Title: Journal of Environmental Monitoring

Title: Journal of Environmental Monitoring

ISO Abbreviated Title: J. Environ. Monit.

JCR Abbreviated Title: J Environ Monitor

ISSN: 1464-0325

Issues/Year: 6

Journal Country/Territory: England

Language: English

Publisher: Royal Soc Chemistry

Publisher Address: Thomas Graham House, Science Park, Milton Rd, Cambridge CB4 0WF, Cambs, Eng

Subject Categories:

Environmental Sciences: Impact Factor 0, 126/126 (1999); Impact Factor 1.068, 48/127 (2000)

? Appelblad, P.K., Baxter, D.C. and Thunberg, J.O. (1999), Determination of metal-humic complexes, free metal ions and total concentrations in natural waters. Journal of Environmental Monitoring, 1 (3), 211-217.

Full Text: 1999\J Env Mon1, 211.pdf

Abstract: A comparison of two systems for the quantitation of metal-humic complexes and free metal ions, consisting of the separation by coupled ion exchange columns followed by detection by inductively coupled plasma mass spectrometry or cold vapour atomic fluorescence spectrometry, is presented. The systems evaluated comprised the serially coupled anion and cation exchangers, Sephadex A-25/Chelex 100 and Dowex 1X8/Chelamine Metalfix. Separation and preconcentration of the species studied were accomplished with both systems, elution being carried out using 2 M HNO3. Total concentrations, metal-humic complex fractions and free metal ion fractions of Al, Ba, Cd, Co, Cu, Fe, Hg, Mn, Pb, Sr, U and Zn in nine natural waters were determined. Statistical evaluation of the data from the two cation exchange materials, including results for additional elements, showed better precision (for Al, Ba. Cr, Cu and Mo) and higher recoveries (Al, Ba, Cd, Fe, Sr and Zn) for Chelex 100 than Chelamine Metalfix for free metal ions. On the other hand, Chelamine Metalfix recovered a significantly greater amount of Ni. The amounts of metal-humic complexes were compared with modelled distributions of these species, and one advantage of the preferred Sephadex A-25/Chelex 100 system is that the elements studied are all correctly classified with respect to their binding strengths to humic substances, which is not the case with the Dowex 1X8/Chelamine Metalfix pair. With the preferred system, metal-humic complexes can be reliably determined, as indicated by the results of equilibrium speciation modelling. However, comparison with the total concentrations showed statistically significant, non-quantitative recoveries of Al, Cu, Hg, Mn. U and Zn from some samples. Thus a combination of speciation and total concentration measurements is required to obtain a complete representation of the distribution of trace elements in natural waters.

Keywords: Acid, Adsorption, Bog-Water, Heavy-Metals, Plasma-Mass-Spectrometry, Preconcentration, Speciation, Substances, Systems, Trace-Metals

? Ouddane, B., Skiker, M., Fischer, J.C. and Wartel, M. (1999), Distribution of iron and manganese in the Seine river estuary: Approach with experimental laboratory mixing. Journal of Environmental Monitoring, 1 (5), 489-496.

Full Text: 1999\J Env Mon1, 489.pdf

Abstract: The physico-chemical behaviour of iron and manganese has been observed during many surveys covering various hydrodynamic conditions in the Seine river estuary system. The results obtained confirm the non-conservative behaviour of these two metals. Generally, dissolved iron exhibits non-conservative removal and shows a rapid decrease in low salinity; it is moved from fresh waters with high concentrations to saline waters with very low concentrations. This can be attributed to the flocculation processes as confirmed by laboratory experiments. Dissolved manganese versus salinity curves exhibit a peak concentration in the low salinity zone. Laboratory mixing experiments have been undertaken comparing iron and manganese adsorption/desorption from suspended material versus salinity, using a series of water samples collected in the up-river and marine regions in order to assess the importance of particulate material and salinity on iron and manganese distributions. The salinity was controlled by varying the marine to fresh water ratio. The reaction kinetics aspect is developed in more detail for manganese in the last series of remobilization experiments starting from a stock of suspended particles collected in the upstream river site (Caudebec) in mixtures of waters, according to time and salinity. This study has allowed us to show that iron and manganese behaviour in the Seine estuary is strongly influenced: (i) by the high turbidity zone and by the presence of calcium carbonate which could stabilise the Mn(II) form; and (II) by the increase of salinity, calcium, magnesium and suspended matter concentrations and by complex formation.

Keywords: Behavior, Dissolved Mn, Laptev Sea, Lena River, Marine-Sediments, North-Sea, Scheldt Estuaries, Suspended Matter, Tamar Estuary, Trace-Metals

? Pacáková, V., Pockevičiute, D., Armalis, S., Štulík, K., Li, J.H. and Veselý, J. (2000), A study of the distribution of lead, cadmium and copper between water and kaolin, bentonite and a river sediment. Journal of Environmental Monitoring, 2 (2), 187-191.

Full Text: 2000\J Env Mon2, 187.pdf

Abstract: Experiments were carried out to monitor the equilibrium distribution of lead, cadmium and copper between an aqueous phase modelling natural water and a solid phase modelling natural sediment, under varying conditions. The aqueous phase was analysed using ETAAS and differential pulse anodic stripping voltammetry (DPASV), whereas XRD and FTIR were used to study the solid phase. Sorption isotherms at constant pH were measured. Conditional distribution constants were calculated as functions of the pH, the time of equilibration and the amount of solid material. The results obtained stress the need for standardization of the approaches to the study of water-sediment interactions in order to be able to evaluate and compare the extensive data from field measurements and to predict these interactions.

Keywords: Metal Distribution Coefficients, Heavy-Metal, Trace-Metals, Sorption, Adsorption, Prediction, Lakes

? Anderson, P., Davidson, C.M., Duncan, A.L., Littlejohn, D., Ure, A.M. and Garden, L.M. (2000), Column leaching and sorption experiments to assess the mobility of potentially toxic elements in industrially contaminated land. Journal of Environmental Monitoring, 2 (3), 234-239.

Full Text: 2000\J Env Mon2, 234.pdf

Abstract: Made-up ground collected from layers of a trial pit excavated on a former industrial site was treated with artificial rainwater in a series of column leaching and sorption experiments. Metal mobility and the ability of various layers of material obtained from the pit to act as sources or sinks of potentially toxic elements were assessed. Samples from different layers varied in their abilities to raise the pH of rainwater applied at pH 3.5 and 4.3, and this was reflected in the amounts of metals mobilised by the rainwater as it percolated through the soil column. Material from the top two layers of the pit released cadmium, copper, manganese, lead, nickel and zinc to the aqueous phase, but the lower layers, with higher buffering capacity, were able to resist acidification even when the equivalent of 12 months’ rainfall (western UK) was applied. Column sorption experiments confirmed the ability of material from layer 4 (48-50 cm) to take up copper, manganese and zinc. Metals were determined in the leachates by flame and electrothermal atomic absorption spectrometry and principle anions by ion chromatography.

Keywords: BCR, Cadmium, Heavy-Metals, Lead, Operational Speciation, Sediment, Sequential Extraction Procedures, Soils, Spectrometry, Water

? Belmouden, M., Assabbane, A. and Ichou, Y.A. (2000), Adsorption characteristics of a phenoxy acetic acid herbicide on activated carbon. Journal of Environmental Monitoring, 2 (3), 257-260.

Full Text: 2000\J Env Mon2, 257.pdf

Abstract: The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) by two powdered coal activated carbons was studied in aqueous solution. The modelling of the adsorption equilibrium showed that the adsorption of 2,4-D fitted a Langmuir isotherm. Adsorption was influenced by the activated carbon type, adsorbent concentration and solution characteristics. The adsorption was found to decrease with an increase in pH over the range 1.5-9. Maximum adsorption occurred at pH approximate to 2.5, which corresponds to the 2,4-D pK(a) value. The amount of 2,4-D adsorbed was also found to depend on the NaCl concentration.

Keywords: Adsorption, Soil

? Agdi, K., Bouaid, A., Esteban, A.M., Hernando, P.F., Azmani, A. and Camara, C. (2000), Removal of Atrazine and four organophosphorus pesticides from environmental waters by diatomaceous earth-remediation method. Journal of Environmental Monitoring, 2 (5), 420-423.

Full Text: 2000\J Env Mon2, 187.pdf

Abstract: A new viable remediation technique based on the use of diatomaceous earth is proposed to improve the ecological system. Its ability to remove atrazine and the four organophosphorus pesticides parathion-methyl, chlorpyriphos, fenamiphos and methidathion from river and waste waters has been proven. A series of experiments including variable conditions, such as temperature, pH, contact time, pesticide concentration and adsorbent quantity, were performed to demonstrate the efficiency of pesticide removal from three different water samples. The batch experiments showed that diatomaceous earth was able to remove 95% of chlorpyriphos, 75% of methidathion and parathion-methyl and 55% of atrazine and fenamiphos from all types of waters tested. The individual adsorption of each pesticide on diatomaceous earth could be described by the Freundlich isotherm and a tentative adsorption mechanism was proposed. The Freundlich coefficient (K-f) and Freundlich constant (1/n) appeared to be closely related to the physicochemical properties (K-ow, solubility) of the compounds. The actual results support the conclusion that diatomaceous earth has the potential to serve as an extractant in remediation techniques.

Keywords: Pond Southern Germany, Organic-Carbon, Adsorption, Sorption, Sediment

? Carrilho, E.N.V.M. and Gilbert, T.R. (2000), Assessing metal sorption on the marine alga Pilayella littoralis. Journal of Environmental Monitoring, 2 (5), 410-415.

Full Text: 2000\J Env Mon2, 410.pdf

Abstract: Increasing interest in the development of biological materials for metal sorption led us to investigate the brown marine alga, Pilayella littoralis, as a biological sorbent. This work focuses on the harvest, preparation and evaluation of P. littoralis from Nahant beaches for use as a metal biosorbent. This biomass was used in batch tests with synthetic solutions. Its metal uptake properties, including metal binding capacity, the pH dependence of metal uptake and the kinetics of metal sorption, were investigated. Most metal sorption occurred within the first 5 min of exposure and the metals were optimally bound to the algae at pH 5.5. The algal binding capacities for Al(III), Cd(II), Co(II), Cr(VI), Cu(II), Fe(III), Ni(II) and Zn(II), were 2000, 430, 560, 90, 850, 700, 390 and 450 mu mol g^-1 of dried biomass, respectively. Metals were desorbed with 0.12 mol l^-1 HCl and determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

Keywords: Binding, Biomass, Chlorella-Vulgaris, Preconcentration, Spectrometry

? Suzuki, T.M., Tanaka, D.A.P., Tanco, M.A.L., Kanesato, M. and Yokoyama, T. (2000), Adsorption and removal of oxo-anions of arsenic and selenium on the zirconium(IV) loaded polymer resin functionalized with diethylenetriamine-N,N,N’,N’-polyacetic acid. Journal of Environmental Monitoring, 2 (6), 550-555.

Full Text: 2000\J Env Mon2, 550.pdf

Abstract: A polymer adsorbent in which a Zr(IV)-edta complex analogue is immobilized has been prepared and applied to the removal of oxo-anions of As(III), As(V) and Se(IV). Effective retention of these anions has been demonstrated with the proposed polymer complex system. The adsorption mechanism of oxo-anions onto the Zr(IV)-chelated polymer complex has been investigated using Zr(IV)-edta as the model compound. The formation of mixed complexes with oxo-anions has been exemplified by the isolation of the carbonate complex K-2[Zr(CO₃)EDTA]3H₂O, the structure of which has been confirmed by X-ray crystallography. NMR study suggests that oxo-anions that form weak or moderate conjugate acids, including those of As(III), As(V) and Sc(IV), can form mixed complexes with Zr(IV)-edta using the unsaturated coordination site. However, oxo-anions of strong conjugate acids did not show any appreciable interaction with this complex. According to these observations, retention of oxo-anions on the Zr(IV)-chelated polymer complex has been interpreted by st ligand substitution reaction. The adsorption characteristics of As(III), As(V) and Se(IV) on the Zr(IV)-loaded resin have been examined with respect to the equilibrium adsorption, percentage extraction and the effect of co-existing ions. The adsorption and desorption cycles of the oxo-anions have been demonstrated using a column packed with the proposed resin without any loss of column performance, which indicates the possibility for repeated use.

Keywords: Adsorption, Drinking-Water, Exchange Resin, Mercury, Metal-Ions

? Elizalde-Gonzalez, M.P., Mattusch, J. and Wennrich, R. (2001), Application of natural zeolites for preconcentration of arsenic species in water samples. Journal of Environmental Monitoring, 3 (1), 22-26.

Full Text: 2001\J Env Mon3, 22.pdf

Abstract: Zeolites of the clinoptilolite type produced in Mexico and Hungary were investigated with respect to their sorption efficiency for various redox species of arsenic. Long-term experiments showed that arsenate remains stable for a long period in spiked deionised water and drinking water, as well as in the surface water of the Biela valley in Saxony, Germany. Both clinoptilolites are able to decrease the initial arsenic concentration of 200 mug l^-1 by more than 75% in deionised, drinking, ground and sur face waters. In the case of the Mexican zeolite, both the arsenite and the arsenate concentrations (200 mug l^-1)can be lowered from 200 mug l^-1 to 10 mug l^-1 which is the World Health Organisation’s (WHO’s) recommended maximum level. It was found that the presence of cations and anions in the natural waters of Biela, Germany, and Zimapan, Mexico, did not reduce the efficiency of the selected zeolites. The Hungarian zeolite removed 75% of the arsenate in the Zimapan water and only 50% when the sample was first acidified. This zeolite totally desorbed the fixed arsenic into a water volume that was half the volume in the adsorption experiment.

Keywords: Drinking-Water, Mexico

? Schmit, K.H. and Wells, M.J.M. (2002), Preferential adsorption of fluorescing fulvic and humic acid components on activated carbon using flow field-flow fractionation analysis. Journal of Environmental Monitoring, 4 (1), 75-84.

Full Text: 2002\J Env Mon4, 75.pdf

Abstract: Activated carbon treatment of drinking water is used to remove natural organic matter (NOM) precursors that lead to the formation of disinfection byproducts. The innate hydrophobic nature and macromolecular size of NOM render it amenable to sorption by activated carbon. Batch equilibrium and minicolumn breakthrough adsorption studies were performed using granular activated carbon to treat NOM-contaminated water. Ultraviolet (UV) absorption spectroscopy and flow field-flow fractionation analysis using tandem diode-array and fluorescence detectors were used to monitor the activated carbon sorption of NOM. Using these techniques, it was possible to study activated carbon adsorption properties of UV absorbing, fluorescing and nonfluorescing, polyelectrolytic macromolecules fractionated from-the total macromolecular and nonmacromolecular composition of NOM. Adsorption isotherms were constructed at pH 6 and pH 9. Data were described by the traditional and modified Freundlich models. Activated carbon capacity and adsorbability were compared among fractionated molecular subsets of fulvic and humic acids. Preferential adsorption (or adsorptive fractionation) of polyelectrolytic, fluorescing fulvic and humic macromolecules on activated carbon was observed. The significance of observing preferential adsorption on activated carbon of fluorescing macromolecular components relative to nonfluorescing components is that this phenomenon changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the composition that existed in the aqueous phase prior to adsorption. Likewise, it changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the adsorbed phase. This research increases our understanding of NOM interactions with activated carbon which may lead to improved methods of potable water production.

Keywords: Adsorption, Chemistry, Molecular-Weight Distributions, Organic-Matter, Research, Substances

? Dutta, K., Bhattacharjee, S., Chaudhuri, B. and Mukhopadhyay, S. (2002), Chemical oxidation of CI Reactive Red 2 using Fenton-like reactions. Journal of Environmental Monitoring, 4 (5), 754-760.

Full Text: 2002\J Env Mon4, 754.pdf

Abstract: A detailed investigation on the kinetics of the oxidative degradation of a reactive dye, C. I. Reactive Red 2 by hydroxyl radicals generated by H₂O₂ and Fe²⁺ has been carried out in aqueous acidic media. Effects of different parameters like initial concentration of dye, H₂O₂, Fe²⁺, pH of the solution, reaction temperature and added electrolytes on the oxidation process have been studied. The results indicate that 1.6310^-4 mol dm^-3 dye can be most effectively degraded at a dye: Fe²⁺: H₂O₂ molar ratio of 1: 0.22: 8.13 at pH similar to 2.7 and at 299 K. The addition of excess 2-propanol or t-butyl alcohol, well known scavengers of hydroxyl radicals, almost stopped the degradation of the dye indicating the absence of any possible reductive pathways in the degradation. The results may be useful for designing the treatment systems of wastewater containing various reactive dyes.

Keywords: Visible-Light Irradiation, Waste-Water Treatment, Hydrogen-Peroxide, Hydroxyl Radicals, Aqueous-Solution, Rate Constants, Photocatalytic Degradation, Superoxide Ion, Reagent, Dye

? Bowman, J.C., Zhou, J.L. and Readman, J.W. (2002), Sorption and desorption of benzo(a) pyrene in aquatic systems. Journal of Environmental Monitoring, 4 (5), 761-766.

Full Text: 2002\J Env Mon4, 761.pdf

Abstract: The sorptive behaviour of polycyclic aromatic hydrocarbons (PAHs) is critical to controlling their transport, fates and effects in the environment. Experiments are described which detail the behaviour of a model compound (benzo(a) pyrene) under simulated aquatic conditions. The kinetics of sorption were comparable to those of other PAH compounds. The sorption equilibrium was extensively studied and found to be affected by several key parameters, notably sediment concentration. The sorption coefficient decreased substantially with the sediment concentration, from 9580 ml g^-1 at a sediment concentration of 0.067 g l^-1 to 1110 ml g^-1 at a sediment concentration of 9.8 g l^-1. The results are consistent with previous reports and often explained by the presence of colloids. In this paper the dry weight concentration of colloids was determined and used for deriving the true sorption coefficient, which is up to an order of magnitude higher than the observed partition coefficient. The sorption of benzo(a) pyrene was also dependent on some of the particle properties, and the sorption coefficient was found to increase with the organic carbon content and specific surface area of sediment particles. The desorption of benzo(a) pyrene from sediment was shown to be relatively rapid, with implications for the potential remobilisation of benzo(a) pyrene and similar compounds.

Keywords: Aromatic-Hydrocarbons, Coefficients, Contaminated Soils, Humber Estuary, Kinetics, Naphthalene, Organic-Carbon, Phenanthrene, Sediments, Solids Concentration

? Mbui, D.N., Shiundu, P.M., Ndonye, R.M. and Kamau, G.N. (2002), Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin. Journal of Environmental Monitoring, 4 (6), 978-984.

Full Text: 2002\J Env Mon4, 978.pdf

Abstract: Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (II) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds. The effects of different operating conditions (such as contact time, concentration of the phenolic compounds, adsorbent quantity, temperature, and pH) were assessed by evaluating the phenolic compound removal efficiency as well as the extent of their color formation reactions (where applicable). RHA exhibits reasonable adsorption capacity for the phenolic compounds and follows both Langmuir and Freundlich isotherm models. Adsorption capacities of 1.5310^-4, 8.0710^-5, and 1.6310^-6 mol g^-1 were determined for phenol, resorcinol and 2-chlorophenol, respectively. Nearly 100% adsorption of the phenolic compounds was possible and this depended on the weight of RHA employed. For the detection experiments, pyrocatechol and pyrogallol present in water formed coloured complexes with RHA, with the rate of colour formation increasing with temperature, weight of RHA, concentration of the phenolic compounds and sonication. This study has proven that RHA is a useful agricultural waste product for the removal and detection of some phenolic compounds.

Keywords: Activated Carbon, Adsorption, Aqueous-Solution, Biosensor, Drinking, Electrochemical Detection, Liquid-Chromatography, Pollutants, Removal, Sensor, Water

? Bryan, N.D., Barlow, J., Warwick, P., Stephens, S., Higgo, J.J.W. and Griffin, D. (2005), The simultaneous modelling of metal ion and humic substance transport in column experiments. Journal of Environmental Monitoring, 7 (3), 196-202.

Full Text: 2005\J Env Mon7, 196.pdf

Abstract: Pulsed column experiments using Co, fulvic acid and porous sediment packing, along with up/down-flooding experiments using Eu, humic acid and intact sandstone blocks have been performed. The elution of metal and humic and their distribution along the sandstone columns have been measured. A mixed equilibrium and kinetic coupled chemical transport model has been used to simulate the results. In both cases, one exchangeable and one non-exchangeable component have been used to simulate the interaction of metal and humic substance. For the pulsed experiments, a simple equilibrium approach was used to model humic sorption, while a two component, kinetic model was required for the sandstone columns.

Keywords: Acids, Competitive Adsorption, Desorption, Displacement, Iron-Oxide, Mobility, Natural Organic-Matter, Particles, Sandy Aquifer, Sorption

? Al Rmalli, S.W., Harrington, C.F., Ayub, M. and Haris, P.I. (2005), A biomaterial based approach for arsenic removal from water. Journal of Environmental Monitoring, 7 (4), 279-282.

Full Text: 2005\J Env Mon7, 279.pdf

Abstract: We demonstrate that the non-living, dried roots of the water hyacinth plant [Eichhornia crassipes (Mart.) Solms] can rapidly remove arsenic from water. Atomic absorption spectrometry was used to demonstrate that more than 93% of arsenite (As(III)) and 95% of arsenate (As(v)) were removed from a solution containing 200 mu g As 1^-1 within 60 minutes of exposure to a powder produced from dried roots. No difference in removal efficiency was observed between the two oxidation states of As studied. The amount of arsenic remaining in solution was found to be less than 10 mu g 1^-1 which is the WHO guideline limit value for As in drinking water. The presence of arsenic in drinking water in a number of countries in the developing world has been found to be much higher than the WHO level, affecting the health of millions of people. In this paper, we show that a biomaterial produced from dried water hyacinth roots, a plant that is found in abundant supply in many parts of the world, can provide a simple, effective and yet cheap method for removing arsenic from contaminated water.

Keywords: Accumulation, Adsorption, Bangladesh, Cadmium, Contaminated Drinking-Water, Crassipes, Groundwater, Hyacinth Roots, Phytoremediation, Plants

? Tighe, M., Lockwood, P. and Wilson, S. (2005), Adsorption of antimony(v) by floodplain soils, amorphous iron(III) hydroxide and humic acid. Journal of Environmental Monitoring, 7 (12), 1177-1185.

Full Text: 2005\J Env Mon7, 1177.pdf

Abstract: Antimony (Sb) emissions to the environment are increasing, and there is a dearth of knowledge regarding Sb fate and behaviour in natural systems. In particular, there is a lack of understanding of sorption of the oxidised Sb(V) species onto soils and soil phases. In this study sorption of Sb(V) by two organic rich soils with high levels of oxalate extractable Fe was examined over the pH range of 2.5-7. Furthermore, the sorption behaviour of Sb(V) was examined in two phases mimicking those dominant in the experimental soils, namely a solid humic acid and an amorphous Fe(OH)₃, across the same pH range. Sorption of Sb by the soils and the humic acid fitted a Freundlich type isotherm, with the equation parameters reflecting changes in bonding affinity corresponding to pH changes. The soils sorbed > 75% of the added Sb in all trials, and 80-100% at pH values less than approximately 6.5. The Fe(OH)₃ retained > 95% of the added Sb in all experiments. The humic acid sorbed up to 60% of the added Sb at acidic pH values, but sorption decreased to zero at higher pH values. Further adsorption studies are recommended, such as examining the effects of ion competition and changes in ionic strength.

Keywords: Adsorption, Arsenic Sorption, Chemistry, Ferrihydrite, Goethite, Hydrous Oxides, Iron Hydroxide, Minerals, Phosphate, Retention, Sediments

? Perez-Quintanilla, D., del Hierro, I., Fajardo, M. and Sierra, I. (2006), Preparation of 2-mercaptobenzothiazole-derivatized mesoporous silica and removal of Hg(II) from aqueous solution. Journal of Environmental Monitoring, 8 (1), 214-222.

Full Text: 2006\J Env Mon8, 214.pdf

Abstract: Mesoporous silicas (SBA-15 and MCM-41) have been functionalized by two different methods. Using the heterogeneous route the silylating agent, 3-chloropropyltriethoxysilane, was initially immobilized onto the mesoporous silica surface to give the chlorinated mesoporous silica Cl-SBA-15 or Cl-MCM-41. In a second reaction a multifunctionalized N,S donor compound (2-mercaptobenzothiazol) was incorporated to obtain the functionalized silicas denoted as MBT-SBA-15-Het and MBT-MCM-41-Het. Using the homogeneous route, the functionalization was achieved via the one step reaction of the mesoporous silica with an organic ligand containing the chelating functions, to give the modified mesoporous silicas denoted as MBT-SBA-15-Hom or MBT-MCM-41-Hom. The functionalized mesoporous silicas were employed as adsorbents for the regeneration of aqueous solutions at pH 6 contaminated with Hg(II) at room temperature. Results obtained indicate that mercury adsorption was higher in the mesoporus silicas prepared by the homogeneous method, and the maximum adsorption value (0.24±0.02 mmol Hg(II) g^-1) was obtained for MBT-SBA-15-Hom. The chemically stability in acid medium of the functionalized silicas, possibility its regeneration washing with concentrate HCl, resulting in the reuse of the adsorbent material for several cycles.

Keywords: Adsorbents, Adsorption, Functionalized Monolayers, Gel, Molecular-Sieves, Remediation, Self-Assembled Monolayers, Solid-State Nmr, Supports Samms, Surface

? Bryan, N.D., Jones, D.L.M., Keepax, R.E., Farrelly, D.H., Abrahamsen, L.G., Pitois, A., Ivanov, P., Warwick, P. and Evans, N. (2007), The role of humic non-exchangeable binding in the promotion of metal ion transport in groundwaters in the environment. Journal of Environmental Monitoring, 9 (4), 329-347.

Full Text: 2007\J Env Mon9, 329.pdf

Abstract: Metal ions form strong complexes with humic substances. When the metal ion is first complexed by humic material, it is bound in an ‘exchangeable’ mode. The metal ion in this fraction is strongly bound, however, if the metal-humic complex encounters a stronger binding site on a surface, then the metal ion may dissociate from the humic substance and be immobilised. However, over time, exchangeably-bound metal may transfer to a ‘non-exchangeable’ mode. Transfer into this mode and dissociation from it are slow, regardless of the strength of the competing sink, and so immobilisation may be hindered. A series of coupled chemical transport calculations has been performed to investigate the likely effects of non-exchangeable binding upon the transport of metal ions in the environment. The calculations show that metal in the non-exchangeable mode will have a significantly higher mobility than that in the exchangeable mode. The critical factor is the ratio of the non-exchangeable first-order dissociation rate constant and the residence time in the groundwater column, metal ion mobility increasing with decreasing rate constant. A second series of calculations has investigated the effect of the sorption to surfaces of humic/metal complexes on the transport of the non-exchangeably bound metal. It was found that such sorption may reduce mobility, depending upon the humic fraction to which the metal ion is bound. For the more weakly sorbing humic fractions, under ambient conditions (humic concentration etc.) the non-exchangeable fraction may still transport significantly. However, for the more strongly sorbed fractions, the non-exchangeable fraction has little effect upon mobility. In addition to direct retardation, sorption also increases the residence time of the non-exchangeable fraction, giving more time for dissociation and immobilisation. The non-exchangeable dissociation reaction, and the sorption reaction have been classified in terms of two Damkohler numbers, which can be used to determine the importance of chemical kinetics during transport calculations. These numbers have been used to develop a set of rules that determine when full chemical kinetic calculations are required for a reliable prediction, and when equilibrium may be assumed, or when the reactions are sufficiently slow that they may be ignored completely.

Keywords: Adsorption, Borne Americium(III) Migration, Column Experiments, Desorption, Iron-Oxide, Natural Organic-Matter, Porous-Media, Sandy Aquifer, Substances, Transuranic Radionuclides

? Burns, J.M. and Ferry, J.L. (2007), Adsorption of domoic acid to marine sediments and clays. Journal of Environmental Monitoring, 9 (12), 1373-1377.

Full Text: 2007\J Env Mon9, 1373.pdf

Abstract: Conditional solid-water distribution coefficients (K-d) for the adsorption of domoic acid (DA) to a series of complex sediments and clays were determined in artificial seawater. K-d ranged from 5.11 L g^-1 to 0.97 L g^-1, with a corresponding ranking of: kaolinite > Gulf of Mexico sediment > Santa Barbara Basin sediment > Bread and Butter Creek sediment > poorly crystallized kaolin > Ca-montmorillonite > Na-montmorillonite > well crystallized kaolin > diatomaceous earth. Adsorption correlated with the anion exchange capacity of the clays tested (R-2 = 0.98), but not the more structurally complex sediments. The effect of added transition metals (Fe(III), Cu(II), Al(III)) and terrestrially derived dissolved organic matter (Suwannee River DOM, SRDOM) on DA adsorption to Na-montmorillonite, well crystallized kaolin, and Gulf of Mexico sediment, was also tested. The addition of transition metals led to increased adsorption to all surfaces by a factor of 2-7, presumably by enabling the adsorption of DA-metal complexes. SRDOM enhanced DA adsorption by a factor of approximately 2.5. The release of adsorbed DA from sediments was also examined. Under our conditions, adsorbed DA equilibrated with the overlying aqueous phase within minutes with approximately 50% release.

Keywords: Adsorption, Amino-Acids, Amnesic Shellfish Poison, Black Carbon, Environmental-Conditions, Gulf-of-Mexico, Harmful Algal Blooms, Metal-Ions, Organic-Matter, Pseudo-Nitzschia, Red-Tide

? Rokhina, E.V., Sillanpaa, M., Nolte, M.C.M. and Virkutyte, J. (2008), Optimization of pulp mill effluent treatment with catalytic adsorbent using orthogonal second-order (Box-Behnken) experimental design. Journal of Environmental Monitoring, 10 (11), 1304-1312.

Full Text: 2008\J Env Mon10, 1304.pdf

Abstract: Novel catalytic adsorbent (ruthenium on carbon) was employed for the treatment of pulp mill effluent in the presence of hydrogen peroxide. Mathematical model and optimization of the process regarding the most favorable COD (%), TOC (%) and color (%) removal rates was developed and performed with experimental design taking into account catalytic adsorption process kinetics. As the initial experimental design, 3(3-1) half-fractional factorial design (H-FFD) was accomplished at two levels to study the significance of the main effects, such as catalytic adsorbent (g l^-1) and hydrogen peroxide (ppm) concentrations using the response surface methodology (RSM). Finally, a four factor-three coded level central composite design (CCD) with 28 runs was performed in order to fit a second-order polynomial model. Validation of the model was accomplished by different criteria including coefficient of determination and the corresponding analysis of variance. The achieved removal rates for TOC (up to 75%), COD (up to 73%) and color (up to 68%) were observed for the defined optimal conditions: 1 gl^-1 of ruthenium on carbon, 7 ppm of hydrogen peroxide, pH 4 and ambient temperature. The proposed method benefited significantly improved TOC, COD and color removal efficiency, regenerability and reusability of the catalytic adsorbent and unaltered initial pH of an effluent in comparison to traditional adsorption or oxidation processes.

Keywords: Activated Carbon, Adsorption, Air, Hydrogen-Peroxide, Oxidation, Phenol

? Hu, D.F. and Coats, J.R. (2009), Laboratory evaluation of mobility and sorption for the veterinary antibiotic, tylosin, in agricultural soils. Journal of Environmental Monitoring, 11 (9), 1634-1638.

Full Text: 2009\J Env Mon11, 1634.pdf

Abstract: Veterinary medicines, including antibiotics, are utilized in large quantities in intensive livestock farming. It is evidenced that tylosin, one of the most frequently used antibiotics, is only partially metabolized in animals and not completely degraded in the manure storage stage before application to the farmland. In order to assess the mobility of tylosin in soil, a soil-column leaching study and a simple batch sorption experiment were conducted in the laboratory. Tylosin had strong sorption to various soils, with sorption distribution coefficients ranging from 42 to 65 ml/g. The range of concentrations in leachate was detected from non-detectable to 0.27 ng/mL after four simulated rainfall events in one month, and leachability of tylosin is dependent on soil properties and manure amendment. Percentage of clay, organic matter, cation exchange capacity, and manure amendment were positively correlated with sorption, and negatively correlated with mobility of tylosin in soil. The majority of tylosin was not recovered in the testing system, indicating that tylosin was most likely mineralized, or irreversibly bound to solid particles since no major degradation products were detected. Some trace level tylosin residues from manure-applied farmlands may be the major source to surface water systems through soil erosion and preferential flow processes.

Keywords: Degradation, Environment, Metronidazole, Nitrification, Olaquindox, Oxytetracycline, Performance Liquid-Chromatography, Swine-Manure, Transport, Water

? Neale, P.A., Mastrup, M., Borgmann, T. and Schafer, A.I. (2010), Sorption of micropollutant estrone to a water treatment ion exchange resin. Journal of Environmental Monitoring, 12 (1), 311-317.

Full Text: 2010\J Env Mon12, 311.pdf

Abstract: Micropollutants occur in natural waters from a range of sources. Estrogenic compounds are naturally excreted by humans and hence stein predominantly from wastewater effluents. Due to their small molecular weight and concentration their effective control is a challenge. In this study magnetic ion exchange(MIEX (R)), which was developed to remove natural organic matter (NOM) from surface water, was investigated for such a micropollutant, estrone. The interaction of estrone with the resin occurs as a side effect when NOM is removed. This interaction results in some degree of removal. However, the accumulation of those hazardous materials on the resin, which can be associated with accidental release, as well Lis the concentration in the regeneration brine of the process, is environmentally more significant. For this reason a thorough investigation of interaction phenomena was undertaken. Estrone and polymeric materials (such as ion exchange resins or membranes) interact through a number of mechanisms including specific and non-specific interactions. Sorption and desorption of estrone were studied as a function of pH, temperature, natural organic matter concentration, sulfate concentration and ionic strength to elucidate possible mechanisms. The results demonstrated that the resin removed around 70% estrone at high pH conditions (>10.4) when estrone was predominantly negatively charged. However, below pH 10.4, when estrone was neutral, approximately 40% of estrone still sorbed due to hydrogen bonding. The optimum temperature for estrone sorption was observed to be in the 15 to 35 degrees C range, while the presence of other anions, including natural organic matter reduced estrone removal due to competition for anion exchange sites. Desorption of estrone was most effective with 2 M NaCl regeneration brine concentration when estrone was negatively charged (98% desorption). However, when estrone was neutral there was no significant difference between 1 M and 2 M NaCl. The results presented in this Study indicate that polar non-ionic micropollutants were removed by magnetic ion exchange resin due to sorption to the resin polymer. This has implications for treatment, however, the accumulation of micropollutants on polymeric materials in water treatment as well as the abundance of such micropollutants in the regeneration brine are risks that warrant monitoring.

Keywords: Desorption, Microextraction, Municipal Sewage, Natural Organic-Matter, Nf, Ro Membranes, Ozonation, Pharmaceuticals, Removal, Treatment Plants, Treatment Works, Waste-Water

? Pan, B.J., Xiao, L.L., Nie, G.Z., Pan, B.C., Wu, J., Lv, L., Zhang, W.M. and Zheng, S.R. (2010), Adsorptive selenite removal from water using a nano-hydrated ferric oxides (HFOs)/polymer hybrid adsorbent. Journal of Environmental Monitoring, 12 (1), 305-310.

Full Text: 2010\J Env Mon12, 305.pdf

Abstract: Selenite (SeO₃^2-) is an oxyanion of environmental significance due to its toxicity when taken in excess. In the present study, a hybrid adsorbent (HFO-201) was prepared by irreversibly impregnating hydrated ferric oxide (HFO) nanoparticles within a commercial available anion-exchange resin (D-201), and its adsorption towards selenite from water was investigated in batch and column tests. HFO-201 exhibited improved sorption selectivity toward selenite as compared to the polymeric anion exchanger D-201, Two possible adsorption interactions were responsible for selenite removal by HFO-201, the electrostatic interaction from the ammonium groups bound to the D-201 matrix, and the formation of inner-sphere complexes between the loaded HFO nanoparticles and selenite. In a wide pH range (i.e., 3-8), increasing Solution pH was found to result in a decrease of selenite removal on HFO-201. Adsorption isotherms fit the Freundlich model well, and selenite adsorption increased with increasing ambient temperature, indicating its endothermic nature. Column adsorption tests suggested that satisfactory removal of selenite from 2 mg/L to less than 0.01 mg/L could be achieved by HFO-201 even in the presence of the commonly encountered anionic competition at greater concentration, with the treatment capacity or similar to 1200 bed volume (BV) per run, while that for D-201 was only less than 30 BV under otherwise identical conditions. Furthermore, the exhausted HFO-201 was amenable to efficient in situ regeneration with a binary NaOH-NaCl solution.

Keywords: Adsorption, Arsenic Removal, Groundwater, Hydroxides, Ions, Iron Oxyhydroxide, Mechanisms, Nanoparticles, Polymer, Sorption, Spectroscopy