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Mr. Raid Alrefai
Dublin City University

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0 Anaerobic Digestion
0 Biogas
0 Bioplastics
0 Response Surface Methodology
0 Thermoplastics

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Journal article
Published: 09 August 2021 in Energies
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Dates are an important food source in many countries that produce different types of dates. Dates have a significant amount of waste, either from planting or eating them. A large amount of seeds are produced from eating it. This study is considered to explore the quantity and the quality of biogas produced from the Sagai date seeds through the anaerobic digestion process (AD) before and after oil extraction and exploitation of oil in biodiesel production. In addition, the study aims to tests the resulted digestate from the AD process. This test was performed to ensure that the digestate contains the three basics elements (N, P and K) to be used in agriculture. In its preparation, the date seeds were ground after washing via a grinding machine without exposure to any other treatment process. Design of Experiments (DOE) was applied in determining the effect of temperature, volatile solid and sludge quantity on the resulted biogas. The energy balance at the optimum results was calculated. The highest biogas volumes from the AD of date seed before and after oil extraction were 4140 cc and 3534 cc, respectively, at 37 °C, 4.2 g-VS and 50% sludge quantity. While the highest methane/g-VS were 1143.8 cc/g-VS and 949.6 cc/g-VS, respectively, at 37 °C, 1.1 g-VS and 50% sludge quantity. The oil obtained using the Soxhlet method at 70 °C, 1:4 ratio of date seeds to n-hexane solvent and 5 h reaction time was 16% of the date seed mass (79% biodiesel and 9% glycerine). Therefore, the resultant effect from the main findings indicated that the study supports the investigation of the possibility of exploiting date seeds in the production of biogas, biodiesel and bio-fertiliser.

ACS Style

Alla Alrefai; Raid Alrefai; Khaled Benyounis; Joseph Stokes. Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds. Energies 2021, 14, 4851 .

AMA Style

Alla Alrefai, Raid Alrefai, Khaled Benyounis, Joseph Stokes. Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds. Energies. 2021; 14 (16):4851.

Chicago/Turabian Style

Alla Alrefai; Raid Alrefai; Khaled Benyounis; Joseph Stokes. 2021. "Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds." Energies 14, no. 16: 4851.

Journal article
Published: 17 December 2020 in Energies
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A significant expansion of anaerobic digestion (AD) processes would certainly result in a reduction in the current dependence on fossil fuels. The operational costs, the large amounts of digestate generated and the expenses of dealing with it and the volatility of the fuel indexes represent major environmental and economical challenges to the diffusion of AD. Increasing the bio-products of AD could possibly help in increasing its profitability and limit these challenges. This study investigates the influence of mango starch and seed coats on the biogas produced from mango waste. To overcome the environmental challenges, the digestate was tested and its bio-fertiliser potential proven. The study reached the conclusion that the effect of the starch on the AD biogas of mango waste is low while the effect of the seed coats is quite high. This finding supports further investigations to evaluate the effect of the production of mango starch and seed coat-based products on the profitability of AD. The highest energy balance achieved was 65% at 32 °C, 3.93 g-VS organic concentration and 37% sludge concentration, which yielded a maximum CH4 yield of 62.5%. This finding encourages the application of gate fees for accepting bio-waste, which may help in overcoming its economic challenges.

ACS Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. Enhancing the Economic Viability of Anaerobic Digestion by Exploiting the Whole Biomass of Mango Waste and Its Residues after Digestion. Energies 2020, 13, 6683 .

AMA Style

R. Alrefai, A.M. Alrefai, K.Y. Benyounis, J. Stokes. Enhancing the Economic Viability of Anaerobic Digestion by Exploiting the Whole Biomass of Mango Waste and Its Residues after Digestion. Energies. 2020; 13 (24):6683.

Chicago/Turabian Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. 2020. "Enhancing the Economic Viability of Anaerobic Digestion by Exploiting the Whole Biomass of Mango Waste and Its Residues after Digestion." Energies 13, no. 24: 6683.

Encyclopedia
Published: 15 September 2020 in Reference Module in Materials Science and Materials Engineering
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Due to the negative impacts of the petroleum plastics, the shift to bio-products has become a requirement not an alternative like any time before. Substituting petroleum plastics with bioplastics produced from starch extracted from conventional starch sources would deplete these sources. The study aims primarily to investigate the properties of thermo-plastic starch produced from three un/conventional starch sources for reducing the pressure on the common conventional sources. To achieve so, the study compared between the properties of bioplastic sheet produced from potato starch as conventional source with bioplastic sheets produced form mango and avocado starch as un-conventional sources. In terms of the mechanical and physical properties, mango starch and avocado starch bioplastic sheets showed poor properties compared to the properties of the potato starch bioplastic sheet. For improving the properties, pretreated mango seed coat fibres were used as reinforced materials. Also, the three starch and fibres were blended with each others in an aid of Mixture design of Design expert software to find the optimal mixture in terms of properties and cost. It was reached that, the optimal quantity of the starch and fibre at the optimal bioplastic sheet in terms of properties is 90 g potato starch, and 10 g mango fibres. While, the optimal quantity in terms of cost was located at 47 g potato starch, 7.6 g mango starch, 35.3 g avocado starch and 10 g mango fibres.

ACS Style

Raid Alrefai; Alla M. Alrefai; Khaled Benyounis; Joseph Stokes. A Comparative Study of the Properties of the Bio-Plastic Sheets Produced From Three Conventional and Unconventional Starch Sources. Reference Module in Materials Science and Materials Engineering 2020, 1 .

AMA Style

Raid Alrefai, Alla M. Alrefai, Khaled Benyounis, Joseph Stokes. A Comparative Study of the Properties of the Bio-Plastic Sheets Produced From Three Conventional and Unconventional Starch Sources. Reference Module in Materials Science and Materials Engineering. 2020; ():1.

Chicago/Turabian Style

Raid Alrefai; Alla M. Alrefai; Khaled Benyounis; Joseph Stokes. 2020. "A Comparative Study of the Properties of the Bio-Plastic Sheets Produced From Three Conventional and Unconventional Starch Sources." Reference Module in Materials Science and Materials Engineering , no. : 1.

Review
Published: 15 September 2020 in Reference Module in Materials Science and Materials Engineering
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Petroleum plastics are heavily used nowadays in all aspects of life. Due to their negative impacts on almost all living, environment and others, the transformation to bioplastic has become a necessary requirement rather than an option. Starch-based bioplastic that is separated from the conventional starch sources is one of the main common types of biopolymers, nowadays that has proven its potentials in some industrial applications. The poor properties and the brittleness of Starch-based bioplastic have impeded the wide application of starch in real applications. The additions of polymers, bio-fillers or bio-fibers to the starch are some of the ways currently used to enhance the properties. Due to that and the excessive uses of the conventional starch and bio-fibers, there is a crucial need to discover other sources of starch and biofibre and study their properties. The present article depicts negative impacts of the conventional plastics and reviews the major aspects of starch-based bioplastic as an alternative bio-product. It also reviews the characteristics of some of the conventional and non-conventional starch sources which are extracted from the wastes of fruits and vegetables. The study suggested further investigations on the production of starch-based bio-plastic from unconventional starch and bio-fillers.

ACS Style

Raid Alrefai; Alla M. Alrefai; Khaled Benyounis; Joseph Stokes. A Review on the Production of Thermo-Plastic Starch From the Wastes of Starchy Fruits and Vegetables. Reference Module in Materials Science and Materials Engineering 2020, 1 .

AMA Style

Raid Alrefai, Alla M. Alrefai, Khaled Benyounis, Joseph Stokes. A Review on the Production of Thermo-Plastic Starch From the Wastes of Starchy Fruits and Vegetables. Reference Module in Materials Science and Materials Engineering. 2020; ():1.

Chicago/Turabian Style

Raid Alrefai; Alla M. Alrefai; Khaled Benyounis; Joseph Stokes. 2020. "A Review on the Production of Thermo-Plastic Starch From the Wastes of Starchy Fruits and Vegetables." Reference Module in Materials Science and Materials Engineering , no. : 1.

Journal article
Published: 28 May 2020 in Energies
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Cassava is a form of food that is rich in starch abundant in many countries. Several bio-products can be extracted from its starch and used as an alternative for oil-based products. This study primarily aims to investigate the influence of the starch isolated from cassava peel on the quantity and quality of the biogas produced via anaerobic digestion. Beating pre-treatment was applied for the first time to isolate the starch and mechanically pre-treat the substrate. The influence of temperature, volatile solid and sludge quantity investigations were analysed with the aid of Design of Experiments (DOE). An optimisation process was applied in calculating the energy balance at the optimal results and this was needed in evaluating the impact of the starch on the biogas produced. The study revealed that the influence of the starch on the biogas quality is quite low and, as such, negligible. The largest biogas volume as obtained was 3830 cc at 37 °C, 4.2 g-VS and 50% sludge quantity, while at the same time the maximum CH4 g−1-VS was 850 cc g−1-VS at 37 °C, 1.1 g-VS and 50% sludge quantity. The optimal results show the energy gain could be achieved based on the set criteria.

ACS Style

Alla Mohammed Alrefai; Raid Alrefai; Khaled Younis Benyounis; Joseph Stokes. Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process. Energies 2020, 13, 2713 .

AMA Style

Alla Mohammed Alrefai, Raid Alrefai, Khaled Younis Benyounis, Joseph Stokes. Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process. Energies. 2020; 13 (11):2713.

Chicago/Turabian Style

Alla Mohammed Alrefai; Raid Alrefai; Khaled Younis Benyounis; Joseph Stokes. 2020. "Impact of Starch from Cassava Peel on Biogas Produced through the Anaerobic Digestion Process." Energies 13, no. 11: 2713.

Journal article
Published: 11 May 2020 in Energies
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Anaerobic digestion (AD) has undergone many developments since its first appearance. Despite that, there are still some environmental and economical obstacles that are limiting its sustainability. On the other hand, different types of starch have proven their effectiveness in some different applications. Food processing industries are considered one of the largest generators of waste in the environment. With an aid of the response surface methodology (RSM), the proposed study aimed to find an optimised way to overcome the obstacles by studying the impacts of the starch isolated from the potato peels on the biogas produced from the AD of potato peels before and after starch separation. The study found that potato peels represented approximately 12.5% of the potato total weight. The starch has only a slight influence on the quantity of the biogas produced and much lower influences on its quality. This finding suggests further investigation is required on the production of starch bio-based products simultaneously with the biogas and bio-slurry, which may mitigate environmental influences and economical obstacles of AD and make it more commercially attractive. The study showed also that the highest energy gain by the g-VS/0.2 L of potato peels was 62.9% at 35 °C, 1.62 g-VS/0.2 L organic concentration and 50% sludge concentration, which yielded a maximum CH4 of 72.4%.

ACS Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. An Evaluation of the Effects of the Potato Starch on the Biogas Produced from the Anaerobic Digestion of Potato Wastes. Energies 2020, 13, 2399 .

AMA Style

R. Alrefai, A.M. Alrefai, K.Y. Benyounis, J. Stokes. An Evaluation of the Effects of the Potato Starch on the Biogas Produced from the Anaerobic Digestion of Potato Wastes. Energies. 2020; 13 (9):2399.

Chicago/Turabian Style

R. Alrefai; A.M. Alrefai; K.Y. Benyounis; J. Stokes. 2020. "An Evaluation of the Effects of the Potato Starch on the Biogas Produced from the Anaerobic Digestion of Potato Wastes." Energies 13, no. 9: 2399.

Encyclopedia
Published: 15 May 2019 in Encyclopedia of Renewable and Sustainable Materials
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The transformation to renewable energy has become a necessary requirement rather than an optional. The attentions towards the renewable energy are increasing at a fast pace, due to the expected depletion of conventional fuel and the major impacts associated with it on the global environment. Despite the proven advantages of using anaerobic digestion (AD) for the conversion of a large variety of biomass into biogas and the development on it throughout the past few years, there still exist some challenges threatening the prosperity and sustainability of AD. From an environmental point of view, AD could contribute in major issues if it is applied extensively due to the accumulation and the improper handling of the huge amounts of the AD digestate generated. Economically, compared to fossil fuel’s market and the expenses of the energy consumed in the AD process and the cost of preserving the digestate and others, biogas which is the only major product of AD is not competitive enough compared to the prices of its counterparts. To limit these issues, many research have investigated an integration approach. This approach has the potential to increase the economic feasibility of AD through producing multiple bioproducts simultaneously in addition to the biogas. It can offer an optimal solution as well, for bio-fuel production and waste management. As it is a new approach, the scientific literatures on it are relatively few. This paper discusses an integration approach of AD and fungal fermentation for producing multiple bioproducts and byproducts with low waste generated. This approach is still at an early stage and requires more investigation to prosper and increase the application of it in AD plants.

ACS Style

Raid Alrefai; Alla M. Alrefai; Joseph Stokes; Khaled Y. Benyounis. The Production of Biogas, Biodiesel as High-Value Bio-Based Product and Multiple Bio-Products Through an Integration Approach of the Anaerobic Digestion and Fermentation Processes. Encyclopedia of Renewable and Sustainable Materials 2019, 686 -694.

AMA Style

Raid Alrefai, Alla M. Alrefai, Joseph Stokes, Khaled Y. Benyounis. The Production of Biogas, Biodiesel as High-Value Bio-Based Product and Multiple Bio-Products Through an Integration Approach of the Anaerobic Digestion and Fermentation Processes. Encyclopedia of Renewable and Sustainable Materials. 2019; ():686-694.

Chicago/Turabian Style

Raid Alrefai; Alla M. Alrefai; Joseph Stokes; Khaled Y. Benyounis. 2019. "The Production of Biogas, Biodiesel as High-Value Bio-Based Product and Multiple Bio-Products Through an Integration Approach of the Anaerobic Digestion and Fermentation Processes." Encyclopedia of Renewable and Sustainable Materials , no. : 686-694.

Journal article
Published: 01 January 2017 in Journal of Fundamentals of Renewable Energy and Applications
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The rapid increase in the world population has caused an enormous increase in the demand of energy. Growing demand has resulted in a shortfall in conventional energy resources. Due to that and because of the major negative impacts of fossil fuel on the environment and other aspects as well, the necessity toward finding alternative cheap, renewable, and environmentally friendly energy resources has significantly arose. Biomass as an energy resource has a potential to be a good alternative for non-renewable energy resources. Anaerobic digestion process is one of the most commonly biological conversion process used in converting biomass into biofuels. It has been extensively applied in many studies for converting several types of feedstocks and has proved its significant effectiveness. (AD) digestates are generally composed of solid and liquid streams. Those streams are rich in nutrients and contain undigested materials which have not been digested in the digestion process. Despite the significant effectiveness, it would contribute in major issues if it has been applied at large scale, as the amount of digestates which would be generated is quite high. Due to that and to take an advantage of the digestates in the production of biofuel and bioproducts as well, the interests in enhancing and utilizing anaerobic digestion residues have recently much increased. Bioethanol is one of the most promising liquid biofuel. It is eco-friendly alternative to fossil fuels. In recent years, number of studies have investigated the integration approach of producing biogas and bioproduct in which would result in zero waste. However, this paper discusses mainly an integration approach for producing two promising renewable energies can be utilized in many applications with no waste generated. This approach is still at an early stage and requires further studies to improve the properties of the biofuels and high-value bio-based products produced.

ACS Style

Raid Alrefai; Benyounis Ky; Stokes J. Integration Approach of Anaerobic Digestion and Fermentation Process Towards Producing Biogas and Bioethanol with Zero Waste: Technical. Journal of Fundamentals of Renewable Energy and Applications 2017, 7, 1 -6.

AMA Style

Raid Alrefai, Benyounis Ky, Stokes J. Integration Approach of Anaerobic Digestion and Fermentation Process Towards Producing Biogas and Bioethanol with Zero Waste: Technical. Journal of Fundamentals of Renewable Energy and Applications. 2017; 7 (6):1-6.

Chicago/Turabian Style

Raid Alrefai; Benyounis Ky; Stokes J. 2017. "Integration Approach of Anaerobic Digestion and Fermentation Process Towards Producing Biogas and Bioethanol with Zero Waste: Technical." Journal of Fundamentals of Renewable Energy and Applications 7, no. 6: 1-6.