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A widely used disinfectant worldwide, chloroxylenol, has been related to eco-toxicological threats in water environments on account of its relatively high chemical stability and large consumption. Researchers on the School of Engineering of the Hong Kong University of Science and Technology (HKUST) have discovered a promising alternative often known as 2,6-dichlorobenzoquinone (2,6-DCQ), which works more effectively in combating certain common bacteria, fungi and viruses, and could be rapidly degraded and detoxified in receiving waters.
This groundbreaking study is led by Prof. ZHANG Xiangru from HKUST’s Department of Civil and Environmental Engineering, who has been studying disinfection byproducts (DBPs) for a few years. Throughout the pandemic outbreak, Prof. Zhang noticed that chloroxylenol is structurally much like some halo-phenolic DBPs previously discovered by his team, which have been shown to rapidly degrade by solar photolysis.
Inspired by the structural property and degradability of some halo-phenolic DBPs, the research team managed to pick an efficient broad-spectrum disinfectant from the DBPs that could be rapidly degraded and detoxified in receiving waters. The research team tested the efficacy of 10 different DBPs in inactivating various pathogens, including E. coli (a style of bacteria related to colorectal cancer), Staphylococcus aureus (bacteria), Candida albicans (fungi), and bacteriophage MS2 (viruses). They found that 2,6-DCQ was 9 to 22 times simpler than chloroxylenol in inactivating these bacteria, fungi, and viruses.
Moreover, they found that the developmental toxicity of two,6-DCQ to marine polychaete embryos decreased quickly on account of its rapid degradation via hydrolysis in receiving seawater, even within the absence of sunlight. Two days after being discharged into seawater, 2,6-DCQ exhibited 31 times lower developmental toxicity in comparison with chloroxylenol.
“We discovered that the chosen DBP exhibited substantially stronger antimicrobial efficacy than chloroxylenol and that its concentration and associated developmental toxicity in receiving seawater decreased rapidly, even in darkness,” Prof. Zhang said.
He emphasized the pressing need for simpler and eco-friendly disinfectants, particularly within the wake of the COVID-19 pandemic. “Chloroxylenol has been often detected in aquatic environments; as an illustration, its concentration has reached as much as 10.6 μg/L in river water in Hong Kong. Toxicological studies have reported adversarial effects of chloroxylenol on aquatic organisms, including endocrine disruption, embryonic mortality, and malformations. Chronic exposure to chloroxylenol at environmental concentrations (~4.2 μg/L) could cause gene regulation and morphological changes in rainbow trout.”
The team’s discovery of two,6-DCQ as a promising alternative is a crucial step towards addressing this global need. The outcomes suggest that 2,6-DCQ could also be used as a disinfectant on a big selection of occasions, including personal care products (equivalent to hand cleansers, detergent, and soap), paint, textiles, metal working fluids, medical scrubs, in addition to sanitation for households, food processing equipment, surgical instruments, and public places.
“This progressive study not only provides a possible solution to higher support human biosecurity while prioritizing environmental sustainability, but in addition carries significant implications for the event of green disinfectants and other green industrial products by exploiting the marginally alkaline nature of seawater. For instance, scientists may design and develop other industrial products equivalent to pesticides, pharmaceuticals, and private care products that could be rapidly degraded by hydrolysis in receiving seawater,” Prof. Zhang elaborated.
Their findings have been published within the first-rate multidisciplinary journal Nature Communications. The research team included Dr. HAN Jiarui, currently a Research Assistant Professor at HKUST, and Dr. LI Wanxin, currently an Assistant Professor at Xi’an Jiaotong-Liverpool University. They’re each PhD graduates from HKUST’s Department of Civil and Environmental Engineering and were postdoctoral fellows in Prof. Zhang’s group in the course of the study.
Looking ahead, Prof. Zhang plans to explore the relationships between disinfection efficiency and degradability of halophenols with their molecular fingerprints through machine learning. He hopes future investigations will make clear the further development of optimal disinfectants.
