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Publication
Solving urban water microplastics with bacterial cellulose hydrogels: leveraging predictive computational models
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Advisor(s)
Abstract(s)
The prevalence of microplastics (MPs) in both urban and aquatic ecosystems is concerning, with wastewater
treatment plants being considered one of the major sources of the issue. As the focus on developing sustainable
solutions increases, unused remnants from bacterial cellulose (BC) membranes were ground to form BC hydrogels
as potential bioflocculants of MPs. The influence of operational parameters such as BC:MPs ratio, hydrogel
grinding, immersion and mixing time, temperature, pH, ionic strength, and metal cations on MPs flocculation
and dispersion were evaluated. A response surface methodology based on experimental data sets was computed
to understand how these parameters influence the flocculation process. Further, both the BC hydrogel and the
hetero-aggregation of MPs were characterised by UV–Vis, ATR-FTIR, IGC, water uptake assays, fluorescence, and
scanning electron microscopy. These highlights that the BC hydrogel would be fully effective at hetero aggregating MPs in naturally-occurring concentrations, thereby not constituting a limiting performance factor
for MPs’ optimal flocculation and aggregation. Even considering exceptionally high concentrations of MPs (2 g/
L) that far exceed naturally-occurring concentrations, the BC hydrogel was shown to have elevated MPs floc culation activity (reaching 88.6%: 1.77 g/L). The computation of bioflocculation activity showed high reliability
in predicting flocculation performance, unveiling that the BC:MPs ratio and grinding times were the most critical
variables modulating flocculation rates. Also, short exposure times (5 min) were sufficient to drive robust particle
aggregation. The microporous nature of the hydrogel revealed by electron microscopy is the likely driver of
strong MPs bioflocculant activity, far outperforming dispersive commercial bioflocculants like xanthan gum and alginate. This pilot study provides convincing evidence that even BC remainings can be used to produce highly
potent and circular bioflocculators of MPs, with prospective application in the wastewater treatment industry
Description
Keywords
Bacterial cellulose Biopolymer Microplastics Flocculation Bioremediation . Faculdade de Ciências Exatas e da Engenharia
Citation
Publisher
Elsevier