Agnieszka Pilarska

The Influence of Spray Drying on the Dispersive and Physicochemical Properties of Magnesium Oxide

Magnesium hydroxide was obtained in a precipitation reaction with the use of magnesium nitrate or magnesium sulphate and sodium hydroxide. The influence of the temperature of the process, the mode and rate of substrate supply, as well as the concentration and ratio of the substrates on the products properties, were tested. The intermediate product Mg(OH)2 was subjected to drying by static and spray techniques followed by calcination to obtain magnesium oxide. To establish the effect of the synthesis conditions and drying techniques on the dispersive and physicochemical properties of the magnesium oxide obtained, this product was characterized using a number of experimental methods to obtain the bulk density, polydispersity index, and particle size distribution in the nano- and micrometric ranges. Moreover, the wettability profiles in water system were examined. For selected magnesium oxide samples the crystalline structure was determined by the WAXS method, and adsorptive properties (surface area, volume, and size of pores) as well as electrical properties (dielectric permittivity and electrical conductivity) were measured. Application of all the above-mentioned methods enabled a comprehensive characterization of the products and revealed a significant effect of spray drying on their properties, in particular on their dispersion and morphology.

Use of MgO to Promote the Oxyethylation Reaction of Lauryl Alcohol

Abstract Synthesis of magnesium hydroxide was performed by the precipitation method with the use of magnesium sulfate and sodium hydroxide. The infiuence of temperature and ratio of reagents was studied. Magnesium hydroxides, and the magnesium oxides obtained from them by thermal decomposition, were analyzed to determine their bulk density, polydispersity and particle size. The magnesium oxide with the largest surface area was tested as a catalyst in the oxyethylation of lauryl alcohol, and shown to be selective but poorly reactive in comparison with commercially available catalysts. Further studies are needed to improve its reactivity.

Physico-chemical and dispersive characterisation of magnesium oxides precipitated from the Mg(NO3)2 and MgSO4 solutions

Physico-chemical and dispersive characterisation of magnesium oxides precipitated from the Mg(NO3)2 and MgSO4 solutions An attempt was made to synthesise magnesium oxide of a high degree of dispersion permitting its use as adsorbent or catalyst. The synthesis method proposed was precipitation with the use of magnesium nitrate or magnesium sulfate. The influence of temperature, the mode and the rate of dosing, the concentration and the ratio of the reagents on the properties of the final product was analysed. Magnesium oxides were obtained by thermal decomposition of magnesium hydroxides and subjected to thorough analysis. The results permitted selection of the reaction systems ensuring synthesis of the final products of the desired properties.

Treatment of dairy waste by anaerobic co-digestion with sewage sludge

Abstract The results of anaerobic digestion (AD) of buttermilk (BM) and cheese whey (CW) with a digested sewage sludge as inoculum is described. The substrate/inoculum mixtures were prepared using 10% buttermilk and 15% cheese whey. The essential parameters of the materials were described, including: total solids (TS), volatile solids (VS), pH, conductivity, C/N ratio (the quantitative ratio of organic carbon (C) to nitrogen (N)), alkalinity, chemical oxygen demand (COD). The potential directions of biodegradation of the organic waste types, as used in this study, are also presented. Appropriate chemical reactions illustrate the substrates and products in each phase of anaerobic decomposition of the compounds that are present in buttermilk and cheese whey: lactic acid, lactose, fat, and casein. Moreover, the biogas and biomethane production rates are compared for the substrates used in the experiment. The results have shown that buttermilk in AD generates more biogas (743 m3/Mg VS), including methane (527 m3/Mg VS), when compared with cheese whey (600 m3/Mg VS, 338 m3/Mg VS for biogas and methane, respectively).

Functional polypropylene composites filled with ultra-fine magnesium hydroxide

Abstract Magnesium hydroxide was prepared under controlled conditions from aqueous Mg(NO3)2 and NaOH solutions. The small, nanoplate-shaped particle size distribution was monomodal from 164 to 459 nm. Functional polypropylene/Mg(OH)2 and polypropylene/polypropylene 1% maleic anhydride/Mg(OH)2 composites were prepared containing 10% or 30% Mg(OH)2. The composites have a high Young’s modulus (twice that of polypropylene) and comparable tensile strength but less ductility. EDX examination of the fractured composite surfaces suggested a homogeneous Mg(OH)2 distribution for composites produced with the addition of polypropylene grafted with maleic anhydride. The polypropylene/Mg(OH)2 composites showed good antibacterial activity. The polypropylene/polypropylene 1% maleic anhydride/Mg(OH)2 composites were less effective. Graphical Abstract

THE IMPACT OF EXTRUSION ON THE BIOGAS AND BIOMETHANE YIELD OF PLANT SUBSTRATES

The objective of the present work was to determine the effect of pretreatment by extrusion on the biogas and biomethane yield of lignocellulosic substrates such as maize silage and maize straw silage. The biogas yields of the substrates before and after treatment were compared. Moreover, energy efficiency of pretreatment by extrusion was analyzed in order to assess the applicability of the process in an agricultural biogas plant. Extrusion tests were carried out in a short single-screw extruder KZM-2 in which the length-to-diameter ratio of the screw was 6:1 and rotational speed was 200 rpm. The biogas yield tests of the plant substrates after extrusion were carried out in a laboratory scale, using 15 biofermenters operated in a periodic manner, at a constant temperature of 39°C (mesophilic digestion) and controlled pH conditions. The gas-emission analysis was performed using a certified gas analyzer from Geotech GA5000. Pretreatment by extrusion was observed to improve the quantity of methane generated: in terms of fresh matter for maize silage subjected to extrusion, the methane yield was 16.48% higher than that of the non-extruded silage. On the other hand, maize straw silage after extrusion gave 35.30% more methane than did the same, non-extruded, material. Differences in yields relative to dry organic matter are also described in this paper. Taking into account the amount of energy that is spent on pretreatment and the generated amount of methane, the energy balance for the process gives an idea of the economics of the operation. For maize silage, energy efficiency was lower by 13.21% (-553.2 kWh/Mg), in contrast to maize straw silage, where the increase in energy was 33.49% (678.4 kWh/Mg). The obtained results indicate that more studies on the pretreatment and digestion of maize silage are required in order to improve the efficiency of its use for making biogas. To fully utilize its potential, it is necessary to know thoroughly the effect of the extrusion process and of biogas production on energy efficiency at different conditions.

Utilization of vegetable dumplings waste from industrial production by anaerobic digestion.

Abstract This paper provides the analysis of results of biogas and methane yield for vegetable dumplings waste: dough with fat, vegetable waste, and sludge from the clarifier. Anaerobic digestion of food waste used in the experiments was stable after combining the substrates with a digested pulp composed of maize silage and liquid manure (as inoculum), at suitable ratios. The study was carried out in a laboratory scale using anaerobic batch reactors, at controlled (mesophilic) temperature and pH conditions. The authors present the chemical reactions accompanying biodegradation of the substrates and indicate the chemical compounds which may lead to acidification during the anaerobic digestion. An anaerobic digestion process carried out with the use of a dough-and-fat mixture provided the highest biogas and methane yields. The following yields were obtained in terms of fresh matter: 242.89 m3 Mg−1 for methane and 384.38 m3 Mg−1 for biogas, and in terms of volatile solids: 450.73 m3 Mg−1 for methane and 742.40 m3 Mg−1 for biogas. Vegetables and sludge from the clarifier (as fresh matter) provided much lower yields.

An assessment of adaptive and antagonistic properties of Trichoderma sp. strains in vegetable waste composts

Abstract The experiment consisted in monitoring the count of moulds and three selected Trichoderma sp. isolates (T1 - Trichoderma atroviride, T2 - Trichoderma harzianum, T3 - Trichoderma harzianum) in vegetable (onion and tomato) waste composted with additives (straw, pig manure). Additionally, the aim of the study was to determine the type of interaction occurring between autochthonous fungi isolated from composts after the end of the thermophilic phase and Trichoderma sp. strains applied in the experiment. Number of microorganisms was determined by the plate method, next the identification was confirmed. The rating scale developed by Mańka was used to determine the type of interactions occurring between microorganisms. The greatest count of moulds in onion waste composts was noted in the object which had simultaneously been inoculated with two strains T1 - T. atroviride and T3 - T. harzianum. The greatest count of moulds was noted in the tomato waste composts inoculated with T2 - T. harzianum strain. Microscope identification revealed that Penicillum sp., Rhizopus sp., Alternaria sp. and Mucor sp. strains were predominant in onion waste composts. In tomato waste composts Penicillium was the predominant genus, followed by Rhizopus. The test of antagonism revealed the inhibitory effect of Trichoderma isolates on most autochthonous strains of moulds. Tomato waste composts proved to be better substrates for the growth and development of Trichoderma sp. isolates. The results of the study show that vegetable waste can be used in agriculture as carriers of antagonistic microorganisms.

Evaluation of the fertilizer value of digestate pulp from biogas plant and its composts

Streszczenie. Artykuł niniejszy stanowi kontynuację pracy tych samych autorów (Pilarska i in., 2015), w której przedstawiono charakterystykę składu chemicznego oraz aktywności enzymatycznej różnych pofermentów uzyskanych w wyniku fermentacji metanowej gnojowicy z różnymi dodatkami organicznymi i kompostów z tych pofermentów. Drugi etap doświadczenia, którego wyniki przedstawiono w obecnej publikacji, polegał na aplikacji uzyskanych materiałów oraz ocenie ich wartości nawozowej. W tym celu wiosną 2012 roku założono doświadczenie wazonowe, w którym wykorzystano jałową glebę pobraną z gruntów rolnych znajdujących się na terenie Wielkopolski. Wartość nawozową badanych materiałów organicznych oceniano na podstawie ich wpływu na właściwości gleb oraz plony suchej masy tymotki łąkowej (Phleum pratense L.). W wykonanym doświadczeniu wykazano korzystny wpływ stosowania przefermentowanych i kompostowanych odpadów na badane parametry gleb. Oddziaływanie użytych materiałów na

Directions of utilisation of waste from green areas

Abstract Each year communities generate large quantities of municipal waste, including green waste such as grass and leaves. According to the waste catalogue, they may be treated as belonging to the group 20 02 (garden and park waste), and more specifically, to the group 20 02 01 – biodegradable waste. The aim of the study is to characterise the development directions of the green waste generated in the municipalities. Skilful management of this waste is extremely important. The following work focuses on three different technologies that enable efficient management of the green waste: methane fermentation, pelletising and composting. According to many authors, the most common technologies are pelletising and composting. In contrast, biogas fermentation of green waste in the municipalities is performed on a much smaller scale than other technologies. This may be due to the fact that this technology requires a significant expertise and is more complicated in terms of technology