The adsorption of methyl tert-butyl ether by granular activated carbon was investigated. The experimental data were analyzed using the Freundlich isotherm and the Langmuir isotherm. Although equilibrium data were found to follow Freundlich isotherm model, it were fitted better by the Langmuir model with a maximum adsorption capacity of 204.1 mg/g. The kinetic data obtained at different concentrations were analyzed to predict the constant rate of adsorption using three common kinetic models: pseudo-first-order, pseudo-second-order equation and INTRAPARTICLE DIFFUSION equation. The pseudo-second-order model was suitable for describing the adsorption kinetics for the removal of methyl tert-butyl ether from aqueous solution onto granular activated carbon. Both the Lagergren first-order rate constant k1 and pseudo-second-order rate constant k2 decrease with increasing initial concentrations of methyl tert-butyl ether and the INTRAPARTICLE DIFFUSION rate constant kp shows the reverse characteristic. Analysis of sorption data using a boyd plot confirmed that external mass transfer is the main rate-limiting step at the initial stage of adsorption. Results illustrate that granular activated carbon is an effective adsorbent for methyl tert-butyl ether and also provide specific guidance into adsorption of methyl tert-butyl ether on granular activated carbon in contaminated groundwater.

Background and Objectives: The presence of heavy metals in aqueous sources is one of the most important problems that effects on health and environment. Adsorption by microorganisms using methods has many advantages. For this purpose, used microorganisms such as fungi, bacteria, and algae for removing heavy metals.Method: In this study the use of non-living fungal of Penicillium camemberti as biosorbent for removal of copper ions from aqueous solution was investigated in batch system and fixed bed column. In the batch system, for the biological absorption of copper, the parameters of temperature, pH, the dosage of bio sorbent and contact time were optimized. In the kinetic study of the bio sorption of copper metal by means of the non-living fungus, the Lagergren INTRAPARTICLE DIFFUSION models have been used.Findings: Considering the obtained results, it is determined that the biological absorption of copper using fungus follows from the second order equation because in the second order state, the amounts of qcal are close to the amounts of qexp and also R2>0.97.The results also demonstrate that an intra-particle DIFFUSION mechanism play a significant role in the sorption process. In continues system, the biosorbent was turned into granul and the effects of hight and flow rate studied. The structure of Penicillium camemberti was characterized by IR spectrometer.Disscusion and Conclusion: The results also demonstrate that adsorption mechanism plays a significant role in the sorption process. The maximum bio sorption obtained from the batch process was 86.52% for biomass in pH=5.5.

In the present study, Juglans regia shells were used to prepare activated carbon by acid treatment method. J. regia shell-based activated carbon was used for the adsorption of two synthetic dyes namely, a basic dye malachite green and an acid dye amido black 10B. The prepared adsorbent was crushed and sieved to three different mesh sizes 100, 600 and 1,000 mm. The adsorbent was characterized by scanning electron microscopy, surface acidity and zero-point charge. Batch experiments were carried out by varying the parameters like initial aqueous phase pH, adsorbent dosage and initial dye concentration. The equilibrium data were tested with Langmuir, Freundlich, Redlich-Peterson and Sips isotherm at three different temperatures 293, 300 and 313 K and it was found that the Freundlich isotherm best fitted the adsorption of both the dyes. Kinetic data were tested with pseudo first-order model and pseudo second-order model. The mechanism for the adsorption of both the dyes onto the adsorbent was studied by fitting the kinetic data with INTRAPARTICLE DIFFUSION model and Boyd plot. External mass transfer was found to be the rate-determining step. Based on the ionic nature of the adsorbates, the extent of film DIFFUSION and INTRAPARTICLE DIFFUSION varied; both being system specific. Thermodynamic parameters were also calculated. Finally, the process parameters of each adsorption system were compared to develop the understanding of the best suitable system.

Activated carbon produced from fluted pumpkin (Telfairia occidentalis) seed shell was utilized for the removal of lead (II) ion from simulated wastewater. Adsorption tests were carried out in series of batch adsorption experiments. Several kinetic models (Bhattacharya-Venkobacher, Elovich, pseudo first and second order, intra-particle and film DIFFUSION) were tasted for conformity to the experimental data obtained. The Langmuir and Freundlich adsorption models were also used to test the data. The amount of lead (II) ion adsorbed at equilibrium from a 200mg/L solute concentration was 14.286mg/g. The experimental data conform very well to the pseudo-second order equation where equilibrium adsorption capacities increased with increasing initial lead (II) concentration. The rate of the adsorption process was controlled by the film (boundary layer) DIFFUSION as the film DIFFUSION co-efficient values obtained from data analysis were of the order of 10 6cm2/s. From the plots, the linear regression coefficient (R2) of the Langmuir model was higher than that of the Freundlich: the adsorption isotherm obeyed the Langmuir model better than the Freundlich model.

Batch adsorption experiments using activated carbon prepared from Morringa Indica bark were conducted to remove fluoride from aqueous solution. A minimum contact time of 25 min was required for optimum fluoride removal. The influence of adsorbent, dose, pH, co-ions (cations and anions) on fluoride removal by the activated carbon has been experimentally verified. The adsorption of fluoride was studied at 30°C, 40°C and 50°C. The kinetics of adsorption and adsorption isotherms at different temperatures were studied. The fluoride adsorption obeyed both Langmuir and Freundlich isotherms and followed a pseudo first order kinetic model. The thermodynamic studies revealed that the fluoride adsorption by Morringa Indica is an endothermic process indicating an increase in sorption rate at higher temperatures. The negative values of DG° indicate the spontaneity of adsorption. SEM and XRD studies confirmed the surface morphological characteristics of the adsorbent and the deposition of fluoride on the surface of the material.

Background: Prostate cancer is the third leading cause of death and is the most common cause of cancer in elderly men. Regarding to the low accuracy of screening methods such as prostate-specific antigen (PSA), Digital Rectal Examination (DRE) and trans rectal ultrasound (TRUS) in detection and localization of tumor, Magnetic Resonance Imaging (MRI) and DIFFUSION Weighted Imaging (DWI) attracted many attentions in the past years. DWI reveals micro-molecular DIFFUSION, which is the Brownian motion of the spins in biologic tissues. This technique can delineate pathologic lesions with high tissue contrast against generally suppressed background signal. In this paper, the value of DWI in detection of prostate cancer is studied.Methods: In this cross-sectional study, the studied population are suspicious patients to prostate cancer based on high Prostatic Specific Antigen level or abnormal Digital Rectal Examination who refered for prostate biopsy to radiology department of Hazrate- Rasoul Hospital during the year 2011. The results of DWI are compared to biopsy results for all patients.Results: Eighty five patients are selected. The DWI sensitivity in detecting of prostate cancer is 100%, specificity 97.1% and positive and negative predictive values are 89.5% and 100%, respectively. The results showed that if DWI reports the prostate cancer as negative, the result was highly reliable and if it reports as positive, although the report was not 100% reliable, but it still had high reliability, more than 90%.Conclusion: DWI had high accuracy in detecting prostate cancer for patients with cancer. Also the accuracy of this method for patients without prostate cancer was acceptable compared to the other common methods.

Background: Multiple sclerosis (MS) is a chronic disease that begins most commonly in young adults and is characterized pathologically by multiple areas of central nervous system (CNS) white matter inflammation, demyelination, and glial scarring. The most valuable aid for diagnosis is magnetic resonance imaging (MRI). New type of MRI has been developed on the basis of molecular DIFFUSION which capable of detecting acute and active lesions. Early diagnosis and treatment is possible to stop or slowdown progression of disease. The aim of this study is to compare the findings of conventional and DIFFUSION- weighted (DW) MRI in detection cerebral lesions of MS.Methods: Thirty patients with clinically definite MS and 30 healthy volunteers were studied in a descriptive-prospective survey over a twelve-month period of time.Conventional and DW MRI were used in both groups. Total number, morphology, location and the mean size of the intra-cerebral plaques of MS were compared between group. The sensitivity and the specificity of both imaging methods in detecting these plaques were determined.Results: Thirty patients with MS with the mean age of 32.76±8.79 years and 30 healthy individuals with the mean age of 32.75±9.23 years were enrolled. Plaque within the brain was significantly higher by the conventional method (P<0.05). Ovoid lesions were greater in number in the conventional method group. More lesions were detected by the conventional method in the areas of periventricle, centrum semiovale and corpus callosum. Regarding the size of plaque, the minimum measurement was significantly lower in the conventional method group. The sensitivity of both methods was 100%. The specificity of conventional and DW MRI was 86.6% and 96.6%, respectively.Conclusion: In our study the sensitivity of both methods was the same but the specificity of DW MRI was higher. DW MRI may detect lesions which are not detectable by the routine methods.

The study of the kinetics and thermodynamics of the adsorption process can provide valuable information for the proper design and control of adsorption systems. The influence of temperature on the kinetics of Zn2+ sorption on an Iranian sepiolite sample was investigated through a series of batch experiments. Consistent with an exothermic reaction, an increase in the temperature resulted in decreasing Zn2+ adsorption rate. The sorption kinetics was tested for pseudo-first-order, pseudo-second-order, and INTRAPARTICLE DIFFUSION models, and the rate constants were calculated. Results showed that the adsorption kinetics followed the pseudo-second-order kinetic model. The INTRAPARTICLE DIFFUSION model described that sorption of Zn onto the sepiolite particles is a two-step process, and INTRAPARTICLE DIFFUSION is not the only rate-limiting step. The results obtained from the study of thermodynamic data indicated that sorption of Zn onto sepiolite is non-spontaneous and less favored at higher temperatures.