T. Zhang,H. Yu,J. Li,H. Song,S. Wang,Z. Zhang,S. Chen
Water pollution by pathogenic bacteria is a major threat to human health, and less-than-ideal disinfection and antimicrobial strategies have been developed to address waterborne pathogens. A green light–triggered photocatalytic antimicrobial rose bengal (RB)–modified cotton fabric (CF) (RB-CF) was prepared for wastewater disinfection by covalently binding RB to a CF surface. The antimicrobial rates of RB-CF against gram-positive Staphylococcus aureus and gram-negative Escherichia coli were both greater than 99.99% due to the generation of singlet oxygen that inactivates microbes under green light irradiation. Most importantly, RB-CF exhibited high stability, negligible cytotoxicity, and no release of free RB during the photocatalytic process, which was the key to its long-term antimicrobial activity and use security. Its long-term antimicrobial activity was further verified by the repeated photocatalytic disinfection; more than 99.99% of bacteria were inactivated even after five cycles. Therefore, this work may offer a potential avenue to develop low-cost, non-toxic, and durable antimicrobial fabrics with great potential for industrial and health-care applications, including but not limited to water purification , wastewater disinfection, masks, and protective clothing.
Qian Lei,Junjian Zheng,Jinxing Ma,Xueye Wang,Zhichao Wu,Zhiwei Wang
An electrochemical dynamic membrane filtration (EDMF) system for simultaneous solid-liquid separation (also protecting electrodes against fouling) and sewage disinfection was developed. At a low voltage of 2.5 V, efficient disinfection performance was achieved in the EDMF, with ~100% log removal efficiency (no detectable bacteria in the effluent). Results also demonstrated that the EDMF system, operated at membrane flux of 100 L/(m 2 h), could maintain long-lasting bacterial disinfection efficiency of real wastewater (~100% log removal) in continuous flow tests. Transmembrane pressure (TMP) increased from 0.8 kPa to 22 kPa within 80 d (one operation cycle), and cleaning of EDMF could effectively restore TMP and biocidal behaviors for subsequent filtration cycles. In contrast, without dynamic membrane, the disinfection efficiency was decreased from initial ~100% log removal (with no detectable live bacteria) to ~44.4% log removal within 7 d. Reactive oxygen species (ROS)-mediated oxidation was responsible for bacteria disinfection in the EDMF, and HO• and H 2 O 2 generated in this system played a dominant role, causing damage to cell membranes and K + leakage from cytosol. Moreover, catalase and superoxide dismutase for intracellular ROS attenuation were inhibited, resulting in the increase of intracellular oxidative stress and thus high-efficient disinfection. These results highlight the potential of EDMF system to be used for wastewater treatment and disinfection.
Wanhe Qi,Songming Zhu,Abubakar Shitu,Zhangying Ye,Dezhao Liu
Under Minamata Convention restrictions, mercury-free UV source was in need for ultraviolet disinfection in recirculating aquaculture systems (RAS). Ultraviolet emitting diodes (UV-LEDs) seemed a potential mercury-free UV source and had gained increasing attention in water disinfection. In this study, a mercury-free UVA-LED and low concentration peroxymonosulfate (PMS) combination was proposed for E. coli (CGMCC 1.3373) inactivation and real RAS wastewater disinfection. Results showed that UVA-LED and low concentration PMS combination enhanced E. coli inactivation over UVA-LED alone. A synergistic effect on E. coli inactivation with synergy factor of 58.7 % was found when combining UVA-LED irradiation with 1 mg/L PMS. Kinetic rate constant increased by up to 139 % by UVA-LED and 1 mg/L PMS combination, which implied the required UV fluence to 2-log E. coli inactivation was saved up to 42 %. Also, UVA-LED and 1 mg/L PMS combination showed disinfection potential for real RAS wastewater treatment. Mechanism study revealed that the Cl − , · OH and SO 4 ·- played important roles and · OH was dominant radical in saline solution by UVA-LED/PMS process compared to that in phosphate buffered solution(PBS). The E. coli inactivation was caused by UVA-LED irradiation and reactive species generated in UVA-LED/PMS system. Our study provided a potential strategy to introduce the mercury-free UV-LED into RAS and a better understanding of UVA-LED/PMS disinfection process.
危险品化学品经营许可证（带存储）