Speciation of copper in ashes from municipal solid waste combustion

Copper is one of the most important trace elements in municipal solid waste (MSW) combustion. Knowledge of the speciation of copper is fundamental for the understanding of the effects of copper compounds on the combustion chemistry as well as of the environmental impact of the ash. An increased understanding of the chemistry of copper in combustion and in the ashes could support the development of management and recycling techniques, not only for the copper metal but also for the bulk of the ash. It could also increase the understanding of how it might be possible to reduce the amount of dioxins formed and thereby reducing the toxicity of the ashes as well as the flue gases. In this work the speciation of copper in four ash flows from a bubbling fluidized bed (BFB) boiler and one fly ash from a grate fired mass burn (MB) combustor has been investigated using synchrotron based X-ray absorption spectrometry. Additionally the copper speciation of leaching residues from the BFB filter ash and MB fly ash, leached in ammonium nitrate and nitric acid, have also been investigated. The results from the BFB ash flows showed that copper occurred mainly as copper metal, copper oxides and mixed oxides in the ashes from and close to the combustion bed. The concentrations of copper sulphate, hydroxides and chlorides increased further down the BFB flue gas system, closer to the filter. Copper in oxidation states 0, +I and +II was found in all ash flows, except in the BFB filter ash where mainly copper(II) was found. The MB fly ash showed significantly different copper speciation than in the BFB fly ash, with mainly phosphate or silicate together with a mix of copper metal, copper(II) oxide and copper(I) chloride. The residues from leaching with ammonium nitrate showed that the copper speciation was similar in both residues, containing a mix of mainly phosphate or silicate together with a mix of copper(II) oxide and copper(I) chloride. The results showed that the chemical speciation may be an important factor affecting the release of copper. This work also included the collection of XAS-data for a large number of copper compounds that could possibly be present in ashes. This collection of XAS-data will be useful in future work

Leaching for recovery of copper from municipal solid waste incineration fly ash: Influence of ash properties and metal speciation.

Recovery of metals occurring in significant amounts in municipal solid waste incineration fly ash, such as copper, could offer several advantages: a decreased amount of potentially mobile metal compounds going to landfill, saving of natural resources and a monetary value. A combination of leaching and solvent extraction may constitute a feasible recovery path for metals from municipal solid waste incineration fly ash. However, it has been shown that the initial dissolution and leaching is a limiting step in such a recovery process. The work described in this article was focused on elucidating physical and chemical differences between two ash samples with the aim of explaining the differences in copper release from these samples in two leaching methods. The results showed that the chemical speciation is an important factor affecting the release of copper. The occurrence of copper as phosphate or silicate will hinder leaching, while sulphate and chloride will facilitate leaching

Phosphorus cluster production by laser ablation

Neutral and charged phosphorus clusters of a wide size range have been produced by pulsed laser ablation (PLA) in vacuum at 532, 337, and 193 nm ablating wavelengths and investigated by time-of-flight mass spectrometry. The neutral P_n clusters are even-numbered with local abundance maxima at n = 10 and 14, while the cationic and anionic clusters are preferentially odd-numbered with (P_7)+, (P_21)+, and (P_17)- being the most abundant ions. The dominance of the magic clusters is more pronounced at 337-nm ablation that is explained by efficient direct ejection of their building blocks under these conditions. Nanocrystalline phosphorus films have been produced by PLA in ambient helium gas

Energy consumptions and CO2 emissions resulting from different handling strategies of glass from end-of-life vehicles

Every year a large number of vehicles become useless. They become end-of-life vehicles (ELV) and need to be scrapped. The materials from a vehicle will be taken care of for reuse, recycling, recovery or disposal. For the glass, there are at least three scenarios, with different handling techniques: 1. dismantling of the glass from the ELV before the ELV is shredded 2. separation of the glass, from the shredder waste, to be used for new glass products, or 3. separation of the glass along with some other inorganic fractions, from the shredder waste, to be used for filling material. The purpose of this study is to investigate and compare the environmental impacts from these three scenarios. The investigation is from a life-cycle perspective, beginning when the ELV arrives at the vehicle dismantler and ending when the glass has become a new product. The glass is not a hazardous material and all emissions to the environment are directly linked to the use of energy, with one exception. When new glass products are produced from virgin materials, some chemically bound carbon is released as CO2, which will be prevented if recycled glass is used instead. All results are therefore presented as energy consumptions and CO2 emissions. The recycling of glass results in small reductions in energy consumptions and CO2 emissions, compared with recycling of other materials. In this study, scenario 1 presents itself with a higher possible recycling rate and also the highest savings of energy and CO2. Scenario 2 has the second highest savings and a brighter future in technical development within the recycling business. The simplest option presented in this study is scenario 3, with savings close to zero

Transparency of Executive Directors'' Remuneration

Following rising remuneration levels, significant owner reactions to excessive executive pay, and a request for more executive accountability, there has been increased focus on disclosure of more complete information on the pay levels, program structure and performance criteria for key executives in most European markets. In general, the academic research in the area has been about the conformance of disclosure with different regulations and recommendations, and several comparative studies have been made. But after thorough investigation, nothing has been found on the demand of information. Therefore, this study has analyzed how transparent the reporting of executive directors’ remuneration is in Swedish listed companies, by examining to what extent the demand for information is satisfied by the annual reports. The study has been divided into two parts where the first part analyzes the demand for information by compiling the regulations and recommendations, interviewing different stakeholders and reviewing the discussion in media. The demanded variables have then been placed in four different levels of transparency; 1) basic disclosure – contains mandatory information required by the Annual Accounts Act, 2) general disclosure – contains additional information but the nature of the information is still very general, 3) extended disclosure – contains more firm-specific information, 4) full disclosure – contains all variables demanded. The constructed classification system is used in the second study where the annual reports of companies listed on OMX Stockholm Large Cap have been analyzed. The study shows that the market for information on directors’ remuneration is in disequilibrium, caused by a supply deficit, where none of the studied companies fulfill a higher level of transparency than general disclosure

Utökade tilläggsupplysningar vid övergången till IASBs standarder

Studiens syfte är att förklara och analysera hur mycket årsredovisningens tilläggsupplysningar har ökat i omfång, i och med införandet av IASBs standarder i Sverige, samt hur detta påverkar finansanalytiker i sin analys av börsnoterade företag. För att kartlägga hur mycket tilläggsupplysningarna har ökat i omfång har en kvantitativ metod använts. Antalet sidor och antalet noter i 60 börsnoterade företags årsredovisningar har räknats för åren 2002 och 2006 samt även år 2004 för antalet sidor. För att analysera hur finansanalytikerna har påverkats av de utökade tilläggsupplysningarna har en kvalitativ metod valts. Intervjuer har genomförts med sju finansanalytiker på sju stora analysföretag. Som referensram för analysen har bl.a. IASBs kriterier för redovisningens kvalitativa egenskaper valts, teorier om olika redovisningsperspektiv, finansanalytikernas roll på aktiemarknaden, deras informationsinhämtning, the Functional Fixation Hypothesis och teorier om kommunikation och lärande. Empirin tyder på att finansanalytikerna anser att tilläggsupplysningarnas kvalitativa egenskaper endast har förändrats marginellt. Användningen av årsredovisningens noter är mycket varierande. Dels beroende på vilket företag och vilken bransch som analyseras och dels på vilken information finansanalytikern är inriktad på. Inställningen till noterna som analysverktyg varierar också, där vissa finansanalytiker anser att det är en stor och viktig del av analysen medan andra tycker att informationen är för gammal och otillgängligt skriven. Studiens slutsats är att årsredovisningens noter har fördubblats men finansanalytikerna har inte påverkats mer än marginellt. Finansanalytikerna kan utifrån sin användning av noterna delas in i tre kategorier; 1) Finansanalytiker som använder sig andra informationsaspekter och därför påverkas endast marginellt, 2) Finansanalytiker som använder sig av noterna och som är hjälpta av den ytterligare informationen 3) Finansanalytiker som använder sig av noterna, men får uttömmande direktinformation från företagen de analyserar och därför bara påverkas marginellt

Electron-spectroscopy study of LiC60: Charge transfer and dimer formation

Li−C60 compounds Lix¯C60 were studied for average Li concentration x¯<~1 using photoelectron spectroscopy. Strong evidence is found for the formation of LiC60 dimers, as well as a second phase. The study suggests that the smallest alkali-metal Li bonds to C60 largely ionically for certain configurations. An investigation of the Li 1s level shows that under certain conditions the energetics favor a backdonation of the transferred electron to the Li ion

Lix@C60: Calculations of the Encapsulation Energetics and Thermodynamics

Li@C60 and Li@C70 can be prepared and thus, their calculations at higher levels of theory are also of interest. In the report, the computations are carried out on Li@C60, Li2@C60 and Li3@C60 with the B3LYP density-functional theory treatment in the standard 3-21G and 6-31G* basis sets. The computed energetics suggests that Lix @C60 species may be produced for a few small x values if the Li pressure is enhanced sufficiently. In order to check the suggestion, a deeper computational evaluation of the encapsulation thermodynamics is carried out

Dynamics of Thermal Electron Emission from Highly Excited C₆₀

Gas-phase fullerenes emit thermal electrons after femtosecond laser excitation in the wavelength range 400–800 nm. We have used angular-resolved photoelectron spectroscopy (PES) to study the influence of the laser’s electric field on the dynamics of the thermally emitted electrons. The laser field introduces an asymmetry in the thermal electron distributions with respect to the laser polarization direction, which was confirmed by carrying out experiments at different wavelengths. A simple model could reproduce the trends in measured apparent temperatures in the PES. The asymmetry effect was exploited in a pump–probe experiment to estimate the time scale for thermal electron emission. It was found that, when 400 nm, 120 fs laser pulses of 2 TW cm–2 intensity are used, thermal electrons are emitted up to ca. 300 fs after the peak of the laser pulse. The pump–probe scheme should be applicable to a wider range of complex molecules and clusters showing thermal electron emission on a femtosecond time scale