Which is better for optimizing the biosorption process of lead - central composite design or the Taguchi technique?

The aim of this study is to evaluate central composite design (CCD) and the Taguchi technique in the adsorption process. Contact time, initial concentration, and pH were selected as the variables, and the removal efficiency of Pb was chosen for the designated response. In addition, face-centered CCD and the L9 orthogonal array were used for the experimental design. The result indicated that, at optimum conditions, the removal efficiency of Pb was 80%. However, the value of R2 was greater than 0.95 for both the CCD and Taguchi techniques, which revealed that both techniques were suitable and in conformity with each other. Moreover, the results of analysis of variance and Prob > F < 0.05 showed the appropriate fit of the designated model with the experimental results. The probability of classifying the contributing variables by giving a percentage of the response quantity (Pb removal) made the Taguchi model an appropriate method for examining the effectiveness of different factors. pH was evaluated as the best input factor as it contributed 66.2% of Pb removal. The Taguchi technique was additionally confirmed by three-dimensional contour plots of CCD. Consequently, the Taguchi method with nine experimental runs and easy interaction plots is an appropriate substitute for CCD for several chemical engineering functions.

Data on the effect of geological and meteorological parameters on indoor radon and thoron level- case study: Kermanshah, Iran.

The present study was aimed to evaluate the relationship between indoor radon and thoron concentrations, geological and meteorological parameters. The radon and thoron concentrations were determined in three hospitals in Kermanshah, the west part of Iran, using the RTM-1688-2 radon meter. Also, the type and porosity of the underlying soil and the meteorological parameters such as temperature, humidity, atmospheric pressure, rainfall and wind speed were studied and the obtained results analyzed using STATA-Ver.8. In this study the obtained radon concentration was furthered in buildings which constructed on the soil with clayey gravel and sand feature than the soil with clay characteristic and little pasty with a significant difference (P < 0.05). While the lower coefficient about 1.3 was obtained in measured the thoron concentration and a significant difference was not observed. So the soil porosity can extremely effect on the indoor radon amount. Among all studied meteorological parameters, temperature has been determined as the most important meteorological parameter, influence the indoor radon and thoron concentrations.

Data on performance of air stripping tower- PAC integrated system for removing of odor, taste, dye and organic materials from drinking water-A case study in Saqqez, Iran.

Unpleasant taste or smell are more importantly constituents of drinking-water, lead to complaints from consumers. Dye and organic matter as well change in disinfection practice may generate taste and an odorous compound in treated water. According to low efficiency of conventional methods to remove taste and odor compounds, present study was aimed to evaluate the performance of air stripping tower- Poly Aluminum Chloride (PAC) integrated system to remove odor and taste, dye and organic materials from drinking water. Different air to water ratio and PAC doses were used to remove considered parameters in certain condition. The results of this study indicated that the maximum removal efficiency of 86.2, 76.47, 58.46 and 41.27% of taste and odor, dye, COD and TOC were achieved by the air stripping tower- PAC integrated system, respectively. However, the physico-chemical characteristics of water and adsorbent effect on the of substances removal efficiency considerably. It can be stated that the air striping tower - PAC integrated system is able to reduce the odor and taste-causing substances and organic matter to a level which is recommended by the Institute of Standards and Industrial Research of Iran.

Natural airborne dust and heavy metals: a case study for kermanshah, Western iran (2005-2011).

BACKGROUND: Dust pollution has become a serious environmental problem especially in recent decades. The present study aim was the investigation of the levels of PM10 concentration in Kermanshah, western Iran and also measured five important heavy metals (Pb, Cd, As, Hg and Cr) in some samples during 2005 to 2011. METHODS: A total 2277 samples were collected from air pollution measurement station belonging to the Department of Environment in Kermanshah. Furthermore, four samples were collected during dusty days to determine the selected heavy metals concentration. The samples were analyzed statistically using the SPSS Ver.16. RESULTS: The highest seasonal average concentration in spring was recorded in 2008 with 216.63µg/m(3), and the maximum values of 267.79 and 249.09µg/m(3) were observed in summer and winter in 2009, respectively. The maximum concentration of 127.1µg/m(3) was in autumn in 2010. The metals concentration (Pb, Cd, As, Hg and Cr) of samples were 42.32±5.40, 37.45±9.29, 3.51±2.07, 1.88±1.64 and 0µg/g in July, 2009, respectively. CONCLUSION: According to National Ambient Air Quality of USEPA guidelines, the most days with non-standard, warning, emergency and critical conditions were related to 2009 (120 days) while the least polluted days were recorded in 2006 (16 days). There are concerns about the increasing frequency and intensity trend of dust storms in recent years as a result of special condition in neighboring Western countries which it could endanger public health and environment. All measured heavy metals except mercury was higher than the standard level of WHO and USEPA.

A systematic review of radon investigations related to public exposure in iran.

BACKGROUND: The main sources of radiation exposure of all living organisms including humans are natural. In fact, radon and its decay products are the cause of 50% of the total dose that is derived from natural sources. Because of the significant health hazards of radon gas, its levels are widely monitored throughout the world. Accordingly, considerable researches have also been carried out in Iran. OBJECTIVES: The aim of this research is a systematic review of the most recent studies associated with evaluation of radon gas levels in Iran. The main emphasis of this study was on public exposure to radon gas. MATERIALS AND METHODS: The most important route of exposure to such radiation is indoor places. In this investigation measurement of radon in water resources, tap water, indoor places and exhalation of radon from building material, the major sources of indoor radon gas emission, were considered. RESULTS: Significantly high levels of radon gas were found mostly in water and residenvial buildings. CONCLUSIONS: It conclusion with regard to the study of building materials, granite stone and adobe coverings cannot be recommended for construction purposes.