Powder activated carbon/Fe3O4 hybrid composite as a highly efficient heterogeneous catalyst for Fenton oxidation of tetracycline: Degradation mechanism and kinetic

In this work, we prepared and used a composite of powder activate carbon/Fe3O4 magnetic nanoparticles (PAC/Fe3O4 MNPs) as a heterogeneous catalyst to remove tetracycline (TC) from aqueous solution. By using XRD, BET, VSM, SEM, TEM and EDX techniques, also, we tried to characterize the catalyst. The effects of pH, H2O2, catalyst dosages and also initial TC concentration on the degradation process were assessed. Based on the results, it was indicated that at low pH values and initial TC concentrations, the efficiency of the process is higher than the other values and concentrations studied in this work. Under the ambient conditions and setting the initial pH value and TC concentration at respectively 3.0 ± 0.2 and 10 mg L-1, the optimal dosage of reagents were recorded to be 0.3 g L-1 catalyst and 80.0 mM H2O2. The values of observed rate constants, kobs, increased by increasing the catalyst loading in the system; however, these values decreases when the initial TC concentration was increased. Our findings indicated that all of TC concentration was nearly degraded during the 180 min reaction. Regarding the reusability of PAC/Fe3O4 MNPs, the results showed that TC and TOC removal efficiencies of 94.5 and 32.3, respectively, can be achieved after four consecutive runs. By conducting the stability experiments, it was confirmed that PAC/Fe3O4 MNPs is a promising and effective catalyst in Fenton reactions and can be used to treat TC-contaminated water with very low loss of catalytic activity. © 2015 The Royal Society of Chemistry

Removal of total petroleum hydrocarbons from polluted urban soils of the outskirts of Ahvaz, southwestern Iran

Earlier phases of economic expansion and urban development have resulted in significant sources of urban soil contamination. Petroleum hydrocarbons are one of the most common groups of persistent organic contaminants in the environment. In this study, two types of treatment in 3 concentrations were prepared that were included plant treated by 1% oil pollution, treatment by 1% contamination without plant (as control), plant treated by 5% oil pollution, the 5% pollution treatment without plant (control), 10% oil pollution treatment with plant and 10% treatment without plant (control) that 3 replicates were prepared for each treatment. The obtained extracts were concentrated to 1 mL under a gentle stream of nitrogen gas, and then 2 μg of the sample was injected into a UNICAM 610 series gas chromatograph equipped with a flame ionization detector. Primary Total petroleum hydrocarbons amount in 1%, 5% and 10% concentration was respectively: 9027.40 mg/kg, 49599.03 mg/kg and 99548.28 mg/kg. After 4 months its amount in different concentration with plant was 126.43 mg/kg, 4463.92 mg/kg and 19611.50 mg/kg. The best total petroleum hydrocarbons removal efficiency was observed in all concentration at 120th day. The results of this study showed that vetiver can remove petroleum hydrocarbons from contaminated soils effective. <br /

Determining biokinetic coefficients for the upflow anaerobic sludge blanket reactor treating sugarcane wastewater in hot climate conditions

Acknowledgements The managing director of Imam Khomeini (pbuh) Agro-Industry in Shushtar and the laboratory expert of Agro-Industry Treatment Plant are highly appreciated for their cooperation in conducting this study.Peer reviewedPostprin

Survey of PAC Performance for Removal of Turbidity, COD, Coliform Bacteria, Heterotrophic Bacteria from Water of Karoon River

Backgrounds and Objectives: Selection of proper coagulants for turbidity removal and determination of effective methods to reduce coagulants dose and related costs in water treatment plants is of critical importance. The present study investigates the effect of returned sludge on improving the performance of poly-aluminum chloride (PAC) in turbidity, coliform bacteria, heterotrophic bacteria removal from drinking water during rapid mixing phase. Materials and Methods: In order to determine the optimal returned sludge volume injected during rapid mixing with PAC for turbidity, total coliform and hetrophic bacteria, experiments were conducted based on variables such as injected silt volume (from 0 - 125 ml), and varying turbidities from 58 - 112 NTU. At the end of each JAR experiments, remaining turbidity , microbial parameters of samples were measured . Coagulant efficiency in turbidity removal and microbial parameters were determined by Covariance, Duncan analyses and graphs were drawn by MS Excel . The results statistically showed significant among variables (P&lt;0.05). Results: The results showed that the maximum turbidity removal efficiency of 98.92 at 30 ppm was 10 ml while the maximum turbidity removal efficiency of 98.31 at 10 ppm was 4 ml. The maximum total coliform removal efficiency&nbsp; of 95.68 obtained for 10 ppm in 10 cc injected sludge volume.Conclusion: This study shows that addition of returned sludge to flash mixing can reduce the turbidity of samples

Evaluation of the Hospital Wastewater Activated Sludge Extended Aeration System in the Removal of Estrogenic Compounds (Case Study: Khuzestan Hospitals)

Background and Objective: Estrogen is a steroid hormone that is in the water and cause risks for aquatic organisms, especially fish is. Estrogenic hormones naturally (caused by endocrine) or artificial (due to hormonal contraceptives such as birth control pills) to sewage and hospital to find. This study aimed to determine the amount of estrogen in the sewage and Golestan and Abuzar hospital in Ahvaz were studied. Material and Methods: Sampling was done by tracking estrogen in the aquatic environment. 56 samples 4 months in different parts of the Golestan and Abuzar hospital wastewater treatment plant in Ahvaz were taken. Sample a little electro luminescence (ECL) were analyzed by laboratory Iranian city of Ahvaz. In this study, different forms of estrogen (estrone, 17-beta-estradiol, estriol, 17-alpha-ethinyl estradiol) has been studied as estrogen. Results: Mean hormone found in raw wastewater to the Golestan hospital wastewater treatment plant effluent from the treatment plant hormone 69.08 ng/l and 7.28 ng/l mean. Mean testosterone in Ahvaz Abuzar hospital treatment input 70.61 ng/l and 18.94 ng/l is refinery output. According to the results of high impact biological treatment is the removal of estrogenic compounds. Conclusion: Secondary treatment of sewage is effective in reducing hormones that can do this at this stage of the biological treatment effect

A salt resistant biosurfactant produced by moderately halotolerant Pseudomonas aeruginosa (AHV-KH10) and its application for bioremediation of diesel-contaminated sediment in saline environment

A halotolerant bacterial strain was isolated from oily-contaminated sites of Persian Gulf, which characterized as Pseudomonas aeruginosa (AHV-KH10) by 16S rRNA gene sequencing. This strain was used for bioremediation of diesel-contaminated sediments. Biosurfactant production was initially screened by using oil displacement test and drop-collapse method, followed by measurement of surface tension (ST) of growth medium. Produced biosurfactant was a rhamnolipid type biosurfactant and lowered the ST to 33.4 mN/m at the given critical micelle concentration (CMC) of 75 mg/L. Addition of 3 CMC rhamnolipid, inoculums size of 15 mL, biodegradation in slurry phase and salinity level of 6% led totally to a diesel biodegradation rate of 70% for initial concentration of 1000 mg/kg after 35 days. The maximum diesel removal occurred at the salinity content of 6% indicating the moderately halo-tolerant characteristics of isolated strain. Evaluation of bacterial growth showed a biomass yield of 0.33 mg VSS/mg diesel in selected conditions. The field performance of Pseudomonas aeruginosa AHV-KH10 was proved through the removal of the TPH content in unwashed sediment, which varied from 2390 to 1875 mg/kg within four months

The Study on Biodegradability Enhancement of Landfill Leachate by Fenton Oxidation

"n "n "nBackgrounds and Objectives: Leachate is one of the landfill products and also a wastewaterbearing the most advers effects on the environment. Biological methods are usually employed for treatment of young leachate (1-2 years) wich is of high concentration of organic compounds with low molecular weight. However these methods are not approprate for mature leachate (5-10years) due to having high rate of compounds with molecular weight and the presence of materials resistant to biodegradation and toxic compounds . Advanced oxidation process such as Fenton reagent used in treatment or biodegrability improvement of strong wastewater. In the present study the degrability improvement of mature leachate through oxidation fenton process in bench scale and in batch reactorhas been investigated."nMaterials and Methods: The samples have been taken from Ahwaz landfill and factors such as initial COD and BOD, pH, BOD5/COD were studies as degradability, the amount of Hydrogen Peroxide, Fe(II), optimal reaction time and optimal pH."nResults:The highest amount of COD removal was observed in PH=3-3.5 and 90 minutes of reaction time. H2O2=29700mg/land Fe2+=16500 mg/l in [Fe2+]/[H2O2]=1/14.8 molarity ratio were obtained as optimal amounts BOD5/COD was equal to 0.38."nConclusion: This study indicates that Fenton oxidation enhances the biodegradability of leachate