- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
STUDY OF AN ANNULAR PHOTOREACTOR WITH TANGENTIAL INLET AND OUTLET.II. THE UV/H <sub/>2</sub> O <sub/>2</sub> REACTIVE FLOW
摘要： The concentration profiles of species involved in the degradation of phenol by an advanced oxidation processes (AOP) are modeled using a CFD tool, in an annular reactor whose fluid dynamics was the object of a previous study. The reactive flow was fully described together with the kinetic model, which encompasses large kinetic constants, such as 101 0 L mol-1 s-1, and the radiation field. Phenol degradation can be simulated b y using relaxation factors of 1012 kg m-3 s-1 at least. The hydroxyl radical concentration profile, depends on the radiation field, performed by the discrete ordinate (DO) and the discrete transfer (DT) methods. Phenol can be completely degraded along the reactor. A centrifugal effect was observed, with higher concentration of degradation products along the inner wall at the reactor outlet.
关键词： Fluence rate,Advanced oxidation process,Computational fluid dynamics,Phenol degradation,Degradation kinetics,Parameter estimation,Modeling
更新于2025-09-10 09:29:36
-
Degradation and transformation of natural organic matter accountable for disinfection byproduct formations by UV photolysis and UV/chlor(am)ine
摘要： This research aimed to investigate the degradation of natural organic matter responsible for the formation of trihalomethane (THM), haloacetic acid (HAA) and haloacetonitrile (HAN) during UV photolysis and a co-exposure of UV with chlorine (UV/chlorine) and chloramine (UV/chloramine). Low pressure UV (LPUV) and vacuum UV (VUV) lamps were used for photolysis. VUV and LPUV irradiation changed aromatic/unsaturated structures to aliphatic ones, resulting in decreased THM and HAN formation. Following irradiation for 60 minutes, LPUV decreased THM and HAN by 16% ± 2% and 20% ± 6%, respectively. VUV decreased THM and HAN formation by 23% ± 3% and 20% ± 8%, respectively. HAA formation increased following photolysis. UV/chlorine treatment decreased THM, HAA and HAN. Higher chlorine doses had an inversely proportional relationship with THM and HAN formation. A chlorine dose of 4 mg·L?1 led to the greatest reductions, corresponding to 42% ± 2%, 10% ± 10% and 18% ± 6% for THM, HAA and HAN, respectively. UV/chloramine decreased the formation of THM more than UV/chlorine. With a chloramine dose of 4 mg·L?1, THM, HAA and HAN formation decreased by 74% ± 10%, 10% ± 10% and 11% ± 10%, respectively. This study showed the potential use of UV/chlor(am)ine for controlling the formation of THM, HAA and HAN.
关键词： UV/chlor(am)ine,advanced oxidation process,disinfection byproducts,UV photolysis
更新于2025-09-09 09:28:46
-
A systematic investigation on the bactericidal transient species generated by photo-sensitization of natural organic matter (NOM) during solar and photo-Fenton disinfection of surface waters
摘要： In this work, the role of dissolved oxygen in the solar and the photo-Fenton-mediated E. coli inactivation process was put under scrutiny. The effect of transient species that were produced in the Nordic Reservoir (NR) NOM, SR Humic acid (SRHA), and SR Fulvic acid (SRFA) was studied in presence of various natural organic matter isolates (NOM), namely Suwannee River (SR) NOM, detail. The role of 1??2 in this reaction was systematically evaluated by modifying the O2 concentration (N2/O2 purging) and the matrix composition (10, 50, and 100% deuterium oxide (D2O) v/v). In the presence of NOM, 1??2 was generated and the enhancement of E. coli inactivation rate due to charge transfer from triplet state to molecular oxygen. The comparison between SR and NR NOM showed that for these compounds, triplet state of NOM (3NOM*), and 1??2 were the more favorable active species in E. coli inactivation, respectively. Also, the second order rate constants (????.???????? 2???? ) of E. coli with 3NOM*, and 1??2 were calculated by using the steady state approximation. The obtained results showed that the rate values of 1??2 related to NR NOM was ~ 5.6 times higher than SR NOM, while the rate values of 3NOM* for SR NOM was ~ 8.7 times higher than NR NOM. We also determined the effect of these organic matter isolates in the photo-Fenton process and its constituents (solar/Fe2+, solar/H2O2, and solar/Fe2+/H2O2). In presence of NOM, the photo-Fenton process inactivation rates increased which confirmed that the combined processes has additional pathways generated with disinfecting effect during solar exposure of bacteria.
关键词： solar disinfection (SODIS),singlet oxygen,triplet state,Advanced oxidation process (AOPs),E. coli
更新于2025-09-09 09:28:46
-
Exploration of charge carrier delocalization in the iron oxide/CdS type-II heterojunction band alignment for enhanced solar-driven photocatalytic and antibacterial applications
摘要： Recyclable magnetic photocatalysts of iron oxide (IO)/CdS core/shell nanocrystals (CSNCs) were prepared by a facile sequential one-pot method using 3, 3'-thiobispropanoic acid (TDP) as a bridge. The CSNCs showed redshift in absorption edge, decrease in the optical band gap, reduced exciton decay rates and increment in particle size. Quenching studies have been employed to understand the position of the electron/hole wave-functions at the IO/CdS interface. Antimicrobial tests have also been performed using broth tube dilution and disc diffusion methods against S. aureus. Additionally, photocatalytic properties of IO/CdS CSNCs have been evaluated for the decomposition of xylenol blue. In comparison with CdS quantum dots (QDs) and iron oxide nanoparticles (IONPs), the IO/CdS CSNCs showed improved photocatalytic and bactericidal activities. Finally, levels of oxidative damage to proteins and lipids were evaluated.
关键词： Photocatalysis,Wave-function engineering,Advanced oxidation process,Iron oxide/CdS nanocrystals,Photocatalytic bacterial inactivation
更新于2025-09-04 15:30:14