Papers by Keyword: UV/H₂O₂

Abstract: In the study, UV alone and UV/H₂O₂ treatment experiments were performed using secondary treated wastewater spiked with 30 pharmaceuticals. UV intensity of 0.384 mW/cm² was used for calculating UV dose introduced to tested water during each treatment. UV doses of 38 mJ/cm² to 5,644 mJ/cm² were needed for 90% degradation of the 30 pharmaceuticals in secondary effluent. These UV doses are much higher than those required for typical disinfection (40 mJ/cm² ~ 140 mJ/cm²). It can be known that considerable UV dose will be required for the effective removal of pharmaceuticals in secondary effluent. All the pharmaceuticals except 7 pharmaceuticals including cyclophosphamide and 2-QCA (727 mJ/cm² ~ 1,695 mJ/cm²) were degraded by more than 90% under UV dose of 691 mJ/cm² (contact time : 30 min) during UV/H₂O₂ treatment. As a consequence, it is considered that UV/H₂O₂ treatment can contribute to the reduction of energy consumption for the effective pharmaceuticals removal as well as the improvement of the photodegradation rates for the investigated pharmaceuticals.

Abstract: – Oxytetracycline (OTC), a widely used of veterinary antibiotic, was degraded inside a UV/H₂O₂ system. Kinetic study was conducted at 30°C of temperature and pH 6.37, as suggested by the previous optimization experiment. About 250, 375 and 500 ppm initial OTC concentration were used for the kinetic studies, at H₂O₂ concentration of 0.116 M. The experimental data were plotted against the pseudo zero-th, first and second order of kinetic. Based on regression coefficient value, the data was well fitted with the pseudo first order of kinetic. The calculated value of k_obs was 0.181 min^-1.

Abstract: Effluent containing high concentration of alkanolamine from a sweetening process of natural gas plant is commonly generated during maintaining, cleaning and scheduled inspection of the absorption and desorption column. The effluent is not readily biodegradable and cannot be treated in the conventional biological treatment. Advanced oxidation processes (AOPs) is a promising method for the treatment of recalcitrant organic contaminant. Most methods used are Fenton reagent, UV/Ozone and UV/H₂O₂. Based on the advantages of the UV/H₂O₂ such as no formation of sludge during the treatment, high ability in production of hydroxyl radical and applicable in the wide range of pH, the UV/H₂O₂ has been chosen to treat the effluent from refinery plant, which has high concentration of methyldietnaolamine (MDEA). The factors influencing in the degradation of refinery wastewater that contain MDEA were screened using response surface methodology (RSM). It was found that degradation process of the refinery effluent was highly dependent on oxidant concentration (H₂O₂) and initial pH. Temperature of oxidation process was found oppositely. Since the temperature gave insignificant effect on the TOC removal process, hence the independent factor temperature will be eliminated during the further optimization process condition of degradation. Thus, the optimization process condition of degradation will be more effective and simpler.

Abstract: The efficacy of the UV-H₂O₂ treatment to degrade the antibiotic chloramphenicol (CHL) was investigated at 20 °C using a low-pressure mercury lamp as UV source. A two-level factorial design was used to study the effects of initial CHL (c₀ = 4080 mg L¹) and H₂O₂ (h₀ = 2050 mM) concentrations, reaction time (t = 3070 min) and irradiance level (I = 400800 μW cm²) on CHL degradation. Under the best conditions (c₀ = 40 mg L¹, h₀ = 20 mM, t = 70 min, I = 800 μW cm²), almost 96% of the antibiotic was degraded. No residual antibiotic activity was detected in the treated solution, thereby confirming the efficacy of the UV-H₂O₂ process.

Abstract: The degradation of atrazine in UV/H₂O₂ advanced oxidation process was studied. The combined UV/H₂O₂ process could effectively degraded atrazine, which is attributed to the strong oxidation strength of hydroxyl radical produced. Results show that atrazine degradation rate was affected by H₂O₂ concentration and initial atrazine concentration. The degradation rate constant (k) increased with H₂O₂ concentration from 20 to 80 mg/L and decreased when H₂O₂ concentration exceeded 120 mg/L. The degradation rate of atrazine decreased with increasing atrazine concentration. NO₃^-¡¢Cl^-¡¢HCO₃^- have inhibitory action on atrazine degradation. The higher inorganic anions concentration was, the stronger inhibitory action would be. When their concentrations were 0.5¡¢5 and 20 mmol/L, respectively, their inhibitory action order is HCO₃^- > NO₃^->Cl^- all the time.

Abstract: At present, many researchers focus on UV/H2O2 technology which is used to treat wastewater. In this paper, using “UV” and “Hydrogen Peroxide” as key words, all literatures in EI Index from 1969 to 2011 were searched by principle of literature metrology analysis. A detailed analysis was carried out in view of the year, journal, institution, country and language to reveal the status of international research and development on this technology. The statistics results show that a total of 1936 articles is published in 42 years and the literature number has increased year by year. The most articles were published in the last 10 years. Chinese researcher publishes the most articles all over the word. University is the main publication institution and English is the main language. Most of the articles were published on Journal of Hazardous Materials, Water Research and Water Science & Technology.

Abstract: The degradation of Benzyl butyl phthalate (BBP) at low concentration (μg•L^-1 range) by the direct UV irradiation, H₂O₂ oxidation and UV/H₂O₂ advance oxidation process was investigated in this study. The experiment results showed that the decomposition efficiency of UV or H₂O₂ was worse than that of UV/H₂O₂. Under the condition of 24.26μw•cm^-2 UV irradiation and 2.49 mM H₂O₂, the degradation efficiency of BBP at low concentration was over 90% after 30 min. In addition, the solution pH was found to have no significant effect on the photo-degradation of BBP. The degradation of low concentration BBP in the tail water of municipal sewage plant was 84.23% with UV/H₂O₂ at the UV irradiation (24.26μw•cm^-2) and H₂O₂ (2.49 mM) without adjusting pH.

Abstract: nanosized titania catalyst and transition metal doped titania photocatalysts such as TiO₂/Ag, TiO₂/Cu and TiO₂/Ag/Cu were used for photocatalytic degradation of Amaranth. Doping of titania was done with impregnation method. Photocatalytic activity was checked in terms of percentages of decolorization, COD removal and TOC removal. It was found that TiO₂/Ag/Cu doped photocatalyst was more effective for Amaranth dye degradation under feasible treatment conditions. For decolorization, Amaranth took irradiation time of 210 min with UV/H₂O₂ but it took only 60 min with TiO₂/Ag/Cu doped photocatalyst. Only 29% COD and 49% TOC removal were achieved with homogeneous photodegradation, whereas with TiO₂/Ag/Cu heterogeneous photodegradation, 100% COD and 98% TOC removal was achieved in 9h for 50 ppm aqueous Amaranth solution. The relative electrical energy consumption per order of magnitude for photocatalytic degradation of Amaranth was considerably lower with TiO₂/Ag/Cu catalyst than that with UV/H₂O₂ and other combinations of doped photocatalyst. The photocatalysts were characterized using XRD and TEM analysis.

Abstract: Hyperbolic model could be established to describe the degradation performance of Methylene Blue (MB) using UV/H₂O₂ process. The effects of initial H₂O₂ dosage on MB removal, instant ▪OH concentration and reaction rate were investigated. The results show that the optimal H₂O₂ dosage is 13.24 mM and after 50min the MB removal is around 85%. The MB degradation process is followed the hyperbolic model which can calculate instant ▪OH concentration and reaction rate.

Abstract: Estrogens such as estrone (E1), 17β-estradiol (E2) and estriol (E3) which are excreted by humans and animals or synthetic compounds such as 17α-ethinylestradiol (EE2) are a group of biologically active compounds that are synthesized from cholesterol and have a steroid ring in common. Steroid estrogens harm to organisms at very low concentrations with much more endocrine function than other EDCs. Obviously, it is an important issue to explore their degradation mechanisms and effective methods. In the present studies, 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) were used as target compounds, and the photodegradation of them were investigated in aqueous solution using natural sunlight produced using a xenon lamp, or ultraviolet light via a Hg lamp.