Iranian Journal of

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MicrosoftInternetExplorer4 Background and Objectives: Arsenic is one of the most toxically contaminants in groundwater and soils. Due to the ability of bio-accumulation of arsenic III in plants through irrigation with contaminated water and its entrance to the food chain, irreparable hazards would be caused. The aim of this research is the feasibility study of arsenic III removal from polluted water using calcium peroxide nanoparticles synthesized and also studying the effective parameters. Moreover, the adding effect of nanoparticles on the important parameters of irrigation would be assessed.
Materials and Methods: In this research, we first synthesized CaO₂ nanoparticles through chemical precipitation and then studied the arsenic removal efficiency from contaminated water samples. Nevertheless, the impact of the effective parameters including pH, initial arsenic III concentration, and CaO2 nanoparticles concentration were investigated. Finally, relevant results to nanoparticles effect on the important irrigation water quality parameters were presented.
Results: Our results showed that synthesized particles were in the range of 25-50 nanometers. In addition, the efficiency of the CaO₂ nanoparticles in arsenic III removal was 88 percent under following conditions:  irrigation pH range 6.5-8.5, nanoparticles dosage 40 mg/L, arsenic initial concentration 400 µg/L, and 30 minuts retention time. Moreover, the nanoparticles synthesized did not have any undesirable impact on significant parameters in irrigation water.
Conclusion: Generally, it can be concluded that CaO₂ nanoparticles based on the in situ chemical oxidation had significant effect on the reduction of arsenic III until lower than recommended standards for irrigation water. High rate of process and relatively short reaction time, and having no negative effects on the significant parameters of irrigation indicate that CaO₂ nanoparticles have significant potential in removal of arsenic III from contaminated water.

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Background and Objective: This study was designed to assess the safety and health risk in Ilam gas refinery and evaluation of TOPSIS method performance in risk assessment.
Materials and Methods:  After identifying 955 hazards case, the risks were ranked separately in the health and safety sectors using criteria such as exposure level, severity and probability of the occurrence and use TOPSIS multi-criteria evaluation method. Due to the impossibility of determining the level of risk using TOPSIS method, the FEMA method was used for this purpose, and the risk number (RPN) options was calculated.
Results: In the field of safety assessment, personal injury, financial, burns and death from fire due to storage flammable materials in the warehouse, with a similarity to the ideal solution (Cli) of 0.56 was identified as the highest risk. In assessing the health risk, poisoning and impact on the health of employees caused by microbial agents due to the use of expired food in cooking in the restaurant unit as well as respiratory injuries of drivers due to inhalation and gas leakage in the process area and traffic of drivers in the site Cli = 0.66 was identified as the highest risk.
Conclusion: TOPSIS, as a new approach, is capable of being used in the industry's risk ranking and assessment. All the risks were placed at a moderate to low level. Despite the necessity of determining the measures to control the risks, these risks were not an emergency.