Removal of Zn(II) and Pb (II) ions Using Rice Husk in Food Industrial Wastewater

The adsorption behavior of Zn2+ and Pb2+ ions on rice husk was investigated using Rice Husk to remove the metals ions in dairy wastewater. The removal of mentioned heavy metal ions from aqueous solutions was studied by batch method. The main parameters that influencing Zn 2+ and Pb2+ sorption on rice husk were: amount of adsorbent, contact time and pH value of wastewater. The influences of pH (2–9), contact time (5-70min) and adsorbent amount (0.5-3 g) have been studied. The percent adsorption of Zn 2+ and Pb2+ ions increased with an increase in contact time and dosage of rice husk. The binding process was strongly affected by pH and the optimum pH for Zn 2+ and Pb2+ ions were 7.0 and 9.0, respectively. The experimental data were analyzed by Langmuir isotherm. The maximum adsorption capacity of the adsorbent for Zn 2+ and Pb2+ ions was calculated from the Langmuir isotherm and found to be 19.617 and 0.6216 mg/g, respectively. Actually the percent of removing Zn 2+ and Pb 2+ ions reached maximum to 70% and 96.8%, respectively. @JASEMJ. Appl. Sci. Environ. Manage. December, 2010, Vol. 14 (4) 159 - 16

Cadmium removal from industrial sewage by using Bentonite and Kaolinite absorbent gravels

Many types of water pollutants have been identified and categorized. Heavy metals is one of the most important and hazardous ones. Among all heavy metals, cadmium has a significant effect on all living organisms. Cadmium can be dissolved in water and be absorbed by Plants and then concentrates and moves up the food chain. Which causes toxication in Plants and causing Cancer and numerous other illnesses in humans and other living beings. Using surface absorption is proved to be a suitable method for removing heavy metals from industrial sewages. In this study, Bentonite and Kaolinite were used as surface absorption agents and White Cement was used as a binding agent to keep particles in a firm gravel shape. When poured into the current of sewage, surface absorbing gravels can remove Cadmium ions from sewage. Performance affecting factors such as optimum mass ratio between absorbent agent and binder agent, an optimum mass ratio between Bentonite and Kaolinite, gravels diameter, primary concentration of Cadmium, contact duration and sewage pH was separately examined and optimized by measuring post contact concentration of Cadmium of the samples. Results showed that gravels with absorbent: binder ratio of 3:1, absorbent mass made out of 80% bentonite and 20% kaolinite, when broken to a diameter of 4.75mm < D <6.35mm can refine sewage with 250ppm primary concentration of Cadmium and pH of 7.5 up to 99.97% in 5 hours contact duration

Modified Concrete Ability for Removing Cadmium (2) From Wastewater

Cadmiumis found in high concentrations in industrial wastewater. In this study, using two adsorbent in concrete has been discussed. The solutions of iron nanoparticle as the first absorbent have been used in amounts of 20, 30 and 40 mg/l. The rice husk as the second adsorbent was converted to rice husk ash in 500 to 650°C. The rice husk ash mixed to 40% by weight of cement in the concrete structure. Samples, with nanoparticle, with rice husk, and combination nanoparticles and rice husk, were constructed. The samples under the different conditions such as pH, contact time, concentration of absorbent and cadmium concentrations in solution were examined. The maximum absorption 97.5% could be occurred in optimum contact time 6 hours, absorbent concentration 40 mg/l, the optimum pH 3 and wastewater concentration 10 ppm. To remove cadmium, modified concrete can be suggested as new and efficient method

Study on the Status of SO2 in the Tehran- Iran

An air quality analysis for Tehran, the capital city of Iran, is conducted for SO2, with the measurements taken from 1995 to 2002. Measurements were taken from the seven main monitoring stations in different locations of the city. These stations are controlled by Department of Environment of Iran. As a first step; annual, seasonal and diurnal variations were studied. The yearly variation does not show any specific trend initially but in the recent years it seems there is a little upward trend. The pick of concentration of SO2 can be seen during 6-12 hour and during the winter season especially in January. The main purpose of this study is to see the effect of the meteorological parameters on the concentration of pollutant. For this purpose, the wind velocity, relative humidity, temperature, dew point, wind direction and rainfall are considered as independent variables. The relation between concentration of pollutant and meteorological parameters can be expressed by one linear regression equation. It is obvious from the equation that the wind speed, daily temperature and humidity have reverse effect on the concentration of SO2. To plan and execute air pollution control programs, one must predict the ambient air concentrations that will result from any planned set of emissions. For this purpose, a two-dimensional atmospheric diffusion model for ambient air concentration of SO2 was considered. Geostrophic winds, surface roughness, mixing height of the atmosphere, emission rate of the pollutant sources and background pollutant concentration have been taken as the input parameters. The airspace over the city to the mixing height was divided into multiple cells. Conservation of mass equations for each cell were solved for slightly stable and highly stable atmospheric conditions of city. The results of this equation were adjusted by the actual data (taken from monitoring stations).Then the modified dispersion equation for concentration of SO2 in Tehran has been suggested. @JASE

DIOXIDE TITANIUM NANOPARTICLES EFFICIENCY ON REMOVING WATER HETEROTROPHIC BACTERIA POPULATION

Water source pollution is increasing in recent years and use of new methods ofcontaminants removal is required. Nanotechnology is a suitable technique forenvironmental applications. Titanium dioxide is one of most commonly usednanoparticles containing interesting properties for water and wastewater treatment.Purpose of this study was determination of nanoparticles efficiency for removingof heterotrophic bacteria.Spread plate method was used for enumeration ofheterotrophic bacteria. Variables of pH, nanoparticle concentration, and contacttime were investigated to remove heterotrophic bacteria. pH 7, contact time 90minutes and heterotrophic population 305 were optimum condition for maximumremoval efficiency. Investigation showed also suitability of titanium dioxidenanoparticles for real water samples. It showed that TiO2 nanoparticles have goodantibacterial features, so that they were able to remove heterotrophic bacteria.

Application of Artificial Neural Network (ANN) for Modelling Chromium(VI) removal using Iron Oxide Nanoparticles

Nowadays, one of the most important environmental pollution is heavy metals industrial wastewater. Among the various types of heavy metals, chromium is one of the hazardous and toxic environmental pollutants. In order to prevent damage caused by chromium, it seems essential to prevent its entrance to the environment. The purpose of this study was modelling chromium removal using iron oxide nanoparticles through artificial neural network model for estimating the best removal Cr(VI) model. The optimum conditions (more than 90% removal efficiency) achieved were at pH=3, initial concentration of Cr = 10 mg/L; dosage of Fe2O3 = 1 g/L; contact time = 60 minutes, and temperature =25 . After backpropagation (BP) training, the ANN model was able to predict adsorption efficiency with a tangent sigmoid transfer function (Tansig) at hidden layer with 11 neurons and a linear transfer function (Purelin) at out layer. The Levenberg-Marquardt algorithm (LMA) was applied, giving a minimum mean squared error (MSE) for training and cross validation at the ninth place of decimal. The high correlation coefficient (R2ANN = 0.996) between the model and its closeness to the experimental coefficient (R2Exp = 0.998) showed that the model is able to predict the removal of Cr(VI) from aqueous solutions by iron oxide nanoparticles

Erosión y desertificación.-Risk evaluation of ground water table decline as a type of desertification. A case study area: Southern Iran

ABSTRACT This paper presents a model to assess risk of ground water table decline. Taking into consideration eleven indicators of lowering of ground water table the model identifies areas with ‘Potential Risk’ (risky zones) and areas of ‘Actual Risk’ as well as projects the probability of the worse degradation in future. The Mond river basin, located centrally to this zone, has been selected as a test area to assess the risk of lowering of ground water table. For this purpose two sub basins of the Payab and Qareh Aghaj have been chosen for detailed study. By fixing the thresholds of severity classes of the eleven indicators a hazard map for each indicator was first prepared in GIS. The risk map was prepared by overlaying eleven hazard maps in the GIS, deploying the new model. The GIS analysis has made it possible to distinguish the areas with ‘potential risk’ from those widespread areas that showed the ‘actual risk’ of lowering of water table. Although the areas under potential risk form a lower proportion in the both sub basins, but the vulnerable potential risk areas with moderate and severe classes are more in the Qareh Aghaj plains compared to the Payab. A conclusion is that the already over evacuated lands (severe risk + moderate actual risk) are more widespread in the Qareh Aghaj plains (54%), with semi arid climate, compared to the Payab (10%), with arid climate. Areas under potential risk when classified into subclasses with different probability levels the model projects a statistical picture of the risk of lowering of ground water table

Sensitive determination of Lead in Soil and Water samples by Cloud Point Extraction-Flame Atomic Absorption Spectrometry Method

Abstract : Cloud point extraction has been used for sensitive pre-concentration of lead after complex with 1-(2-pyridylazo)-2naphthol (PAN) followed determination of it&apos;s by flame atomic absorption spectrometry method. The analyte is quantitatively extracted to the phase rich in the nonionic Surfactant Triton X-114. The parameters which affecting the separation phase and detection process, were optimized under the optimum experimental conditions (pH=8, 1×10 -1 mol l -1 PAN, 0.5% w/v Triton X-114). Calibration graph showed linear trend in rang of 20-300 µg 1 -1 with detection limit 8 µg 1 -1 of lead (II). The enrichment, preconcentration factors achieved 50, 35 respectively. The proposed method was analyzed for soil and water samples which gave satisfactory results. Lead in soil and water samples, which gathered from petrochemical factory, has been measured approximately around 30 µg l -1 and 1 µg 1 -1 respectively. These amounts are more than limit threshold of lead. Regarding to achieved data, water and soil of case study is polluted