WATER RESEARCH
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2024
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IF 11.4
Qing Bai,Qian-Yuan Wu,Bei Ye,Yun-Peng Wu,Ju-Won Lee,Min-Yong Lee,Wen-Long Wang
The KrCl* excimer lamp (UV222) is a promising alternative of low-pressure mercury lamp (UV254) for UV-based advanced oxidation processes (UV-AOPs), because it is mercury-free and has high photon energy. But there lacks a comprehensive assessment of UV222-AOPs based on different radicals. Herein, the properties (e.g., oxidant decay and innate radical quantum yield), and micropollutant degradation, were comprehensively studied for representative oxidants (i.e., hydrogen peroxide, persulfate (PDS), monochloramine, and free active chlorine (FAC)) under UV222 irradiation. UV222 outperformed UV254 for the activation of oxidants with 2.6-14.4 times fluence-based kinetic constant ( k F ). The main reason of enhanced activation varied with oxidants: higher UV absorption for H 2 O 2 , higher innate quantum yield for monochloramine and FAC, and both reasons for PDS. Overall, PDS was the optimum oxidant under UV222 for the degradation of 8 representative micropollutants because of effective promotion of radical formation, as confirmed by radical competitive kinetics and modeling simulations. In real water, UV222/PDS still show advantages than UV254/PDS in terms of micropollutant elimination efficacy (3.2-5.3 times) and energy consumption (33.9%-57.6% lower) though it was more inhibited by water constituents via competing for UV222 photons. This study fills gaps in photochemistry knowledge and will facilitate engineering practice of UV222-AOPs.
研究领域:
环境科学
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化学工程
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光化学
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PubMed
高影响因子
DENTAL MATERIALS
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2024
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IF 4.6
Xuedong Bai,Mengxiao Xu,Shixin Jin,Edmond H.N. Pow,Yanning Chen,James K.H. Tsoi
Objectives To proof the feasibility of direct colour printing on 3Y-TZP using 222 nm UV-C through investigating the degree and durability of the colour changes, and testifying whether surface, mechanical and biological properties are influenced by the treatment. Methods 222 nm UV-C light (Irradiance: 1.870 mW/cm 2 ) was used to treat 3Y-TZP for durations from 15 min to 24 h. ΔE*, TP, crystalline structure, surface morphology, S a , BFS and biological activities were investigated before and after irradiation. SPSS 28.0 was used for statistical analysis (α = 0.05). Results 222 nm UV-C irradiation was capable to shade white 3Y-TZP into tooth colours. With the increase of ΔE*, TP decreased, such that the longer the irradiation time, the higher the ΔE* (logarithmic relationship) and lower the TP. Despite the induced optical changes being prone to fade, the process can be predicted by inversely proportional relationships between ΔE*, TP and the testing points. The treated surface exhibited enhanced hydrophilicity, while the recovery phenomenon was observed. Other properties were not altered by the treatment. Significance This is the seminal study demonstrating the feasibility of direct colour printing on 3Y-TZP using 222 nm UV-C. The new relationship between the colour centre and E g of 3Y-TZP was established, whereas the induced optical changes were stabilised after a certain period and were highly predictable by controlling the irradiation periods. The irradiation was only correlated to the electron excitation and oxygen vacancies, and would not lead to any changes of other properties. A simple, safe and promising approach to achieve satisfactory colours on 3Y-TZP in clinical practice can be developed.
研究领域:
材料科学
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牙科医学
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表面工程
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高影响因子
CHEMOSPHERE
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2023
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IF 8.8
Jiaming Gan,Ting Zhu,Yizhan Zhang,Dailin Li,Ting Li,Min Zhao,ZengXia Zhao,Lei Wang
Since the coronavirus disease 2019 (COVID-19) pandemic epidemic, the excessive usage of chlorinated disinfectants raised the substantial risks of disinfection by-products (DBPs) exposure. While several technologies may remove the typical carcinogenic DBPs, trichloroacetic acid (TCAA), their application for continuous treatment is limited due to their complexity and expensive or hazardous inputs. In this study, degradation and dechlorination of TCAA induced by an in situ 222 nm KrCl* excimer radiation as well as role of oxygen in the reaction pathway were investigated. Quantum chemical calculation methods were used to help predict the reaction mechanism. Experimental results showed that UV irradiance increased with increasing input power and decreased when the input power exceeded 60 W. Decomposition and dechlorination were simultaneously achieved, where around 78% of TCAA (0.62 mM) can be eliminated and 78% dechlorination within 200 min. Dissolved oxygen showed little effect on the TCAA degradation but greatly boosted the dechlorination as it can additionally generate hydroxyl radical (•OH) in the reaction process. Computational results showed that under 222 nm irradiation, TCAA was excited from S 0 to S 1 state and then decayed by internal crossing process to T 1 state, and a reaction without potential energy barrier followed, resulting in the breaking of C–Cl bond and finally returning to S 0 state. Subsequent C–Cl bond cleavage occurred by a barrierless •OH insertion and HCl elimination (27.9 kcal/mol). Finally, the •OH attacked (14.6 kcal/mol) the intermediate byproducts, leading to complete dechlorination and decomposition. The KrCl* excimer radiation has obvious advantages in terms of energy efficiency compared to other competitive methods. These results provide insight into the mechanisms of TCAA dechlorination and decomposition under KrCl* excimer radiation, as well as important information for guiding research toward direct and indirect photolysis of halogenated DBPs.
研究领域:
环境科学
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化学工程
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高影响因子
WATER RESEARCH
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2024
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IF 11.4
Zi-Bo Jing,Wen-Long Wang,Yu-Jia Nong,Lu Peng,Zi-Chen Yang,Bei Ye,Min-Yong Lee,Qian-Yuan Wu
Low-pressure mercury lamps emitting at 254 nm (UV254) are used widely for disinfection. However, subsequent exposure to visible light results in photoreactivation of treated bacteria. This study employed a krypton chloride excimer lamp emitting at 222 nm (UV222) to inactivate E. coli . UV222 and UV254 treatment had similar E. coli -inactivation kinetics. Upon subsequent irradiation with visible light, E. coli inactivated by UV254 was reactivated from 2.71-log to 4.75-log, whereas E. coli inactivated by UV222 showed negligible photoreactivation. UV222 treatment irreversibly broke DNA strands in the bacterium, whereas UV254 treatment primarily formed nucleobase dimers. Additionally, UV222 treatment caused cell membrane damage, resulting in wizened, pitted cells and permeability changes. The damage to the cell membrane was mainly due to the photolysis of proteins and lipids by UV222. Furthermore, the photolysis of proteins by UV222 destroyed enzymes, which blocked photoreactivation and dark repair. The multiple damages can be further evidenced by 4.0–61.1 times higher quantum yield in the photolysis of nucleobases and amino acids for UV222 than UV254. This study demonstrates that UV222 treatment damages multiple sites in bacteria, leading to their inactivation. Employing UV222 treatment as an alternative to UV254 could be viable for inhibiting microorganism photoreactivation in water and wastewater.
研究领域:
微生物学
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环境科学
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光生物学
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Tao Yang,Ge Zeng,Maoju Jiang,Peng Su,Chenlong Liu,Qixiao Lv,Wenqi Li,Xiangyang Hou,Juan Li
Periodate (PI)-based advanced oxidation processes have gained increasing interest. This study for the first time elevates the light-activation capacity of PI by using far UVC at 222 nm (UV 222 /PI) without extra chemical inputs. The effectiveness and the underlying mechanisms of UV 222 /PI for the remediation of micropollutants were studied by selecting atenolol (ATL) as a representative. PI possessed a high molar absorption coefficient of 9480–6120 M −1 cm −1 at 222 nm in the pH range of 5.0–9.0, and it was rapidly decomposed by UV 222 with first-order rate constants of 0.0055 to 0.002 s −1 . ATL and the six other organic compounds were effectively degraded by the UV 222 /PI process under different conditions with the fluence-based rate constants generally two to hundred times higher than by UVA photolysis. Hydroxyl radical and ozone were confirmed as the major contributors to ATL degradation, while direct photolysis also played a role at higher pH or lower PI dosages. Degradation pathways of ATL were proposed including hydroxylation , demethylation , and oxidation. The high energy efficiency of the UV 222 /PI process was also confirmed. This study provides a cost-effective and convenient approach to enhance PI light-response activity for the treatment of micropollutants.
研究领域:
环境科学
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化学工程
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水处理
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高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2025
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IF 11.3
Yu-Jia Nong,Qian-Yuan Wu,Yuan-Chu Qin,Zi-Bo Jing,Er-Dong Wang,Qing Bai,Wen-Long Wang
UV/sulfite technologies offer promising advanced reduction processes (ARPs) for the degradation and dehalogenation of halogenated organic compounds (HOCs), but are limited by the low absorption of sulfite at a conventional wavelength of 254 nm (UV254). This study introduces a wavelength-optimized far-UVC KrCl* lamp (UV222)/sulfite as transformative ARPs. Sulfite exhibited 45.6-fold stronger absorption at 222 nm compared with 254 nm, coupled with a higher innate quantum yield (Φinnate) of 0.128 mol·Ein–1 versus 0.115 mol·Ein–1. This wavelength optimization generated 29.2-fold higher steady-state concentration of eaq–, with optimal performance at basic pH (>9) and moderate sulfite dosages (0.4–0.75 mM). HOC degradation and dehalogenation showed clear structure-dependent patterns. The enhancive effect of UV222 over UV254 negatively correlated with HOCs’ susceptibility to UV photolysis due to competitive absorption between sulfite and target compounds. Electron-withdrawing halogens significantly favored reductive degradation over oxidation, enabling UV222/sulfite to outperform UV222/H2O2 by 1.3–37.1 times in degradation and 1.9–48.6 times in dehalogenation efficiency, with prominent enhancement particularly for polyhalogenated HOCs. In real water matrices, nitrate and nitrite inhibited HOCs’ degradation through UV absorption and eaq– scavenging. Compared with UV254/sulfite, UV222/sulfite reduced energy costs by 92.7% and required lower sulfite doses. This study provides insights into the wavelength-matching mechanism for UV/sulfite, offering an economical and efficient solution for the remediation of recalcitrant HOCs.
研究领域:
环境科学
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光化学
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水处理
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化学工程
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污染修复
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高影响因子
Journal of Water Process Engineering
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2026
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IF 6.6
Sung-Hyo Jung,Sung-Hak Hong,Heejin Yang,Chang-Gu Lee
UV 222 /hBN exhibited 3-fold higher k PFOA than UV 254 /hBN under equal UV fluence. • UV 222 induced relatively higher C hole than UV 254 with strengthened light activity. • Acidic pH enhanced PFOA adsorption and hole utilization particularly under UV 222 . • UV 222 /hBN demonstrated greater robustness against water matrices than UV 254 /hBN. Hydrophobic hexagonal boron nitride (hBN) has attracted attention as a promising material for the UV-C light-driven photocatalysis of aqueous per - and polyfluoroalkyl substances (PFASs). Far UV-C light centered at 222 nm (UV 222 ) could provide a suitable irradiation source for contending wide band gap of hBN, serving as an alternative to conventional 254 nm UV-C (UV 254 ). This study investigated the first application of a KrCl lamp emitting UV 222 in combination with hBN to degrade perfluorooctanoic acid (PFOA) and compared it with UV 254 under equal UV fluence. UV 222 demonstrated superior hBN activation performance, with UV 222 /hBN exhibiting a higher PFOA degradation rate constant and more extensive chain shortening and defluorination than UV 254 /hBN. These enhancements were attributed to the higher light absorbance of hBN under UV 222, supported by the higher photocurrent response, as well as contributions from direct photolysis. Photogenerated holes were identified as the main reactive species, and their concentration was estimated to be 2.7 times higher in UV 222 /hBN than in UV 254 /hBN. Notably, acidic pH conditions enhanced PFOA adsorption, thereby promoting hole utilization, and the photocatalytic promotion effect was more pronounced under UV 222 than under UV 254 . Moreover, the inhibitory effect of natural water matrix components, including inorganic ions and natural organic matters, was also minimal in UV 222 /hBN. This study demonstrated that far UV-C serves as an effective hBN activation source, offering a viable engineering strategy for the photocatalytic treatment of PFASs. Download: Download high-res image (124KB) Download: Download full-size image
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高影响因子
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