Abstract
The Sewage Sludge Directive 86/278/EEC was adopted about 30 years ago with a view to encourage sewage sludge reuse in agriculture and to regulate its use. Meanwhile, some EU Member States ...have adopted stricter standards and management practices than those specified in the Directive. In particular, the majority of Member States has introduced more stringent standards for sludge quality, including stricter limits for most potentially toxic elements, organic contaminants and other elements. In general, untreated sludge is no longer applied and in several Member States it is prohibited. In some cases, stringent standards have resulted in an effective ban on use of sludge in agriculture. Moreover, the implementation of the Urban Wastewater Treatment Directive 91/271/EC should increase EU production of sewage sludge, thus enhancing problems related to sustainable sewage sludge management. Additionally, European legislation prohibits the landfill and water deposits of sewage sludge. The latest trends in the field of sludge management,
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combustion, pyrolysis, gasification and co-combustion, have generated significant scientific interest. This trend is specially strong visible in “new” EU Members countries which have to introduce strong EU Directive in their low system. Here the review the state of knowledge and technology in thermal methods for the utilization of municipal sewage sludge to obtain useful forms of energy such as pyrolysis, gasification, combustion, and co-combustion taking into consideration Poland situation is presented.
In European Union 75% of used tires should be recycled. The most common method of used tires disposal, is burning in cement kilns, which does not solve the problem. Pyrolysis process can be an ...alternative way of utilization of tires. The aim of the researches was to check the influence of pyrolysis products (gas and oil fractions) on environment. Samples from pyrolysis process, like light oil fractions or pyrolysis gases were analyzed using gas chromatography. The pyrolysis installation should be hermetical, because of the PAHs which were detected in a light fraction of oil. In exhaust gases BTEX and PAHs were not detected.
Zgodnie z dyrektywami obowiązującymi w krajach należących do Unii Europejskiej, zużyte opony samochodowe powinny być w 75% poddawane recyklingowi. Najbardziej popularną metodą zagospodarowania opon jest ich spalanie w cementowniach, jednakże sposób ten nie wykorzystuje w pełni zasobów energetycznych zużytych opon. Proces pirolizy jest alternatywnym rozwiązaniem. Przeprowadzone badania miały na celu sprawdzenie wpływu zarówno procesu pirolizy, jak i lotnych produktów pirolizy (gaz i lekka frakcja olejowa) na środowisko. Próbki analizowano przy użyciu chromatografu gazowego. Wnioski, które sformułowano po analizie wyników, to m.in. konieczności hermetyzacji i kontroli szczelności reaktorów, w których przeprowadzany jest proces pirolizy. W lekkiej frakcji olejowej wykryto lotne związki wielopierścieniowych węglowodorów aromatycznych, natomiast w gazach odlotowych nie wykryto BTEX (benzen, toluen, etylobenzen oraz ksyleny) oraz wielopierścieniowych węglowodorów aromatycznych.
Cilj istraživanja bio je procijeniti gubitak mase i volumena čestica borovine srednje veličine podvrgnutih pirolizi. Uzorci drva različitih veličina i oblika pirolizirani su pri 500 °C i pri ...različitim vremenima trajanja pirolize. Za usporedbu je provedena termogravimetrijska analiza borovih čestica. Nakon toga pirolizirani su uzorci analizirani metodom radiografije. Pronađena je veza između različitih analiza. Brzina zagrijavanja većih čestica je niža, a primijećen je i vremenski jaz između toplinskog raspadanja hemiceluloze i celuloze. Istraživanja su pokazala da su važan dio analize procesa pirolize brzina zagrijavanja biomase i veličina uzorka. Kako se veličina uzorka povećava, tako se povećava i vrijeme pirolize, i to nelinearno. Usto, rad upućuje na velike mogućnosti radiografskih metoda u analizi procesa pirolize.
Posljednjih godina provedena su različita istraživanja koja ukazuju na veliki potencijal prerade posliježetvenih ostataka za proizvodnju energije. Zahvaljujući novim tehnologijama posliježetveni ...ostaci se mogu na razne načine iskoristiti za dobivanje toplinske i električne energije te tekućih ili plinovitih goriva. Jedan od oblika pretvorbe poljoprivrednih ostataka za dobivanje energije je proces pirolize. Stoga je cilj ovog istraživanja bio utvrditi svojstva slame nekoliko važnijih vrsti žitarica (slama pšenice, ječma, zobi i tritikala) s ciljem uvida u njihov potencijal za proizvodnju energije izravnim sagorijevanjem i pirolizom. Istraživanje je pokazalo da se konačni produkti pirolize slame žitarica, biougljen i bioulje, mogu koristiti kao sirovine za proizvodnju energije (neposredno ili kao sirovina u su spaljivanju), dok se biougljen može koristiti i kao poboljšivač tla.
In this dissertation photocatalytic degradation of 5-(4-substituted phenylazo)-6- hydroxy-4-methyl-3-cyano-2-pyridone using simulated sun light was investigated. The commercial TiO2, Aeroxide P25 and ...immobilized films were used as photocatalysts. The first part of the dissertation describes synthesis and characterization of arylazo pyridone dyes. The arylazo pyridone dyes having different substituents (from electron-donating to electon-withdrawing) on phenyl ring of diazo component were synthesized by two ways. The first synthesis way includes diazotization-coupling reactions and involves the conversion of 4-sulphoaniline to the diazonium ion intermediate 4-sulphobenzendiazonium ion, followed by the reaction with 3-cyano-6- hydroxy-4-methyl-2-pyridone. In the second way, the dyes were synthesized by coupling diazonium salts with ketoesters followed by condensation with cyanoacetamide. The influence of electronic effects of substituents group in the arylazo component on the absorption spectra, azo/hydrazo tautomerism and acid constants of dyes was investigated and quantified using Hammett equation (principle of linear free energy relationship-LFER). The obtained results showed that electron-withdrawing substituents in the arylazo component increase π,π-conjugation in hydrazo tautomer, while electron-donating substituents increase π,π-conjugation in azo tautomer. In addition, it was observed that the electronic behaviour of the nitrogen atoms of azo and hydrazo group is different between derivates with electron-donating and electron-withdrawing substituents. The results also showed that the quantity of hydrazo component and pKa values increased with increasing electron-donating and electron-withdrawing efects of substituents. In the second part of the dissertation the photocatalytic degradation of synthesized dyes using commercial TiO2 Aeroxide P25 was investigated. The influence of different process parameters (catalyst concentration, initial dye concentration, temperature, pH, H2O2 concentration, ethanol concentration) on photodegradation rate of 5-(4-sulpho phenylazo)-6-hydroxy-4-methyl-3-cyano-2-pyridone was studied. The reaction kinetics analysis showed that photodegradation exhibits pseudo first-order kinetics according to Langmuir-Hinshelwood model. The results from TOC analysis showed that dye is efficiently mineralized using investigated photocatalytic process. In addition, the effect of substituents in the diazo component of the dyes on their photocatalytic degradation was studied and quantified using Hammett equation. The results indicated that the photodegradation rates were in a good degree dependent on the substituent electronic effects being accelerated by electron-withdrawing groups and retarded by electrondonating groups. The third part of the dissertation describes the photocatalytic degradation of 5-(4- sulphophenylazo)-6-hydroxy-4-methyl-3-cyano-2-pyridone using porous TiO2 films. TiO2 films were prepared on stainless steel substrate by spray pyrolysis technique. Two groups of films were synthesized: first from hydrothermally prepared colloidal TiO2 solution and second group using TiO2 Aeroxide P25 suspension. The prepared films were annealed at different temperatures and characterized using following methods: (1) X-ray diffraction analysis (XRD) (2) Hg-porosimetry and N2-physisorption (3) Scanning electron microscopy (SEM) (4) Photo-electron spectroscopy (XPS) (5) UVVisible Diffuse Reflectance spectroscopy (DR UV/Vis). The obtained results showed that films annealed at different temperature had different structural, textural and morphological properties. The results from photocatalytic tests showed that photoactivity of the films decreased with increasing anenealing temperature, due to alterations in the films properties. Comparation of photoactivity of films with different thickness showed that, due to limitations imposed by light transport and dye diffusion, the inner parts of films are less active than outer parts. These difusion limitations depends on textural properties of films. In addition, the photoactivity of TiO2 powder Aeroxide P25 and corresponding film was compared. The difference in photoactivity arises not only from diffusion limitations in films, but also from the presence of different metals in film layer.
U ovom radu proučavana je fotokatalitička degradacija arilazo piridonskih boja, 5-(4- supstituisani fenilazo)-6-hidroksi-4-metil-3-cijano-2-piridona, korišćenjem simulirane sunčeve svetlosti. Kao katalizatori korišćeni su komercijalni TiO2 (Aeroxide P25) i TiO2 filmovi. U prvom delu rada opisana je sinteza i karakterizacija arilazo piridonskih boja. Arilazo boje su sintetisane na dva načina. Prvi način sinteze obuhvata reakcije diazotovanja supstituisanih anilina i kuplovanja dobijene diazonijum soli sa 6-hidroksi- 4-metil-3-cijano-2-piridonom. Drugim načinom arilazo piridonske boje su dobijene kuplovanjem diazonijum soli sa ketoestrom uz ciklizaciju nastalog proizvoda etil 3- okso-2-(supstitisanifenildiazenil)butanoata sa cijanoacetamidom. Da bi se ispitao uticaj elektronskih efekata supstituenata na apsorpcione spektre sintetisanih boja, azo-hidrazo tautomeriju i konstante kiselosti, sintetisano je jedanaest boja koje su se razlikovale po prirodi supstituenta na fenilnom jezgru diazo komponente. Ovi uticaji su kvantifikovani korišćenjem Hammett-ove jednačine (princip linearnih korelacija slobodnih energija - LFER princip). Dobijeni rezultati su pokazali da elektron-akceptori prisutni na fenilom jezgru utiču na povećanje π,π-konjugacije u hidrazo tautomeru, dok elektron-donori utiču na povećanje π,π-konjugacije u azo tautomeru. Pokazano je da je elektronsko ponašanje atoma azota azo i hidrazo grupe različito kod boja sa elektron-donorskim i elektronakceptorskim supstituentima. Takođe, dobijeni rezultati su pokazali da je udeo hidrazo komponente i konstanta kiselosti najmanji kod nesupstituisanih boja, dok sa povećanjem elektron-donorskih i elektron-akceptorskih svojstava supstituenata u diazo komponenti boja ove vrednosti rastu. U drugom delu rada proučavana je fotokatalitička degradacija arilazo piridonskih boja korišćenjem komercijalnog katalizatora TiO2, Aeroxide P25. Ispitivan je uticaj sledećih reakcionih parametara na brzinu fotodegradacije 5-(4-sulfofenilazo)-6-hidroksi-4-metil- 3-cijano-2-piridona: količina katalizatora, početna koncentracija boje, temperatura, pH, koncentracija H2O2, prisustvo etanola. Pokazano je da reakcije fotodegradacije slede kinetiku pseudo prvog reda, prema Langmuir-Hinselwood-ovom modelu. Rezultati TOC analize su pokazali da se boja može uspešno demineralizovati ispitivanim fotokatalitičkim procesom. U ovom delu rada proučavan je i uticaj elektronskih svojstava suspstituenata na fenilnom jezgru supstituisanih boja na brzine fotodegradacije. Brzine fotodegradacije su korelisane sa Hammett-ovim konstantama supstituenata. Najveće brzine degradacije su dobijene kod boja sa elektronakceptorskim supstituentima, dok su najmanje brzine degradacije dobijene kod boja sa elektron-donorskim supstituentima. U trećem delu rada proučavana je fotodegradacija arilazo boje, 5-(4-sulfofenilazo)-6- hidroksi-4-metil-3-cijano-2-piridona korišćenjem poroznih TiO2 filmova. TiO2 filmovi su sintetisani na nosaču od nerđajućeg čelika metodom sprej pirolize. Pripremljene su dve grupe filmova: prva grupa polazeći od koloidnog TiO2 rastvora dobijenog hidrotermalnim postupkom i druga grupa polazeći od suspenzije TiO2, Aeroxide P25. Dobijeni filmovi su žareni na različitim temperaturama, a potom okarakterisani primenom sledećih metoda: (1) rendgenostrukturna analiza (XRD), (2) Hgporozimetrija i N2-fizisorpcija, (3) skenirajuća elektronska mikroskopija (SEM), (4) foto-elektronska spektroskopija X-zracima (XPS), (5) difuziono-refleksiona spektroskopija ultravioletne i vidljive oblasti (DR UV/Vis). Dobijeni rezultati su pokazali da strukturna, morfološka i teksturalna svojstva filmova zavise u velikoj meri od temperature žarenja. Rezultati fotokatalitičkih testova su pokazali da se fotoaktivnost filmova smanjuje sa povećanjem temperature žarenja, usled promena u njihovim svojstvima. Poređenjem fotoaktivnosti filmova različitih debljina zaključeno je da su usled difuzionih ograničenja boje i/ili slabijeg prodiranja svetlosti, donji delovi filma manje aktivni nego gornji. Pokazano je da difuzija boje i svetlosti zavisi od teksturalnih svojstava filmova. U radu je izvršeno i poređenje fotoaktivnosti Aeroxide P25 TiO2 praha, i filma dobijenog iz suspenzije TiO2, Aeroxide P25. Dobijeni rezultati su pokazali da je fotoaktivnost filmova značajno manja u odnosu na fotoaktivnost ogovarajućih prahova ne samo usled difuzionih ograničenja u sloju filma, već najverovatnije i usled prisustva metala iz nosača.
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