Urban runoff treatment using nano-sized iron oxide coated sand with and without magnetic field applying

Increase of impervious surfaces in urban area followed with increases in runoff volume and peak flow, leads to increase in urban storm water pollution. The polluted runoff has many adverse impacts on human life and environment. For that reason, the aim of this study was to investigate the efficiency of nano iron oxide coated sand with and without magnetic field in treatment of urban runoff. In present work, synthetic urban runoff was treated in continuous separate columns system which was filled with nano iron oxide coated sand with and without magnetic field. Several experimental parameters such as heavy metals, turbidity, pH, nitrate and phosphate were controlled for investigate of system efficiency. The prepared column materials were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDXA) instruments. SEM and EDXA analyses proved that the sand has been coated with nano iron oxide (Fe3O4) successfully. The results of SEM and EDXA instruments well demonstrate the formation of nano iron oxide (Fe3O4) on sand particle. Removal efficiency without magnetic field for turbidity; Pb, Zn, Cd and PO4 were observed to be 90.8%, 73.3%, 75.8%, 85.6% and 67.5%, respectively. When magnetic field was applied, the removal efficiency for turbidity, Pb, Zn, Cd and PO4 was increased to 95.7%, 89.5%, 79.9%, 91.5% and 75.6% respectively. In addition, it was observed that coated sand and magnetic field was not able to remove NO3 ions. Statistical analyses of data indicated that there was a significant difference between removals of pollutants in two tested columns. Results of this study well demonstrate the efficiency of nanosized iron oxide-coated sand in treatment of urban runoff quality; upon 75% of pollutants could be removed. In addition, in the case of magnetic field system efficiency can be improved significantly

Defluoridation of water via Light Weight Expanded Clay Aggregate (LECA): Adsorbent characterization, competing ions, chemical regeneration, equilibrium and kinetic modeling

International audienceNatural, H2O2 and MgCl2 - modified Light Weight Expanded Clay Aggregate (LECA) were used as fluoride adsorbents. Characterization of LECA and its modified forms was done by infra-red, X-ray diffraction, scanning electron microscope and X-ray fluorescence studies. The specific surface area of HML and MGML was 3.34 and 3.97 times greater than that of NL (11.72 m2/g). Improved chemical composition of Magnesium (as oxide) to 15.6% by 2 M MgCl2 solution was ascertained through XRF results. The fluoride levels were reduced (within the safe limit of WHO: 0.5-1.5 mg/L−1) to 0.39 mg/L, 1.0 mg/L and 0.075 mg/L respectively using natural (NL), H2O2 (HML) and MgCl2 - modified LECA (MGML) at a pH of 6.0 and initial fluoride concentration of 10 g/L for an equilibrium time of 120 min. The sorption capacities of 8.53 mg/g, 17.83 mg/g and 23.86 mg/g were determined for NL, HML and MGML respectively. Validation of kinetic and isotherm models was checked for the present fluoride sorption dynamics. The thermodynamic data revealed that the present fluoride sorption was spontaneous, exothermic and ends up with decrease in randomness. Prediction of fluoride sorption mechanism for onto natural and modified LECA forms was also elucidated. Chloride and sulfate were the highly competing species against fluoride sorption. Regeneration efficiency of the spent LECA materials prompted the ability of MGML even after five cycles of adsorption-regeneration processes

Removal of hardness agents, calcium and magnesium, by natural and alkaline modified pumice stones in single and binary systems

International audienceNatural and alkaline modified pumice stones were used for the adsorption of water hardening cations, Ca2+ and Mg2+. The adsorbents were characterized using XRF, XRD, SEM and FTIR instrumental techniques. At equilibrium time and for 150 mg/L of a given cation, removal efficiencies were 83% and 94% for calcium and 48% and 73% for magnesium for raw and modified pumices, respectively. The optimal pH for raw and modified pumices were found to be 6.0, leading to the removal of 79 and 96% of calcium and 51 and 93% of magnesium by 10 g/L of raw and modified pumice adsorbents, respectively. Maximum adsorption capacities were 57.27 and 62.34 mg/g for Ca2+ and 44.53 and 56.11 mg/g for Mg2+ on the raw and modified pumices, respectively. Ca2+ and Mg2+ adsorption capacities of the pumice adsorbents decreased in the presence of competing cations. Less than 300 min were needed to achieve 99 and 92% desorption of the adsorbed Ca2+ and 100 and 89% of the adsorbed Mg2+ from the natural and modified pumices, respectively. After treating synthetic water solution simulating an actual water stream with the alkali-modified pumice, total hardness of the treated sample met the required standard for drinking water, namely below 300 mg/L of CaCO3 (297.5 mg/L). The studied pumice adsorbents, and especially the treated pumice, can be therefore considered as promising low cost adsorbents, suitable for the removal of hardness ions from drinking water

Removal of tetracycline antibiotic from aqueous solutions using natural and modified pumice with magnesium chloride

Background: Tetracycline is one of the most commonly used antibiotics that cause pollution of surface water, groundwater and soil when it enters the environment. Objective: The purpose of this study was to investigate the modified pumice capacity with magnesium chloride in order to remove tetracycline antibiotics from aqueous solutions and compare the modified pumice with natural pumice. Materials and methods: The various and effective factors on adsorption were evaluated; these factors include pH, amount of adsorbent, tetracycline concentration, time and the impact of confounding factors. Thermal and chemical regeneration of the adsorbent was performed. Results: The highest amount of tetracycline adsorption in the synthetic solution that was reached at 180 min (adsorbent: 12 g/L, pH: 3) using modified pumice with magnesium chloride (50 mg/L) was 95%. The highest amount of tetracycline adsorption in the synthetic solution that was reached at 180 min (adsorbent: 8 g/L, pH: 3) using natural pumice (75 mg/L) was 93.3%. In the synthetic solution, interfering factors, such as nitrate, chloride, sulfate and water hardness increased the tetracycline adsorption for modified pumice. The adsorption efficiency was reduced by alkalinity. In the presence of all the interfering factors (except alkalinity) and thermal regeneration, the modified pumice showed better results when compared with the natural pumice. Conclusion: Natural and modified pumice have a relatively good efficiency in tetracycline adsorption from real solutions. Their availability, ease of use, and thermal regeneration capacity put forward their great potential to be used in the adsorption of tetracycline antibiotic from the wastewater of pharmaceutical industries

Health risk assessment of heavy metal intake due to fish consumption in the Sistan region, Iran

The heavy metal (Pb, Cd, Cr, and Ni) content of a fish species consumed by the Sistan population and its associated health risk factors were investigated. The mean concentrations of Pb, Cd, and Cr were slightly higher than the standard levels. The Ni content of fish was below the maximum guideline proposed by the US Food and Drug Administration (USFDA). The average estimated weekly intake was significantly below the provisional tolerable intake based on the FAO and WHO standards for all studied metals. The target hazard quotients (THQ) of all metals were below 1, showing an absence of health hazard for the population of Sistan. The combined target hazard quotient for the considered metals was 26.94 × 10â��3. The cancer risk factor for Pb (1.57 × 10â��7) was below the acceptable lifetime carcinogenic risk (10â��5). The results of this study reveal an almost safe level of Pb, Cd, Cr, and Ni contents in the fish consumed by the Sistan population

Investigation of Modified Pumice with HCl and NaOH for Removal of Fluoride from Aqueous Solution

Background: Fluoride is an essential element for human health body, since in standard levels, it prevents the tooth decay. If fluoride concentration in drinking water exceeds from standard levels, it can leads to some diseases such as alzeimer syndrome, sterility, brittle bones, and thyroid disorder. So, removal of excess amounts of fluoride seems to be essential in order to health protection and prevention of the environment. Methods: In this work, modified pumice with HCl and NaOH were used for removal of fluoride from aqueous solution. Several experimental parameters including pH (2-10), temperature (20-60°C), adsorbent dosage (2-10 g/L), initial fluoride concentration (5-20 mg/L), and contact time were studied. All experiment were conducted in batch system by keeping constant one parameter and changing others. Results: Results showed that removal efficiency was increased with increase in contact time, initial fluoride concentration and adsorbent dosage. The maximum removal efficiency was observed at pH 6, 10 g/L adsorbent dosage, 20°C solution temperature, 90 min reaction time and 20 mg/L of fluoride concentration. Moreover, the maximum removal efficiency was observed by adsorbents modified with HCl. In general, results revealed that modified Pumice with HCL could remove 96% of fluoride at 90 min contact time, pH=6, 20°C and 20 mg/L of fluoride concentration. Conclusion: Results showed that pumice modified with HCl and NaOH had high capacity in removal of fluoride which the capacity was higher for pumice  modified with HCl

EFFECT OF MEDIUM NUTRIENTS ON Cr(III) REMOVAL BY PHANEROCHAETE CHRYSOSPORIUM, Aspergillus niger AND A. oryzae

International audienceIn this work, the effect of the addition of some nutrients on fungal growth and removal of Cr(III) were investigated. The considered fungi, isolated from real tanning factory environment were Phanerochaete chrysosporium, Aspergillus niger and A. oryzae. Firstly, the optimal conditions for fungal growth were determined as a function of pH, contact time, temperature and agitation speed. Secondly, the effect of the addition of some nutrients on fungal growth was examined. Without the addition of any nutrient, the best growth conditions were found to be pH 5, 30oC temperature, 150 rpm agitation speed and 30 hours contact time. Except sodium nitrite, all tested nutrients, namely NH4Cl, (NH4)2SO4, NaNO2, NaNO3, NH4H2PO4, and KH2PO4, enhanced fungal growth, and hence Cr(III) removal which appeared clearly related to growth. NH4H2PO4 (in the range 4-6 g/L) was found to be the most efficient nitrogen source for fungal growth, resulting in an increase of fungal concentrations from an initial value of 0.8 g/L to maximum values of 4.8, 4.1 and 4.4 g/L for A. niger, A. oryzae and P. chrysosporium, respectively. Regarding phosphorus supply, 8 g/L KH2PO4 was found to be the optimum amount, leading to 5.7 g/L of biomass and hence an almost total chromium removal, showing the positive phosphorus effect on growth. Under the optimum conditions, chromium was almost totally removed (at least 99.8 %) for Aspergillus species, and especially A. niger, which appeared to be more efficient than P. chrysosporium. Maximum removal efficiencies on tanning effluent were 63, 52 and 43% for A. niger, A. oryzae and P. chrysosporium, respectively. These results are promising considering the high chromium content of the real effluent (1000 - 1300 mg/L)

Removal of CR (III) from model solutions by isolated Aspergillus niger and Aspergillus oryzae living microorganisms: Equilibrium and kinetic studies

International audienceBiosorption by fungi is a efficient method for removal of heavy metals which have been recently used by many researchers. The aim of the present work was the seeking and the isolation of sustainable microorganisms and their application for the removal of Cr (III) from simulated and real solutions. To isolate sustainable microorganisms, soil samples were taken from rawhide, tannery tanks and effluents discharged environment. Aspergillus niger and Aspergillus oryzae were the two types of isolated fungi from tanning factory environment. Fungal growth and chromium removal efficiency were studied as a function of maximum fungal tolerance to Cr (III) concentration, pH, temperature, contact time, agitation speed and nutrients addition. The optimal conditions for fungal growth were 30 h at pH 5.2, an agitation speed of 150 rpm and 30 °C in a medium containing yeast powder and di-hydrogen ammonium phosphate as nutrients. Maximum biomass concentration increased from 0.8 to 4 g/L for both fungi in the above mentioned conditions. Maximum fungal tolerance and chromium removal were found to be 600 mg/L and 95-98% of Cr (III). Equilibrium data were found to follow a Langmuir isotherm model and maximum sorption capacities were 185 and 208 mg/g for A. niger and A. oryzae, respectively. Experimental data was accurately fitted onto pseudo-second order kinetic model. Promissing results were also recorded on a real effluent, since in the above optimal conditions, chromium removal yields were 72 and 67% for A. niger and A. oryzae, respectively. However and owing to the high variability of the effluent, subsequent work is needed to confirm these positive results irrespective of the characteristics of the inlet effluent

Removal of Cr (III) from model solutions and a real effluent by Phanerochaete chrysosporium isolated living microorganism: equilibrium and kinetics

International audienceRemoval of Cr (III) was investigated using Phanerochaete chrysosporium-isolated living microorganism; pH, contact time, temperature and nutrients addition were examined. It was found that P. chrysosporium can tolerate up to 600 mg/L chromium solution. The optimal growth conditions of the biosorbent were found to be 35°C, 26 h contact time and pH = 5. In addition, a complex nitrogen substrate, yeast powder, was shown to be most efficient than a synthetic one, like di-hydrogen ammonium phosphate. High chromium removal (98%) was observed in these optimal growth conditions. Experimental data were found to follow a Langmuir isotherm model (r 2 > 0.99). Maximum sorption capacity for the present biosorbent was 213 mg/g according to the Langmuir isotherm model, namely significantly higher than the values reported in the literature, even for activated carbon. The fitting of experimental data onto kinetic models showed the relevance of the pseudo-second-order model (r 2 > 0.99) for Cr (III) sorption by P. chrysosporium. In addition, a real effluent was obtained from tanning factory and was treated to examine process feasibility on real effluents

Removal of Tetracycline from Synthetic Solution by Natural LECA

Background: Antibiotic in environment can be accumulated in soil and sediment and then adversely affect the ecosystem function as well as decrease the natural degradation rate of pollutants by producing a antibiotic-resistant microorganisms. The antibiotic-resistant genes can also transfer to drinking water resources and then, leading untreatable human disease. Methods: Natural LECA was supported from rural resources and washed with deionized water for several time and then used as natural adsorbent. The adsorbents were characterized with a scanning electron microscope (SEM), Fourier Transform Infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF) and X ray diffract meter (XRD). All experiments were conducted in a batch reactor. Various parameters such as initial adsorbent mass (2, 4, 6, 8 and 10 g/L), initial antibiotic concentration (50, 100, 150 and 200 mg/L), initial solution pH (3, 5, 7, 9, and 11) and contact time (1-210 min) were investigated. Results: The Results of present work showed the high removal efficiency of the adsorbent for adsorption of Tetracycline from aqueous solution. Higher removal efficiency was observed for Tetracycline at pH 3, 180 min contact time, 10 g/L of adsorbent dose and 200 mg/L of initial antibiotic concentration. In optimum condition, up to 49% of tetracycline was removed. Conclusion: Overall, the results of the present work well demonstrated that natural LECA as an inexpensive adsorbent could remove effectively the antibiotics namely Tetracycline from aqueous solution