This work aimed to prepare nanocellulose-based Pickering emulsions using cinnamon essential oil. Different formulations were investigated by varying the preparation time, homogenization speed, oil and nanocellulose concentration, and morphology. The emulsions were first characterized by droplet size, morphologies, and storage stability. The Design of Experiments (DoE) was used to evaluate the parameter’s effects on the emulsions’ stability, and the emulsions with optimum particle size and stability were evaluated by antimicrobial activity. The more stable emulsions required higher energy in the system to obtain efficient emulsification. The cellulose nanocrystal (CNC) emulsions showed a 30% oil volume as a constant to obtain a low creaming index (34.4% and 42.8%) and zeta potential values around −29 mV, indicating an electrostatic stabilization. The cellulose nanofiber (CNF) emulsions showed 100% stability after a month using a 20% oil volume as a constant and Zeta potential values around −15 mV, indicating a steric stabilization. CNF-emulsions’ inhibition halos for Bacilus subtilis were 30.1 ± 3.7% smaller than those found in CNC-emulsions (65 ± 2.9 mm), while Pseudomonasaeruginosas almost do not present differences in the inhibition halos. These results suggest that the nanocellulose morphology may promote a regulation on the EO migration to the medium, as well that this migration ratio does not affect the bacteria.

A critical issue in active packaging development using essential oils (EOs) is the high concentrations of these to obtain antimicrobial activity in the films. Therefore, this work was carried out to develop nanocomposite films, pursuing a potential minimal EO concentration with antimicrobial effectiveness, which could be applied in packaging. The films were prepared using lowdensity polyethylene (LDPE) containing a hybrid of montmorillonite and essential oil (MMT-EO), using two different EOs, carvacrol and eugenol, with 2 and 6 wt% oil concentration. The films were obtained in three steps. In the first (hybrid production), mixtures of montmorillonite clay with eugenol or carvacrol EOs were prepared. In the second (hybrid incorporation), these hybrids were incorporated into LDPE, obtaining LDPE/MMT-EO nanocomposites. Finally, a thermoforming process prepared the polymeric films. The samples were characterized by XRD and mechanical, contact angle and antimicrobial properties. The XRD results showed higher crystallinity for LDPE/MMT-EO compared to LDPE. The MMT was exfoliated into lamella forms, which could work as a physical barrier, reducing the oil diffusion. Besides, the contact angle results showed an increase in the hydrophilicity with the addition of the hybrids, which improved the antimicrobial action of the film. LDPE/MMT-E3 (1 wt% MMT and 2 wt% eugenol) showed the highest crystallinity, oil diffusivity, and mechanical and antimicrobial properties. These samples presented a reduction of a 2 log count of Staphylococcus aureus. The sum of the structural and antimicrobial properties of the LDPE/MMT-E3 film indicates its potential for food packaging.

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Submerged Membranes Bioreactors (SMBR) are an established technology for wastewater treatment for water recovery and reuse. However, its routine application is still compromised by the high energy consumption to overcome the fouling effect. This study evaluated the effect of aluminum sulfate and cationic polymer in the orthophosphate removal and sludge filterability improvement in the mixed liquor of a SMBR pilot system. Parameters such as coagulant concentration, filtration time, extracellular polymeric substances (EPS) reduction and orthophosphate removal were evaluated by using a jar-test and a stirred cell. As results, aluminum sulfate and polymer additions improved the filtration index (FI 30) from 25% to 32 %, for both chemicals. Timeto-filter (TTF) results evidenced a positive and significant correlation between aluminum sulfate dosage and colloidal EPS reduction.

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