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Item type:Publication, Green algae as a sustainable source for energy generation and storage technologies(Elsevier Ltd, 2022-10-01)In light of the environmental and human health threats posed by electronic waste, taking advantage of the properties and compounds of green algae presents timely and sustainable energetic alternatives. This review is focused on the technologies developed to use green micro- and macro-algae for energy storage and generation. The main applications of these algae-based technologies include the extraction of bio-fuels and the fabrication of energy storage and energy conversion devices. Bio-oil, H2-rich syngas, and H2 are among the essential bio-fuels produced from green algae feedstock. The hydrogen production of these green algae-derived bio-fuels ranges from 16.8 to 84.1 %. Cellulose, activated carbon, among other materials and compounds extracted from green algae have been used to fabricate electrodes and separation membranes which are part of batteries and supercapacitors, two of the most crucial energy storage devices available for electronic systems. The specific capacitance and current density of these devices have reached 1617 F/g and 31 A/g, respectively. Natural dyes extracted from green algae have been proved to be suitable for the development of novel dye-sensitized solar cells (DSSC), with an open circuit voltage in the range of 0.62 V – 0.75 V. In addition, microbial fuel cells have been tailored to use the oxygen released by the photosynthetic reactions of algae growth as an oxygen source for the cathodic reactions that convert H2 into electricity. Although a wide range of energy applications of green algae are presented, there are still many challenges to overcome before obtaining commercially viable and scalable technologies. Further research needs are discussed. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, ULVAN FROM ULVA NEMATOIDEA AS A NOVEL ACTIVE SURFACE MATERIAL FOR TRIBOELECTRIC NANOGENERATORS(Cisa Publisher - Eurowaste Srl, 2025-03-01)Marine algae represent an underutilized biomass resource. Biopolymers can be extracted from different types of algae. Alginates and carrageenans are among the most common biopolymers extracted from brown and red algae. They find applications in the food and biomaterials industries, among others. However, other available marine algae are not commercially exploited. For instance, green algae from the Ulvaceae family remain largely unexploited and have no industrial applications. In particular, Ulva species can serve as a promising source for the extraction of a biopolymer known as ulvan. This work reports the development of triboelectric nanogenerators (TENGs) for energy harvesting applications using ulvan extracted from the green algae Ulva nematoidea. Ulvan was extracted via an alkaline method. The extracted ulvan was dissolved in water, poured into petri dishes, and dried to form thin films. TENGs were prepared using Ulvan-Kapton® and Ulvan-Polytetrafluoroethylene (PTFE) triboelectric pairs. The Ulvan-Kapton® TENG showed a maximum voltage of 2.12 V and a short-circuit current of 1.6 µA while the Ulvan-PTFE TENG showed a maximum voltage of 43.60 V and a short-circuit current of 5.6 µA. This performance is similar to the performance of other TENGs fabricated from commercial biopolymers. This suggest that ulvan extracted from Ulva nematoidea have potential applications as active surface of TENGs for the development of sustainable energy harvesting devices. This work shows that bio-based materials from green algae can serve as a potential alternative for renewable energy generation. Further research will allow to enhance mechanical properties, electrical performance, and durability of ulvan-based TENGs to improve their practical applicability.4 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effects of morphology and extraction procedures on the chemical, thermal and dielectric properties of ulvan polysaccharides(Elsevier BV, 2025-09-01)This study presents the first comparative analysis of ulvan polysaccharides extracted from two morphologically distinct Ulva species native to the Peruvian coast: Ulvan papenfussii (blade-like) and Ulvan nematoidea (filamentous). Ulvans were extracted under two different conditions (pH 7 and pH 13) to investigate the combined influence of species-specific morphology and extraction methods on their physicochemical and molecular properties. Regardless of species or extraction conditions, all ulvan samples exhibited complex, multimodal molecular weight distributions, most notably in U. nematoidea. Extraction at pH 7 produced ulvans with higher sulfate contents, with U. nematoidea displaying the highest levels. Structural and chemical characterization via FTIR revealed distinct differences in sulfate positioning and uronic acid content between the species. Thermal analysis (DSC) indicated higher glass transition temperatures in U. nematoidea, likely due to its elevated sulfate content. Dielectric relaxation spectroscopy demonstrated that both taxonomic origin and extraction conditions significantly influence ulvan molecular dynamics. These findings, interpreted through Havriliak-Negami and Vogel-Fulcher-Tammann-Hesse modeling, underscore the importance of algal morphology and processing conditions in shaping the structure-property relationships of ulvans. The results offer new insights into tailoring ulvans for applications as functional bio-based polymers.2