半导体光催化氧化法处理印染废水的研究

研究了用光催化氧化的方法实际印染废水的可能性，催化剂为TiO2，并将其制膜固定在光反应器内壁上，以125W高压汞灯为源，对某丝绸厂的印绸厂的印废水进行了处理实验，取得了脱色率100％，CODCr去除率85．6％的效果。     

Effects of Fe2O3, organic matter and carbonate on photocatalytic degradation of lindane in the sediment from the Liao River,China

Fourteen sediment samples with different content of Fe₂O₃ were collected from the lower reaches of the Liao River in China. The photodegradation of lindane on the surfaces of these sediments was investigated to observe the effects of Fe₂O₃ and other photoinducable substances, such as TiO₂ and organic substances, on photodegradation of lindane. A partial least-squares (PLS) analysis model was developed to find out the statistical relationship between the photodegradation and the contents of these photoinducable substances. It was concluded from the PLS analysis that inorganic carbon and organic carbon have negative effects, whereas Fe₂O₃ and TiO₂ accelerate the photodegradation of lindane in the sediment samples when 365 nm UV light was used as light source. In all cases of the experiments, the photodegradation of lindane in the sediment samples were fitted for pseudo-first-order kinetics.     

Photodegradation of Dyes in Aqueous Solutions containing Fe(III) -hydroxy Complex II. Solar Photodegradation Kinetics

The solar photodegradation of five dyes, C.I. reactive red 2, C.I. reactive blue 4, C.I. reactive black 8, C.I. basic red 13, and C.I. basic yellow 2, were studied in a sunlight/Fe(III)-hydroxy system. It was observed that the photodegradation of these five dyes were pseudo-first order reactions, which has a little difference with the photodegradation kinetics of the dyes with UV-light as the irradiation source. The comparison between the two studies is also conducted.     

水中isoproturon的紫外降解动力学研究

采用atrazine法测定了紫外反应装置的光强,通过H_2O_2法测定了装置的有效光程值。进而通过这些光强和光程,建立了低压紫外条件下水中常见的苯脲类除草剂—isoproturon的拟一级降解动力学模型。基于此,文章考察了不同紫外强度和不同pH下isoproturon的紫外降解特性。Isoproturon的紫外降解反应的拟一级反应速率常数随着紫外强度的增大而逐渐增加,进而求算得isoproturon的量子产率为0.00405 mol/einstein。溶液的p H在5~9范围内变化时,isoproturon的紫外降解效率不会受到显著影响。结果表明:增大紫外光强时可实现isoproturon这种新兴污染物的有效降解,而改变溶液的p H则无明显的提高效果。     

Evaluation and in situ assessment of photodegradation of polyaromatic hydrocarbons in semipermeable membrane devices deployed in ocean water

Semipermeable membrane devices (SPMDs) were deployed in water using four different methods: a typical SPMD cage with and without a mesh cover, a bowl chamber and without any protection. In addition to routinely used performance reference compounds (PRCs), perdeuterated dibenz[a,h]anthracene was added. Due to its high sampler to water partition coefficient no measurable clearance due to diffusion was expected during the deployment period, hence any observed loss could be attributed to photodegradation. The loss of PRCs was measured and SPMD-based water concentrations determined. Results showed that a typical SPMD deployment cage covered with mesh provided the best protection from photodegradation. Samplers which had undergone the highest photodegradation underestimated PAH water concentrations by up to a factor of 5 compared to the most protected SPMDs. This study demonstrates that the potential for photodegradation needs to be addressed when samplers are deployed in water of low turbidity.     

Effect of transition metal ions on photocatalytic activity of ZnO in bleaching of some dyes

The photocatalytic bleaching of some dyes (erythrosin-B, fast green FCF and eosin Y) was carried in the presence of semiconducting zinc oxide and was observed spectrophotometrically. The effects of various operating variables like pH, concentration of dyes, amount of semiconductor and light intensity on the efficiency of the reaction were also observed. Attempts have been made to study the effect of the addition of other metal ions (Fe²⁺, Ni²⁺, Ag⁺, Cu²⁺, Co²⁺, V²⁺ and Mn²⁺). All the added metal ions increase the reaction rate to some extent. It was also observed that Fe²⁺ is most effective in photobleaching of erythrosin-B, whereas V²⁺ is more effective in the cases of fast green FCF and eosin Y. A tentative mechanism has been proposed.     

Microwave mediated synthesis and characterization of CeO2-GO hybrid composite for removal of chromium ions and its antibacterial efficiency

A facile fabrication and processing of cerium oxide-graphene oxide(CeO_2-GO) hybrid nanocomposites without the use of any surfactant or any organic solvents using chemical method and treatment with microwave irradiation technique are reported. In-situ hexagonal nano cerium oxide particles embedded on the layered surface of GO sheets were investigated for the photodegradation of dyes, removal of chromium Cr(VI) ions and against antibacterial studies. The results imply that hybrid nanocomposites shows enhanced 5-folds of photocatalytic activities in UV(ultraviolet) light irradiation and exhibited rapid efficiency in the elimination of chromium ion better than the pure GO and CeO_2, which are inhibited by competent photosensitive electron inoculation and controlling the electron–hole recombination. The synergetic effect of CeO_2-GO composites played a vital role in showing better results against model bacterium than GO and CeO_2 are due to higher physical interaction endorsed to the stress of membranes acute by piercing edges,large surface area, and higher adsorptive conditions of graphene oxide sheets tailored with ceria particles. The amount of charge transferred at the interface increases with the concentration of O atoms, demonstrating the interaction between CeO_2 and GO is much stronger than CeO_2 and GO are due to the decrease of the average equilibrium distance between the interfaces. The CeO_2-GO interface staggered band alignments existing between the CeO_2 surfaces and GO which shows an excellent synergism. The structure and morphology of composites were tested by X-ray diffraction(XRD), Fourier transform infrared(FTIR), Raman, X-ray photoelectron spectroscopy(XPS), and high-resolution transmission electron microscope(HR-TEM).     

Phototransformation and ecotoxicity of the drug Naproxen-Na

The phototransformation of naproxen Na in aqueous medium has been investigated. Irradiation of the drug in drinking water affords seven photoproducts. Three of them are dimeric photoproducts isolated for the first time. The compounds, isolated by chromatographic processes, have been identified by spectroscopic means. The toxicity of the photoproducts and the parent drug has been assayed on Daphnia magna and Vibrio fischeri. The results indicate that some photoproducts are more toxic than naproxen.     

Photodegradation of methylmercury in Jialing River of Chongqing,China

Photodegradation (PD) of methylmercury (MMHg) is a key process of mercury (Hg) cycling in water systems, maintaining MMHg at a low level in water systems. However, we possess little knowledge of this important process in the Jialing River of Chongqing, China. In situ incubation experiments were thus performed to measure temporal patterns and influencing factors of MMHg PD in this river. The results showed that MMHg underwent a net demethylation process under solar radiation in the water column, which predominantly occurred in surface waters. For surface water, the highest PD rate constants were observed in spring (12 × 10^− 3 ± 1.5 × 10^− 3 m²/E), followed by summer (9.0 × 10^− 3 ± 1.2 × 10^− 3 m²/E), autumn (1.4 × 10^− 3 ± 0.12 × 10^− 3 m²/E), and winter (0.78 × 10^− 3 ± 0.11 × 10^− 3 m²/E). UV-A radiation (320–400 nm), UV-B radiation (280–320 nm), and photosynthetically active radiation (PAR, 400–700 nm) accounted for 43%–64%, 14%–31%, and 16%–45% of MMHg PD, respectively. PD rate constants varied substantially with the treatments that filtered the river water and amended it with chemicals (i.e., Cl⁻, NO₃⁻, dissolved organic matter (DOM), Fe(III)), which reveals that suspended particulate matter and water components are important factors in affecting the PD process. For the entire water column, the PD rate constant determined for each wavelength range decreased rapidly with water depth. UV-A, UV-B, and PAR contributed 27%–46%, 6.2%–12%, and 42%–65% to the PD process, respectively. PD flux was estimated to be 4.7 μg/(m²·year) in the study site. Our results are very important to understand the cycling characteristics of MMHg in the Jialing River of Chongqing, China.     

溶液中阴离子和腐殖酸对UV/H2O2降解2,4-二氯酚的影响

研究了UV/H2O2工艺对2,4-二氯酚(2,4-DCP)的去除效果和水中阴离子、腐殖酸对该工艺降解2,4-DCP的影响.结果表明:UV/H2O2工艺可以有效地去除水中2,4-DCP,光降解过程符合一级反应动力学模型;在H2O2投加量为8 mg/L、1个30 W低压汞灯照射下,2,4-DCP在蒸馏水和自来水中反应速率常数分别为0.023 2、0.016 2 min-1;NO-3、Cl-、HCO-3对2,4-DCP光降解有抑制作用,当3种阴离子摩尔浓度为0.5、10.0、20.0 mmol/L时,对2,4-DCP光降解的抑制程度为HCO-3＞NO-3＞Cl-;腐殖酸在低浓度时,促进光降解反应进行,在高浓度时,2,4-DCP的光降解受到抑制.自来水中的反应速率常数低于蒸馏水中的反应速率常数是由于水中多种阴离子和腐殖酸影响的结果.