32 research outputs found

    Nanofiltration combined with ozone-based processes for the removal of antineoplastic drugs from wastewater effluents

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    Over the past years, there has been an increasing concern about the occurrence of antineoplastic drugs in water bodies. The incomplete removal of these pharmaceuticals from wastewaters has been confirmed by several scientists, making it urgent to find a reliable technique or a combination of techniques capable to produce clean and safe water. In this work, the combination of nanofiltration and ozone (O3)-based processes (NF + O3, NF + O3/H2O2 and NF + O3/H2O2/UVA) was studied aiming to produce clean water from wastewater treatment plant (WWTP) secondary effluents to be safely discharged into water bodies, reused in daily practices such as aquaculture activities or for recharging aquifers used as abstraction sources for drinking water production. Nanofiltration was performed in a pilot-scale unit and O3-based processes in a continuous-flow column. The peroxone process (O3/H2O2) was considered the most promising technology to be coupled to nanofiltration, all the target pharmaceuticals being removed at an extent higher than 98% from WWTP secondary effluents, with a DOC reduction up to 92%. The applicability of the clean water stream for recharging aquifers used as abstraction sources for drinking water production was supported by a risk assessment approach, regarding the final concentrations of the target pharmaceuticals. Moreover, the toxicity of the nanofiltration retentate, a polluted stream generated from the nanofiltration system, was greatly decreased after the application of the peroxone process, which evidences the positive impact on the environment of implementing a NF + O3/H2O2 process

    How do Graphene Composite Surfaces Affect the Development and Structure of Marine Cyanobacterial Biofilms?

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    The progress of nanotechnology has prompted the development of novel marine antifouling coatings. In this study, the influence of a pristine graphene nanoplatelet (GNP)-modified surface in cyanobacterial biofilm formation was evaluated over a long-term assay using an in vitro platform which mimics the hydrodynamic conditions that prevail in real marine environments. Surface characterization by Optical Profilometry and Scanning Electron Microscopy has shown that the main difference between GNP incorporated into a commercially used epoxy resin (GNP composite) and both control surfaces (glass and epoxy resin) was related to roughness and topography, where the GNP composite had a roughness value about 1000 times higher than control surfaces. The results showed that, after 7 weeks, the GNP composite reduced the biofilm wet weight (by 44%), biofilm thickness (by 54%), biovolume (by 82%), and surface coverage (by 64%) of cyanobacterial biofilms compared to the epoxy resin. Likewise, the GNP-modified surface delayed cyanobacterial biofilm development, modulated biofilm structure to a less porous arrangement over time, and showed a higher antifouling effect at the biofilm maturation stage. Overall, this nanocomposite seems to have the potential to be used as a long-term antifouling material in marine applications. Moreover, this multifactorial study was crucial to understanding the interactions between surface properties and cyanobacterial biofilm development and architecture over time

    Incidence of Maxillary Sinusitis Following Le Fort I Osteotomy: Clinical, Radiographic, and Endoscopic Study

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    Purpose: The correction of maxillomandibular deformities may require maxillary osteotomy procedures that usually present low rates of postoperative complications, such as maxillary sinusitis. The present study evaluated the incidence of maxillary sinusitis after Le Fort I osteotomy in 21 adult patients who underwent maxillary surgery (Le Fort I osteotomy) or bimaxillary surgery (Le Fort I osteotomy plus sagittal mandibular osteotomies) for correction of dentofacial deformities. Patients and Methods: Verification of the presence of maxillary sinusitis was assessed through a brief questionnaire, x-rays (Waters views), and nasal endoscopy before surgery and 6 to 8 months after surgery. Results: Analysis of results showed an incidence of 4.76% of maxillary sinusitis as a postoperative complication in the studied population. Conclusion: Symptomatic patients with a positive radiographic finding or an increased risk for postoperative sinusitis will benefit from endoscopic evaluation to aid in treatment planning and follow-up. 0 2011 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:346351, 201169234635
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