Malatjie Terrence S, Botha Tarryn L, Kuvarega Alex T, Madima Ntakadzeni, de Bruyn Karin, Tekere Memory, Nkambule Thabo T I, Mamba Bhekie B, Msagati Titus A M
Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida Science Campus, P/Bag X6, Roodepoort, 1709, South Africa.
College of Agriculture and Environmental Sciences Laboratories, University of South Africa, Science Campus, Florida, Johannesburg, 1710, South Africa.
Chemosphere. 2022 Mar;291(Pt 2):132891. doi: 10.1016/j.chemosphere.2021.132891. Epub 2021 Nov 17.
A wide range of semiconductor-assisted photocatalytic nanomaterials (NMs) are currently being considered and investigated as potential photocatalysts in water treatment. The applications of nanocomposites composed of nano-structured titania (nano-TiO) and multi-walled carbon nanotubes (MWCNTs) nanocomposites is growing markedly on account of enhanced photocatalytic efficiency. However, concurrent with the increasing production and application comes a serious concern of these emerging nanosystems about their potential risks in aquatic systems, and thereby potentially threatening aquatic organisms via toxic mechanisms that are, at present, poorly understood. In the present study, the lethal toxic effect and oxidative stress induced by TiO/MWCNT-CNF nanocomposite in freshwater Pseudokirchneriella subcapitata were assessed. The growth inhibition and sublethal oxidative stress produced by the nanocomposites were evaluated on green microalgae P. subcapitata after 3 days of exposure at 24 h intervals. Moreover, the nanocomposites were physicochemically characterized using a combination of analytical techniques (XRD, SEM/EDS, HRTEM, TGA, UV-Visible spectroscopy). Evaluation of the hybrid for the photocatalytic degradation of Acid Violet 7 dye indicated an enhanced dye removal performance for TiO/MWCNT-CNF (96.2%) compared to TiO (75.2%) after 2 h of visible light irradiation. While the nanocomposite showed good potential for the degradation of the azo dye, overall, the findings herein indicated that acute exposure of P. subcapitata to various concentrations of TiO/MWCNT-CNF nanocomposite may cause algal growth inhibition including undesirable sublethal oxidative stress effects. The findings of this study contribute to a better understanding of the potential hazards of the developing nanocomposites materials towards the nano-bioremediation materials to treat wastewaters.
目前，多种半导体辅助光催化纳米材料（NMs）正在被考虑和研究，作为水处理中潜在的光催化剂。由于光催化效率提高，由纳米结构二氧化钛（纳米TiO）和多壁碳纳米管（MWCNTs）组成的纳米复合材料的应用正在显著增加。然而，随着这些新兴纳米系统产量和应用的增加，人们严重担心它们在水生系统中的潜在风险，从而可能通过目前尚不清楚的毒性机制威胁水生生物。在本研究中，评估了TiO/MWCNT-CNF纳米复合材料对淡水斜生栅藻的致死毒性效应和氧化应激。在24小时间隔暴露3天后，对绿色微藻斜生栅藻评估纳米复合材料产生的生长抑制和亚致死氧化应激。此外，使用多种分析技术（XRD、SEM/EDS、HRTEM、TGA、紫外-可见光谱）对纳米复合材料进行了物理化学表征。对该杂化物光催化降解酸性紫7染料的评估表明，与TiO（75.2%）相比，TiO/MWCNT-CNF在可见光照射2小时后对染料的去除性能有所提高（96.2%）。虽然纳米复合材料显示出对偶氮染料有良好的降解潜力，但总体而言，本文的研究结果表明，斜生栅藻急性暴露于各种浓度的TiO/MWCNT-CNF纳米复合材料可能会导致藻类生长抑制，包括不良的亚致死氧化应激效应。本研究结果有助于更好地理解新型纳米复合材料对用于处理废水的纳米生物修复材料的潜在危害。
