl₂), three nitrates (NaNO₃, Mg(NO₃)₂ and Ca(NO₃)₂), and three sulfates (NH₄)₂SO₄, Na₂SO₄ and MgSO₄) were carried out. The effects of species and concentration of salts on the separation performance of the ESNA 1 membrane were investigated. The experimental results showed that the rejection to most salts by the ESNA 1 membrane decreased with the growth of the concentration. Then, the reflection coefficient and solute permeability of ESNA 1 membrane were calculated by the Spiegler-Kedem equation from experimental data. The reflection coefficients of the ESNA 1 membrane to salts are all above 0.95. The salt permeabilities, except for magnesium and calcium salts, increased with the growth of concentration. The sequence of rejection to anions by the ESNA 1 membrane is R(SO²⁻₄) > R(Cl⁻) > R(NO⁻₃) at the same concentration which ranges from 10 mol/m³ to 100 mol/m³. The sequence of rejection to anions by the ESNA 1 membrane can be written as follows: R(Na⁺) > R(K⁺) > R(Mg²⁺) > R(Ca²⁺) at 10 mol/m³ concentration and R(Mg²⁺) > R(Ca²⁺) > R(Na⁺) > R(K⁺) at 100 mol/m³ concentration.     

A diamino based resin modified silica composite for the selective recovery of tungsten from wastewater

A new adsorbent was developed by synthesizing 1,8‐diaminonaphthalene formaldehyde resin (DANFR) and coating it over the surface of silica gels. The silica composite was then treated with HCl for the activation of binding sites (?NH₃⁺Cl^?) on its surface. The structure of DANFR and its coating over the silanols were thoroughly characterized. Further, the adsorbent was applied to remove tungsten (W) from printed circuit board recycling unit wastewater that contained various co‐metal ions such as Na⁺, K⁺, Ca²⁺, Mg²⁺, Pb²⁺, NH₄⁺, Zn²⁺, Cu²⁺ and Mn²⁺. The selective removal was achieved due to the anion exchange mechanism of Cl^? with W(VI) while other cations get repelled from the surface (?NH₃⁺) of the DANFR‐silica composite. X‐ray photoelectron spectroscopy studies, Raman spectra and overlay chromatograms of ion chromatography demonstrated selective separation of WO₄^2? species from the wastewater. A removal capacity of 55.32 mg g^?1 for W(VI) was achieved from the wastewater within 45 min of reaction (pH ca 6.0). Simultaneous treatment with neat aqueous solution of W brings out 63.27 mg g^?1 of W(VI) removal. Finally, recovery of WO₄^2? ions and regeneration of the adsorbent were carried out by using alkaline solution which demonstrated successful desorption, as investigated by using ion chromatography. © 2016 Society of Chemical Industry     

Automated Low-Pressure Carbonate Eluent Ion Chromatography System with Postsuppressor Carbon Dioxide Removal for the Analysis of Atmospheric Gases and Particles

We present a low-pressure, automated, semi-continuous Gas-Particle Ion Chromatograph to measure soluble ionogenic gases and soluble ionic constituents of PM_2.5. The system utilizes a short separation column, an isocratic carbonate eluent and post suppressor CO₂ removal. Measured constituents include ammonium, nitrate, and sulfate in the particle fraction, and nitric acid, sulfur dioxide, and ammonia among soluble gases. Two independent sampling channels are used. In one channel, a wet denuder collects soluble gases. In the second channel, following removal of large particles by a cyclone and soluble gases by a wet denuder, a hydrophobic filter-based particle collector collects and extracts the soluble components of PM_2.5. The aqueous particle extract is aspirated by a peristaltic pump onto serial cation and anion preconcentrator columns. Gas samples are similarly loaded onto another set of serial cation and anion preconcentrator columns. The cation preconcentrator is eluted with NaOH and the evolved NH₃ is passed across a membrane device whence it diffuses substantially into a deionized water receptor stream; the conductivity of the latter provides a measure of NH₃ (NH₄ ⁺). The anion preconcentrator column(s) are subjected to automated periodic analysis by ion chromatography. This system provides data every 30 min for both particles (NO₃ ^?, SO₄ ^{2 ?} and NH₄ ⁺) and gases (HNO₃, SO₂ and NH₃). Gas and particle extract samples are each collected for 15 min. The analyses of the gas and particle samples are staggered 15 min apart. The limit of detection (S/N = 3) for NO₃ ^?, SO₄ ^2? and NH₄ ⁺ are 2.6, 5.3, and 2.1 ng/m³, respectively.     

Removal of arsenate from ionic mixture by anion exchanger water-soluble polymers combined with ultrafiltration membranes

This study shows the influence of Cl^?, SO₄ ^2?, NO₃ ^?, SiO₃ ^2?, Na⁺, and Ca²⁺ on arsenate removal by anion exchanger polymers using the liquid-phase polymer-based retention (LPR) technique. The LPR was carried out in the presence of anion exchanger soluble polymers containing quaternary ammonium salts. These polymers were characterized by NMR. Compared with As(V) removal from deionized water, the results showed that in the presence of ionic mixture, the As(V) removal capacity decreased. However, P(ClVBTA) showed As(V) removal ability of 91?% when the ionic mixture was used. Polymers with chloride exchanger groups showed a higher ability to remove arsenate than the polymer that contains methyl sulfate as anion exchanger group. At higher arsenate concentration (47.6?mg L^?1), arsenate retention by the water-soluble polymers ranged between 58 and 91?%. This removal capacity increased gradually reaching 100?% retention when the arsenate concentration in the cell was minimum (5.5?mg?L^?1). The values of maximum retention capacity were 264?mg?g^?1 for P(ClMPTA), 260?mg?g^?1 for P(ClVBTA), and 200?mg?g^?1 for P(ClAPTA) at the total filtrate volume of 300?mL. The charge–discharge process found to be suitable for saturate the polymer with As(V) and then eluting As(V) for regenerating the extracting capacity of polymer.     

Ion flotation and solvent sublation of cobalt cyanide complexes

An experimental investigation into the batch ion flotation of cobalt complex anions with the cationic surfactant, cetylpyridinium chloride is described. The concentration ratio of cetyl-pyridinium: cobalt in the foam was determined and found to be 2.0–2.7 for CoCl₂ plus KCN solution and 3.0–3.3 for K₃[Co(CN)₆] solution. Spectroscopic measurements of the former anion show that mainly [Co(CN)₅H₂O]²- anions were floated. The [Co(CN)₆]^3- flotation was established in the presence of Cl^?, Br^?, I^?, CN^?, NO₃^? and SO₄^2- anions. The accelerating influence of the ion flotation produced by the presence of Cl^?, Br^?, I^?, CN^?, NO₃^? and SO₄^2- increased as their partial molal volume increased. The solvent sublation of [Co(CN)₆]^3- anions was established in the presence of these anions.     

Polystyrene anchored vanillin Schiff base—Complexation and ion removal studies

A set of six new polystyrene anchored metal complexes have been synthesized by the reaction of the metal salt with the polystyrene anchored Schiff base of vanillin. These complexes were characterized by elemental analyses, Fourier transform infrared spectroscopy, diffuse reflectance studies, thermal studies, and magnetic susceptibility measurements. The elemental analyses suggest a metal : ligand ratio of 1 : 2. The ligand is unidentate and coordinates through the azomethine nitrogen. The Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) complexes are all paramagnetic while Zn(II) is diamagnetic. The Cu(II) complex is assigned a square planar structure, while Zn(II) is assigned a tetrahedral structure and Mn(II), Fe(III), Co(II), and Ni(II) are all assigned octahedral geometry. The thermal analyses were done on the ligand and its complexes to reveal their stability. Further, the application of the Schiff base as a chelating resin in ion removal studies was investigated. The polystyrene anchored Schiff base gave 96% efficiency in the removal of Ni(II) from a 20‐ppm solution in 15 min, without any interference from ions such as Mn(II), Co(II), Fe(III), Cu(II), Zn(II), U(VI), Na⁺, K⁺, NH₄⁺, Ca²⁺, Cl^?, Br^?, NO₃^?, NO₂^?,and CH₃CO₂^?. The major advantage is that the removal is achieved without altering the pH. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1536–1539, 2005     

Air Quality Profile of Inorganic Ionic Composition of Fine Aerosols at Two Sites in Mumbai City

The levels of PM ₁₀ , PM _2.5 , and NO ₂ were studied at a kerbsite and ambient site in Mumbai. Measurements were also made for eight inorganic ions (F ^? , Cl ^? , NO ₃ ^? , SO ^2? ₄ , Na ⁺ , K ⁺ , NH ₄ ⁺ , Ca ²⁺ , and Mg ²⁺ ) in the PM _2.5 fraction. During the study period, PM _2.5 , PM ₁₀ and NO ₂ levels ranged between 11–91, 18–125, and 8–64 μ g m ^{? 3} at a ambient site whereas at the kerbsite the ranges were 10–176, 21–189, and 4–55 μ g m ^?3 respectively. Average PM _2.5 values were 42 μ g m ^{? 3} at ambient and 69 μ g m ^?3 at the kerbsite. The measured ions accounted for about 50% of the PM _2.5 mass. Non-sea-salt (nss) sulfate contributed 91% and 85% of the ionic mass at the ambient and kerbsite sites respectively. Due to biomass sources of K, only about 5% of K ⁺ was from seas salt. The average equivalent ratio of NH ₄ ⁺ to nss- SO ² ₄ ^? , and NO ₃ ^? was over 1, indicating high source strength of ammonia.