|
|
Study and characterization of organic substances in a biochar sample
Vojáčková, Beáta ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis characterizes biochar from a physico-chemical point of view. The theoretical part deals with biochar as a soil conditioner, its properties, use, production, and last but not least, effect of its sorroundings. For better characterization of organic and inorganic matter a phosphate buffer was used. This buffer ensures their specific extraction due to a neutral pH. The second path is to use rainwater, which simulates the condition of the soil environment. In the experimental part are discussed both; purified buffer-extracted samples and rainwater samples, which were studied by thermogravimetric analysis (TGA), elemental analysis (EA) and by infrared spectroscopy with Fouier transform (FTIR-ATR). Conductivity and pH were also measured. Moisture and ash content, which represent the inorganic non-combustible fraction, were determined using thermogravimetry. The extraction yields were converted to ashless wt. % based on these values. Results of EA provided us with information on the content of biogenic elements and basic physico-chemical characteristics of biochar. In contrast, the FTIR method defined the presence of individual functional groups and specific constitutive units, which are present in the extracts. This information allows us to better understand the environmental impact of biochar on the soil ecosystem.
|
|
|
Chemical modifications of polypropylene surfaces
Pospíšek, Marek ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
Diploma thesis is focused on modification and characterization of polypropylene (PP) products surfaces by the chemical way. In theoretical part of thesis are summarized the current knowledge of this topic including characterization methods. Polypropylene surfaces were modified by acrylic monomers (acrylic acid, acrylic acid with 20 mol% content of sodium acrylate and acryl amide). Modified surfaces were characterized by infrared spectroscopy with ATR technique. The comparative parameter was carbonyl index determined from absorption peaks of functional methyl groups (2950 cm-1 ) and functional carbonyl groups (1700-1750 cm-1) of FTIR-ATR spectra. Determination of effect of initiator concentration on the modification process was done for acetophenone and benzophenone. There were determined the time dependence of carbonyl index for time from 0 to 600 s of mentioned monomers. In the same condition were modified test specimens designed for preparation of adhesive joints. Joints were bonded by cyanoacrylate adhesive that provide reaction with surface of polyacrylic acid. There were founded conditions of modification that provided strength of adhesive joints higher than strength of original PP. There were identified changes of surface roughness by using of confocal microscopy.
|
|
|
Identification of contamination sources in the PET recycling
Snopková, Martina ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
This paper deals with the identification of plastic contaminants in polyethylene terephthalate (PET) flakes obtained by mechanical recycling of PET bottles. The presence of contaminants in recycled material is undesirable and it is necessary to implement and optimize technologies to separate them. For improving the effectiveness of separation, it is crucial to determine the material of the contaminant. Papers that are focusing on the contaminant analysis in PET flakes are sporadic. In practice, there are not enough sources for enhancing the effectiveness of separation based on the material of the contaminant. The goal of this thesis is to provide missing information about the materials of plastic impurities. Obtained findings will contribute to efficiency improvement of contaminant separation and production of better-quality recycled material. For contaminant analysis, Fourier-transform infrared spectroscopy with attenuated total reflection technique (FTIR-ATR) was used. The samples were analyzed using an ALPHA II device with an ALPHA-P module with the diamond crystal. It was found out that the most frequented contaminants are polymers polystyrene (PS) and its modifications, polyethylene terephthalate glycol (PETG), PET mixed with other polymers or additives, polypropylene (PP), polyamide (PA), styrene acrylonitrile (SAN) and polyvinylchloride (PVC). Based on these results, the recommendations for enhancing the efficiency of separation were developed. Some of the results pointed out the actual problems that complicate PET bottle recycling.
|
|
|
Identification of contamination sources in the PET recycling
Snopková, Martina ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
This paper deals with the identification of plastic contaminants in polyethylene terephthalate (PET) flakes obtained by mechanical recycling of PET bottles. The presence of contaminants in recycled material is undesirable and it is necessary to implement and optimize technologies to separate them. For improving the effectiveness of separation, it is crucial to determine the material of the contaminant. Papers that are focusing on the contaminant analysis in PET flakes are sporadic. In practice, there are not enough sources for enhancing the effectiveness of separation based on the material of the contaminant. The goal of this thesis is to provide missing information about the materials of plastic impurities. Obtained findings will contribute to efficiency improvement of contaminant separation and production of better-quality recycled material. For contaminant analysis, Fourier-transform infrared spectroscopy with attenuated total reflection technique (FTIR-ATR) was used. The samples were analyzed using an ALPHA II device with an ALPHA-P module with the diamond crystal. It was found out that the most frequented contaminants are polymers polystyrene (PS) and its modifications, polyethylene terephthalate glycol (PETG), PET mixed with other polymers or additives, polypropylene (PP), polyamide (PA), styrene acrylonitrile (SAN) and polyvinylchloride (PVC). Based on these results, the recommendations for enhancing the efficiency of separation were developed. Some of the results pointed out the actual problems that complicate PET bottle recycling.
|
|
|
Study and characterization of organic substances in a biochar sample
Vojáčková, Beáta ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis characterizes biochar from a physico-chemical point of view. The theoretical part deals with biochar as a soil conditioner, its properties, use, production, and last but not least, effect of its sorroundings. For better characterization of organic and inorganic matter a phosphate buffer was used. This buffer ensures their specific extraction due to a neutral pH. The second path is to use rainwater, which simulates the condition of the soil environment. In the experimental part are discussed both; purified buffer-extracted samples and rainwater samples, which were studied by thermogravimetric analysis (TGA), elemental analysis (EA) and by infrared spectroscopy with Fouier transform (FTIR-ATR). Conductivity and pH were also measured. Moisture and ash content, which represent the inorganic non-combustible fraction, were determined using thermogravimetry. The extraction yields were converted to ashless wt. % based on these values. Results of EA provided us with information on the content of biogenic elements and basic physico-chemical characteristics of biochar. In contrast, the FTIR method defined the presence of individual functional groups and specific constitutive units, which are present in the extracts. This information allows us to better understand the environmental impact of biochar on the soil ecosystem.
|
|
|
Chemical modifications of polypropylene surfaces
Pospíšek, Marek ; Petrůj, Jaroslav (referee) ; Kučera, František (advisor)
Diploma thesis is focused on modification and characterization of polypropylene (PP) products surfaces by the chemical way. In theoretical part of thesis are summarized the current knowledge of this topic including characterization methods. Polypropylene surfaces were modified by acrylic monomers (acrylic acid, acrylic acid with 20 mol% content of sodium acrylate and acryl amide). Modified surfaces were characterized by infrared spectroscopy with ATR technique. The comparative parameter was carbonyl index determined from absorption peaks of functional methyl groups (2950 cm-1 ) and functional carbonyl groups (1700-1750 cm-1) of FTIR-ATR spectra. Determination of effect of initiator concentration on the modification process was done for acetophenone and benzophenone. There were determined the time dependence of carbonyl index for time from 0 to 600 s of mentioned monomers. In the same condition were modified test specimens designed for preparation of adhesive joints. Joints were bonded by cyanoacrylate adhesive that provide reaction with surface of polyacrylic acid. There were founded conditions of modification that provided strength of adhesive joints higher than strength of original PP. There were identified changes of surface roughness by using of confocal microscopy.
|
guest ::
