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May 20, 2024

염소의 효능

npj Clean Water 4권, 기사 번호: 48(2021) 이 기사 인용 6666 액세스 7 인용 8 Altmetric Metrics 세부 정보 염소 용액은 생물학적 생산에 광범위하게 사용됩니다.

npj Clean Water 4권, 기사 번호: 48 (2021) 이 기사 인용

6666 액세스

7 인용

8 알트메트릭

측정항목 세부정보

염소 용액은 생물학적으로 안전한 식수 생산에 광범위하게 사용됩니다. POU(사용 지점) 식수 처리 시스템의 기능은 중앙 집중식 처리 시스템과 유통 네트워크가 실용적이지 않은 위치에서 관심을 얻었습니다. 본 연구에서는 POU 식수 응용 분야에 사용하기 위한 세 가지 염소 기반 소독제(차아염소산염 이온[OCl-], 차아염소산[HOCl] 및 전기화학적으로 활성화된 용액[ECAS])의 항균 및 항생물막 활성을 조사했습니다. 상대 항균 활성은 대장균을 사용하여 살균 현탁 분석(BS EN 1040 및 BS EN 1276) 내에서 비교되었습니다. 질병통제센터(CDC) 생물막 반응기 내에서 확립된 고착성 녹농균을 활용하여 항 생물막 활성을 비교했습니다. HOCl은 유기 부하(소 혈청 알부민)가 있는 경우 >50 mg L-1 유리 염소에서 플랑크톤 대장균에 대해 가장 큰 항균 활성을 나타냈습니다. 그러나 ECAS는 ≥50 mg L−1 유리 염소에서 P. aeruginosa 생물막에 대해 OCl- 및 HOCl에 비해 상당히 더 큰 항생물막 활성을 나타냈습니다. 이러한 증거에 따르면 HOCl이 주요 염소종(HOCl 및 ECAS)인 소독제는 POU 식수 적용에 적합한 대체 염소 기반 소독제가 될 것입니다.

인간 질병의 주요 원인은 생물학적으로 오염된 물을 섭취하는 것입니다1. 이는 특히 저소득(즉, 1인당 국민총소득(GNI)이 1025달러 미만) 및 최빈개도국(지속 가능한 발전에 대한 심각한 구조적 장애에 직면한 46개 저소득 국가)과 관련이 있습니다. 기본적인 위생 서비스를 이용할 수 있습니다. 2. 이는 생물학적으로 안전한 물의 생산과 공급을 보장하기 위해 주로 중앙 집중식 식수 처리 시스템을 활용하는 중상위 국가(1인당 GNI $4036~$12,475) 및 고소득 국가(1인당 GNI > $12,476)와 대조적입니다3. 식수 소독의 주요 역할은 병원성 미생물을 제어하고 처리된 물이 생물학적으로 마시기에 안전한지 확인하는 것입니다. 차아염소산나트륨[NaOCl] 형태의 염소는 저렴하고 효과적인 항균 특성으로 인해 가장 널리 사용되는 소독제입니다4. 재분배 네트워크 내에 잔류 염소(0.5–5 mg L−1)가 존재하면 미생물 재성장이 제한되어 물 공급 시점에서 생물학적으로 안전한 물을 유지하는 데 도움이 됩니다3. 대장균, 총대장균군, 장구균, 클로스트리디움 퍼핑젠스3,5 등 배설물 존재를 추정하는 지표 유기체를 모니터링하여 소독 처리 과정의 효율성을 보장합니다. 처리된 물에 있는 이러한 지표 유기체에 대한 권장 한계는 잠재적인 병원성으로 인해 0 CFU 100 mL−1입니다3,5. 불행하게도 염소 소독제를 사용하면 트리할로메탄8 및 할로아세트산9과 같은 소독 부산물[DBP]6,7이 형성됩니다. 이러한 부산물은 돌연변이 유발성 및 발암성을 나타내는 것으로 알려져 있으므로10 매우 바람직하지 않습니다.

Point-of-use [POU] drinking water treatment systems do not require distribution networks and therefore negate the need to maintain residual chlorine levels. The World Health Organization recommends free chlorine concentrations of between 0.2 and 0.5 mg L−1 at point of delivery and use3. The use of conventional chlorine-based disinfectants, such as hypochlorite (OCl-), within POU water disinfection requires the storage and transportation of hazardous chemicals and can also cause the formation of harmful DBPs and the deterioration of taste and odour11. Ultraviolet and ozone are well established as disinfection technologies within both decentralised/POU12,13 and large scale drinking water treatment14,3.3.CO;2-1." href="/articles/s41545-021-00139-w#ref-CR15" id="ref-link-section-d367130989e520"15, but an added benefit of implementing electrochemcially activated solutions [ECAS] is it has capability to be used externally to water treatment systems as part of food production16,17 or in healthcare settings18,19. A limited number of studies have compared ECAS against commonly used chlorine agents for decentralised disinfection applications20,21. Although these preliminary studies were promising, neither study reported the pH of the ECAS studied or their effectiveness against biofilms./p>95%), and dissolved chlorine [Cl2] (<5%)25,26. Additional metastable antimicrobial species including; OH-, O3, H2O2 and O2- are also theorised to be generated although there lifetime and activity within active solutions is debated27,28. The antimicrobial properties of ECAS result from a combination of HOCl and the metastable species that give rise to the observed high ORP values. The mode of action of such solutions is then physical rupture of the inner and outer cell membranes19,29, leading to disruption and failure of microbial functionality, such as energy generation mechanisms23./p>5-log reduction) and there was no significant difference between the three disinfectants, whereby HOCl resulted in a complete log reduction, for OCl- a log reduction of 7.871 ± 0.74 log10 CFU mL−1 was achieved whilst ECAS achieved a 6.806 ± 1.09 log10 CFU mL−1 reduction. At 50 mg L−1 FC, OCl- did not achieve the required 5-log reduction (4.531 ± 0.15 log10 CFU mL−1), resulting in significantly lower antimicrobial activity compared to both HOCl and ECAS (p < 0.0001), whereby there was no significant difference between HOCl and ECAS treatment (p > 0.05). At the lowest FC concentration tested (25 mg L−1) ECAS was the only disinfectant to reduce the bacterial load ≥5 log10 CFU mL−1 (Fig. 2), resulting in a 6.077 ± 1.441 log10 CFU mL−1 log reduction. The log reductions obtained for OCl- and HOCl treatment were both significantly less than ECAS (p < 0.001), whereby HOCl resulted in a 3.207 ± 0.505 log10 CFU mL−1 log reduction, which was significantly greater than the 1.945 ± 0.222 log10 CFU mL−1 log reduction exhibited by OCl- (p = 0.0011). The 5-log reduction CT values for OCl-, HOCl and ECAS with a low organic load demonstrated that NaOCl exhibited the highest CT value (88.96 mg min L−1), followed by HOCl (34.78 mg min L−1) and then ECAS (20.94 mg min L−1)./p> 0.05). However, ECAS resulted in the greatest log reduction (1.606 ± 0.954 log10 CFU mL−1), followed by HOCl (0.978 ± 0.202 log10 CFU mL−1) and OCl- (0.025 ± 0.004 log10 CFU mL−1). The organic loading tested under dirty conditions does not represent concentrations expected within POU drinking water systems. However, results highlight the need to reduce organics present to ensure sufficient antimicrobial activity throughout disinfection stages of drinking water treatment./p> 0.05). In fact, there was no significant reduction in biofilm density between 0 (control) and 5 mg L−1 FC (p > 0.05) for any test disinfectant. Overall, the results demonstrate a dose-response of increasing antimicrobial efficacy with increasing FC concentrations. Interestingly, for ECAS the greatest increase in antimicrobial activity (p = 0.009) occurred at ≥25 mg L−1 FC, whereas the greatest increases for HOCl and OCl- were observed between 0 and 25 mg L−1 (p < 0.0001)./p>25 mg L−1 (i.e. 50, 100, 150 mg L−1). Interestingly, there was no significant difference in the antimicrobial activity exhibited by ECAS at an FC concentration of 25 mg L−1 in either the presence or absence of low organic loading (clean BSA conditions). This shows that low concentrations of organic matter do not unduly interfere with the mechanism of action for ECAS under these experimental conditions. ECAS exhibits very high ORP value (>+1100 mV), due to both reactive chlorine and oxygen species, which in turn drives rapid oxidation reactions. However, the presence of higher concentrations of organic matter will ultimately reduce the ORP through oxidation-reduction reactions50, contributing to a resultant reduction in antimicrobial activity of ECAS, as has been previously observed50,51. Interestingly, previous work by Robinson et al. in 201352 demonstrated that antimicrobial activity of ECAS could be maintained when stored for a 398 day period at 4 °C in the dark, despite showing no detectable FC after 277 days (e.g. < 0.01 mg L−1). This demonstrates the importance of the additional antimicrobial species, other than those that are chlorine derived, contributing to an increased antimicrobial activity. Thus, helping explain the greater antimicrobial activity of ECAS at a FC of 25 mg L−1 in the presence of clean BSA conditions when compared to equivalent HOCl and NaOCl solutions. Further increasing the organic loading of BSA (3.0 g L−1; dirty BSA conditions) within the bactericidal assay greatly reduced the antimicrobial activity of OCl- and ECAS at all FC concentrations tested. In comparison the antimicrobial activity of HOCl was not significantly reduced at FC concentrations >25 mg L−1. Therefore, it is clear that HOCl produced via the dissolution of NaDCC demonstrates a greater antimicrobial activity against planktonic bacteria under dirty BSA conditions. Chemically derived HOCl is more stable than electrochemically generated HOCl solutions, as they do not possess metastable antimicrobial species, that form at the anodic surface53. Chemically derived HOCl also degrades at a slower rate when exposed to sunlight (UV)54, in comparison to electrochemically generated HOCl which degrade at an increased rate55. This highlights the importance of selecting the most appropriate disinfectant for use in POU treatment systems. For example, in instances where filtration or removal of organic matter from bulk water is not standard practice or is difficult, HOCl would provide greater antimicrobial efficacy, compared to NaOCl or ECAS./p>3.3.CO;2-1./p>