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1.
Anal Methods ; 16(17): 2654-2660, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38623688

ABSTRACT

Nickel stands out as one of the prevalent heavy metal ionic pollutants found in water. It is urgent to devise a simple, efficient, budget-friendly, highly-selective and proficient method for detecting Ni(II). This work reports an approach to design a nanofluidic diode for the ultrasensitive and label-free detection of nickel ions based on layer-by-layer assembly of polyarginine (PA) and polyglutamic acid (γ-PGA) on the inner surface of asymmetric nanochannels. We can tune the adsorption/desorption characteristics of the asymmetric nanochannels for Ni2+ by adjusting the pH changes, i.e., the PA-γ-PGA modified nanochannels adsorb Ni2+ at pH 6 and desorb at pH 3 in aqueous solution. This pivotal adjustment facilitates the reusable and specific detection of nickel ions with a detection limit of 1 × 10-8 M. Moreover, the system demonstrates commendable stability and recyclability, enhancing its practical applicability. This innovative system holds promise for recognizing and detecting nickel ions in diverse environments such as water, blood, and cells. The robust performance and adaptability of our proposed system instill confidence in its potential for future applications.

2.
J Colloid Interface Sci ; 667: 212-222, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38636223

ABSTRACT

The application of supermolecular naonostructures in the photocatalytic carbon dioxide reduction reaction (CO2RR) has attracted increasing attentions. However, it still faces significant challenges, such as low selectivity for multi-electron products and poor stability. Here, the cuprous oxide (Cu2O)-modified zinc tetraphenylporphyrin ultrathin nanosheets (ZnTPP NSs) are successfully constructed through the aqueous chemical reaction. Comprehensive characterizations confirm the formation of type-II heterojunction between Cu2O and ZnTPP in Cu2O@ZnTPP, and the electron transfer from Cu2O to ZnTPP through the Zn-O-Cu bond under the static contact. Under the visible-light irradiation (λ > 420 nm), the optimized Cu2O@ZnTPP sample as catalyst for photocatalytic CO2RR exhibits the methane (CH4) evolution rate of 120.9 µmol/g/h, which is âˆ¼ 4 and âˆ¼ 10 times those of individual ZnTPP NSs (28.0 µmol/g/h) and Cu2O (12.8 µmol/g/h), respectively. Meanwhile, the CH4 selectivity of âˆ¼ 98.7 % and excellent stability can be achieved. Further experiments reveal that Cu2O@ZnTPP has higher photocatalytic conversion efficiency than Cu2O and ZnTPP NSs, and the photoinduced electron transfer from ZnTPP to Cu2O can be identified via the path of ZnTPP→ (ZnTPP•ZnTPP)*→ ZnTPP-→ Zn-O-Cu â†’ Cu2O. Consequently, Cu2O@ZnTPP exhibits a shorter electron-hole separation lifetime (3.3 vs. 9.3 ps) and a longer recombination lifetime (23.1 vs. 13.4 ps) than individual ZnTPP NSs. This work provides a strategy to construct the organic nanostructures for photocatalytic CO2RR to multi-electron products.

3.
Environ Pollut ; 339: 122736, 2023 Dec 15.
Article in English | MEDLINE | ID: mdl-37838321

ABSTRACT

Recently, it has been reported that chlorine dioxide (ClO2) and (bi)sulfite/ClO2 showed excellent performance in micropollutant removal from water; however, the degradation mechanisms and application boundaries of the two system have not been identified. In this study, bisphenol A (BPA) was chosen as the target contaminant to give multiple comparisons of ClO2 and S(IV)/ClO2 process regarding the degradation performance of contaminant, generation of reactive species, transformation of products and toxicity variation. Both ClO2 and S(IV)/ClO2 can degrade BPA within 3 min. The BPA degradation mechanism was mainly based on direct oxidation in ClO2 process while it was attributed to radicals (especially SO4·-) generation in S(IV)/ClO2 process. Meanwhile, the effect of pH and coexisting substances (Cl-, Br-, HCO3- and HA) were evaluated. It was found that ClO2 preferred the neutral and alkaline condition and S(IV)/ClO2 preferred the acidic condition for BPA degradation. An unexpected speed-up of BPA degradation was observed in ClO2 process in the presence of Br-, HCO3- and HA. In addition, the intermediate products in BPA degradation were identified. Three exclusive products were found in ClO2 process, in which p-benzoquinone was considered to be the reason of the acute toxicity increase in ClO2 process.


Subject(s)
Chlorine Compounds , Water Pollutants, Chemical , Water Purification , Oxides/toxicity , Oxides/chemistry , Chlorine Compounds/toxicity , Chlorine Compounds/chemistry , Phenols/toxicity , Oxidation-Reduction , Chlorine/chemistry , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/analysis
4.
Anal Chem ; 95(36): 13456-13462, 2023 Sep 12.
Article in English | MEDLINE | ID: mdl-37624577

ABSTRACT

Artificial solid-state nanochannels have garnered considerable attention as promising nanofluidic tools for ion/molecular detection, DNA sequencing, and biomimicry. Recently, nanofluidic devices have emerged as cost-effective detection tools for heavy metal ions by modifying stimuli-responsive materials. In this work, high-purity glycyl-l-histidyl-l-lysine (GHK) peptide is synthesized by using 7-diphenylphosphonooxycoumarin-4-methanol (DPCM) as a protecting group and auxiliary carrier by homogeneous synthesis of photocleavable groups. Subsequently, we developed a GHK-modified asymmetric nanochannel nanofluidic diode by covalently attaching the GHK peptide to the inner surface of the nanochannels. This modification facilitated specific recognition and ultra-trace level detection of Cu2+ ions, achieving a detection limit of 10-15 M. Due to the robust complexing ability between Cu2+ and GHK peptide, the GHK-modified asymmetric nanochannels can form GHK-Cu complexes on the inner surface of nanochannels when Cu2+ passes through the nanochannels. This results in changes of current-potential (I-V) properties, which facilitated Cu2+ detection. Theoretical calculations confirmed the high affinity of the GHK peptide for Cu2+, thereby ensuring excellent Cu2+ selectivity. To evaluate the applicability of our system for detecting Cu2+ in real-world scenarios, we analyzed the concentration of Cu2+ in tap water. The GHK-Cu complexes could be dissociated by adding EDTA to the solution, enabling the regeneration and reuse of this ultrasensitive and label-free Cu2+ detection system using GHK-modified asymmetric multi-nanochannels. We anticipate that the GHK-modified asymmetric nanochannels will find future applications in the label-free detection of Cu2+ in domestic water.

5.
STAR Protoc ; 4(3): 102392, 2023 Sep 15.
Article in English | MEDLINE | ID: mdl-37393610

ABSTRACT

The lack of systems to automatically extract epidemiological fields from open-access COVID-19 cases restricts the timeliness of formulating prevention measures. Here we present a protocol for using CCIE, a COVID-19 Cases Information Extraction system based on the pre-trained language model.1 We describe steps for preparing supervised training data and executing python scripts for named entity recognition and text category classification. We then detail the use of machine evaluation and manual validation to illustrate the effectiveness of CCIE. For complete details on the use and execution of this protocol, please refer to Wang et al.2.


Subject(s)
COVID-19 , Natural Language Processing , Humans , Language , COVID-19/epidemiology
6.
Macromol Biosci ; 23(7): e2200559, 2023 07.
Article in English | MEDLINE | ID: mdl-36945731

ABSTRACT

Currently, gastrointestinal bleeding in the colon wall and the small bowel is diagnosed and treated with endoscopes. However, the locations of this condition are often problematic to treat using traditional flexible and tethered tools. New studies commonly consider untethered devices for solving this problem. However, there still exists a gap in the extant literature, and more research is needed to diagnose and deliver drugs in the lower gastrointestinal tract using soft robotic carriers. This paper discusses the development of an untethered, magnetically-responsive bio-inspired soft carrier. A molding process is utilized to produce prototypes from Diisopropylidene-1,6-diphenyl-1,6-hexanediol-based Polymer with Ethylene Glycol Dimethacrylate (DiAPLEX) MP-3510 - a shape memory polymer with a low transition temperature to enable the fabrication of these carriers. The soft carrier design is validated through simulation results of deformation caused by magnetic elements embedded in the carrier in response to an external field. The thermal responsiveness of the fabricated prototype carriers is assessed ex vivo and in a phantom. The results indicate a feasible design capable of administering drugs to a target inside a phantom of a large intestine. The soft carrier introduces a method for the controlled release of drugs by utilizing the rubbery modulus of the polymer and increasing the recovery force through magnetic actuation.


Subject(s)
Drug Delivery Systems , Polymers , Temperature , Drug Delivery Systems/methods , Excipients , Gastrointestinal Agents , Magnetic Phenomena
7.
J Colloid Interface Sci ; 638: 123-134, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36736114

ABSTRACT

The zinc-based photocatalysts for CO2 reduction have attracted increasing attention, however, usually exhibit low CO2-to-CH4 selectivity. Here, the graphene oxide (GO)-coated zinc tetraphenylporphyrin (ZnTPP/GO) nanocomposites are successfully synthesized through a simple method. It is found that with the increase of GO content, the crystallinity of ZnTPP nanocrystals enhances with the size decrease, and then the light absorption can easily match with the solar spectrum. The optimal ZnTPP/GO sample exhibits the CH4 evolution rate of 41.6 µmol g-1 h-1 and CH4 selectivity of >95%, which are higher than those of ZnTPP nanocrystals (7.8 µmol g-1 h-1 and 50.3%). The systematic characterizations confirm that the generation of axial coordinated ZnOC bonds between ZnTPP and GO plays a key role in the formation of ZnTPP/GO nanostructure and their synergic effect on photocatalytic CO2 reduction. The encapsulation of GO on ZnTPP nanocrystals not only promotes the CO2 adsorption, interfacial reaction, and stability, but also accelerates the separation of photoinduced carriers on ZnTPP (0.1 ps vs. 425.9 ps), the transportation from ZnTPP to GO (2.3 ps vs. 83.6 ps), and their final enrichment on GO. This work provides a new strategy to apply graphene and organic nanomaterials in artificial photosynthesis.


Subject(s)
Graphite , Nanocomposites , Zinc Oxide , Zinc , Carbon Dioxide
8.
Environ Pollut ; 318: 120925, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36566677

ABSTRACT

Microplastics (MPs), an emerging pollutant, have been increasingly raising concern due to the potential impacts on aquatic organisms. Moreover, the environmental aged MPs always exhibit different environmental behavior and interaction effect with organic pollutants from virgin MPs. In this work, the single and combined toxicity impact on Chlorella pyrenoidosa, a symbiont representative, has been investigated between MPs (e.g., polyamide microplastic (PA6), 75 µm) and organic pollutants (e.g., sulfamethoxazole (SMX) and dicamba (DCB)). Growth inhibition, chlorophyll accumulation, superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) were investigated with the primary or UV-aged PA6. Above 0.5 g/L PA6 (primary or UV-aged) inhibited cell growth and chlorophyll accumulation after 96 h cultivation as compared with the control. Besides, the inhibition impacts have enhanced as the UV-aging time extending in the single PA6 systems. The algae growth inhibition rate after 96 h cultivation in both the system i.e., single (PA6: 6.9%) and combined (PA6-SMX: 14.2%, PA6-DCB: 14.9%) was slightly lower than that of exposing in organic pollutants alone (SMX: 23.9%, DCB: 25.0%), while the chl. b concentration in 60 days UV-aged PA6 combined with SMX (1.19 mg/L) or DCB (1.40 mg/L) systems were higher than in single SMX (1.04 mg/L) or DCB (1.33 mg/L) system. In addition, there were several differences of the cellular oxidative stress in the combined system of SMX and DCB. Specially, it was not noticeable of three enzymatic activities for SMX exposing in the presence of primary or UV-aged PA6. While SOD, CAT, and MDA activities was obviously increasing after exposing in PA6 and DCB combined system, indicating the significant synergistic effect on algae cells damage. This research verified the remarkable combined toxicity between UV-aged MPs and organic pollutants on microalgae.


Subject(s)
Chlorella , Microalgae , Water Pollutants, Chemical , Chlorophyll , Microplastics/toxicity , Plastics/pharmacology , Superoxide Dismutase , Water Pollutants, Chemical/analysis , Ultraviolet Rays
9.
Environ Res ; 216(Pt 4): 114819, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36395859

ABSTRACT

The huge application of synthetic dyes caused a severe impact in the environment. In the present study, a physico-chemical strategy of heterogeneous-Fenton catalyzed by the natural ferrous ore has been established for toxic chemical degradation, of which the complex and high-expense repetitive pH adjustment procedures were escaping. And this natural heterogeneous catalyst also could be recycled and sustainable for toxic substances treatment involved in synergetic adsorption and oxidation. The siderite, served as an adsorbent and catalyst for the degradation of methylene blue (MB). Siderite exhibited a better adsorption capacity with a saturated adsorption capacity of ∼11.08 mg/g. Batch adsorption experiments have verified that adsorption rate and adsorption equilibrium followed pseudo-second-order rate model and Langmuir isotherm equation, respectively. The combination with H2O2, showed significant enhancement of MB degradation without any pH adjustment. The effect of siderite dosage, H2O2 dosage, MB concentration, initial pH, and reaction temperature on MB degradation was investigated, which also has indicated the excellent catalytic performance of siderite. About 99.71% of MB was degraded in 480 min with initial pH of 7.0, reaction temperature of 25 °C, siderite, and H2O2 dosage of 2.5 g/L and 122.38 mM, respectively. It was found that siderite could be reused and remained high degradation efficiency on MB after 5 times reutilization, which also could demonstrate the sustainable and effective process to degrade organic pollution. The generation of reactive species including ·OH and O2·- have been confirmed based on scavenger test and electron spin resonance (ESR) analysis, which was dominated by heterogeneous reaction. The possible degradation mechanisms of MB have been predicted based on spectrum scanning and GC-MS analysis. Moreover, acute toxicity assessment with marine photobacterium Vibrio fisheri was conducted to investigate the toxicity change in the adsorption/oxidation coupled process. This sustainable heterogeneous-Fenton technology has been verified as a promising and applicable process for toxic organic chemicals removal due to effective mineralization and detoxification assisted with the natural ore mineral through the simple operation and mild condtions.


Subject(s)
Methylene Blue , Water Pollutants, Chemical , Methylene Blue/chemistry , Hydrogen Peroxide , Water Pollutants, Chemical/chemistry , Kinetics , Adsorption , Catalysis
10.
Environ Pollut ; 316(Pt 2): 120579, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36336186

ABSTRACT

Tetrabromobisphenol A (TBBPA), a representative brominated flame retardant (BFR), generally could be debrominated and degraded effectively in photolysis systems with the high energy consumption. In this study, the novel sulfate radical (SO4•-) generation resource of dithionite (S2O42-), activated by the common transition metal of Fe3+, has been applied for establishing an innovative homogeneous advance treatment system for BFR treatment in water. When coupling Fe3+ with S2O42-, TBBPA degradation efficiency could be remarkably improved from 38.7% to 93.8% with the debromination and mineralization efficiency of 83.9% and 18.5% in 60 min, respectively. The primary reactive species also have been identified as SO3•-, SO4•- and •OH responsible for TBBPA treatment and the contributions of SO4•- and •OH have been calculated as 43.8% and 28.4% for TBBPA degradation, respectively. In Fe3+/S2O42- system, TBBPA was effectively degraded in a wide initial pH range (3.0-9.0), whose activation energy was calculated as 32.01 kJ mol-1. Due to the only operation of reagents dosing, the energy consumption and cost could be decreasing significantly without any light energy input and reaction conditions (e.g., pH and dissolved oxygen) adjustment compared with the general photolysis process. Moreover, some possible degradation approaches of TBBPA also have been proposed via GC-MS including debromination, hydroxylation, methylation, and mineralization in Fe3+/S2O42- system. And these probable degradation pathways also have been confirmed with the decreased Gibbs free energy (ΔG) based on density functional theory (DFT). This study has revealed that it was promising of Fe3+/S2O42- system for BFRs degradation and detoxification efficiently through the simple operation and mild condtions.


Subject(s)
Flame Retardants , Polybrominated Biphenyls , Polybrominated Biphenyls/metabolism , Flame Retardants/metabolism , Photolysis , Water
11.
PeerJ Comput Sci ; 8: e1112, 2022.
Article in English | MEDLINE | ID: mdl-36262140

ABSTRACT

Background: With the growth of trajectory data, the large amount of data causes a lot of problems with storage, analysis, mining, etc. Most of the traditional trajectory data compression methods are focused on preserving spatial characteristic information and pay little attention to other temporal information on trajectory data, such as speed change points or stop points. Methods: A data compression algorithm based on the spatio-temporal characteristics (CASC) of the trajectory data is proposed to solve this problem. This algorithm compresses trajectory data by taking the azimuth difference, velocity difference and time interval as parameters in order to preserve spatial-temporal characteristics. Microsoft's Geolife1.3 data set was used for a compression test to verify the validity of the algorithm. The compression results were compared with the traditional Douglas-Peucker (DP), Top-Down Time Ratio (TD-TR) and Opening Window (OPW) algorithms. Compression rate, the direction information of trajectory points, vertical synchronization distance, and algorithm type (online/offline) were used to evaluate the above algorithms. Results: The experimental results show that with the same compression rate, the ability of the CASC to retain the forward direction trajectory is optimal, followed by TD-TR, DP, and then OPW. The velocity characteristics of the trajectories are also stably retained when the speed threshold value is not more than 100%. Unlike the DP and TD-TR algorithms, CASC is an online algorithm. Compared with OPW, which is also an online algorithm, CASC has better compression quality. The error distributions of the four algorithms have been compared, and CASC is the most stable algorithm. Taken together, CASC outperforms DP, TD-TR and OPW in trajectory compression.

12.
Ther Clin Risk Manag ; 18: 799-812, 2022.
Article in English | MEDLINE | ID: mdl-35992228

ABSTRACT

Purpose: Selective serotonin reuptake inhibitors (SSRIs) are the preferred treatments for depression. The most common adverse drug reactions are symptoms involving the digestive system, leading to low compliance in patients with depression. Therefore, it is important to assess the safety of SSRIs with respect to the digestive system. Several meta-analyses have compared the risks of digestive side effects of SSRIs and other antidepressants. We aimed to compare the risks of various SSRIs (fluoxetine, escitalopram, citalopram, paroxetine, and sertraline) for adverse reactions of the digestive system. Methods: Systematic searches returned 30 randomized controlled trials (n = 5004) of five antidepressants and placebos. Results: Fluoxetine had the lowest probability of digestive side effects, ranking fifth at 0.548. Sertraline had the highest probability of digestive side effects, with a probability of 0.611. For gastrointestinal tolerability, escitalopram was better than paroxetine (odds ratio [OR] =0.62, 95% confidence interval [CI] 0.43-0.87) and sertraline (OR=0.56, 95% CI 0.32-0.99). Conclusion: Fluoxetine exhibited distinct advantages compared to other SSRIs, while sertraline had the greatest likelihood of digestive system side effects. These findings will help doctors understand the relative advantages of various antidepressants.

13.
J Environ Manage ; 321: 116034, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-36027733

ABSTRACT

In this study, dithionite (DTN) was used to degrade Tetrabromobisphenol A (TBBPA), a widely applied brominated flame retardants, under anaerobic conditions with the reaction terminator of nitrate. The optimization of reaction parameters including TBBPA concentration, DTN concentration and pH value were conducted by response surface methodology (RSM) based on central composite design (CCD). The degradation process could be simulated accurately by a quadratic model with the correlation coefficient R2 of 0.9550. The interaction between pH and DTN concentration was significant with the p-value of 0.0017. Moreover, the maximum TBBPA removal was 87.6 ± 3.2% and obtained at TBBPA concentration of 2.00 µM, the DTN concentration of 322.31 µM, and the pH of 6.14 under anaerobic conditions. It was found that the factors influenced TBBPA removal followed the order: pH > DTN concentration > TBBPA concentration. The major active products from DTN are SO32- and S2O32-. In addition, different inhibitions of natural water matrix including chloride, bicarbonate, sulfide and humic acid on TBBPA degradation had been confirmed. According to the identified six intermediates via gas chromatography-mass spectrometry (GC-MS), two steps of the degradation pathways were speculated, including the breakage of C-Br bond and C-C bond. This study provides a convenient way to degrade TBBPA.


Subject(s)
Flame Retardants , Polybrominated Biphenyls , Anaerobiosis , Dithionite , Flame Retardants/metabolism , Polybrominated Biphenyls/chemistry , Polybrominated Biphenyls/metabolism
14.
J Hazard Mater ; 436: 129254, 2022 08 15.
Article in English | MEDLINE | ID: mdl-35739773

ABSTRACT

Advanced oxidation process (AOPs) is one of the most effective technologies for organic pollutants removal. In this study, diverse reactive species generation and enhanced sulfamethoxazole (SMX) degradation were investigated based on persulfate (PDS) activated by Fe2+&dithionite (DTN). When involving Fe2+&dithionite in PDS, SMX degradation efficiency reached 84 % within 30 min following a pseudo-first-order kinetic, which was higher than those in Fe2+/PDS (50.4 %) and Fe2+/O2/DTN (41.3 %). SO4•- and •OH were identified as dominant reactive species with a crucial role of FeSO3+ based on quenching experiment and electron spin resonance (ESR). The contributions of SO4·-, ·OH, and other species to SMX degradation were 60.1 %, 33.9 %, and 6 %, respectively. In Fe2+/DTN/PDS system, SMX was effectively degraded under nearly neutral pH (5.0-9.0), with activation energy of 96.04 kJ·mol-1. The experiments and density functional theory (DFT) calculation demonstrated that three functional groups (benzenesulfonamido, benzene ring, and oxazole ring) were attacked for SMX degradation. Moreover, acute toxicity to Vibrio fischeri has enhanced in the earlier degradation process due to the intermediates and weaken with the continuous reaction. This work not only provides a high-activity SO4·--AOP for refractory pollutant treatment with possible dual radical generation resources, but elucidated diverse reactive species formation with Fe2+&dithionite.


Subject(s)
Sulfamethoxazole , Water Pollutants, Chemical , Density Functional Theory , Dithionite , Kinetics , Oxidation-Reduction , Sulfamethoxazole/toxicity , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity
15.
Environ Res ; 205: 112430, 2022 04 01.
Article in English | MEDLINE | ID: mdl-34843722

ABSTRACT

Carbon neutrality has been received more attention and emerged in wastewater treatment processes. Due to the development of treating technologies with the rising of new-emerging pollutants, the coupled chemical processes also should remain current for the goal of carbon-neutral operation. Among of those updated strategies, several advanced oxidation processes (AOPs) based on dithionite (DTN, S2O42-), a common water treatment agent, have been established for refractory organic contaminations removal. However, in terms of DTN detection, the traditional formol-titration method has several application limits including the low detection sensitivity and high consumption of formaldehyde. In this study, compared with traditional method, a low energy consumption technology has been developed based on the potassium ferricyanide with the carbon consumption decreasing by about 5 times. Moreover, detection limit of DTN (mmol/L level) also was lower than the titration method. The method was established based on the fact that every 1 mol of DTN can react with 2 mol [Fe(CN)6]3- under alkaline condition. According to that potassium ferricyanide (K3 [Fe(CN)6]) has the maximum absorption at 419 nm wavelength, a fitting equation based on the linear relationship between the absorbance variation of K3 [Fe(CN)6] and DTN amount in the ranges of 0-30 µmol with the detection limit of 0.6 µmol was established with the determination coefficient of 0.99935. It was found that there was no obvious influence of the ubiquitous foreign species with the amount lower than 6 mM, 4 mM, 6 mM, 4 mM and 1 mg/L for Cl-, HCO3-, NO3-, SO42- and NOM, respectively. Moreover, methanol and tert-butanol were employed to verify the influence of the presence of organic matters on the determination of DTN and no impact was observed in this study. The proposed method provides a new way for DTN detection with stable and countable performance in the related AOPs with the low electric energy and carbon source consumption and high detection efficiency.


Subject(s)
Ferricyanides , Technology , Dithionite , Oxidation-Reduction , Spectrophotometry/methods
16.
Environ Geochem Health ; 44(11): 3837-3851, 2022 Nov.
Article in English | MEDLINE | ID: mdl-34713368

ABSTRACT

Eutrophication has become a great concern in recent years with the algae blooms in source water resulting in a serious threat posing to the safety of drinking water. Chlorine dioxide (ClO2) has been served as an alternative oxidant for preoxidation or disinfection during drinking water treatment process due to its high oxidation efficiency and low risk of organic by-products formation. However, the generation of inorganic by-products including chlorite (ClO2-) and chlorate (ClO3-) has become a potential problem when applied in drinking water treatment. In this study, ClO2 preoxidation-assisted coagulation/precipitation process was applied to improve the raw water quality, especially algae, turbidity, chemical oxygen demand (CODMn), and UV254, and explore the formation mechanisms of inorganic by-products. It was found that the polymeric aluminum chloride (PAC) and ClO2 have shown the best raw water treatment performance with the optimal dosage of 10 mg/L and 0.8 mg/L, respectively. Moreover, the initial pH also has exhibited a notable influence on pollutants treatment and by-products generation. Due to the adverse influence of algae and natural organic matters (NOM) and the generation of by-products, it was significant to investigate their inhibition effect on the water quality and the production of ClO2- and ClO3- in the ClO2 preoxidation-assisted coagulation/precipitation process. Moreover, it was applicable of this process to apply for the algae-containing raw water (calculated as Chl.a lower than 50 µg/L) treatment with the ClO2 dosage of less than 0.8 mg/L to achieve optimum treatment performance and minimum by-products generation.


Subject(s)
Drinking Water , Environmental Pollutants , Water Purification , Chlorates , Aluminum Chloride , Water Purification/methods , Oxides , Oxidation-Reduction , Oxidants , Chlorine
17.
Small ; 17(24): e2100969, 2021 06.
Article in English | MEDLINE | ID: mdl-33938137

ABSTRACT

Solar-driven evaporation is regarded as a sustainable wastewater treatment strategy for clean water recovery and salt condensation. However, achieving both high evaporation rate and long-term stability remain challenging due to poor thermal management and rapid salt accumulation and blocking. Here, a T-shape solar-driven evaporator, composed of a surface-carbonized longitudinal wood membrane (C-L-wood) is demonstrated as the top "" for solar harvesting/vapor generation/salt collection and another piece of natural L-wood as the support "" for brine transporting and thermally insulating. The horizontally aligned micro-channels of C-L-wood have a low perpendicular thermal conductivity and can effectively localize the thermal energy for rapid evaporation. Meanwhile, the brine is guided to transport from the support L-wood ("") to the centerline of the top evaporator and then toward the double edge (""), during which clean water is evaporated and salt is crystallized at the edge. The T-shape evaporator demonstrates a high evaporation rate of 2.43 kg m-2 h-1 under 1 sun irradiation, and is stable for 7 days of the outdoor operation, which simultaneously realizes clean water evaporation and salt collection (including Cu2+ , CrO42- , Co2+ ), and achieves zero-liquid discharge. Therefore, the T-shape design provides an effective strategy for high performance wastewater treatment.


Subject(s)
Solar Energy , Water Purification , Sunlight , Water , Wood
18.
Sci Total Environ ; 699: 134258, 2020 Jan 10.
Article in English | MEDLINE | ID: mdl-31522056

ABSTRACT

The degradation efficiency of bisphenol A (BPA) was investigated in the process of persulfate (PS) coupled with dithionite (DTN) as a function of concentration of BPA, PS, DTN and solution pH. A simple response surface methodology (RSM) based on central composite design (CCD) was employed to determine the influence of individual and interaction of above variables and the optimum processing parameters. It is satisfactory of a quadratic model with low probabilities (<0.0001) at a confidence level of 95% to predict the BPA degradation efficiency. The model was well fitted to the actual data and the correlation coefficients of R2 and R2-adj were 0.9270 and 0.8885, respectively. In addition, the obtained optimum conditions for BPA degradation were 1.79 µM, 131.77 µM, 93.64 µM for BPA, PS, DTN and pH = 3.62, respectively. It achieved a degradation efficiency >90% within 150 min. Moreover, the trapping experiment of active species demonstrated that SO4·- and ·OH were the dominant species and natural water matrix showed an obvious inhibition effect on BPA degradation. The BPA degradation pathway was predicted based on GC-MS results in this study.

19.
Water Sci Technol ; 79(3): 573-579, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30924812

ABSTRACT

Persulfate-based advanced oxidation has been widely applied in environmental remediation for degrading contaminants. In recent years, numerous kinds of organic analytes including pesticides, dyes and pharmaceuticals, have emerged and related researches on the activation methods, the mechanism and the application have been performed. The activation is critical in persulfate-based advanced oxidation because the persulfate alone has a weaker oxidation potential to degrade these organic pollutants. Hence various activation methods have been extensively investigated to achieve a higher oxidation efficiency. These novel methods are gradually expanding the applicability and practicality. This review focuses on the classification of the different activation methods based on whether it is related to the substances or not. The effect of the environmental conditions (solution pH, dosage and the co-existing substance) on the oxidation capacity are also discussed.


Subject(s)
Environmental Restoration and Remediation , Sulfates/chemistry , Water Pollutants, Chemical/chemistry , Oxidation-Reduction
20.
Water Sci Technol ; 79(3): 589-596, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30924814

ABSTRACT

Heavy metal contamination from electroplating wastewater is a serious risk to terrestrial life and public health. The complexed metal cannot be effectively removed by traditional precipitation without decomplexing. In this work, four ozone-based advanced oxidation processes, O3, O3/H2O2, O3/UV and O3/H2O2/UV to decomplex electroplating wastewater were investigated and their performance compared. Ethylenediaminetetraacetic acid (EDTA) and citric acid are the most common components of electroplating wastewater. They were used as representatives to study the decomplexation and mineralization of complexes in the ozone-based advanced oxidation processes. Among all, the highest degradation and mineralization efficiency of EDTA occurred in O3/UV and was 65% and 53% in 60 min, respectively. For citric acid, the highest degradation (77%) and mineralization (56%) efficiency was observed in the O3/H2O2/UV process. This indicates that selection of the advanced oxidation process is determined by the target contaminant.


Subject(s)
Electroplating , Ozone/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/chemistry , Hydrogen Peroxide , Metallurgy , Oxidation-Reduction , Ultraviolet Rays , Wastewater/chemistry , Water Pollutants, Chemical/analysis , Water Purification
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