IRANIAN JOURNAL OF HEALTH AND ENVIRONMENT
Year:2011 | Volume:3 | Issue:4 (10)|Papers Count:12

Backgrounds and Objectives: Anthraquinone dyes such as reactive blue29 in water resources and industrial wastewater effluents are one of the most environmental setbacks in many countries. Various methods have been considered to remove these dyes One of which is adsorption.Materials and Methods: All adsorption experiments were conducted in different pHs and various concentrations of adsorbents. The initial concentration of reactive blue 29 chosen in this study was 30mg/L. Adsorption isotherms were determined and correlated with Longmuir, Freundlich and BET models.Results: The maximum adsorption capacity of reactive blue 29 onto single wall carbon nanotubes was 496mg/g. Results showed that the best pH for adsorption was 5 followed by pH3 and 8. Kinetic study showed that the equilibrium time for adsorption of RB 29 to SWCNT is 4 hr.Conclusion: According to the results obtained BET isotherm fitted well the experiment. It shows the adsorption of reactive blue 29 onto single wall carbon nanotubes is multilayers and the mechanism of SWCNTs adsorption toward RB29 is based on weak van der waals forces.

Backgrounds and Objectives: Phenol and phenolic compounds are widely used in industry and daily liFe, and are of high interest due to stability in the environment, dissolution ability in water and health problems. In this regard, phenol removal from water is of high importance. The purpose of this study was to investigate the efficiency of photodegradation process for removal of phenol from aqueous system by use of Fe-doped TiO2 nanoparticles prepared by sol-gel method.Materials and Methods: Phenol concentrations of 5, 10, 50 and 100 mg/L were prepared and exposed to UV and Fe-doped TiO2, separately and simultaneously. Also the effect of initial phenol concentration, Fe-doped TiO2 loading and pH were studied. Various doses of photocatalist investigated for Fe- doped TiO2 were 0.25, 0.5 and 1 g/L. pH was studied at three ranges, acidic (pH=3), neutral (pH=7) and alkaline (pH=11).Results: Maximum degradation was obtained at acidic pH, 0.5 g/L of Fe-doped TiO2 for all of phenol concentrations. With increasing initial concentration of phenol, photocatalytic degradation decreased. In comparison with Fe-doped TiO2/UV process, efficiency of UV radiation alone was low in phenol degradation (% 64.5 at 100 mg/l of phenol concentration). Also the amount of phenol adsorbed on the Fe-doped TiO2 was negligible at dark conditions.Conclusion: Results of this study showed that Fe (III) - doped TiO2 nanoparticles had an important effect on photocatalytic degradation of high initial phenol concentration when Fe (III) -doped TiO2/ UV process applied.

Backgrounds and Objectives: Chlorophenol compounds are used frequently in industries including: petrochemical, producing pesticide and herbicides, producing antimicrobial agents, pharmaceutical and refineries. These compounds can enter the environment through the wastewater industries.This investigation has studied the application of Fenton-like process (Fe0/H2O2) in removal of Para-chlorophenol.Materials and Methods: A laboratory scale study was done on a synthetic wastewater containing Para-chlorophenol. Concentration of 10 mg/L of Para-chlorophenol was prepared then optimal values of affecting parameters such as pH, hydrogen peroxide, and iron powder and detention time in the process for Para-chlorophenol removal were determined.Results: The optimum pH, molar ratio of hydrogen peroxide on Para-chlorophenol, hydrogen peroxide on iron powder and time were 4, 18.8, 0.4 and 5 minutes respectively. The results showed that removal efficiency in optimal conditions for concentrations of 10, 50 and 100 mg/L are 93.9, 94.4 and 94.3 respectively. The study showed the rate of mineralization of Para-chlorophenol is not completed.Conclusion: According to the results of this study and high resistance in degradation by biological processes, Fenton like process can be used for conversion Para-chlorophenol resistant compound to other compounds with ability of higher biological degradation and lower toxicity.

Backgrounds and Objectives: Reactive dyestuff has potential of toxicity, carcinogenesis and mutagenesis for mammals and aquatic organisms. The current physical and chemical methods such as adsorption, coagulation, precipitation, filtration and … can been used for removing of dyestuff.Biological treatment which is effective and economic for decontamination of dyestuff wastewaters was preferred because of limitation and difficulty of physicochemical methods. In order to investigate the trend of pollution reduction of color compounds, ability of Remazol Black-B dyestuff removal from aqueous medium by bacterial consortium under anoxic conditions was studied.Materials and Methods: The mix culture of bacteria from textile industries activated sludge was enriched in luria broth medium containing RB-B dyestuff as a carbon source. Then biodegradation was assessed in 4 batch reactors. Microbial population of bacterial and decolorization quantities of samples were detected by MPN and UV-Vis spectrophotometer.Results: Decolorization efficiency by the bacterial consortium was obtained more than 99% for 50 and 250 mg/L concentrations in 72 and 144 h (3 and 6 days) respectively, while for the initial concentration of 500 mg/L was 98.1 in 240 h (10 days) of biodegradation period. Dyestuff reduction rate after completed removal was about 0.69, 1.74, 2 mg/L/h for initial concentration of 50, 250, 500 mg/L respectively.Conclusion: Results showed that Alcaligenes denitrificans and Alcaligenes xylosoxidans bacteria which were isolated from activated sludge have good potential of RB-B dyestuff removal and this removal is depending on primary concentration of dye. Removal efficiency increased as primary concentration went up.

Backgrounds and Objectives: Treatment of colored wastewater is one of the important challenges of environmental engineers. Adsorption process is a key option for removal of organic matter from wastewater. The aim of present work was to investigate pumice stone as an adsorbent for removal of Acid Black 1 from aqueous solution.Materials and Methods: Removal of Acid Black 1 by pumice stone was investigated. Acid Hyrdo Chloric (HCL) 1 N was used to increse adsorbent porosity. Various parameters such as pH, initial dye concentration and contact time were studied.Results: Results showed that removal of Acid Black 1 was increased by increasing of contact time and initial dye concentration although it was decreased by increasing of pH. Experimental data was best fitted to Longmuir isotherm model (r2>0.98). Study of diffusion model revealed that intraparticle diffusion is rate-controlling step in removal of Acid Black 1 by pumice stone.Conclusion: The results indicated that pumice stone was a dominant adsorbent for Acid Black 1 removal.

Backgrounds and Objective: Surfactants are one of the largest pollutants which exist in urban and industrial wastewaters. Large quantities of surfactants have entered to the environment since last de-cade due to increased use of synthetic detergent in industrial and home consumptions. In this study, the efficiency of UV/H2O2 process in removal of linear alkylbenzane sulfonate (LAS) from aqueous solutions was investigated.Materials and Methods: In this study methylene blue active substane (MBAS) method and spectrometery were used to determine anion and residual surfactant respectively. In this study important variables were H2O2 concentration, initial concentration of surfactant, pH and duration of UV radia-tion. The effect of UV/H2O2 process on the degradation of LAS was analyzed statistically by using Multiple Linear Regression test.Results: The resulted showed that after 20 minute, ultraviolet radiation solely removed 38.44 per-cent of Anionic detergent, Hydrogen peroxide showed no significant removal of detergent solution in the time course study. The efficiency of UV/H2O2 process in 10, 20 and 30 minute were to 86.2, 90 and 96.5%, respectively.Conclusion: The results showed that the efficiency of ultraviolet radiation and hydrogen peroxide process in anionic detergent was not significant thoogh it was considerable in combination process (UV/H2O2).

Background and Objective: Nickel (II) and cadmium (II) are important in environmental pollutant.Biosorption of heavy metals can be an effective process for the removal and recovery of heavy metal ions from aqueous solutions because of the decrease in sludge problems, economical issues, high efficiency and compatibility with the environment.Materials and Methods: power of wasted activated sludge have been contact with nickel (II) and cadmium (II) solutions in 0.25 and 0.75 milli molar invarious pHs and mixing pace, at 24-26oC temperature on batch reactor system. After two hours (continuously 5-420 min in kinetic study) samples were analyzed with atomic absorption spectrophotometer.Results: The kinetic study results show that equilibrium adsorption time for nickel (II) and cadmium (II) reached within 2 hr, but the profile curve of cadmium (II) biosorption was smoother than nickel (II) biosorption. Both metals adsorption followed the Langmuir model and the maximum adsorption capacity (qmax) for nickel (II) and cadmium (II) was 0.195 and 0.37 milli mole per gram respectively.The increase in pH resulted in adsorption increase for both metals. For cadmium (II) at 0.25 and 0.75 mMinitial concentration there was no adsorption at pH 2 where as nickel (0.25 mM) adsorption was observed at the same pH. The optimum mixing rate for both metals was 200 rpm and this effect was more obviously in greater concentration.Conclusion: Like othe biosorbents, wasted activated sludge showed greater capacity for cadmium (II) biosorption than nickel (II). Cadmium (II) in modeling and biosorption characteristics study had more conformity than nickel (II).

Background and Objectives: Dual media filters have two different layer beds consist of sand and Anthracite. Advantage of dual media filters is longer run duration and more filtration rate. The purpose of this study was to achieve a performable model to improve single media Filters in water treatment plants.Materials and Methods: in this cross-sectional study, two pilots; mono and dual media were made and in a 5 month period samples taking were done. Total samples taken from input and output of each pilot, was 40. The samples then introduced for the measurment of turbidity and total organic carbon. Meanwhile the filters head loss also quantified in 40 times head loss measurement was done.Results: Average turbidity removal in mono and two layer pilots were 63 and 65 percent respectively. Average removal of Total Organic Carbon in mono and two media pilots were 40 and 66 percent respectively. Head loss in dual and single media pilots were 0.68 and 1.15 m respectively.Conclusion: Although average torbidity removal disparity between two pilots was not significant the amount of total organic carbon removed was considerable. Average head loss in single media pilot was more than dual media type. Ratio of UFRV in dual media to mono media filter was 51: 30 it shows that filtration rate capacity will be improved up to70 percent by changing media type.

Backgrounds and Objectives: Water contamination with arsenic has been recognized as a serious problem and its epidemiological problems to human health have been reported. The objective of this study was to explore the possibility modified wheat straw using sodium bicarbonate for removing arsenic from aqueous solution.Materials and Methods: Adsorption process was accomplished in a laboratory-scale batch with emphasis on the effect of various parameters such as pH, contact time, arsenic concentration and adsorbent dosage on adsorption efficiency. In order to understand the adsorption process, sorption kinetics and equilibrium isotherms were also determined.Results: It was found that adsorption of the arsenic was influenced by several parameters such as arsenic initial concentration, adsorbent dosage and solution pH. Maximum absorption efficiency was achieved at pH 7. As expected the amount of arsenic adsorbed on wheat straw incresed as its concentration went up. Among the models tested, namely the Langmuir, Freundlich, and Dubinin Radushkevich isotherms, the adsorption equilibrium for arsenic was best described by the Langmuir and Freundlich models. It was also found that adsorption of arsenic by wheat straw followed pseudo second-order kinetics. Mean free energy of adsorption (15.8 kJ mol-1) indicates that adsorption of arsenic by wheat straw might follow a chemisorption mechanism. Desorption studies show that arsenic ions are strongly bounded with the adsorbent and exhibit low desorption.Conclusion: It is concluded that that adsorption by modified wheat straw is an efficient and reliable method for arsenic removal from liquid solutions.

Backgrounds and Objectives: Owing to the fact that the major environmental problem is production of surplus sludge in wastewater treatment plant, reducing the volume of produced sludge was objective of this research.Materials and Methods: An anaerobic-aerobic SBR with working volume of 10 L was used to make micro-organism adapted and a polymer production reactor (PPR) with working volume of 1.5 L was used for producing polymer munisipal wastewater which contained different concentration of volatile fatty acids was consodered as the feed source (acetate and propionate) and this system was evaluated with SRT of 5, 7 and 10 days.Results: The maximum polymer production efficiency observed within 5 days (SRT=5 days) though this efficiency was not significant in comparison with the two others time courses study. In this research the maximum polymer production efficiency at optimum condition was 25% of the sludge dry weight.Conclusion: Experiment revealed that producing polymer from activated sludge reduced the volume of sludge and the maximum reduced sludge volume was obtained 19%.

Backgrounds and Objectives: High level of nitrate ion in the water resources cause some health and environmental problems. The aim of this research is to study nitrate removal by Zero-Valent Magnesium (ZVM) and MgCl2-modified pumice from aqueous solutions.Materials and Methods: The pumice granules were modified by MgCl2. The removal of nitrate was studied in a batch system. The pH, initial nitrate concentration and sorbent mass parameters and the Langmuir and Freundlich models were studied in the sorption of nitrate onto the pumice. The ZVM was also used in a bach system and the previous parameters were studied.Results: The removal efficiencies of nitrate by ZVM at the initial pH of 3, 5 and 7 with controlling the pH were 70%, 40% and 30%, respectively. These values are much higher than the values of the condition during which the pH was not controled. The nitrate removal efficiency increased by increasing of initial nitrate concentration in a constant molar ratio of Mgo/NO3. The removal efficiencies of nitrate by the modified pumice at the initial pH of 3, 6.5 and 10 (when pH kept under control) were 49%, 29% and 16%, respectively. By increasing of the initial nitrate concentration the removal efficiency increased. The values of R2 for the Langmuir and Freundlich models were 0.944 and 0.810, respectively. The sorption process Fitted well the Langmuir model with a monolayer sorption capacity of 0.68 mg/g.Conclusion: The modified pumice had lower efficiency than ZVM in the removal of nitrate ion and its usage is not considerably affected bye the pH in comparison with ZVM. The pH of the solution should be cansiderd as a main controling parameter to get an optimum efficiency in the nitrate-ZVM process.

Backgrounds and Objectives: The aim of these research is examining the relation among noise psychological stubbornness and mental health with the life quality of rasht housewives.Materials and Methods: After measuring the amount of noise in different streets, the researcher chose randomly 50 housewives from noisy streets of Rasht, and completed the study questionnaire. Then they analyzed data with peirson correlation and regression analysis.Results: The results showed that there is significant of perception of noise, psychological stubbornness and mental health with the quality of life. The amount of F parameter of regression analysis at P<0/01 level was significant and 91% of variance among noise with psychological stubbornness, mental health, with the quality of common life. Among the amount of noise, psychological stubbornness and mental health, the noise perception and mental health are able to making clear the quality of housewives’ life; it means that increasing the amount variance of psychological stubbornness to equation wouldn’t lead to increase significantly.Conclusion: paying attention to the effectiveness variables like noise and psychological like mental health on quality of life, Societies’ development and achievement and decreasing social services, present study suggest that all responsible organizations who work about societies’ health are trying to set their programs forward to promote the quality of the whole society life and do this by decreasing the dangerous and effects of environmental variables and strength the psychological variables.