title: The impact of silver and titanium dioxide nanoparticles on the in-vessel composting of municipal solid waste.
abstract: The study evaluated the impact of commercial silver doped titanium dioxide nanoparticles (Ag-TiO2NPs) and silver nanoparticles (AgNPs) on the in-vessel composting of municipal solid waste (MSW), using fluorescence excitation-emission matrix (EEM) spectroscopy as a tool to evaluate the microbial degradation of MSW and subsequent soil application of compost. The fate of NPs present in mature compost used as a top-layer soil conditioner was investigated using a column approach at laboratory scale. The results suggested that the presence of either Ag-TiO2NPs or AgNPs did not inhibit the microbial degradation process within the range of metal concentrations used (5/225, 10/450, 20/900, 50/2250mg Ag/Ti per kg of organic matter for Ag-TiO2NP and 5, 10, 20, 50mg Ag per kg of organic matter for AgNPs). Higher concentrations of Ag-TiO2NP and AgNPs resulted in a higher inorganic carbon removal, and lower formation of humins. Formation of humins was higher for non-contaminated MSW and compost. EEM peaks shifted towards the humic substances (HS) region during in-vessel composting, indicating that microbial degradation occurred and that NPs did not have any effect on humification and therefore on compost stability. The leaching results suggested that only a low percentage of the total NPs (in weight) in compost, up to ca. 5% for Ag and up to ca. 15% for Ti, leached out from the columns, which was assumed the amount that potentially could leach to the environment. These results suggested that NPs will mainly accumulate in soils' top layers following application of compost contaminated with NP.
authors.affiliation: Institute for Infrastructure and Environment, School of Engineering, The University of Edinburgh, The King's Building, Mayfield Road, Edinburgh EH9 3JL, United Kingdom; Department of Development of West Attica, Region of Attica, 78 Iroon Polytechneiou, 19200 Elefsis, Greece. Electronic address: istamou@patt.gov.gr.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Stamou
authors.affiliation: Institute for Infrastructure and Environment, School of Engineering, The University of Edinburgh, The King's Building, Mayfield Road, Edinburgh EH9 3JL, United Kingdom; Isle Utilities Ltd, King's Cross, London N1 9AB, United Kingdom. Electronic address: b_antizar@hotmail.com.
authors.forename: Blanca
authors.initials: B
authors.lastname: Antizar-Ladislao
mesh_terms: D053768:Metal Nanoparticles / Q000032:analysis*; D012834:Silver / Q000032:analysis; D012987:Soil / Q000737:chemistry; D062611:Solid Waste / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D014025:Titanium / Q000032:analysis; D018505:Waste Management
chemical_list: D012987:Soil; D062611:Solid Waste; C009495:titanium dioxide; D012834:Silver; D014025:Titanium
keywords: Composting; Fluorescence spectroscopy; Humic substances; Municipal solid waste; Silver nanoparticles