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  • 1. Al-Naamani, Laila
    et al.
    Dobretsov, Sergey
    Dutta, Joydeep
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM.
    Burgess, J. Grant
    Chitosan-zinc oxide nanocomposite coatings for the prevention of marine biofouling2017Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 168, s. 408-417Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested. Chitosan-ZnO nanoparticle coatings showed anti-diatom activity against Navicula sp. and antibacterial activity against the marine bacterium Pseudoalteromonas nigrifaciens. Additional antifouling properties of the coatings were investigated in a mesocosm study using tanks containing natural sea water under controlled laboratory conditions. Each week for four weeks, biofilm was removed and analysed by flow cytometry to estimate total bacterial densities on the coated substrates. Chitosan-ZnO hybrid coatings led to better inhibition of bacterial growth in comparison to chitosan coatings alone, as determined by flow cytometry. This study demonstrates the antifouling potential of chitosan-ZnO nanocomposite hybrid coatings, which can be used for the prevention of biofouling. (C) 2016 Elsevier Ltd. All rights reserved.

  • 2. Beijer, K.
    et al.
    Björlenius, Berndt
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Shaik, S.
    Lindberg, R. H.
    Brunström, B.
    Brandt, I.
    Removal of pharmaceuticals and unspecified contaminants in sewage treatment effluents by activated carbon filtration and ozonation: Evaluation using biomarker responses and chemical analysis2017Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 176, s. 342-351Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traces of active pharmaceutical ingredients (APIs) and other chemicals are demonstrated in effluents from sewage treatment plants (STPs) and they may affect quality of surface water and eventually drinking water. Treatment of effluents with granular activated carbon (GAC) or ozone to improve removal of APIs and other contaminants was evaluated at two Swedish STPs, Käppala and Uppsala (88 and 103 APIs analyzed). Biomarker responses in rainbow trout exposed to regular and additionally treated effluents were determined. GAC and ozone treatment removed 87–95% of the total concentrations of APIs detected. In Käppala, GAC removed 20 and ozonation (7 g O3/m3) 21 of 24 APIs detected in regular effluent. In Uppsala, GAC removed 25 and ozonation (5.4 g O3/m3) 15 of 25 APIs detected in effluent. GAC and ozonation also reduced biomarker responses caused by unidentified pollutants in STP effluent water. Elevated ethoxyresorufin-O-deethylase (EROD) activity in gills was observed in fish exposed to effluent in both STPs. Gene expression analysis carried out in Käppala showed increased concentrations of cytochrome P450 (CYP1As and CYP1C3) transcripts in gills and of CYP1As in liver of fish exposed to effluent. In fish exposed to GAC- or ozone-treated effluent water, gill EROD activity and expression of CYP1As and CYP1C3 in gills and liver were generally equal to or below levels in fish held in tap water. The joint application of chemical analysis and sensitive biomarkers proved useful for evaluating contaminant removal in STPs with new technologies.

  • 3. Campos Pereira, H.
    et al.
    Ullberg, M.
    Kleja, D. B.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. Swedish University of Agricultural Sciences, Sweden.
    Ahrens, L.
    Sorption of perfluoroalkyl substances (PFASs) to an organic soil horizon – Effect of cation composition and pH2018Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 207, s. 183-191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate prediction of the sorption of perfluoroalkyl substances (PFASs) in soils is essential for environmental risk assessment. We investigated the effect of solution pH and calculated soil organic matter (SOM) net charge on the sorption of 14 PFASs onto an organic soil as a function of pH and added concentrations of Al3+, Ca2+ and Na+. Often, the organic C-normalized partitioning coefficients (KOC) showed a negative relationship to both pH (Δlog KOC/ΔpH = −0.32 ± 0.11 log units) and the SOM bulk net negative charge (Δlog KOC = −1.41 ± 0.40 per log unit molc g−1). Moreover, perfluorosulfonic acids (PFSAs) sorbed more strongly than perfluorocarboxylic acids (PFCAs) and the PFAS sorption increased with increasing perfluorocarbon chain length with 0.60 and 0.83 log KOC units per CF2 moiety for C3–C10 PFCAs and C4, C6, and C8 PFSAs, respectively. The effects of cation treatment and SOM bulk net charge were evident for many PFASs with low to moderate sorption (C5–C8 PFCAs and C6 PFSA). However for the most strongly sorbing and most long-chained PFASs (C9–C11 and C13 PFCAs, C8 PFSA and perfluorooctane sulfonamide (FOSA)), smaller effects of cations were seen, and instead sorption was more strongly related to the pH value. This suggests that the most long-chained PFASs, similar to other hydrophobic organic compounds, are preferentially sorbed to the highly condensed domains of the humin fraction, while shorter-chained PFASs are bound to a larger extent to humic and fulvic acid, where cation effects are significant.

  • 4. Eriksson, M.
    et al.
    Faldt, J.
    Dalhammar, Gunnel
    KTH, Tidigare Institutioner                               , Bioteknologi.
    Borg-Karlson, Anna-Karin
    KTH, Tidigare Institutioner                               , Kemi.
    Determination of hydrocarbons in old creosote contaminated soil using headspace solid phase microextraction and GC-MS2001Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 44, nr 7, s. 1641-1648Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Headspace solid phase microextraction (HS-SPME) has been used together with GC-MS to analyze organic substances directly in a soil, heavily contaminated with PAHs/creosote (similar to 300 mg/kg soil), from an old gaswork site in Stockholm, Sweden. The HS-SPME results, both qualitative and quantitative, were compared with traditional liquid extraction using ethyl acetate/hexane (20:80). It was shown that the concentrations determined with HS-SPME at 60 degreesC correlated well, for compounds containing up to two and three aromatic rings (naphthalenes, acenaphthene, acenaphthylene and fluorenes, while a lower concentration was obtained for phenanthrene, anthracene, fluoranthene and pyrene. The total concentrations for each compound determined with HS-SPME ranged from 2 to 25 mug/g soil. Quantification was done using standard addition of compounds directly to the soil samples. The bioavailable fraction of the compounds in the contaminated soil at 20 degreesC was analyzed using external calibration by spiking sterile uncontaminated sand (same texture and particle size as the contaminated soil but without a heavily sorbed organic fraction) with hydrocarbon standards in different concentrations. Storage of exposed fibers at 20 degreesC showed that analysis should be done within two days to make qualitative measurements and earlier (as soon as possible) for quantitative determinations.

  • 5.
    Gustafsson, Jon Petter
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. Swedish University of Agricultural Sciences, Sweden.
    Akram, Muhammad
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Tiberg, Charlotta
    Predicting sulphate adsorption/desorption in forest soils: Evaluation of an extended Freundlich equation2015Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 119, s. 83-89Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sulphate adsorption and desorption can delay the response in soil acidity against changes in acid input. Here we evaluate the use of an extended Freundlich equation for predictions of pH-dependent SO4 adsorption and desorption in low-ionic strength soil systems. Five B horizons from Spodosols were subjected to batch equilibrations at low ionic strength at different pHs and dissolved SO4 concentrations. The proton coadsorption stoichiometry (eta), i.e. the number of H+ ions co-adsorbed for every adsorbed SO42- ion, was close to 2 in four of five soils. This enabled the use of a Freundlich equation that involved only two adjustable parameters (the Freundlich coefficient K-F and the non-ideality parameter m). With this model a satisfactory fit was obtained when only two data points were used for calibration. The root-mean square errors of log adsorbed SO4 ranged from 0.006 to 0.052. The model improves the possibility to consider SO4 adsorption/desorption processes correctly in dynamic soil chemistry models.

  • 6.
    Hansson, Sven Ove
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Filosofi.
    Regulating BFRs - From science to policy2008Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 73, nr 2, s. 144-147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An adequate distribution of responsibilities between scientists and policy-makers requires that a distinction be made between theoretical rationality (what to believe) and practical rationality (what to do). In chemical risk management, it is often necessary to base decisions on indications of risk that do not amount to full scientific proof. Guidelines are offered for how this can be done without infringing upon the integrity of science. Furhtermore, it is shown that the application of standard decision theory to chemical risks yields conclusions very much in agreement with the precautionary principle.

  • 7. Heijerick, D. G.
    et al.
    Janssen, C. R.
    Karlen, C.
    Odnevall Wallinder, Inger
    KTH, Tidigare Institutioner                               , Materialvetenskap.
    Leygraf, Christofer
    KTH, Tidigare Institutioner                               , Materialvetenskap.
    Bioavailability of zinc in runoff water from roofing materials2002Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 47, nr 10, s. 1073-1080Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Corrosion and runoff from zinc-coated materials and outdoor structures is an important source for the dispersion of zinc in the environment. Being part of a large inter-disciplinary research project, this study presents the bioavailability of zinc in runoff water immediately after release from the surface of 15 different commercially available zinc-based materials exposed to the urban environment of Stockholm, Sweden. Runoff water was analysed chemically and evaluated for its possible environmental impact, using both a biosensor test with the bacteria Alcaligenes eutrophus (Biomet(R)) and the conventional 72 h growth inhibition test with the green alga Raphidocelis subcapitata. Chemical speciation modelling revealed that most zinc (94.3-99.9%) was present as the free Zn ion, the most bioavailable speciation form. These findings were confirmed by the results of the biosensor test (Biomet(R)) which indicated that all zinc was indeed bioavailable. Analysis of the ecotoxicity data also suggested that the observed toxic effects were due to the presence of Zn2+ ions. Finally, regression analysis showed that, for this type of runoff samples, the rapid screening biosensor was capable of predicting (a) the total amount of zinc present in the runoff samples (R-2 of 0.93-0.98; p < 0.05) and (b) the observed 72 h-EbC(50)s (R-2 of 0.69-0.97; p < 0.05).

  • 8. Hoppe, Sabina
    et al.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Borg, Hans
    Breitholtz, Magnus
    Can natural levels of Al influence Cu speciation and toxicity to Daphnia magna in a Swedish soft water lake?2015Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 138, s. 205-210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is well known that chemical parameters, such as natural organic matter (NOM), cation content and pH may influence speciation and toxicity of metals in freshwaters. Advanced bioavailability models, e.g. Biotic Ligand Models (BLMs), can use these and other chemical parameters to calculate site specific recommendations for metals in the aquatic environment. However, since Al is not an input parameter in the BLM v.2.2.3, used in this study, there could be a discrepancy between calculated and measured results in Al rich waters. The aim of this study was to evaluate if the presence of Al in a circumneutral (pH 6) soft humic freshwater, Lake St. Envättern, will affect the Cu speciation and thereby the toxicity to the cladoceran Daphnia magna. The results show a statistically significant increase in the free Cu2+ concentration with Al additions and that measured levels of Cu2+ significantly differed from BLM calculated levels of Cu2+. Furthermore, there was also a statistically significant elevated acute toxic response to D. magna at low additions of Al (10μg/L). However, since the large difference between calculated and measured Cu2+ resulted in a significant but minor (factor of 2.3) difference between calculated and measured toxicity, further studies should be conducted in Al rich soft waters to evaluate the importance of adding Al as an input parameter into the BLM software.

  • 9. Kasiuliene, Alfreda
    et al.
    Carabante, Ivan
    Bhattacharya, Prosun
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Vatten- och miljöteknik.
    Caporale, Antonio Giandonato
    Adamo, Paola
    Kumpiene, Jurate
    Removal of metal(oid)s from contaminated water using iron-coated peat sorbent2018Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 198, s. 290-296Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study aimed at combining iron and peat to produce a sorbent suitable for a simultaneous removal of cations and anions from a solution. Peat powder, an industrial residue, was coated with iron by immersing peat into iron salt solutions. The adsorption efficiency of the newly produced sorbent towards As, Cr, Cu and Zn was tested by means of batch adsorption experiments at a constant pH value of 5. Coating of Fe on peat significantly increased the adsorption of As (from <5% to 80%) and Cr (from <3% to 25%) in comparison to uncoated peat. Removal of cations on coated peat slightly decreased (by 10-15%), yet remained within acceptable range. Electron Microscopy combined with X-Ray Energy Dispersive Spectroscopy revealed that iron coating on the peat was rather homogenous and As and Cr were abundantly adsorbed on the surface. By contrast, Cu and Zn displayed a sparing distribution on the surface of the iron coated peat. These results indicate that iron-peat simultaneously target sufficient amounts of both cations and anions and can be used for a one-step treatment of contaminated groundwater.

  • 10. Khai, Nguyen Manh
    et al.
    Oborn, Ingrid
    Hillier, Steve
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630), Miljögeokemi och ekoteknik.
    Modeling of metal binding in tropical Fluvisols and Acrisols treated with biosolids and wastewater2008Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 70, nr 8, s. 1338-1346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is growing concern about the accumulation of metals in tropical agricultural soils. In this study, experimental results from batch studies were used to test whether multi-surface geochemical models could describe metal binding in selected Vietnamese soils. The multi-surface models considered metal binding to iron hydroxides (using the diffuse layer model), organic matter (Stockholm Humic model and NICA-Donnan model), and phyllosilicate clay (Gaines-Thomas equation) as well as complexation to dissolved organic and inorganic ligands in the solution phase. We found that for total dissolved Cd, Cu and Zn the two multi-surface models being tested provided very good model fits for all soils, as evidenced by low root-mean square errors between model predictions and observations. These results suggest that organic matter is an important sorbent for many metals in these soils. However, poor fits were obtained for Cr(III), Mn and Pb for all soils. The study also suggests that the pH is the main factor that controls the solubility of metals in tropical Fluvisols and Acrisols subjected to application of biosolids and wastewater, and that advanced multi-surface models can be used to simulate the binding and release of many trace metals.

  • 11.
    Kietlinska, Agnieszka
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    An evaluation of reactive filter media for treating landfill leachate2005Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 61, nr 7, s. 933-940Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     A laboratory bench-scale column study was conducted to evaluate permeable reactive filter materials as a new method for removal of heavy metals and inorganic nitrogen from landfill leachate. Mixtures of sand and peat, blast-furnace slag (BFS) and peat, and Polonite (R) and peat were tested by loading columns with leachate collected from a pond at Tvetaverket Landfill, Sweden. Sand, peat and Polonite (R) represent natural materials. BFS is a by-product from steel-works. The metal treatment efficiencies of the media were assessed and Polonite (R) was found to perform best, where Mn, Fe, Zn and Cu concentrations were removed by 99%, 93%, 86% and 67%, respectively. This material was also able to reduce inorganic N by 18%. The BFS showed good removal efficiency for Cu (66%), Zn (62%), Ni (19%) and Mo (16%). The sand-peat mixture did not demonstrate a promising removal capacity for any of the elements studied with the exception of Cu (25%). The removal of different elements was suggested to be a combination of several factors, i.e. precipitation, ion exchange and adsorption. Prior to full-scale application of reactive filters at a landfill site, matrix selection, filter design and operational procedures must be developed.

  • 12. Kumar, M.
    et al.
    Ramanatahn, A. L.
    Tripathi, R.
    Farswan, S.
    Kumar, D.
    Bhattacharya, Prosun
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    A study of trace element contamination using multivariate statistical techniques and health risk assessment in groundwater of Chhaprola Industrial Area, Gautam Buddha Nagar, Uttar Pradesh, India2017Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 166, s. 135-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study is an investigation on spatio-chemical, contamination sources (using multivariate statistics), and health risk assessment arising from the consumption of groundwater contaminated with trace and toxic elements in the Chhaprola Industrial Area, Gautam Buddha Nagar, Uttar Pradesh, India. In this study 33 tubewell water samples were analyzed for 28 elements using ICP-OES. Concentration of some trace and toxic elements such as Al, As, B, Cd, Cr, Mn, Pb and U exceeded their corresponding WHO (2011) guidelines and BIS (2012) standards while the other analyzed elements remain below than those values. Background γ and β radiation levels were observed and found to be within their acceptable limits. Multivariate statistics PCA (explains 82.07 cumulative percent for total 6 of factors) and CA indicated (mixed origin) that natural and anthropogenic activities like industrial effluent and agricultural runoff are responsible for the degrading of groundwater quality in the research area. In this study area, an adult consumes 3.0 L (median value) of water therefore consuming 39, 1.94, 1461, 0.14, 11.1, 292.6, 13.6, 23.5 μg of Al, As, B, Cd, Cr, Mn, Pb and U from drinking water per day respectively. The hazard quotient (HQ) value exceeded the safe limit of 1 which for As, B, Al, Cr, Mn, Cd, Pb and U at few locations while hazard index (HI) > 5 was observed in about 30% of the samples which indicated potential health risk from these tubewells for the local population if the groundwater is consumed.

  • 13. Kumar, Manish
    et al.
    Das, Nilotpal
    Goswami, Ritusmita
    Sarma, Kali Prasad
    Bhattacharya, Prosun
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Ramanathan, A. L.
    Coupling fractionation and batch desorption to understand arsenic and fluoride co-contamination in the aquifer system2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 164, s. 657-667Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present work is an attempt to study As and F+ coevality using laboratory based assays which couples fractionation and batch dissolution experiments. Sequential extraction procedure (SEP) resulting into five "operationally defined phases", was performed on sediment and soil samples collected from the Brahmaputra flood plains, Assam, India. High correlation between the Fe (hydr)oxide fraction and total As content of the soil/sediment sample indicates the involvement of Fe (hydr)oxides as the principal source of As. F- being an anion has high potential to be sorbed onto positively charged surfaces. Findings of the SEP were used to design the batch desorption experiments by controlling the Fe (hydr)oxide content of the soil/sediment. Desorption of As and F- was observed under acidic, neutral and alkaline pH from untreated and Fe (hydr)oxide removed samples. Highest amount of As and F- were found to be released from untreated samples under alkaline pH, while the amount leached from samples with no Fe (hydr) oxide was low. The study showed that the Fe (hydr)oxide fraction commonly found in the soils and sediments, had high affinity for negatively charged species like F- oxyanions of As, AsO43- (arsenate) and AsO33- (arsenite). Fe (hydr)oxide fraction was found to play the major role in co-evolution of As and F-. Two sorption coefficients were proposed based on easily leachable fraction and As present in the groundwater of sampling location for understanding of contamination vulnerability from the leaching.

  • 14. Larsson, Maja A.
    et al.
    Hadialhejazi, Golshid
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. Swedish University of Agricultural Sciences, Sweden.
    Vanadium sorption by mineral soils: Development of a predictive model2017Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 168, s. 925-932Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The toxicity of vanadium in soils depends on its sorption to soil components. Here we studied the vanadate(V) sorption properties of 26 mineral soils. The data were used to optimise parameters for a Freundlich equation with a pH term. Vanadium K-edge XANES spectroscopy for three selected soils confirmed that the added vanadate(V) had accumulated mostly as adsorbed vanadate(V) on Fe and Al hydrous oxides, with only minor contributions from organically complexed vanadium(IV). Data on pH-dependent V solubility for seven soils showed that on average 0.36 H+ accompanied each V during adsorption and desorption. The resulting model provided reasonable fits to the V sorption data, with r2 &gt; 0.99 for 20 of 26 soils. The observed KdS value, i.e. the ratio of total to dissolved V, was strongly dependent on V addition and soil; it varied between 3 and 4 orders of magnitude. The model was used to calculate the Freundlich sorption strength (FSS), i.e. the amount of V sorbed at [V] = 2.5 mg L−1, in the concentration range of observed plant toxicities. A close relationship between FSS and oxalate-extractable Fe and Al was found (r2 = 0.85) when one acidic soil was removed from the regression. The FSS varied between 27 and 8718 mg V kg−1, showing that the current environmental guidelines can be both under- and overprotective for vanadium.

  • 15. Mohamed, Alaa
    et al.
    Osman, T. A.
    Toprak, Muhammet Sadaka
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM.
    Uheida, Abdusalam
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM.
    Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions2017Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 180, s. 108-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel composites nanofiber was synthesized based on PAN-CNT/TiO2-NH2 nanofibers using electrospinning technique followed by chemical modification of TiO2 NPs. PAN-CNT/TiO2-NH2 nanofiber were characterized by XRD, FTIR, SEM, and TEM. The effects of various experimental parameters such as initial concentration, contact time, and solution pH on As removal were investigated. The maximum adsorption capacity at pH 2 for As(III) and As(V) is 251 mg/g and 249 mg/g, respectively, which is much higher than most of the reported adsorbents. The adsorption equilibrium reached within 20 and 60 min as the initial solution concentration increased from 10 to 100 mg/L, and the data fitted well using the linear and nonlinear pseudo first and second order model. Isotherm data fitted well to the linear and nonlinear Langmuir, Freundlich, and Redlich-Peterson isotherm adsorption model. Desorption results showed that the adsorption capacity can remain up to 70% after 5 times usage. This work provides a simple and an efficient method for removing arsenic from aqueous solution.

  • 16.
    Renman, Agnieszka
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Long-term phosphate removal by the calcium-silicate material Polonite in wastewater filtration systems2010Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 79, nr 6, s. 659-664Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mineral-based filter material Polonite was tested for its PO4 removal capacity in column and full-scale systems using synthetic and domestic wastewater. Three long-term experiments (67, 68 and 92 wk), operated under different hydrological conditions, were compared. The best PO4 removal capacity (97%) was observed in an intermittent saturated column fed with a synthetic solution (530 L m(-2) d(-1)) without organic matter during 68 wk. An unsaturated column system using municipal wastewater (76.7 L m(-2) d(-1)) showed no tendency for PO4 breakthrough and effluent PO4 concentration was still low (0.2 mg L-1) after 67 wk. For a compact bed filter containing 560 kg of Polonite and fed with 70 m(3) of wastewater from a single house, the average PO4 removal was 89% after 92 wk of operation. The column experiments revealed that a design volume of 1-2 kg of material of a particle size of 2-5 mm was required amount for treating 1 m(3) of wastewater in on-site systems operating at target 90% P mass removal. Poor pre-treatment of the wastewater was suggested to reduce the phosphate removal capacity of Polonite in the bed filter trial, where 8 kg were required per m(3). To measure pH of the treated effluent water proved not to be a simple tool for determining when the filter material is exhausted and should be replaced. (C) 2010 Elsevier Ltd. All rights reserved.

  • 17.
    Stark, Kristina
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    Levlin, Erik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    Plaza, Elzbieta
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik (flyttat 20130630).
    Phosphorus recovery from sewage sludge treated with supercritical water oxidation or incineration2005Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298Artikel i tidskrift (Övrigt vetenskapligt)
  • 18.
    Stark, Kristina
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Plaza, Elzbieta
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Hultman, Bengt
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Phosphorus release from ash, dried sludge and sludge residue from supercritical water oxidation by acid or base2006Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 62, nr 5, s. 827-832Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Leaching of ash and dried sewage sludge were investigated and compared with the leaching results of sludge residue from supercritical water oxidation (SCWO). This article focuses on how the composition of ash and sludge residues influences the extraction of phosphate and heavy metals and if different treatment temperatures of the sludge effect the leachability. Results showed that acid leaching gave a higher release of phosphate than alkaline leaching for all ash and sludge residue samples. Also, alkaline leaching dissolved phosphate with a lower metal contamination than acid leaching. Furthermore, it was found that iron had a low release at both alkaline and acid leaching from ash and from SCWO residue.

    The difference in composition of ash and sludge residue samples had no significant influence on release of phosphate at high concentrations of acid. Phosphate release from ash, dried sludge at 300 degrees C and SCWO residue showed similar results at I M acid leaching. However, it seems to be easier to release phosphate from the SCWO residue than from the ash at low acid concentrations. SCWO residue showed higher release than the other ashes at 0.5 M HCl. Results for alkaline leaching showed higher release from ash at I M NaOH than from SCWO residue or from dried sludge at 300 degrees C. The leaching of phosphate from dried sludge seems to be temperature dependent, as the dried sludge treated at higher temperature showed less release of phosphate. It was found that the pre-treatment of the ash may be important for better release of phosphate.

  • 19. Tiberg, Charlotta
    et al.
    Sjostedt, Carin
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. Swedish Univ Agr Sci, Dept Soil & Environm, Box 7014, SE-75007 Uppsala, Sweden.
    Metal sorption to Spodosol Bs horizons: Organic matter complexes predominate2018Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 196, s. 556-565Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    While metal sorption mechanisms have been studied extensively for soil surface horizons, little information exists for subsoils, for example Spodosol Bs horizons. Here the sorption of cadmium(10, copper(II) and lead(II) to seven Bs horizons from five sites was studied. Extended X-ray absorption fine structure (EXAFS) spectroscopy showed that cadmium(II) and lead(II) were bound as inner-sphere complexes to organic matter. Addition of o-phosphate (to 1 mu mol l(-1)) did not result in any significant enhancement of metal sorption, nor did it influence EXAFS speciation. An assemblage model using the SHM and CD-MUSIC models overestimated metal sorption for six out of seven soil samples. To agree with experimental results, substantial decreases (up to 8-fold) had to be made for the fraction 'active organic matter', f(Hs), while the point-of-zero charge (PZC) of ferrihydrite had to be increased. The largest decreases of f(HS) were found for the soils with the lowest ratio of pyrophosphate-to oxalate-extractable Al (Al-pyp/Al-ox), suggesting that in these soils, humic and fulvic acids were to a large extent inaccessible for metal sorption. The low reactivity of ferrihydrite towards lead(II) can be explained by potential spillover effects from co-existing allophane, but other factors such as ferrihydrite crystallisation could not be ruled out. In conclusion, organic matter was the predominant sorbent for cadmium(II), copper(II) and lead(II). However, for lead(II) the optimised model suggests additional, but minor, contributions from Fe (hydr) oxide surface complexes. These results will be important to correctly model metal sorption in spodic materials. 

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