SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Ziyi Deng,Xiaohan Li,Gaosheng Zhang,Guicong Xiao,Yuan Xie,Ru Nie,Shenglin Mai,Jianyou Long,Ziqing Xiao,Ping Zhang,Huosheng Li
Hypochlorite (ClO − )-based chlorination has shown effectiveness in oxidizing and purifying ammonium nitrogen (NH 4 + -N) and thallium (Tl) individually. However, the co-removal of these contaminants remains understudied. Addressing this gap, our study investigated the behaviors and mechanisms of NaClO-based breakpoint chlorination in oxidizing and removing both Tl and NH 4 + -N. The interaction among thallous ions (Tl + ), NH 4 + -N and NaClO in wastewater created a synergistic oxidation effect, which led to high removal efficiencies, exceeding 97 % for both Tl and NH 4 + -N, achieved with a NaClO concentration of 7 mmol/L, across a pH range of 6 to 10 in less than 5 min. Notably, the presence of Tl + , rather than Tl 3+ or Tl 2 O 3 , significantly enhanced the conversion of hypochlorite alongside NH 4 + -N. This coupled process generated chloramines and nitroxyl, along with oxygen-independent hydroxyl radicals formation, which further transformed into chloride radicals, dichlorine radical anions, and chlorine oxide radicals. Introducing these highly reactive species into the binary-pollutant system marked a substantial improvement over single-pollutant systems, yielding significantly higher removal efficiencies. These findings shed new light on the role of Tl in breakpoint chlorination for wastewater containing both Tl and NH 4 + -N.
研究领域:
环境科学
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污水处理
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产品关联
DOI
高影响因子
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2022
·Vol. 102
·期 11
·4685-4696
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IF 4.125
Lihui Zhang,Min Zhang,Arun S. Mujumdar,Kun Liu
BACKGROUND In order to prolong the storage and inhibit microorganisms of pakchoi, the antibacterial activity and mechanism of ultrasound combined with sodium hypochlorite (NaClO-US), the efficiency of NaClO-US in reducing Escherichia coli , Staphylococcus aureus and Pseudomonas aeruginosa as well as preserving quality of pakchoi were investigated. RESULTS Ultrasound treatment could significantly reduce the usage of NaClO solution from 800 ppm to 500 ppm. NaClO-US decreased the counts of E. coli , S. aureus and P. aeruginosa , which disrupted the bacterial cell membrane with cytoplasmic leakage. In addition, NaClO-US significantly increased cell membrane permeability, while cell membrane integrity decreased, the secondary structure of bacterial proteins showed several obvious changes, such as the increase of random coil content, as well as the decrease of α -helix content. The bacterial counts, E. coli , S. aureus and P. aeruginosa population in pakchoi treated with NaClO-US reduced by 1.89, 1.40, 1.60, 1.72 log CFU g −1 , respectively compared to control sample after storage for 15 days. NaClO-US resulted in minimum chlorophyll depletion, flavor and sensory deterioration. CONCLUSION NaClO-US solution treatment inhibited microorganisms and prolonged storage of pakchoi. © 2022 Society of Chemical Industry.
研究领域:
食品科学
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微生物学
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产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2016
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IF 1.207
Jie Wang,Wenqi Zhong
Experiments on simultaneous absorption of SO 2 and NO X from sintering flue gas via a composite absorbent NaClO 2 /NaClO were carried out. The effects of various operating parameters such as NaClO 2 concentration ( m s ), NaClO concentration ( m p ), molar ratio of NaClO 2 /NaClO ( M ), solution temperature ( T R ), initial solution pH, gas flow ( V g ) and inlet concentration of SO 2 ( C S ) and NO ( C N ) on the removal efficiencies of SO 2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, T R = 55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach 99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO 2 aqueous solution is favorable for the generation of ClO 2 and Cl 2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.
研究领域:
环境工程
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化学工程
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能源技术
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污染控制
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工业生态学
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DOI
高影响因子
Journal of Environmental Sciences
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2024
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IF 5.9
Chenyan Hu,Yihui Wu,Zhengyu Dong,Ziyi Dong,Shengjie Ji,Lili Hu,Xinyu Yang,Hao Liu
A mixed oxidant of chlorine dioxide (ClO 2 ) and NaClO was often used in water treatment. A novel UVA-LED (365 nm)-activated mixed ClO 2 /NaClO process was proposed for the degradation of micropollutants in this study. Carbamazepine (CBZ) was selected as the target pollutant. Compared with the UVA 365 /ClO 2 process, the UVA 365 /ClO 2 /NaClO process can improve the degradation of CBZ, with the rate constant increasing from 2.11×10 −4 sec −1 to 2.74×10 −4 sec −1 . In addition, the consumption of oxidants in the UVA 365 /ClO 2 /NaClO process (73.67%) can also be lower than that of UVA 365 /NaClO (86.42%). When the NaClO ratio increased, both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA 365 /ClO 2 /NaClO process. The solution pH can affect the contribution of NaClO in the total oxidant ratio. When the pH range of 6.0-8.0, the combination process can generate more active species to promote the degradation of CBZ. The change of active species with oxidant molar ratio was investigated in the UVA 365 /ClO 2 /NaClO process. When ClO 2 acted as the main oxidant, HO• and Cl• were the main active species, while when NaClO was the main oxidant, ClO• played a role in the system. Both chloride ion (Cl – ), bicarbonate ion (HCO 3 – ), and nitrate ion (NO 3 – ) can promote the reaction system. As the concentration of NaClO in the reaction solution increased, the generation of chlorates will decrease. The UVA 365 /ClO 2 /NaClO process can effectively control the formation of volatile disinfection by-products (DBPs), and with the increase of ClO 2 dosage, the formation of DBPs can also decrease.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Ao Li,Hongyan Song,Hong Meng,Yingzhou Lu,Chunxi Li
Sodium hypochlorite (NaClO) is a strong oxidant with facile electrochemical regenerability whereby a sustainable oxidative desulfurization (ODS) process of fuel may be viable. Here, a ultrafast deep ODS process was proposed by using ionic liquid (IL) catalyst and NaClO oxidant, and its catalytic mechanism was studied through GC-MS, FTIR, and in-situ ESR technique. The results show that the IL with C 16 alkyl groups makes the amphiphilic catalysts oil dispersible, and the catalytic activity of the imidazolium is higher than that of pyridinium and ammonium based IL catalysts. Dibenzothiophene (DBT) in model oil and real diesel can be oxidized completely within 30 min, and 99% of catalytic performance can be remained after 8 recycled uses. Under the catalysis of [C 16 MIM][PMoO], NaClO is firstly decomposed into radical oxygen species of O 2 − and OH that oxidize Mo = O of the catalyst to its peroxide form Mo(O 2 ), whereby DBT was oxidized into DBTO 2 . The present ultrafast and sustainable ODS process is perspective for industrial application, and the oxidation mechanism revealed here is instructive for ODS of fuel and other catalytic oxidation reactions.
研究领域:
化学工程
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环境科学
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催化化学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2021
·Vol. 45
·期 13
·6108-6119
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IF 3.591
Siyi Li,Xuehui Zhao,Hongwei Zhang
It is very important to reduce the oxidation of free radicals in organic membrane materials for the stability and safety of drinking water production treatment processes. This paper presents a new method for the qualitative and quantitative determination of free radicals in sodium hypochlorite solution by electron spin resonance (ESR) and salicylic acid spectrophotometry. Experiments show that the free radical scavenging rate reaches over 86% after the addition of 0.5 wt% nano-particles. PVDF–PVP/TiO2 and PVDF–PVP/CNT modified membranes are prepared by blending polyvinylidene fluoride (PVDF) with nano titanium dioxide (nano-TiO2) and carboxyl-modified multi-wall carbon nanotubes (MWCNTs-COOH), and are treated in 2000 ppm sodium hypochlorite solution for 30 days. Through surface chemistry (FTIR, XRD), surface morphology (SEM), surface hydrophilicity (contact angle), surface electronegative (zeta potential) and mechanical properties tests, the changes of membrane properties are analyzed during aging. The experimental results show that the nano-particles have a quenching effect on free radicals and inhibit defluorination. It has been proved that under the action of nano-additives, the erosion of free radicals on the membrane material is reduced, the aging rate of the membrane material is decreased, and the chemical stability of the membrane material is improved. In this paper, the reason and mechanism of anti-aging of the nano-particle modified membrane are analyzed, which provides theoretical support for future membrane cleaning technology and prolonging the service life of the membrane.
研究领域:
材料科学
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环境工程
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Junyan Wei,Shengnan Zhang,Ruixue Guo,Ahmed A. Allam,Jamaan S. Ajarem,Naif G. Altoom,Afzal Ahmed Dar,Ruijuan Qu,Zongli Huo,Feng Zhu
In plastic, a 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV328) ultraviolet light absorber is a common additive. When using sodium hypochlorite (NaClO) to disinfect plastic, UV328 may react with NaClO. For this work, we investigated the transformation behavior of UV328 in polyethylene (PE) plastic by NaClO. The reaction rate increased with the initial free active chlorine (OCl − ) concentration and the decrease of the initial UV328 concentration. At room temperature (25 °C) to lower temperatures (0 °C), OCl − could transform UV328, and the reaction activation energy was fitted as 31.10 kJ/mol. Replacement of the plastic carrier (change to polypropylene) had no effect on the reaction process. A total of 12 intermediates were identified, and calculations based on density functional theory (DFT) were used to assist in rationalizing the product structure. Chlorination, hydroxylation, coupling, and bond cleavage were speculated as the main transformation pathways. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were the only two measured disinfection by-products in the system, and their concentration were 18.33 and 18.19 μg/g, respectively. The toxicity prediction by Toxicity Estimation Software Tool (T.E.S.T) illustrated that the toxicity of the transformation products was higher overall than that of UV328 during the reaction. This work can help to deepen the understanding of the transformation behavior of UV328 in PE plastic in NaClO solution.
研究领域:
环境科学
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化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2017
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IF 6.216
Zongping Wang,Jiaqi Ding,Pengchao Xie,Yiqun Chen,Ying Wan,Songlin Wang
Sodium hypochlorite (NaClO) solution has been widely used to restore the flux of fouled membrane. The test of membrane flux herein also suggests that humic acid-fouled membranes could be efficiently cleaned by blending in NaClO solution at off-line mode. However, toxic halogenated by-products were found to form during the chemical cleaning of membrane fouling by NaClO solution. All the halogenated by-products except TCE and MCAA rose significantly with the increase of HA concentration. With prolonged chemical-cleaning time, the concentrations of formed chloral hydrate (CH) and trichloroacetic acid (TCAA) rose monotonically, while chloroform (TCM), trichloroacetonitrile (TCAN), trichloroethylene (TCE), trichloronitromethane (TCNM) followed an obvious increasing and then decreasing pattern. The formed TCM, TCAA and 1,1-dichloro-2-propanone (1,1-DCP) show obvious positive dependences on NaClO concentration, which was contrary to the formation of dichloroacetonitrile (DCAN) and 1,1,1-trichloro-2-propanone (TCP). With increasing the blending pH, both TCM and CH increased apparently, while haloacetic acids (HAAs) and haloacetonitriles (HANs) decreased continuously. Overall, the relatively stable halogenated by-products were favored at higher temperature compared to the unstable ones in the temperature range of 15–35 °C. 1,1-DCP, TCNM, TCM and TCAA were found to be easier to form when using the membranes with medium molecular weight cutoff (3 kDa and 5 kDa). The presence of calcium ions (Ca 2+ ) also affected the formation of halogenated by-products as a result that lots of them were significantly reduced at a Ca 2+ concentration of 10 mg/L. This study suggests that the remained NaClO solution after treatment of fouled membrane would contain some toxic by-products and should be carefully treated.
研究领域:
环境科学
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水处理工程
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DOI
高影响因子
WATER RESEARCH
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2024
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IF 11.4
Zhiwei Zhou,Tianjie Sun,Xing Li,Jiawei Ren,Zedong Lu,Yuankun Liu,Kai Li,Fangshu Qu
Chemical moderate preoxidation for algae-laden water is an economical and prospective strategy for controlling algae and exogenous pollutants, whereas it is constrained by a lack of effective on-line evaluation and quick-response feedback method. Herein, excitation-emission matrix parallel factor analysis (EEM-PARAFAC) was used to identify cyanobacteria fluorophores after preoxidation of sodium hypochlorite (NaClO) at Excitation/Emission wavelength of 260(360)/450 nm, based on which the algal cell integrity and intracellular organic matter (IOM) release were quantitatively assessed. Machine learning modeling of fluorescence spectral data for prediction of moderate preoxidation using NaClO was established. The optimal NaClO dosage for moderate preoxidation depended on algal density, growth phases, and organic matter concentrations in source water matrices. Low doses of NaClO (<0.5 mg/L) led to short-term desorption of surface-adsorbed organic matter (S-AOM) without compromising algal cell integrity, whereas high doses of NaClO (≥0.5 mg/L) quickly caused cell damage. The optimal NaClO dosage increased from 0.2–0.3 mg/L to 0.9–1.2 mg/L, corresponding to the source water with algal densities from 0.1 × 10⁶ to 2.0 × 10⁶ cells/mL. Different growth stages required varying NaClO doses: stationary phase cells needed 0.3–0.5 mg/L, log phase cells 0.6–0.8 mg/L, and decaying cells 2.0–2.5 mg/L. The presence of natural organic matter and S-AOM increased the NaClO dosage limit with higher dissolved organic carbon (DOC) concentrations (1.00 mg/L DOC required 0.8–1.0 mg/L NaClO, while 2.20 mg/L DOC required 1.5–2.0 mg/L). Compared to other predictive models, the machine learning model (Gaussian process regression-Matern (0.5)) performed best, achieving R 2 values of 1.000 and 0.976 in training and testing sets. Optimal preoxidation followed by coagulation effectively removed algal contaminants, achieving 91%, 92%, and 92% removal for algal cells, turbidity, and chlorophyll-a, respectively, thereby demonstrating the effectiveness of moderate preoxidation. This study introduces a novel approach to dynamically adjust NaClO dosage by monitoring source water qualities and tracking post-preoxidation fluorophores, enhancing moderate preoxidation technology application in algae-laden water treatment.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Yujie Cheng,Yujia Zou,Shiwen Yu,Jiaqi Ding,Ying Wan,Lisan Cao,Jingwen Wang,Zongping Wang,Siyang Yue,Pengchao Xie
NaClO has been extensively used for controlling membrane fouling in water and wastewater treatment processes , with bacteria being a common foulant in long-term ultrafiltration . However, the potential impact of NaClO cleaning on membrane structure and the formation of halogenated by-products remains unclear. This study comprehensively investigated the variation of membrane characteristics and formation of halogenated by-products during the chemical cleaning of Escherichia coli ( E. coli ) cell-fouled membrane using NaClO solution. The feed water containing E. coli cells resulted in severe membrane fouling by forming a dense cake layer, while NaClO cleaning achieved complete restoration of membrane flux under optimal conditions. The cleaning performance was compromised under high temperature and acidic conditions due to the lysis of E. coli cells and the limited oxidative capability of HClO. Excellent chemical resistance of polyethersulfone membrane against NaClO was confirmed under appropriate operational conditions. The biofouling and membrane materials played critical roles as precursors in the formation of halogenated chemicals during NaClO cleaning, and the generation pattern of by-products is highly dependent on the composition of membrane foulants. Increasing E. coli concentration, NaClO dosage, temperature and blending time led to the monotonical accumulation of almost all eleven representative by-products. As solution pH rose continuously, several by-products including trichloroacetic acid and chloral hydrate exhibited an initial increasing then decreasing trend, which could be attributed to the relative quantities between their formation and decomposition rates.
研究领域:
环境科学
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水处理工程
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微生物学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Rui Ma,Xiaoxiang Cheng,Xinsheng Luo,Tao Yang,Daoji Wu,Heng Liang
Herein, sodium hypochlorite (NaClO) and peroxomonosulfate (PMS) were systematically compared in enhancing vacuum ultraviolet (VUV) oxidation for alleviating ultrafiltration membrane fouling of effluent organic matter. Results indicated that VUV/NaClO pre-treatment exhibited significantly better performance than VUV/PMS, with the irreversible fouling resistance reduced by 64 %. Simultaneously, 96 % of fluorescent substances were removed by VUV/NaClO, and an apparent decrease in surface deposits was observed, with membrane pores exposed and clearly visible. The calculation results through the extended Derjaguin-Landau-Verwey-Overbeek theory indicated that the enhanced hydrophilicity of pollutants reduced the tendency of pollutants to adhere to the membrane surface, leading to the weakening of membrane fouling degree. In the VUV/PMS process, HO • and SO 4 •– were detected with steady-state concentrations of 8.55 × 10 -14 and 1.53 × 10 -13 M. By contrast, the VUV/NaClO system generated HO • , Cl • , ClO • , and Cl 2 •– with steady-state concentrations of 1.15 × 10 -13 , 8.79 × 10 -14 , 7.30 × 10 -13 and 1.50 × 10 -13 M. In conclusion, VUV/NaClO pre-treatment demonstrated high efficiency and significant potential in improving water quality and decreasing membrane fouling in secondary effluent treatment.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2021
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IF 8.742
Liumo Ren,Shuili Yu,Haijun Yang,Lei Li,Luyang Cai,Qing Xia,Zhiyuan Shi,Guicai Liu
In a practical project of polyvinylidene fluoride (PVDF) ultrafiltration membrane for polymer flooding wastewater treatment , the deterioration of membrane performance was observed after 4 years of operation. The aging effects of sodium hypochlorite (NaClO) on PVDF ultrafiltration membranes were systematically studied, including the membrane properties, filtration performance, and fouling behaviors. During the NaClO aging process, chemical transformations of polyvinylpyrrolidone (PVP) additives dominated the changes in membrane intrinsic characteristics, and the kinetic behavior of PVP decomposition was proposed, which was closely related to the evolution of the membrane pore size. For aged membranes, due to the changes in intrinsic characteristics, the antifouling performance significantly declined: the pseudo-stable flux with feeding solution and flux recovery after physical cleaning decreased by ~55% and ~62%, respectively, after 20 days of aging. The intermolecular forces in combination with the interfacial free energies were used to evaluate the fouling behaviors of aged membranes. The increased energies indicated the more spontaneous foulant‒membrane adhesion and stabilized fouling layers, which deteriorated the irreversible fouling resistance, increased the initial fouling rates and reduced the flux recovery after physical cleaning. Compared to intermolecular forces, foulant‒membrane interfacial free energies can serve as the more sensitive and reliable indicators of membrane fouling .
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）