| 1. |
- Bátori, Veronika, 1980-, et al.
(författare)
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Anaerobic degradation of bioplastics: A review
- 2018
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X. ; 80, s. 406-413
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), leading to renewableenergy production in the form of methane, is a preferable method for dealing with the increasing amountof waste. Food waste is separated at the source in many countries for anaerobic digestion. However, thepresence of plastic bags is a major challenge for such processes. This study investigated the anaerobicdegradability of different bioplastics, aiming at potential use as collecting bags for the OFMSW. Thechemical composition of the bioplastics and the microbial community structure in the AD processaffected the biodegradation of the bioplastics. Some biopolymers can be degraded at hydraulic retentiontimes usually applied at the biogas plants, such as poly(hydroxyalkanoate)s, starch, cellulose and pectin,so no possible contamination would occur. In the future, updated standardization of collecting bags forthe OFMSW will be required to meet the requirements of effective operation of a biogas plant.
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| 2. |
- Bátori, Veronika, 1980-
(författare)
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Fruit wastes to biomaterials : Development of biofilms and 3D objects in a circular economy system
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To address the current plastic pollution problem, the replacement of conventional plastics with bioplastics can be considered. Although the land use of crop cultivation for bioplastics is still negligible, there is an increasing interest in the utilisation of lignocellulosic waste products for the production of bioplastics. A latest trend in researching sources for bioplastic production focuses on the use of fruit and vegetable wastes because of their versatile polysaccharides. Among different fruit wastes, orange waste and apple pomace have been evaluated as raw materials in this thesis.The development of biofilms and 3D objects from the above-mentioned raw materials via the solution casting and compression moulding methods was investigated. Biocomposites are generally made from a bioplastic matrix and reinforcement, or a plastic reinforced with natural fibres. In the present study, pectin was used as a matrix, and cellulosic fibres wereused as reinforcement. Orange waste films had an opaque appearance with a yellowish colour and were very flexible, while the 3D objects had brown colour. The films had mechanical properties comparable with those of commodity plastics, such as 32 to 36 MPa tensile strength. The films were biodegradable under anaerobic conditions, and 3D objects showed good biodegradability in soil. Grafting of orange waste with maleic anhydride was performed in order to improve its properties, e.g. the hydrophilicity of the polysaccharides-based materials. Grafting reduced the density by 40 % and increased the hydrophobicity compared with unmodified orange waste. Further improvements included upgrading the film casting method and incorporating maleic anhydride in the recipe. The lowest amount of necessary maleic anhydride was determined (0.4 %), and the resulting films had a smoother and more uniform surface. The original methods were also applied to apple pomace in order to produce films and 3D objects. Films from apple pomace had an elongation of 55 %, a twofold increase compared to that of orange waste films containing maleic anhydride (28 %). Orange waste and apple pomace were also mixed for 3D object fabrication, achieving the highest strength of 5.8 MPa (ratio of 75 to 25, respectively) a threefold increase compared to that achieved with only orange waste alone (1.8 MPa).The results are promising‚ but further improvements, e.g. in respect to hydrophilicity and upscaling‚ are needed for orange waste and apple pomace to develop into raw materials for next-generation bioplastics.
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| 3. |
- Bátori, Veronika, 1980-, et al.
(författare)
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Synthesis and characterization of maleic anhydride-grafted orange waste for potential use in biocomposites
- 2018
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 13:3, s. 4986-4997
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to develop a less hydrophilic, and therefore more useful, material from orange waste produced in large quantities by the food industry. A new derivative of industrial orange waste was synthesized via esterification with maleic anhydride. The reaction was confirmed via Fourier transform infrared spectroscopy (FTIR), and the degree of substitution of the hydroxyl groups was 0.39 ± 0.01, as determined by a back-titration method. A major change in physical structure was confirmed by scanning electron microscopy (SEM). The flake-like structure of orange waste changed to a sponge-like structure after the reaction, which involved an increased volume and a reduced density by approximately 40%. The sponge-like structure was represented as an agglomeration of particles with a low specific surface area of 2.18 m2/g and a mean pore diameter of 10.7 nm. Interestingly, the grafted orange waste seemed to become more hydrophobic, which was confirmed by a contact angle test; however, the material absorbed more water vapor. Thermogravimetric analysis (TGA) confirmed a thermally more uniform, though, less heat-resistant material. This work suggests a possible way of utilizing orange waste via synthesizing a renewable material with possible applications as a filler in biocomposites.
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