Iranian Journal of

Backgrounds and Objectives: Determination of Fluoride in drinking water has received increasing interest, duo to its beneifical and detrimental effects on health. The aim of this research is investigation of Effect of  activated alumina in fluoride concentration reduction in drinking water.
Materials and Methods: Expriment in batch system and with change effective parameters such as pH(5, 7,9), equilibration time (30, 60, 90, 120 minute), initial fluoride concentration(1.4, 2, 2.4 mg/l) and activated Alumina dosage (0.1, 0.2, 0.3 gr/l) was investigated. Also found data of this research were fited with Langmuir and Freundlich models, kinetic data with pseudo- first order, pseudo- second order and modifited pseudo- first order  models.
Results: The results showed that with increasing of pH of solution, removal efficiency was decreased and optimum pH was found to be in the range of 5 to 7. Also removal efficiency of fluoride was increased with increasing of adsorbent dosage and decreasing of initial concentration of fluoride. Adsorption isotherm data show that the fluoride sorption followed the Langmuir model (r²=0.98). Kinetics of sorption of fluoride onto Activated alumina was well described by pseudo- second order model.
Conclusion: The concentration of Activated Alumina had significant effect on the reduction of fluoride ions concentration in water.The higher fluoride removals were observed for batch experiments at pH=5 because no free fluoride ion is present in the solutions, and it could be casued by electrostatic interactions between the surface of alumina and the dominant fluoride species in solution The kinetic model can adequately describe the removal behaviors of fluoride ion by alumina adsorption in the batch system.

Background and Objectives: Pentachlorophenol (PCP) is an organic compound and phenolic derivatives categorized as priority pollutants that have harmful effects on humans, animals, and plants in low concentrations. Therefore, PCP removal from water and wastewater is very important. The aim of this study was to assess the efficiency of A. niger fungus biomass in PCP absorption. Materials and Methods: This was an experimental study in which different steps of the experiments were performed. A. niger strain was prepared from Persian Type Culture Collection of Iranian Research Organization for Science and Technology (IROST). After activation in potato dextrose agar (PDA) culture plates, fungi were incubated for 7 to 10 days at 25 °C. The prepared A. niger biomass was modified by NaOH and then it was used for PCP absorption assay. The concentration of PCP was measured using high-performance liquid chromatography. Results: The findings of present study showed that contact time is an important and effective factor in the PCP absorption rate. Two hours was selected as the optimum retention time in this experiment and after that the removal percentage did not raise significantly. The results of PCP absorption in different pH demonstrated that the adsorption efficiency decreases by rising pH and initial PCP concentration. The effects of contact time, pH and initial PCP concentration on the absorption process was significant (P-value <0.001). Conclusion: The results show that absorption efficiency increases by rising retention time under constant conditions. In addition, at low pH the modified A. niger biomass could be a good absorber for PCP.

Background and objectives: Nitrate and nitrite threaten the human health. According to recent research works, one of the great sources of exposure to nitrate and nitrite in human diet is vegetables. The aim of this study is to determine the effect of drying and frying processes on nitrate and nitrite levels in abundant vegetables. Materials and methods: In this descriptive – analytical study, 180 vegetable samples were taken randomly from Kermanshah markets. Nitrite and nitrate concentration was determined by Greece- Ilosoay method. Then, freezing and boiling processes were carried out on samples and again, nitrite and nitrate levels were measured. The mean differences were analyzed using ANOVA and SPSS program. Results: the concentrations of nitrate and nitrite were significantly different (p<0.5) in terms of vegetable type, storage process, or consumption. As average, frying and drying process led to increase nitrite and nitrate levels in the vegetables except Garlic chives. Frying process and drying process decreased the nitrite levels by 13 and 52% respectively, while in the case of nitrate, it was 29 and 25% respectively. Conclusion: Reducing nitrite and nitrate levels does not occur in frying and drying processing in vegetables. Therefore, it is essential to study other methods of processing or control of nitrate and nitrite levels in the vegetables. It is crucial to monitor and control the quality of this product and studying other food processing because of the daily intake of vegetables and potential risks of nitrate and nitrite accumulation and its association with some illnesses and gastrointestinal tract cancers. .