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Item type:Publication, Access status: without files , Impact of sulfate on the release of genotoxic metals from hardened cement pastes(Elsevier, 2025-07-15); ; ; ; We investigated the effects of environmentally relevant sulfate concentrations on the leaching behavior of certain metalloids in hardened cement pastes. In our study, different cement pastes made of Portland cement (CEM I), blast furnace slag cement (CEM III/A) and a sulfate-resistant cement (CEM I SR0) were cured for 28 days and leached with ultrapure water and with sulfate-containing water. The released concentrations of the most metals and metalloids were independent of the presence of environmentally relevant sulfate concentrations below 1 µg/L or even below the limit of quantification (LOQ). However, the contact to sulfate-containing water led to an increased chromium release from CEM I, compared to leaching in ultrapure water. Under the same conditions an increased release of vanadium was observed from CEM III/A. A micronucleus test of the selected eluates revealed genotoxic effects which can be very likely attributed to the presence of vanadate. We were further able to connect the different leaching behavior of cement in sulfate-containing water compared to ultrapure water to changes of the specific surface area of the hardened cement pastes.Publicationtype: Journal Article4 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Qualitatively elucidating the molecular characteristics of precursors for saturated halogenated disinfection byproducts in chlorinated urban eutrophic lake water by ultrahigh-resolution mass spectrometryLake eutrophication affects the molecular composition of aquatic dissolved organic matter (DOM) and halogenated disinfection byproducts (Xn-DBPs). However, the effects of autochthonous DOM on the Xn-DBPs formation during disinfection of natural eutrophic water from the perspective of biological metabolism are still poorly revealed. Herein, the natural urban eutrophic lake (UEL) water with slight eutrophication was employed to elucidate the discrepancies in Xn-DBPs formation between autochthonous and allochthonous DOM based on the ultrahigh-resolution mass spectrometry. The number and its proportion of nitrogenous Xn-DBPs in chlorinated UEL water samples were significantly larger (p < 0.05) than those for chlorinated SRNOM. Microbes dominated by Microcystis contributed largely to releasing autochthonous DOM for Xn-DBPs formation upon disinfection. The Xn-DBPs species mainly derived from microorganisms were highly saturated, reduced, bioavailable, nitrogenous, and toxic but lowly oxidized and aromatic than terrestrially derived Xn-DBPs species. Moreover, for the first time, the connection between microbial lipid metabolism and Xn-DBPs species exclusively identified in chlorinated UEL water indicated the considerable contribution of lipid metabolites to saturated Xn-DBPs species. The specific biochemical mechanism of Xn-DBPs formation from autochthonous DOM caused by the lysis of microbe cells highlighted the significant contribution of microbial metabolic activities, particularly lipid metabolism, to the generation of highly saturated and nitrogenous Xn-DBPs during chlorination. This study has also reported a novel data interpretation paradigm for Xn-DBPs research, deepening our understanding towards the formation mechanisms of microbe-derived Xn-DBPs species from the view of microbial metabolic pathways.Publicationtype: Journal Article17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Mathematical modeling of arsenic(V) adsorption onto iron oxyhydroxides in an adsorption-submerged membrane hybrid systemThe adsorption of arsenic (V), As(V), on two porous iron oxyhydroxide-based adsorbents, namely, micro-sized tetravalent manganese feroxyhyte (μTMF) and granular ferric hydroxide (μGFH), applied in a submerged microfiltration membrane hybrid system has been investigated and modeled. Batch adsorption tests were carried out to determine adsorption equilibrium and kinetics parameters of As(V) in a bench-scale slurry reactor setup. A mathematical model has been developed to describe the kinetic data as well as to predict the As(V) breakthrough curves in the hybrid system based on the homogeneous surface diffusion model (HSDM) and the corresponding solute mass balance equation. The kinetic parameters describing the mass transfer resistance due to intraparticle surface diffusion (Ds) involved in the HSDM was determined. The fitted Ds values for the smaller (1–63 μm) and larger (1–250 μm) diameter particles of μGFH and μTMF were estimated to be 1.09 × 10−18 m2/s and 1.53 × 10-16 m2/s, and 2.26 × 10−18 m2/s and 1.01 × 10-16 m2/s, respectively. The estimated values of mass transfer coefficient/ kinetic parameters are then applied in the developed model to predict the As(V) concentration profiles in the effluent of the hybrid membrane system. The predicted results were compared with experimental data for As(V) removal and showed an excellent agreement. After validation at varying adsorbent doses and membrane fluxes, the developed mathematical model was used to predict the influence of different operation conditions on As(V) effluent concentration profile. The model simulations also exhibit that the hybrid system benefits from increasing the amount of adsorbent initially dosed and from decreasing the membrane flux (increasing the contact time).Publicationtype: Journal Article114 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Towards a high quality recycling of plastics from waste electrical and electronic equipment through separation of contaminated fractions(2020-04-05); ; ; ; The aim of this study is to provide an evaluation of the recyclability of plastics derived from electrical equipment from contamination standpoint. A database was created to find trends in potentially toxic elements (PTEs) and bromine concentrations; in relation to unit's application, color, polymer type, and production date. For this study, 142 kg of plastics derived from waste electrical and electronic equipment, from the collection group 5, were analyzed. Less than 1.5 % of the analyzed material indicated hazardous characteristics due to their PTEs concentrations (following RoHS and REACH). Regarding the bromine (Br) content, larger quantities of plastics showed recycling incompatibility; 71 parts with total weight of 11 kg (8 %-wt) contained Br concentrations >2000 mg kg−1. The highest average value of Pb, Cd, Hg and Cr combined falls under the application category ‘tools’, which was as well the trend in appliances from before 1990. The same trend was observed for Br and antimony (Sb) contents; high concentrations were found in appliances from the ‘tools’ category. This study concludes that plastics derived from colored appliances and appliances labeled as tools have to be evaluated before being sent for recycling, due to high contamination risks.Publicationtype: Journal Article129 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Decontamination and recycling of agrochemical plastic packaging waste(2020-01-05); ; ; ; Agrochemical containers shall undergo decontamination before being considered for recycling. This study provides an assessment on the feasibility of the triple-rinsing decontamination procedure, while evaluating the appropriateness of the material's quality for recycling. To achieve the objectives of the study, (1) the effectiveness of the decontamination procedure was investigated; (2) containers´ long storage times and changes on the polymer´s structure were assessed; and (3) the quality of the recycled material was tested. Results showed that the triple-rinsing procedure was ineffective for the container´s complete decontamination, yet a further washing step – performed during the simulation of the recycling process – allowed for an improved degree of decontamination for recycling. Photo-oxidation imposed significant changes on the chemical structure of the polymer, where the active ingredient could be detected by FTIR, even after the application of rinsing and extraction. The chemical structure of the bulk material has not changed, indicating that the pesticide mobilization was only confined to the surface. The mechanical tests showed material quality appropriateness, where tensile strength values were within the suggested ranges, providing a possibility for further utilization of this material when appropriate decontamination is applied.Publicationtype: Journal Article147 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Classification of plastic waste originated from waste electric and electronic equipment based on the concentration of antimony(2019-12-15); ; ; The aim of this research is a preliminary assessment of antimony concentration in plastic fractions deriving from different e-waste. We considered microwave ovens, desktop computers, laptops, mobile phones, a TV case, a PC monitor and LED lamps (63 items in total). The plastic fraction ranged from 8%-wt in computers and microwave ovens, up to 40%-wt in cell phones and 59%-wt in LED lamps. Specific polymers were identified through Near Infrared spectroscopy. The samples followed three parallel procedures: acid digestion with aqua regia; conversion into ashes at 600 °C then acid digestion with aqua regia; leaching according to UNI10802 reference procedure. Plastic components with significant amounts of antimony were the ones derived from desktop computers (25–1900 mg/kg) and from microwave ovens (830 mg/kg), yet their relative amount compared to the total weight of the item was limited. Items with larger plastic fractions showed lower concentrations of antimony (1–6 mg/kg in mobile phones cases and 160–640 mg/kg in plastic components of LED lamps). Leaching tests revealed that the analyzed plastic fractions could be mostly admitted in non-hazardous waste landfills. The analysis of ashed samples highlighted the need to further improve the acidic extraction procedure.Publicationtype: Journal Article165 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Biotechnological strategies for the recovery of valuable and critical raw materials from waste electrical and electronic equipment (WEEE) - A review(2019-01-15); ; ; ; Critical raw materials (CRMs) are essential in the development of novel high-tech applications. They are essential in sustainable materials and green technologies, including renewable energy, emissionfree electric vehicles and energy-efficient lighting. However, the sustainable supply of CRMs is a major concern. Recycling end-of-life devices is an integral element of the CRMs supply policy of many countries. Waste electrical and electronic equipment (WEEE) is an important secondary source of CRMs. Currently, pyrometallurgical processes are used to recycle metals from WEEE. These processes are deemed imperfect, energy-intensive and non-selective towards CRMs. Biotechnologies are a promising alternative to the current industrial best available technologies (BAT). In this review, we present the current frontiers in CRMs recovery from WEEE using biotechnology, the biochemical fundamentals of these bio-based technologies and discuss recent research and development (R&D) activities. These technologies encompass biologically induced leaching (bioleaching) from various matrices,biomass-induced sorption (biosorption), and bioelectrochemical systems (BES).Publicationtype: Journal ArticleScopus© Citations 217 397 847 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Critical air/water blow-down in safety valves at low qualitiesCritical air/water blow-downs in safety valves for qualities from 0.01 to 0.113 and mass flow rates from 1.5 up to 4.3. kg/s have been observed in our test facility. These critical blow-downs are characterized by a large void fraction and by an intense mixing of the phases both in the valve body and in the outlet pipe. A qualitative estimation of the flow pattern in the outlet pipe using the map of Taitel and Dukler suggests that these air/water flows are intermittent flows - presumably slug flows - evolving to annular flows for qualities above 0.1. Intermittent flows are also predicted for critical air/water and air/glycerine flows taken from the literature for the same safety valve at slightly larger relieving pressures.Publicationtype: Journal Article7