UV/H2O2, UV/H2O2/Fe (II) and UV/H2O2/Fe (III) processes are very effective in removing pollutants from wastewater and can be used for treatment of dyestuff units wastewaters. In this study, Rhodamine B was used as a typical organic dye. Rhodamine B has found wide applications in wax, leather, and paper industries. The results from this study showed that this dye was degradable in the presence of hydrogen peroxide under UV-C irradiation (30W mercury light) and Photo-Fenton process. The dye was resistant to UV irradiation. In the absence of UV irradiation, the decolorization efficiency was very negligible in the presence of hydrogen. The effects of different system variables such as initial dye concentration, duration of UV irradiation, and initial hydrogen peroxide concentration were investigated in the UV/H2O2 process. Investigation of the kinetics of the UV/H2O2 process showed that the semi-log plot of the dye concentration versus time was linear, suggesting a first order reaction. It was found that Rhodamine B decolorization efficiencies in the UV/H2O2/Fe (II) and UV/H2O2/Fe (III) processes were higher than that in the UV/H2O2 process. Furthermore, a solution containing 20 ppm of Rhodamine B was decolorized in the presence 18mM of H2O2 under UV irradiation for 15 minutes. It was also found that addition of 0.1 mM Fe(II) or Fe(III) to the solution containing 20 ppm of the dye and 5mM H2O2under UV light illumination decreased removal time to 10 min.

One of the main carcinogenic pollutants occurring in in the wastewater of some chemical industries is ortho toluidine (OT). In this project the removal of OT was investigated by UV/H2O2 and UV/US/H2O2 processes in batch recirculated reactors. The effect of three main factors including initial concentration of OT, H2O2, and pH was investigated as an influencing variables on UV/H2O2 process at 25°C and the optimum conditions were obtained as 40 mM of hydrogen peroxide, 50 mg/l of OT, and pH at 9. The rate constant of the reaction was increased by addition of ultrasonic waves to UV/H2O2 process. The UV/US/H2O2 process was investigated at 25, 30, and 35 °C and the maximum efficiency was found at 35 °C. Through kinetic studies, the psudo first order rate constants were obtained as 0.0442 min-1 (at optimum conditions) and 0.0593 min-1 in UV/H2O2 and UV/US/H2O2 processes, respectively. The removal of total organic carbon (TOC) was obtained as 38 and 52.5% in UV/H2O2 and UV/US/H2O2 processes. Also, the effect of volume and volumetric flowrate of the circulated wastewater and kinetic reactions were explored so that the efficiency of the processes was reduced by increasing in the volume of the wastewater and it was decreased by increasing in the volumetric flowrate of circulated waste water.

Background & Aims of the Study: Organic dyes with a complex structure are often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment and if released to the environment without treatment can endanger the environment and human health. The aim of this study was to evaluate the performance of H2O2 and H2O2/Fe0 Iron in removal of dye Acid Red 18 from aqueous solutions.Materials & Methods: This study was conducted at the laboratory scale. In this study, the removal efficiency of Acid Red 18 from a synthetic solution by H2O2 and H2O2/Fe0 was investigated. As well as Effect of solution pH, dye concentration, Concentration of Nanoscale Zero-Valent Iron, H2O2 and contact time in decolorization efficiency was investigated.Results: Results show that in pH=3, Contact time of 80 minutes, dye concentration of 50 mg/l and Concentration of Nanoscale Zero-Valent Iron of 2 g/l and H2O2 concentration equal to 200 mmol/l, the removal efficiency was about 98%.Conclusions: According to the results of experiments, H2O2/Fe0 has high efficiency in removal of Acid Red 18 from aqueous solution.

Background: Peroxide-producing lactobacilli provide protection from infection for the female reproductive tract. However, in vitro studies demonstrated that H2O2-produced by Lactobacillus is not the cause of inhibition of pathogens. It is not exactly known how H2O2-producing lactobacilli are involved in the protection of the vaginal environment.Objectives: This study aimed to evaluate the importance of the interaction between H2O2-producing lactobacilli and their host for the resistance of the vaginal biotope.Materials and Methods: In this study, we used vaginal lactobacilli (11 H2O2-roducing strains and 11 non-H2O2-producing strains). The influence of epithelial cells on the growth and antibacterial activity of lactobacilli were evaluated. The effects of lactobacilli on the antibacterial activity of the epithelial cells, muramidase and lactoferrin were also determined.Results: Vaginal epithelial cells stimulated the growth and antibacterial activity of H2O2-producing lactobacilli in a greater extent than that of the non-H2O2-producing lactobacilli. Mainly, the H2O2-producing lactobacilli were capable of increasing the activity of the host antimicrobial peptides (muramidase and lactoferrin) as well as the antibacterial activity of the epithelial cells.Conclusions: The involvement of the peroxide-producing lactobacilli in the protection of vagina was due to their ability to effectively interact with the host. This is expressed on one side to stimulate the growth and antagonistic activity of lactobacilli and on the other side to increase the antibacterial activity of the host defense factors (muramidase, lactoferrin and metabolites of epithelial cells).

The removal of glucose from aqueous solutions by different processes such as nano-TiO2, H2O2 and nano- TiO2/H2O2 was investigated and the effect of some parameters such as pH (range of 2-10), nano-TiO2 dosage (0.01-0.05 g), H2O2 concentration (100-500 ppm), glucose concentration (1000-4000 ppm) and temperature (35, 45, 55, 65oC) was studied. The H2O2 and TiO2 concentrations were optimized using different concentrations of them. The optimum conditions of the nano-TiO2/H22O2 treatment were: [H2O2]0=100 ppm, [nano-TiO2]0=0.03 g/L, initial pH=6 and Temperature=65oC.Results showed the pseudo-first-order kinetic model was the most appropriate model, describing the degradation kinetic.

Background and ObjectiveTreatment of hospital wastewaters has an important role in reducing the discharge of organics and pharmaceutical compounds into aquatic environments. Nowadays، advanced oxidation processes were extensively used for the removal of organic compounds from treated effluents. The study aimed to examine organic compounds removal from real treated effluent of a hospital treatment plant using a lab scale UV/H2O2/TiO2 process by optimizing the process. Materials and MethodsThe effluent characteristics including COD، TOC and DOC were measured and recorded. A hybrid advanced oxidation process (UV/H2O2/TiO2) was used for the removal of organic compounds. The experiments were designed using surface response methodology (RSM). The effects of the independent factors including pH، duration of UV irradiation، H2O2 and TiO2 concentrations on COD، TOC، DOC and the approximate cost of treatment were assessed by analysis of variance (ANOVA). ResultsThe optimal condition was 7. 2 for pH، 50 mg/L for H2O2، 100 mg/L for TiO2 and 19. 65 min for irradiation time. This condition provided the maximum removal percentage for organic compounds with a minimum cost. The removal efficiency for TOC، DOC and COD were 63. 9، 52. 9، and 64. 7%، respectively. The treatment cost was approximated to be $ 0. 71 per one liter of the effluent. ConclusionIrradiation and H2O2 concentration had the greatest impact on the cost of the treatment. UV/H2O2/TiO2 process seems to be an expensive process for tertiary treatment of wastewater. However، further investigations are required to evaluate the cost effectiveness of the process for a full scale operation.