Iranian Journal of

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Background and Objectives: Recycling is one of the best alternatives in solid wastes management.  Recycling has few benefits from the viewpoint of economics and environmental. Paper and cardboard are the valuable recyclable materials in solid wastes. The rate of paper recycling is 35% in world. The major production source of paper and cardboard wastes is private and governmental offices and organizations. To be informed about paper production is very important in the solid wastes recycling.Thus, the aim of this study was to determine production rate of paper and cardboard waste and also to determine paper recycling potential in the 20 head offices of Mazandaran province.
Materials and Methods: This study was conducted in the 20 head offices of at province center. The  offices were selected by chance. This study was conducted four months in 2006. paper waste was separated after suspension of work. Collected material weighed on the sensitive scales. Separation and measuring was done for a week per month.
Results: The results showed that more than 2 tons of paper waste was produced in the twenty offices.  The maximum and minimum of paper production was in education and recycling organization, respectively. The maximum and minimum of production rate was 2.08 and 0.192 kg per capita in month that was in the education and Jihad-e-Agriculture organization, respectively. Also the maximum and minimum of paper waste was produced at first work day of week (Saturday) and last work day of week (Thursday), respectively. However, it was not significantly (P >0.05). Paperrecycling operation and marketing was done in an office.
Conclusion: Findings of this study indicated that office solid waste management needs more notice  in Iran. And also calculations showed that paper recycling is economical.

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Background and Objectives: Fluoride is widely used in industries such as manufacture of semiconductors, power plants, glass production etc and release to the environment via their effluents. The purpose of this sturdy was to compare the efficiency of low price adsorbents in fluoride removal from water.
Materials and Methods: The optimum values of pH, contact time and adsorbent dosage were determined and different concentrations of fluoride were experimented in lab scale conditions for bagasse, modified bagasse and chitosan. Then Langmuir and Freundlich coefficient were determined based on optimum conditions.
Results: The pH value of 7, contact time of 60 min and adsorbent dosage of 2 g/L were determined as optimum conditions for all three adsorbents. The most fluoride removal efficiency of 91% was obtained for modified bagasse in optimum conditions.
Conclusion: Based on data obtained in this study, it can be concluded that adsorption by modified bagasse is an efficient and reliable method for fluoride removal from liquid solutions.

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MicrosoftInternetExplorer4 Background and Objectives: Nitrate is one of the most groundwater pollutants in world. Reduction of nitrate to nitrite by microorganisms cause serious health hazards. Nitrate can be eliminated using either adsorbtion or reduction. In this study, we investigated the adsorption of nitate on zeolite and the feasibility of removal improvement using supported  zero valent nano iron on zeolite via the reduction process.
Materials and Methods: The study was done in two phases investigation the zeolite and modified zeolite with zero valent nano iron in nitrate removal from water. First, we determined the optimum pH and time then the effect of adsorbent and nitrate concentration was investigated in one factor at the time. The adsorption isotherm was calculated according to the optimum condition. The physical characteristics of adsorbents were determined using SEM and TEM.
Results: The morphology investigation of adsorbent showed that the particle size of supported zero valent nano iron on zeolite was approximately 30-50 nm in diameter. The best conditions were pH 5, contact time of 120 min and 15 g/L for zeolite, while pH 3, contact time of 50 min and 7.5 g/L for supported  zero valent nano iron on zeolite. The isotherm equations revealed that nitrate adsorption follows Langmiur in both cases.
Conclusion: The supported  zero valent nano iron on zeolite could be considered as a high potential adsorbent for nitrate because it has several adsorbent sites, and Fe⁰ as a function for nitrate reduction.

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Background and Objectives: Toxicity assessment of material related to nanotechnology is necessary before excess development of this industry. On the other hand, specific characteristic of nanomaterials can be used in disinfection of other material. In this study toxicity and antibacterial properties of nano-TiO₂ and nano-CuO were investigated with four bacterial species in solid media.

Material and Methods: Stock suspension of nanoparticles (10g-TSS/L) was diluted using Muller Hinton Agar to achieve 5-6000mg-TSS/L concentration. We prepared three Petri dishes for each concentration and refined bacteria were cultured on these Petri dishes. After culturing of these bacteria on the media containing nanoparticles, growth inhibition was determined. According to this data, 50% growth inhibition (EC₅₀), no observed effect concentration (NOEC) and 100% growth inhibition were determined.

Results: Our results showed that toxicity of TiO₂ is more than CuO in solid media. In this regard, nano-TiO₂ EC₅₀ for Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa was calculated 181, 571, 93 and 933mg-TSS/L respectively. These figures for nano-TiO₂ were 2550, 1609, 946, and 1231mg-TSS/L respectively.

Conclusion: This study showed that compared with other bacteria studied, E. aureus due to high sensitivity and E. coli due to high resistance to both TiO₂ and CuO nanoparticles are more proper as bioindicator in toxicity test and antibacterial test respectively.