Ghafoor Samina, Hussain Syed Zajif, Waseem Sadia, Arshad Salman Noshear
Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences Lahore 54792 Pakistan
Institute of Chemistry, University of the Punjab P. O. Box 54590 Lahore Pakistan.
RSC Adv. 2018 Jun 4;8(36):20354-20362. doi: 10.1039/c8ra01237g. eCollection 2018 May 30.
We report the photosensitization of electrospun titania nanofibers, with a mean diameter of 195 nm, by low bandgap silver sulfide nanoparticles of 11-23 nm mean size with the aim of treating heavy metal ions and pathogenic bacteria simultaneously under simulated solar light irradiation. The 17 nm AgS/TiO nanofibers showed 90% photocatalytic reduction of Cr(vi) at pH of 3 with a pseudo-first order rate constant of 0.016 min which is significantly better than the previously reported for Ag-AgS/TiO composite particles. The antibacterial capability of the AgS/TiO nanofibers was evaluated photo-disinfection of the Gram-positive and Gram-negative bacterial strains. The smallest sized 11 nm AgS/TiO nanofiber showed the best bactericidal efficiency of 100% and 90.6% against Gram-negative and Gram-positive after 1 h of irradiation, respectively, whereas, only 50% and 41% were found to be inactivated in dark. Furthermore, a UV-O treatment of the 11 nm AgS/TiO nanofibers remarkably enhanced the antibacterial activity where 89% and 81% were inactivated in just 10 min of the irradiation. Enhanced photocatalytic activity is attributed to the efficient charge separation and transfer and reduced electron-hole recombination induced by the effective heterojunction formation between TiO and the optimally sized AgS nanoparticles. The disinfection nature of the AgS nanoparticles, role of the generated hydroxyl species under irradiation, and the cell wall damage mechanism is also discussed. This study demonstrates the potential use of these multifunctional composite TiO nanofibers for water remediation.
我们报道了平均直径为195纳米的电纺二氧化钛纳米纤维被平均尺寸为11 - 23纳米的低带隙硫化银纳米颗粒光敏化，目的是在模拟太阳光照射下同时处理重金属离子和致病细菌。17纳米的AgS/TiO纳米纤维在pH值为3时对Cr(Ⅵ)的光催化还原率达90%，其准一级反应速率常数为0.016分钟，这明显优于先前报道的Ag - AgS/TiO复合颗粒。通过对革兰氏阳性和革兰氏阴性细菌菌株进行光消毒来评估AgS/TiO纳米纤维的抗菌能力。尺寸最小的11纳米AgS/TiO纳米纤维在照射1小时后，对革兰氏阴性菌和革兰氏阳性菌的杀菌效率分别达到最佳的100%和90.6%，而在黑暗中仅50%和41%的细菌失活。此外，对11纳米AgS/TiO纳米纤维进行UV - O处理显著增强了抗菌活性，在仅10分钟的照射后就有89%和81%的细菌失活。光催化活性增强归因于TiO与最佳尺寸的AgS纳米颗粒之间有效异质结的形成所导致的有效电荷分离和转移以及电子 - 空穴复合的减少。还讨论了AgS纳米颗粒的消毒性质、照射下产生的羟基物种的作用以及细胞壁损伤机制。这项研究证明了这些多功能复合TiO纳米纤维在水修复方面的潜在用途。
