Fabrication of Fe/ZnO Composite Nanosheets by Nanofibrillated Cellulose as Soft Template and Photocatalytic Degradation for Tetracycline

Sustainable photocatalytic degradation of antibiotic norfloxacin using microfibrillated cellulose@ZnO nanocomposites

Antibiotics from the fluoroquinolone class, such as norfloxacin (NOR), are emerging contaminants with significant environmental and human health impacts. Their safe degradation from water remains a global challenge due to their persistence, lack of biodegradability, and ability to induce resistant bacteria. To the best of our knowledge, for the first time, this work reports the development of highly efficient photocatalytic degradation of NOR using environmentally friendly microfibrillated cellulose@ZnO (MFC@ZnO) photocatalysts. Immobilization of ZnO nanoparticles on MFC has played a crucial role in controlling the particle dimensions of ZnO, keeping them around tens of nanometers. The impact of radiation (UV-A, UV-C, and simulated solar light) on NOR degradation efficiency was investigated. Additionally, the effects of catalyst dosage (0.125-0.5 g L⁻1), NOR concentration (5-20 mg L⁻1), and degradation pH (pH = 5 to 10) were investigated. LC-MS was used to identify degradation intermediates. The results showed over 94% degradation in 40 min via UV-Vis and 90% in 10 min via HPLC, and recyclability tests indicated MFC0.1@ZnO composites can maintain over 95% NOR degradation efficiency after five consecutive 60-min cycles. The highest NOR degradation efficiency was achieved in a significantly reduced time among metal oxide semiconductors (MOS)-based photocatalysts, thus opening new perspectives for the development of eco-friendly photocatalysts, especially towards emerging pollutant degradation.

Nanocellulose for Sustainable Water Purification

Nanocelluloses (NC) are nature-based sustainable biomaterials, which not only possess cellulosic properties but also have the important hallmarks of nanomaterials, such as large surface area, versatile reactive sites or functionalities, and scaffolding stability to host inorganic nanoparticles. This class of nanomaterials offers new opportunities for a broad spectrum of applications for clean water production that were once thought impractical. This Review covers substantial discussions based on evaluative judgments of the recent literature and technical advancements in the fields of coagulation/flocculation, adsorption, photocatalysis, and membrane filtration for water decontamination through proper understanding of fundamental knowledge of NC, such as purity, crystallinity, surface chemistry and charge, suspension rheology, morphology, mechanical properties, and film stability. To supplement these, discussions on low-cost and scalable NC extraction, new characterizations including solution small-angle X-ray scattering evaluation, and structure-property relationships of NC are also reviewed. Identifying knowledge gaps and drawing perspectives could generate guidance to overcome uncertainties associated with the adaptation of NC-enabled water purification technologies. Furthermore, the topics of simultaneous removal of multipollutants disposal and proper handling of post/spent NC are discussed. We believe NC-enabled remediation nanomaterials can be integrated into a broad range of water treatments, greatly improving the cost-effectiveness and sustainability of water purification.

Sonocatalytic degradation of tetracycline antibiotic using zinc oxide nanostructures loaded on nano-cellulose from waste straw as nanosonocatalyst

The aim of the present investigation was the combination of ZnO nanostructures with nano-cellulose (NC) for the efficient degradation of tetracycline (TC) antibiotic under ultrasonic irradiation. The removal efficiency of 12.8% was obtained by the sole use of ultrasound (US), while the removal efficiency increased up to 70% by the US/ZnO treatment process. Due to the integration of ZnO nanostructures with NC, the removal efficiency of 87.6% was obtained within 45 min. The removal efficiency substantially decreased in the presence of tert-butyl alcohol (more than 25% reduction), indicating that ^radOH-mediation oxidation is responsible for the degradation of TC molecules. Peroxymonosulfate (PMS) led to the most enhancing effect on the removal of TC among percarbonate, persulfate and periodate ions. The addition of PMS caused the degradation efficiency of 96.4% within the short contact time of 15 min. The bio-toxicity examination on the basis of inhibition test conducted on activated sludge revealed diminishing the oxygen consumption inhibition percent [I_OUR (%)] from 33.6 to 22.1% during the US/ZnO/NC process. Consequently, the utilization of the US/ZnO/NC process can convert TC molecules to less toxic compounds. However, longer reaction time is required for complete conversion into non-toxic substances.