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  • 1. Ashour, Radwa M.
    et al.
    Abdel-Magied, Ahmed F.
    Abdel-khalek, Ahmed A.
    Helaly, O.S.
    Ali, M.M.
    Preparation and Characterization of Magnetic Iron Oxide Nanoparticles Functionalized by L- cysteine: Adsorption and Desorption Behavior for Rare Earth Metal Ions”2016In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 4, p. 3114-3121Article in journal (Refereed)
    Abstract [en]

    In this work, magnetic iron oxide nanoparticles functionalized with l-cysteine (Cys-Fe3O4NPs) was synthesized and fully characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infra-red (FTIR), thermogravimetric analysis (TGA) and zeta potential measurements. The synthesized Cys-Fe3O4NPs has been evaluated as a highly adsorbent for the adsorption of a mixture of four rare earths RE3+ ions (La3+, Nd3+, Gd3+ and Y3+) from digested monazite solutions. The influence of various factors on the adsorption efficiency such as, the contact time, sample pH, temperature, and concentration of the stripping solution were investigated. The results indicate that Cys-Fe3O4 NPs achieve high removal efficiency 96.7, 99.3, 96.5 and 87% for La3+, Nd3+, Gd3+ and Y3+ ions, respectively, at pH = 6 within 15 min, and the adsorbent affinity for metal ions was found to be in order of Nd3+ > La3+ > Gd3+ > Y3+ ions. Using the Langmuir model, a maximum adsorption capacity of La3+, Nd3+, Gd3+ and Y3+ at room temperature was found to be 71.5, 145.5, 64.5 and 13.6 mg g−1, respectively. The Langmuir isotherm and pseudo-second order model fitted much better than the other isotherms and kinetic models. The obtained results for the thermodynamic parameters confirmed the spontaneous and endothermic nature of the process. Moreover, the desorption was carried out with 0.1 M nitric acid solutions. In addition, Cys-Fe3O4 NPs can be used as a highly efficient adsorbent for the adsorption of La3+, Nd3+, Gd3+ and Y3+ ions from digested monazite solutions.

  • 2.
    Budnyak, Tetyana M.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Natl Acad Sci Ukraine, Chuiko Inst Surface Chem, 17 Gen Naumov Str, UA-03164 Kiev, Ukraine..
    Aminzadeh, Selda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Pylypchuk, Ievgen V.
    Swedish Univ Agr Sci SLU, Dept Mol Sci, Allmas Alle 5, SE-75007 Uppsala, Sweden..
    Sternik, Dariusz
    Marie Curie Sklodowska Univ, 2 M Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Tertykh, Valentin A.
    Natl Acad Sci Ukraine, Chuiko Inst Surface Chem, 17 Gen Naumov Str, UA-03164 Kiev, Ukraine..
    Lindström, Mikael E.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sevastyanova, Olena
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Methylene Blue dye sorption by hybrid materials from technical lignins2018In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 6, no 4, p. 4997-5007Article in journal (Refereed)
    Abstract [en]

    New hybrid sorbents were synthesized from technical lignins and silica and were applied for the removal of Methylene Blue dye (MB) from aqueous solution. Kraft softwood lignins from LignoBoost (LBL) and CleanFlowBlack (CFBL) processes were used to understand the influence of molecular weight and functionality of initial lignins on the properties of the final hybrids. The synthesized materials were applied as adsorbents for the removal of MB from aqueous solutions. The effects of parameters such as contact time, initial concentration of dye and initial pH on the adsorption capacity were evaluated. The hybrids exhibited higher adsorption capacity than the initial macromolecules of lignin with respect to MB. The hybrid based on CFBL exhibited an adsorption capacity of 60 mg/g; this value was 30% higher than the capacity of the hybrid based on LBL, which was 41.6 mg/g. Lignin hybrid materials extract 80-99% of the dye in a pH range from 3 to 10. The equilibrium and kinetic characteristics of MB uptake by the hybrids followed the Langmuir isotherm model and pseudosecond-order model, rather than the Freundlich and Temkin models, the pseudo-first-order or the intraparticle diffusion model. The attachment of the dye to the hybrid surface was confirmed via FE-SEM and FTIR spectroscopy. The mechanism for MB adsorption was proposed. Due to the high values of regeneration efficiency of the surface of both lignin-silica hybrid materials in 0.1 M HCl (up to 75%) and ethanol (99%), they could be applied as effective sorbents in industrial wastewater treatment processes.

  • 3.
    Cetecioglu, Z.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). Istanbul Technical University, Civil Engineering Faculty, Department of Environmental Engineering, 34469, Maslak, Istanbul, Turkey.
    Orhon, D.
    How do sulfamethoxazole and tetracycline affect the utilization of short chain fatty acids under anaerobic conditions?2018In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 6, no 1, p. 1305-1313Article in journal (Refereed)
    Abstract [en]

    The study focused on acute inhibition mechanism and effect of sulfamethoxazole (SMX) and tetracycline (TET) on the carboxylic acid utilization and the methanogenic activity. Duplicate batch reactors were operated in a range of 1–1000 mg/L for each antibiotic. Short chain fatty acid removal was determined in terms of soluble Chemical Oxygen Demand (COD) and specific fatty acid measurements together with methane generation. Additionally, seed sludge was characterized by Fluorescent in situ Hybridization (FISH). The inhibitory impacts of two antibiotics were variable with the initial dose. While in the lower sulfamethoxazole dosage, inhibition was observed in methanogenesis step. 35.8% and 46.8% inhibition in methane production were observed at 25 mg/L and 50 mg/L of SMX amended reactors. In higher SMX doses, short chain fatty acid utilization was inhibited even no acetate produced in the system. Inhibitory effect of tetracycline started at lower dose. 25% inhibition in methane production started at 1 mg/L of TET concentration. Additionally, it affected utilization of butyrate, propionate and acetate together. Tetracycline inhibited total microbial metabolism in terms of substrate utilization and methane generation between 500 mg/L and 1000 mg/L. FISH results showed that the dominant methanogenic group in the sludge was acetoclastic methanogens in term of Methanosarcina and Methanosaeta spp. 

  • 4.
    Sandhi, Arifin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Department of Ecology, Environment and Plant Sciences, Stockholm University, SE 10691 Stockholm, Sweden.
    Landberg, Tommy
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Greger, Maria
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Effect of pH, temperature, and oxygenation on arsenic phytofiltration by aquatic moss (Warnstorfia fluitans)2018In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 6, no 4, p. 3918-3925Article in journal (Refereed)
    Abstract [en]

    Phytofiltration of arsenic (As)-contaminated water could reduce As in irrigation and surface water. In a previous study, we found that the aquatic moss Warnstorfia fluitans efficiently removes arsenic from water contaminated with arsenate and arsenite. This work investigates how factors such as pH, temperature, and oxygenation influence As removal, since these factors vary in the environment. Plants were grown in a medium with 5 or 10 μM arsenite or arsenate and: 1) a pH of 2.5, 6.5, or 9.5; 2) a temperature of 12, 20, or 30 °C; and 3) oxygenation of <2 or 13 mg O2 L−1. Removal of As was monitored over 48–96 h, and the content and speciation of As were analysed in moss plants at the termination of the experiments. Results indicate that As removal was faster in arsenite than arsenate solutions. Arsenic removal from arsenite solution was the fastest, i.e., 80–90% within 2 h, at pH 6.5 and 9.5 and at 20 and 30 °C. At pH 2.5, plants were stressed and the net removal was low throughout the treatment period. Arsenic removal was more efficient at low than high oxygenation levels. Besides this, no As net efflux process was seen in the water system except after 48 h in arsenate-treated medium in high-temperature (30 °C) regimes. Regardless of As species added, usually only arsenite was found in the plants after treatment. Most internal As, i.e., 95% in the arsenate and 85% in the arsenite treatments, was firmly bound to the tissue. The study found that at 20 °C, neutral pH, and low oxygenation, this aquatic moss has great potential for As phytofiltration.

  • 5.
    Solis, Jerry L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE). UMSS Universidad Mayor de San Simón, Bolivia.
    Alejo, L.
    Kiros, Yohannes
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Calcium and tin oxides for heterogeneous transesterification of Babasssu oil (Attalea speciosa)2016In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 4, no 4, p. 4870-4877Article in journal (Refereed)
    Abstract [en]

    Non-edible oils and waste cooking oils are alternatives to uphold a sustainable large scale production of biodiesel considering large volumes and by-products. Babassu oil (Attalea speciosa) offers a challenging case study scenario for the preparation of a heterogeneous catalytic material. This study shows the binary synthesis of calcium and stannic oxide (CaO/SnO2) catalysts for transesterification of oils with high content of free fatty acids (FFAs). The catalysts were prepared with several mass ratios of CaO:SnO2 in the proportions of 1:4, 4:1, 7:3 and 1:1. The catalysts were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and N2-physisorption analyses. Biodiesel production was tested using a 23 full factorial design with variables such as temperature, methanol/oil molar ratio, and catalyst weight relative to oil. Such design statistically proved that there was no significant effect over the response variable. Furthermore a Box-Behnken design surface response analysis using the same three variables with three levels was performed with MATLAB showing a non-linear relation and statistical response of the optimal conditions for biodiesel production. The optimal experimental conditions were found to be 54.1°C, agitation speed at 250rpm with 6wt.% of CaO/SnO2 (7:3 mass ratio of the binary catalyst) and 10:1 (methanol:oil) molar ratio. The catalyst has shown a high potential for conversion of Babassu oil by fine-tuning as a single step by simultaneous esterification and transesterification to biodiesel.

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