[Producing activated carbon from scrap tires by thermo-chemical method and evaluation its efficiency at removal racid black1 dye]

The disposal of waste tires has become an increasingly important issue worldwide in recent years. Tires not only take up large amounts of valuable landfill space, but also create fire hazards and provide a refuge for disease- carrying creatures. The goal of this study was to produce activated carbon from scrap tires .Adsorption of Acid Black1 [AB1] in aqueous solution as a pollutant by the activated carbon was also investigated. Activated carbon was prepared from scrap vehicle tires using a thermo-chemical activation method. The chemical composition and solid structure of prepared activated carbon were analyzed using Scanning Electron Microscopy [SEM] coupled with energy dispersive spectrometry [EDS] and Nitrogen Sas. Micro pore volumes of the sample were determined by the application of the BET and BJH. Predominant composition of prepared activated carbon was C [83.274%] and with area surface of 44.226 and 35.747 m2/gr observed by BET and BJH methods, respectively. Mean pore diameter was 52 nm. The result of this study showed that increasing of initial dye concentration and pH would lead to decrease of adsorption/removal of dye but by increasing of sorbent dosage and contact time, adsorption/removal of dye increased. As the results of present study it can be concluded that the production of the activated carbon from scrap tires, can provide a two-fold environmental and economic benefit; a recycling path is created for scrap tires of vehicles, and a new suitable adsorbent is produced for pollutants removal

[Removal of nitrate by MgCl[2]-modified pumice and zero-valent magnesium from aqueous solutions]

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. The pumice granules were modified by MgCl[2]. 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. 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 controlled. The nitrate removal efficiency increased by increasing of initial nitrate concentration in a constant molar ratio of Mg[0]/NO[3]. 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 R[2] 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. 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 considered as a main controlling parameter to get an optimum efficiency in the nitrate-ZVM process

Comparison between the efficiency of advanced oxidation process and coagulation for removal organophosphorus and carbamat pesticides

Water pollution by pesticides has adverse effects on the environment and human health, as well .In recent years, advanced oxidation processes, have been gone through to a very high degree for pesticides removal. Poly-Aluminum chloride [PAC] used for water treatment, can be effective on pesticides removal. The aim of this research was to study the use of UV/O3 and PAC in the removal of pesticides from drinking water. In this descriptive- analytical survey, specific concentrations of pesticides [1,5,10,15,20 ppm];namely Diazinon, Chlorpyrifos, Carbaril were prepared through addition to deionized water. Dichloromethane was used for samples extraction, samples extracted with Liquid-Liquid and Solid-phase extraction, finally entered bath reactor at pH [6,7,9] .The samples then exposed to UV/O3at contact time of [0.5,1,1.5 and 2 hours]. In the PAC pilot, the effects of various concentrations of pesticides, and PAC - ranging [12/24 and 36 ppm] were investigated for the efficacy of pesticides removal. All samples analyzed by GC/MS/MS and HPLC. It was found that in U V/O3 reactor, with the rise of pH, decrease in pesticides concentration, and rise of contact time, the efficiency of removal increased too. In the PAC pilot, increase in PAC concentration and decrease in pesticides concentration, both increased the efficiency. Besides, both of the methods showed high efficiencies in the removal of both pesticides,i-e. halogenated Organophosphorus [Chlorpyrifos], non- halogenated Organophosphorus [Diazinon] at the degree of over [%80]; In case of carbamate pesticides [e.g. Carbaril] efficiency was over [>%90]. One-Way Anova and Two -Way Anova were used to analyze the obtained data. According these results these two methods are suggested for the removal of pesticides from aqueous solutions

comparative study on arsenic [III] removal from aqueous solution using nano and micro sized zerovalent iron

The present study was conducted for Arsenic [III] removal, one of the most poisonous groundwater pollutants, by synthetic nano and micro size zerovalent iron [n-mZVI]. Batch experiments were performed to investigate the influence of As [III], nZVI and mZVI concentration, pH of solution and reaction time on the efficiency of As [III] removal by Fe[o] particles. Nano ZVI was synthesized by reduction of ferric chloride by sodium borohydrid. Scanning Electron microscope and X-Ray diffraction were used to determine particle size and characterization of produced nanoparticles. Results showed up to 99.9% removal efficiency for arsenic [III] that was obtained by nZVI dosage of 1 g/L at equal time of 10 min and pH=7. The maximum removal efficiency by mZVI obtained in initial arsenic concentration of 1 mg/L and mZVI dosage of 10 g/L after 120 min. and pH=7. It could be concluded that the removal efficiency was enhanced with increasing n-mZVI dosage and reaction time, but decreased with increasing of arsenic concentration and pH for both nano and micro sized ZVI. Nano ZVI presented an outstanding ability to remove As [III] due to not only a high surface area and low particle size but also to high inherent activity

[Possibility of using Moringa peregrina seeds compared with alum and poly aluminum chloride in sewage treatment]

In arid and semi-arid regions of the world, urban runoff as a source of water restoration and is considered valuable. Wastewater treatment, while preserving the environment, it can be considered as water source. The aim of this study to evaluate the possibility of using powder grain Peregrina in wastewater treatment in comparing with Alum and Poly Aluminum Chloride [PAC]. Flocculation and coagulation tests were done by Jar test. Wastewater quality parameters were measured according to standard method. Studies have been showed that in optimum Peregrina concentration, efficiency of turbidity reduction, total hardness, calcium hardness, magnesium hardness, total E. Coli are 95.11, 38, 55.5, 46.6, 97 and 97 percent respectively. It is noted that turbidity reducing directly related with coli form reduction. As, with increasing turbidity reduction, coliform reduction is increased. The most reduction of E. coli with combination of Alum, Poly Aluminum Chloride and Peregrina was 100 percent. In optimum concentration of Alum, Ploy Aluminum Chloride and Peregrina, the quality of treated wastewater would be in the range of environmental standards. Therefore, treated wastewater can be entering to surface water and reuse as irrigation water. The results derived from this study showed that the treated wastewater can be used in a variety of irrigation except sprinkler irrigation due to burn the leaves of plants. [high electrical conductivity]. Also, the low cost of seed Peregrina and good performance in the refining operations, it is suggested that Peregrina as a replacement for poly aluminum chloride and an alum to be used for wastewater treatment

[Photocatalytic removal of hexavalent chromium and divalent nickel from aqueous solution by UV irradiation in the presence of titanium dioxide nanoparticles]

Industrial wastewater included the heavy metal is one of the important sources of environmental pollution. Hexavalent chromium and divalent nickel are founded in plating wastewater which is harmful for human health and environment. Therefore, the purpose of this research is investigation of photocatalytic removal of hexavalent chromium and divalent nickel from aqueous solution using UV/TiO[2] process in a batch system. At first, reactor was designed. Then, optimumdosage of TiO[2] was obtained equal to 1 g/L, with variation TiO[2] dosage at constant pH and initial concentrations of hexavalent chromium and divalent nickel. The effect of pH, contact time and initial concentration of hexavalent chromium was studied at the constant amount of TiO[2] [1gr/L]. The result showed that photocatalytic removal efficiency increased with increasing reaction time and TiO[2] dosage. In addition, it was found that removal efficiency of hexavalent chromium was decreased by increasing initial chromium concentration and pH. But, photocatalytic removal efficiency of nickel ion was increased and decreased by increasing of pH and initial nickel concentration, respectively. The results showed that UV/TiO[2] was an effective method in removal of hexavalent chromium and divalent nickel from aqueous solutions

[Determination of organophosphorous and carbamat pesticides residue in drinking water resources of Hamadan in 2007]

Water contamination by pesticides is considered as an environmental problem today. In terms of agricultural development and diversity of plant pests, the use of pesticides has been increasing. Hamedan province has a suitable agricultural condition, it has enjoyed significant development in this respect. Among all the cities of Hamedan province, Hamedan city has the highest rank in tiller crops. Therefore, yearly use of pesticides is increasing in this area which could be a serious threat to water resources of the city. The aim of this survey was determinaton of Organophosphorous and Carbamat pesticides residue in drinking water resources of Hamadan in 2007. In this survey, 126 water samples were collected from 7 drinking water resources of Hamedan during 12 consecutive months in 2007. for determination of these pesticides, two methods [solid-phase extraction and Liquid-Liquid extraction] were adopted .and samples were analyzed by means of HPLC and GC/MS applying standard methods. Final results showed that the most concentration of Chlorpyrifos and Carbaryl pesticides were found to be about 3.85 ppb [part per billion] and 1.8 ppb in spring and June respectively; the maximum concentration of Diazinon was about 36.5ppb in October [autumn].The minimum concentration of the three pesticides was detected in winter. According to the statistical test Two-Way ANOWA there were significant differences among pesticides concentrations in the water samples in different seasons [p<0.05]. However, there wasn't a significant difference in pesticides concentrations in surface and ground water samples[p>0.05]. Different studies have shown that pesticides residue concentration in water samples have a relationship with the amount of pesticides used in an area, physical and chemical refractory properties of pesticides; and environmental conditions. Thus, using resistant pollutants such as pesticides will be a serious threat to health of water consumers if they are not properly controlled

Evaluation of chemical quality in 17 brands of Iranian bottled drinking waters

The purpose of study was to evaluate and compare chemical quality of Iranian bottled drinking water reported on manufacturer's labeling and standards. This study was a cross-sectional descriptive study and done during July to December 2008. The bottled mineral water collected from shops randomly were analyzed using all parameters address on manufacturer's labeling and the results were compared with the manufacturers' labeling data, WHO Guideline Values, USEPA Maximum Contaminant Levels and the maximum contaminant levels of drinking water imposed by the Iranian legislation. Statistical analysis on data was done with the Kolmogorov-Smirnov test for normal distribution, the paired t-test to compare the data with manufacturer's labeling and the one-sample t-test to compare with standard and MCL values at P<0.05 of confidence level. The results showed a statistically significant difference with manufacturer's labeling values, however there was no significant difference between the values of magnesium and pH and manufacturers' labeling values [P>0.05]. In addition, ph and calcium values were significantly higher that their proposed values indicated by Iranian National Legislation and international MCLs [P<0.05]. Our results are extremely important for the health supervisory agencies such as Ministry of Health and Institute of Standards and Industrial Research of Iran to have more effective controls on bottled water industries, and to improve periodical the proposed standard values

Photocatalytic disinfection of Coliform bacteria using UV/TiO[2]

There are great interests in photocatalytic oxidation of contaminants using titanium dioxide in recent years. The main objective of this research was to study photocatalytic disinfection of Coliform bacteria as water microbial pollution index using TiO[2] and a low pressure UV lamp in a batch reactor. The polluted water was prepared by adding a colony of Coliform in raw water and in separate stages was contacted with UV, TiO[2] and combination of them and various parameters such as contact time, pH and amount of TiO[2] were studied in terms of their effect on reaction progress. The results showed that in simultaneous presence of both UV ray and TiO[2], there was the most effective disinfection of Coliform. This study showed that 100% of Coliform was killed by irradiation for 60-75 min. in the presence of 0.8 gr 1[-1] TiO[2] in pH=7.0. Based on the results, UV/TiO[2] process may be effectively applied for disinfection of polluted water and can be suggested as a effective purifying method for water disinfection

Investigation of clinoptilolite natural zeolite regeneration by air stripping followed by ion exchange for removal of ammonium from aqueous solutions

The purpose of this study was to regenerate clinoptilolite natural zeolite by air stripping followed by removal of ammonium from aqueous solutions. The research was carried out in continuous system. The characteristics of graded clinoptilolite from Semnan [one of the central provinces in Iran] mines were determined and then regeneration tests were done by contacting of 1 N NaC1 solution with given weights of ammonium saturated zeolite. Then the brine of column was transferred to the air stripping column for regeneration. The pH of brine solution before entrance to a stripping column was increased to 11. Air stripped ammonia from the brine was converted to the ammonium ion by using acid scrubber. The outlet effluent from stripping column was collected for reuse. The results showed that the cation exchange capacities were 17.31 to 18.38mg NH[4+]/g of zeolite weight. Regeneration efficiency of zeolite by NaC1 solution and air stripping was in the range of 92%-97% under various operational conditions. However, the efficiency of acid absorption of released ammonia in stripping process was 55% with a major rejection of the surplus ammonia to the atmosphere. It could be concluded that the method studied may be considered as an advanced and supplementary process for treating effluents of aqueous solution and fishponds in existing treatment plants

[Hexavalent chromium removal from aqueous solution by produced iron nanoparticles]

Groundwater treatment by nano particles has received increasing interest in recent years. Chromium is a commonly identified contaminant in soils and groundwater. Zero-valent iron, as a natural reduction agent can be used in controlling of contaminated sites. The aim of this research is investigation of hexavalent chromium removal from aqueous solutions by using of iron nano particles the effective parameters. In this research the synthesized of the iron nano particles has performed by addition of NaBH4 to FeCl3 6H2O solution and Cr[VI] reduction efficiency in Batch system was studied. Also the impact of the important field parameters including pH, initial chromium concentration, nano zero valent iron concentration and retention time were investigated. The results of this research showed that synthesized particles were in nano scale. In pH=3, chromium inlet concentration of 10 mg L-1, nano zero valent iron concentration 0.5 g L-1 and 2 minute retention time, 100% of Cr[VI] was removed. The concentration of nano zero valent iron had significant effect on the reduction of Cr[VI]. The reaction occurred in a wide range of pH value and the reaction efficiency increased significantly with decreasing initial pH. The significant removal efficiency, high rate of process and short reaction time were showed that iron nano particles have significant potential in removal ofCr[VI] from contaminated water

Investigation of photocatalytic degradation of phenol by UV/TiO[2] process in aquatic solutions

The main objective of this research was to study photocatalytic oxidation of phenol in aquatic solutions by using of UV, TiO2 and the combination of them. Phenol compounds are widely used in industries and other daily life. Highly toxicity and carcinogenicity of these compounds can causal considerable adverse effects on the aquatic ecosystems and human health. The study was an experimental research and carried out by phenol 100 mg L-1 solution and contact time, pH and amount of TiO2 were considered in photocatalytic system as the basic variables affecting removal efficiencies. Phenol concentration in inlet and outlet samples was detected by spectrophotometery at 500nm. Combination of UV and TiO2 can cause higher efficiencies of phenol removal. The removal efficiencies of UV, TiO2 and UV/TiO2 photocatalytic oxidation system with various operation conditions had a range of 1.8%-19.64%, 2.38%-17.8% and 34.65%-82.91%, respectively. It was found that increasing of TiO2 concentration and contact time and pH, increasing the amount of phenol that oxidized in combined system and maximum removal coefficients obtained in pH = 11, 9 h contact time and 0.2 gr of TiO2. Combinated UV/TiO2 process may be applied as an effective process for the removal of phenol from aquatic solutions such as industrial wastewaters and polluted water resources

Investigation of ammonia removal from polluted waters by clinoptilolite zeolite

Ammonia nitrogen compounds in the wastewaters and effluents have harmful effects on water resources. Ion exchange with zeolites is a separation process for ammonia removal from effluents. The objective of this research was to study the efficiency of an ammonia removal and the factor affecting to this process. The Clinoptilolite was obtained from Semnan mines at the north part of Iran. The samples were grounded and sieved based on the U.S. standard mesh number 20, 30, 40 and conditioned by ammonia sulfate and sodium chloride solutions. The characteristics of samples for ammonia removal and the selectivity sequence for adsorbing interfering cations were then determined. Results shown that the average ion exchange capacity of zeolite in batch and continuous systems were 6.65-16 and 16.31-19.5 mg NH[4+] /g zeolite weight, respectively. In study on the zeolite for selective cations showed the ranking of K[+], NH[4+], Na[+], Ca[2+] and Mg[2+] respectively. Results indicated that high level of regeneration [95-98%] might be achieved with NaCl solution. Based on the results, Clinoptilolite may be effective applied in wastewater treatment, both from technical and economical aspects