Percorrer por autor "Rodrigues, Filipa"
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- Efficacy of bacterial cellulose hydrogel in microfiber removal from contaminated waters: A sustainable approach to wastewater treatmentPublication . Rodrigues, Filipa; Faria, Marisa; Mendonça, Ivana; Sousa, Edward; Ferreira, Artur; Cordeiro, NereidaMicrofibers (MFs), the dominant form of microplastics in ecosystems, pose a significant environmental risk due to the inadequacy of existing wastewater treatments to remove them. Recognising the need to develop sus tainable solutions to tackle this environmental challenge, this research aimed to find an eco-friendly solution to the pervasive problem of MFs contaminating water bodies. Unused remnants of bacterial cellulose (BC) were ground to form a hydrogel-form of bacterial cellulose (BCH) and used as a potential bioflocculant for poly acrylonitrile MFs. The flocculation efficiency was evaluated across various operational and environmental fac tors, employing response surface methodology computational modelling to elucidate and model their impact on the process. The results revealed that the BCH:MFs ratio and mixing intensity were key factors in flocculation efficiency, with BCH resilient across a range of environmental conditions, achieving a 93.6 % average removal rate. The BCH's strong retention of MFs released only 8.3 % of the MFs, after a 24-hour wash, and the flocculation tests in contaminated wastewater and chlorinated water yielded 89.3 % and 86.1 % efficiency, respectively. Therefore, BCH presents a viable, sustainable, and effective approach for removing MFs from MFs-contaminated water, exhibiting exceptional flocculation performance and adaptability. This pioneer study using BCH as a bioflocculant for MFs removal sets a new standard in sustainable wastewater treatment, catalysing research on fibrous pollutant mitigation for environmental protection.
- Microalgal-based industry vs. microplastic pollution: Current knowledge and future perspectivesPublication . Mendonça, Ivana; Faria, Marisa; Rodrigues, Filipa; Cordeiro, NereidaMicroalgae can play a crucial role in the environment due to their efficient capture of CO2 and their potential as a solution for a carbon-negative economy. Water quality is critical for the success and profitability of microalgal based industries, and understanding their response to emergent pollutants, such as microplastics (MPs), is essential. Despite the published studies investigating the impact of MPs on microalgae, knowledge in this area remains limited. Most studies have mainly focused on microalgal growth, metabolite analysis, and photosyn thetic activity, with significant discrepancies in what is known about the impact on biomass yield. Recent studies show that the yield of biomass production depends on the levels of water contamination by MPs, making it necessary to reduce the contamination levels in the water. However, present technologies for extracting and purifying water from MPs are limited, and further research and technological advancements are required. One promising solution is the use of bio-based polymer materials, such as bacterial cellulose, which offer biode gradability, cost-effectiveness, and environmentally friendly detoxifying properties. This review summarises the current knowledge on MPs pollution and its impact on the viability and proliferation of microalgae-based industries, highlights the need for further research, and discusses the potential of bio-solutions for MPs removal in microalgae-based industries.
- Soluble extracellular polymeric substances and microplastics: exposure-response and circular reuse for removalPublication . Rodrigues, Filipa; Mendonça, Ivana; Faria, Marisa; Gomes, Ricardo; Gómez Pinchetti, Juan L.; Ferreira, Artur; Cordeiro, Nereida; cordeiro, nereidaMicroplastics (MPs) are pervasive in aquatic systems, threatening ecosystems, human health, and microalgal production. Soluble extracellular polymeric substances (S-EPS) can agglomerate particles and aid removal. This study examines S-EPS from the cyanobacterium Cyanocohniella rudolphia (BEA 0786B) to (i) model and optimise S-EPS production, (ii) assess production in water contaminated with polystyrene MPs (PS-MPs), and (iii) test S EPS as a bioflocculant for PS-MPs removal. Response surface methodology (RSM) defined a cost-lean operating window and predicted an optimum S-EPS titre of 113 mg/L at 7 days using 10 g/L nitrogen, 0.98 g/L phosphorus, and a biomass-to-medium ratio of 1:6.87 (w/v). Cultures were challenged with PS-MPs (50 μg/L and 5 mg/L) under static or aerated conditions, and at both exponential and stationary phases, and showed stimulated S-EPS synthesis with increases of up to 34%, depending on hydrodynamics and growth stage. Purified S-EPS were evaluated as a bioflocculant at 2 g/L PS-MPs to probe robustness and rate-limiting mechanisms and to delineate a conservative operating window. Maximum removal of 82% was achieved in freshwater at pH 3.5 with Fe3+ 0.05% (w/w), 25 ◦C, S-EPS dose 400 mg/L (S-EPS:PS-MPs 1:5, w/w), and 60 min flocculation. Zeta potential trends and microscopy support charge neutralisation/bridging as the dominant mechanism. Compatible with standard coagulation/flocculation units, the approach links cost-lean, cultivation-derived S-EPS (typically dis carded) to their reuse as a low-additive pretreatment for algal-cultivation intake waters (freshwater/low salinity), reducing reliance on synthetic coagulants and added salinity/metal-sludge burdens. Overall, C. rudolphia is a promising S-EPS producer, whose production is enhanced by exposure to PS-MPs, and its S-EPS acts as an efficient, bio-based flocculant for PS-MPs. The results support process designs to safeguard microalgal operations and to mitigate microplastic pollution in water. This work integrates RSM-optimised S-EPS produc tion, environmental-level exposure-response, and a high-load removal benchmark, enabling circular, low additive, drop-in pretreatment compatible with standard coagulation/flocculation units.