Mineral–Carbon Sorbents Based on Aluminium Hydroxide and Atactic Poly(propylene)

The present work is an attempt to use the waste water stream, containing considerable amounts of aluminium chloride, for the manufacture of mineral–carbon sorbents. The use of the wastewater has given a possibility of obtaining a suitable mineral matrix of aluminium hydroxide for the sorbents. Atactic poly(propylene) (APP) have been used as the necessary carbon raw material. The modification of aluminium hydroxide was attained by preliminary mixing with the organic component, followed by carbonisation. Optimum conditions for obtaining Al(OH)₃ have been determined and the effect of the amount of carbon matter on the properties of the materials obtained has been evaluated. The studies have enabled to trace the changes in the structure and properties of the sorbents obtained. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mineral-carbon sorbents based on post-decarbonization lime and mixture of hydrocarbons

Summary An attempt was made to obtain mineral-carbon sorbents from waste products of petrochemical industry: lime from the decarbonization of river water to be used in technology and hydrocarbon wastes obtained in the treatment of industrial waste waters. The sorbents were prepared by thermal decomposition of mixtures of the mineral and carbon components. In order to optimize the preparation conditions, physicochemical studies were performed of both the mineral matrix and the mineral-carbon sorbents. Adsorption measurements involving nitrogen, water, and benzene as adsorbates were used for determining the parameters of porous structure of the obtained materials and their hydrophilic-hydrophobic properties. The properties influencing the sorptive properties of the organic compounds present in the petrochemical wastes were pointed out.     

Adsorption and Structural Properties of Mineral–Carbon Sorbents

In the present work an attempt was made to obtain mineral–carbon sorbents by thermal decompositon. The mineral matrix for the sorbents (aluminium hydroxide) was based on petrochemical waste stream containing considerable amounts of aluminium chloride. Reference tests were carried out with a model solution prepared with the use of analytical grade AlCl₃. Atactic polypropylene and hydrocarbon mixtures obtained in the flotation of petrochemical waste waters were used as carbon-containing raw materials. The aim of this work was to determine the adsorption and structural characteristics of the complex sorbents and to check the possibility of evaluation of their hydrophobic-hydrophilic properties. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Analysis in Studies of Technological Waste Materials to Be Subjected to Thermal Treatment

Attempt was made to evaluate the usefulness of thermoanalytical methods, combined with X-ray phase analysis and chemical analyses, for the study of thermal decomposition of waste materials to be subjected to thermal treatment. The object of the studies were petrochemical waste materials intended to be decomposed in a rotary furnace. Results are given of the studies of five selected waste materials. This revised version was published online in August 2006 with corrections to the Cover Date.     

Studies on Thermal Decomposition of Pitch-polymer Compositions

The temperature range of phase transitions has been established for coal–tar pitches modified with various types of polymers. Mass loss rate was determined in relation to modifying polymer type. Simultaneous thermoanalytical method (DTA, DTG, TG), appeared to be very useful in studies on pitch-polymer compositions. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermostability of Selected Enzymes in Organic Wastes and in their Humic Extract

The objective of this study was to evaluate the thermostability up to 70 degrees C for 1 h of selected enzymes present in fresh and composted sewage sludge (SS and SSC) or municipal solid wastes (MSW and MSWC) and their humic extract. After a thermal treatment at 70 degrees C, no beta-glucosidase activity in any humic extract was detected, whereas in SS, SSC, MSW, and MSWC, it was respectively, 35%, 68%, 17%, and 12% compared to thermally untreated samples. By contrast, o-diphenol oxidase activity was even stimulated by thermal treatment in SS samples, but in the humic extracts, this activity decreased by 75-81%. Urease activity in all humic extracts decreased by 70% or more just at 40 degrees C, whereas for organic wastes, this decrease was observed after treatment at 70 degrees C. Alkaline phosphatase (AP) activity was affected by thermal treatment only in MSW and MSWC. In humic extracts, AP activity decreased gradually to zero except for the MSW extract, where 45% activity was retained after treatment at 70 degrees C. In general, thermostability of enzymes in humic extracts was lower than the materials they were extracted from.     

Thermal, spectral and AFM studies of calcium silicate hydrate-polymer nanocomposite material

A non-ionic polymer (poly(vinyl alcohol) (PVA)) has been incorporated into the inorganic layers of calcium silicate hydrate (C–S–H) during precipitation of quasicrystalline C–S–H from aqueous solution. C–S–H and a C–S–H-polymer nanocomposite (C–S–HPN) material were synthesized and characterized by X-ray fluorescence (XRF), energy dispersive spectroscopy (EDS), ²⁹Si magic angle spinning nuclear magnetic resonance (²⁹Si MAS NMR) and ¹³C cross-polarization nuclear magnetic resonance (¹³C CP NMR) spectroscopy, atomic force microscopy (AFM), thermal conductivity, thermogravimetric analysis (TG) and differential thermal analysis (DTA). Thermal conductivity of PVA, C–S–H and C–S–HPN material was studied in the temperature range 25–50°C. C–S–HPN materials exhibited the highest thermal conductivity at 25 and 50°C. The thermal conductivity increases from 25 to 50°C are 7.03, 17.46 and 14.85% for PVA, C–S–H and C–S–HPN material, respectively. Three significant decomposition temperature ranges were observed on the TG curve of C–S–HPN material.     

Testing Adsorbents For Heat Treatment of Pipes

Heat treatment of pipes was performed under industrial conditions at 580°C in a dry protective gas containing a CO₂–CO–H₂–N₂ mixture. A commercial adsorbent (733 kg) used for production ofthe gas removed 52.7 l of water in five h and 22.5 min. During the annealing of pipesoxidation and decarburization were not observed. The results were confirmed bymetallographic analysis. The values of enthalpy of water desorption (36.4–40.5 kJ mol^–1) obtained by DSC and TG measurements were close to those of water evaporation(44.1 kJ mol^–1). This suggests that the bonds between the water molecules andadsorbents were not of chemical but of physical nature. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal behaviour study of some sol–gel iron-silica nanocomposites

Two series of nanocomposites from the Fe_xO_y–SiO₂ system, containing 20 mass% iron oxide were prepared by the alkoxide route of the sol–gel method, in the absence and presence of catalyst. The silica gel has been obtained using tetraethoxysilane. The iron(III) nitrate nonahydrate has been used as iron oxides source. The samples have been prepared in identical conditions, differing only by the gelation times, induced by different surface of evaporation/volume (S/V) ratios of sol let to gelify. Thermal analysis data have established the thermal treatments conditions of the prepared samples and were correlated with X-ray diffraction, IR spectroscopy and TEM results, in order to accomplish a complete structural characterization. The correlation between the structural modifications of the Fe_xO_y–SiO₂ nanocomposites and different conditions of drying has been established.     

Processing-Moisture Resistance and Thermal Analysis of Macro-Defect-Free Materials

The system of sulfoaluminate ferrite belite (SAFB) clinkers premixed with Portland cement (PC) in mass ratio 85:15 in combination with hydroxypropylmethyl cellulose (HPMC) or polyphosphates(poly-P) was used for the syntheses of Macro-Defect-Free (MDF) materials. The subsequent moisture treatment and thermal stability of these MDF materials were investigated. The effect of individual humidity upon the evolution of mass is more intensive than the effects of composition of MDF materials or duration of the original MDF material synthesis. Detailed values of mass changes at 100% relative humidity (RH) and under ambient conditions are strongly affected by the nature of polymer used. A significant improvement of moisture resistance of MDF materials is achieved when the materials are dried after 24 h of finishing the pressure application. In the inter-phase section of MDF material samples, the content ofC-(A,F)-S hydraulic phases, mainly tetracalcium aluminate ferrite monosulphatehydrate (AFm) decomposing by 250°C and CaCO₃ decomposing at 600–700°C increase after the moisture attack, while cross-links in AFm-like section with typical thermoanalytical traces in temperature region 250–550°C remain intact. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal Decompositions of Pure and Mixed Manganese Carbonate and Ammonium Molybdate Tetrahydrate

The thermal decompositions of pure and mixed manganese carbonate and ammonium molybdate tetrahydrate in molar ratios of 3:1, 1:1 and1:3 were studied by DTA and TG techniques. The prepared mixed solid samples were calcined in air at 500, 750 or 1000°C and then investigated by means of an XRD technique. The results revealed that manganese carbonate decomposed in the range 300–1000°C, within termediate formation of MnO₂, Mn₂O₃ andMn₃O₄. Ammonium molybdate tetrahydrate first lost its water of crystallization on heating, and then decomposed, yielding water and ammonia. At 340°C,MoO₃ was the final product, which melts at 790°C. The thermal treatment of the mixed solids at 500, 750 or 1000°C led to solid-solid interactions between the produced oxides, with the formation of manganese molybdate. At 1000°C, Mn₂O₃ and MoO₃ were detected, due to the mutual stabilization effect of these oxides at this temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

Measurement of Spectral Emissivity and Thermal Conductivity of Zirconia by Thermal Radiation Calorimetry

The hemispherical total emissivity of partially stabilized zirconia has been obtained by a spectral analysis of the normal emission spectra between 400–850 K. Thermal conductivity was evaluated with this emissivity and temperature gradient in the sample. Effects of the scattering of the radiation in a ceramic sample are also investigated. In addition, specific heat capacity was measured by thermal radiation calorimetry. Current results are compared with those reported for tetragonal zirconia with the same yttria content and for monoclinic phase. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal Decomposition Studies of Organoplatinum Films

 This study examines the thermal decomposition of 1,5-cyclooctadiene platinum (II) chloride organometallic films, deposited by thermal evaporation. The thin film samples were annealed both in air and hydrogen with well-controlled temperature regimes. After annealing, the decomposed thin films were examined by AFM and STM scanning probe, XPS and TEM microbeam analytical techniques. The experimental results confirm that the thermal decomposition products on silicon substrates are composed predominantly of metallic platinum. Annealing in hydrogen can reduce substantially the decomposition temperature of the material from around 250 to 160 °C but the surface morphology of the decomposed films is significantly different to those annealed in air. The metallic nature of the thermally decomposed films was confirmed by bonding configuration recognition, electronic property probing and microstructure analysis.     

垃圾焚烧飞灰中重金属的热稳定化条件及机理

研究了生活-农业混合型垃圾焚烧飞灰与单一生活垃圾焚烧飞灰（简称混合型飞灰与单一型飞灰）热处理过程中的重金属挥发特性与稳定化效果,并结合FT-IR、XRD检测手段对稳定化机理进行了探讨。结果表明,单一型飞灰中重金属的挥发性普遍高于混合型飞灰,垃圾源氯含量对重金属的挥发性有明显影响。飞灰中Mn、Cr不易挥发,Zn、Cu较易挥发,Pb、Cd挥发性很强,热处理温度超过1 000 ℃时挥发率都超过50%。800 ℃为相对最优的热处理温度,兼顾了热处理过程重金属稳定化与抑制挥发。800 ℃以上时飞灰形成了稳定的硅酸盐结构体系,是重金属热处理后难以浸出的主要机理。     

Thermal behavior of α-(Cu–Al–Ag) alloys

Thermal behavior of α-(Cu–Al–Ag) alloys, i.e. alloys with composition less than about 8.5 mass% Al, was studied using differential scanning calorimetry (DSC), differential thermal analysis (DTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that the presence of silver introduces new thermal events ascribed to the formation of a silver-rich phase and, after addition higher amounts than 8 mass% Ag to the Cu–8 mass% Al alloy it is possible to observe the formation of the γ₁ phase (Al₄Cu₉), which is only observed in alloys containing minimum of 9 mass% Al. These results may be attributed to some Ag characteristics and its interaction with Cu and Al.     

Studies of Benzene Adsorption Layers on Silica Gels by Thermal Analysis and McBain Balance Methods

The Q-TG mass loss and first derivative Q-DTG mass loss accompanying benzene thermodesorption from silica gel samples under quasi-isothermal conditions were studied with a Derivatograph Q-1500 D (MOM, Hungary). The isotherms of adsorption-desorption of benzene vapour on different porous silica gels were measured gravimetrically by using a McBain balance. The benzene mass loss in the adsorption region, obtained from the Q-TG curves, and the adsorption capacity, established gravimetrically, exhibited a satisfactory correlation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Characterization and Physico-Chemical Properties of Fe2O3−Mn2O3/Al2O3 Systems

The effect of ferric and manganese oxides dopants on thermal and physicochemical properties of Mn-oxide/Al₂O₃ and Fe₂O₃/Al₂O₃ systems has been studied separately. The pure and doped mixed solids were thermally treated at 400–1000°C. Pyrolysis of pure and doped mixed solids was investigated via thermal analysis (TG-DTG) techniques. The thermal products were characterized using XRD-analysis. The results revealed that pure ferric nitrate decomposes into Fe₂O₃ at 350°C and shows thermal stability up to1000°C. Crystalline Fe₃O₄ and Mn₃O₄phases were detected for some doped solids precalcined at 1000°C. Crystalline γ-Al₂O₃ phase was detected for all solids preheated up to 800°C. Ferric and manganese oxides enhanced the formation of α-Al₂O₃ phase at1000°C. Crystalline MnAl₂O₄ and MnFe₂O₄ phases were formed at 1000°C as a result of solid–solid interaction processes. The catalytic behavior of the thermal products was tested using the decomposition of H₂O₂ reaction. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal analysis of prealloyed Fe–3Cr–0.5Mo sintered steel

Thermal analysis was done to determine the temperatures of thermal reactions, phase transformations or melting reaction during continuous heating. These reactions are a direct response to the steel composition and to the sintering atmosphere. Simultaneous thermal analysis TG-DTA (STA) shows up the sintering behaviour of sintered low prealloyed chromium steels and their peculiarities. Given the high oxygen affinity of chromium, graphite additions can modify their thermal reactions, and hence the sintering behaviour of the steel. Evidence is given of the effect of carbon on the sintering process and the nature of the oxides.     

Low Temperature Specific Heat and Thermal Stability of Fe–B Ultrafine Amorphous Alloy Particles

Fe–B ultrafine amorphous alloy particles (UFAAP) were prepared by chemical reduction of Fe³⁺ with NaBHO₄ and confirmed to be ultrafine amorphous particles by transmission electron microscopy and X-ray diffraction. The specific heat of the sample was measured by a high precision adiabatic calorimeter, and a differential scanning calorimeter was used for thermal stability analysis. A topological structure of Fe-B atoms is proposed to explain two crystallization peaks and a melting peak observed at T=600, 868 and 1645 K, respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Kinetic Studies on the Thermal Dissociation of β-Cyclodextrin·Ethyl Benzoate Inclusion Complexes

The stability of β-cyclodextrin·ethyl benzoate·6H₂O(β-CD·C₆H₅COOC₂H₅·6H₂O) was investigated by TG and DSC. The mass loss takes place in three stages: the dehydration occurs at 50-120°C; the dissociation of β-CD·C₆H₅COOC₂H₅occurs at 200-260°C; the decomposition of β-CD begins at 280°C. The kinetics of the dissociation of β-CD·C₆H₅COOC₂H₅in a dry nitrogen flow was studied by means of thermogravimetry both at constant temperature and linearly increasing temperature. The results show that the dissociation of β-CD·C₆H₅COOC₂H₅is dominated by a three-dimensional diffusion process (D₃). The activation energy E is 116.19 kJ mol^-1and the pre-exponential factor A 6.5358·10⁹min^-1. Cyclodextrin is able to form inclusion complexes with a great variety of guest molecules, and the studies focus on the energy of binding between cyclodextrin and the guest molecule. In this paper, the β-cyclodextrin·ethyl benzoate inclusion complex was studied by fluorescence spectrophotometry and infrared absorption spectroscopy, and the results show that the stable energy of inclusion complexes of β-CD with weakly polar guest molecules consists mainly of van der Waals interaction. This revised version was published online in July 2006 with corrections to the Cover Date.