[Application of dry activated sludge for lead and cadmium adsorption: isotherm and kinetic modeling]

Heavy metals have an important role on organism life and their high concentration may be a great threat for humans and other organisms' lives. Up to now, various methods have been used for the removal of these metals, which include the adsorption process. The aim of this study was the recovery of municipal disposals, and using as absorbent for lead and cadmium removal from aqueous solutions. Adsorption of lead and cadmium on dry activated sludge was investigated. Activated sludge was obtained from diary industry [Tehran]. All experiments were performed in batch system on 202 synthetic samples to investigate the effects of pH, contact time initial concentration lead and cadmium and adsorbent dose. The most conventional adsorption and kinetic models were applied to describe metal adsorption and dynamic reaction. The results showed that with increasing of adsorbent doses, contact time and pH solution, lead and cadmium removal efficiency increased. The maximum lead and cadmium adsorption was obtained at pH: 6 and an equivalent time of 180 min. With increasing initial concentration of lead and cadmium, removal efficiency decreased. The obtained results in this study were matched with langmuir 2 isotherm [R[2]>0.99] and interparticle diffusion kinetic [R[2]>0.94]. Maximum adsorption capacity of lead and cadmium on dry activated sludge was obtained to be 2.66 and 1.66mg/g, respectively. Maximum constant rate of lead and cadmium was 0.045 and 0.041mg/g.min[0.5], respectively. According to the results, dry activated sludge is recommended as a low cost and available adsorbent to remove lead and cadmium from aqueous solutions

Nasal carriage rate of community- and hospital-acquired methicillin-resistant staphylococcus aureus in children, Kermanshah, Iran

Background: Staphylococcus aureus [S.aureus] is an importantpathogen in human infections.Some strains of S. aureusare methicillin-resistant [MRSA] andcause hospital- and community-acquired infections in children. The aims of this study were to determine nasalcarriage rate of S. aureus and susceptibility pattern of this organism to some antibioticsamong children in Kermanshah province, Iran. Methods: This was a cross-sectional study conducted in Kermanshah province, Iranfrom 2007 to 2008.Nasal swabs were obtained from 274 children who were hospitalized in our university hospital at the time of admission and 219 children upon dischargetime.If result of nasal culture was positive at admission time they considered community acquired and if result at admission time was negative but positive at discharge time they considered hospital acquired. Antibiotic susceptibility patterns of S.aureuswere done by disk diffusion method and results were compared between them. Results: In 55 patients out of 274 cases [20.07%], S. aureus was demonstrated upon admission [community-acquired]. In the remaining 219 cases, S. aureus was detected in 46 cases [21%] at discharge time [hospital-acquired]. The rate of methicillin-resistant S. aureus [MRSA] in community- and hospital-acquired infections were 96.4% and 95.7%, respectively.We observed no statistical significance different in antibiotic resistance pattern between community acquired and hospital – acquired S.aureus except for co-triomoxcazol [P=0.034]. Conclusion: A high rate of MRSA in both community- and hospital-acquired infections were observed

Methyl tert-butyl ether adsorption on surfactant modified natural zeolites

Surfactant-modified clinoptilolite-rich tuff was used for the removal of methyl tert-butyl ether [MTBE] from aqueous solutions. Clinoptilolite zeolite from Miyaneh region of Iran was treated with sodium chloride and then modified with hexadecyltrimethylammonium chloride [HDTMA-Cl] and n-Cetylpyridinium bromide [CPB] to be used in different experimental conditions. The ability of raw or Non-Modified Zeolite [NMZ] and Surfactant-Modified Zeolites [SMZ] to remove MTBE from aqueous solutions was investigated as a function of contact time, pH and concentrations of adsorbent and adsorbate, by using a batch technique in aqueous system. The removal of MTBE from aqueous solutions by modified zeolites seemed to be more effective than non-modified samples. Also, HDTMA-modified zeolite had more effective performance than CPB-modified zeolite. The adsorption efficiency of MTBE onto SMZ[S] was found to increase by contact time and adsorbent concentrations, and by decreasing of pH and adsorbate concentrations. Empirical adsorption models of Langmuir and Freundlich were applied for the experimental data. Results showed that Langmuir isotherm was more suitable for this process. The experimental data fitted very well with the pseudo-second-order kinetic model. It was overally found that Surfactant-Modified Zeolites is an effective adsorbent for removal of methyl tert-butyl ether from contaminated solutions

[Performance of simple nano zeolite Y and modified nano zeolite Y in phosphor removal from aqueous solutions]

Phosphate discharges from domestic and industrial waste water to water bodies. High concentrations of phosphate in water stimulate the eutrophication phenomenon that causes taste and odor in water, losing dissolved oxygen and aquatic life in rivers or surface waters. Aim of this study is survey of phosphate adsorption on simple nano zeolite Y and nano zeolite Y that was modified with a cationic surfactant [HDTMA-Br]. In This study we used simple nano zeolite Y and nano zeolite Y in form of Surfactant Modified Zeolites [SMZs] using batch tests to adsorption of Phosphate from Aqueous Solutions. The adsorbants were contacted with different initial phosphor concentrations [5, 10 and 15 mg/l], pH [4, 7, 12], contact time [30, 60, 90, 120, 150 and 180 minutes] and weight of adsorbant [0.2, 0.4, 0.6, 0.8 and 1g]. the extracted solution was determined for Phosphate concentration by the ammonium molybdate and tin chloride method with spectrophotometric detection at 680 nm. Results of this study show that, with increase in contact time, decrease in pH, increase in zeolites concentration and decrease in initial phosphate concentration, the removal efficiency increased. And the Both isotherm of Langmuir and Freundlich models [r[2]>0.997 and r[2]>0.996 respectively] were agreement with adsorption equilibrium of phosphate. Reduced Chi-Sqr For Langmuir and Freundlich models were [0.00079] and [0.0011] respectively. Pseudo first-order kinetic models fits well with experimental data [r[2]>0.963]. From this survey, it is concluded that performance of modified nano zeolite Y for adsorption of phosphate in same conditions is better than non-modified zeolite Y. In general the modified nano zeolite Y presented a good profile for removal of phosphate. Therefore SMZs is a suitable candidate for removal of Phosphate molecules from contaminated solutions in contaminated waters

[ MIC study of antibiotics used in the treatment of children with urinary tract infections caused by E.coli using E-test and its comparison with disk diffusion]

Urinary tract infection [UTI] is one of the most common bacterial infections in the childhood which could result in chronic renal failure and hypertension. Antibiotic resistance is increasing due to widely using of antibiotics. The aim of this study was to determine the MIC of antibiotics which are using in the treatment of UTI in children by E-test. In this descriptive study, 87 E.coli strains were isolated from the urine samples of the patients with UTI. E.coli antimicrobial susceptibility was determined using E-test. The MIC for each antibiotic was determined and classified using NCCLS criteria. Eighty seven urine samples were collected from 57 girls [65.5%] and 30 boys [34.5%]. The mean age for girls was 61 months and for boys was 41 months [p=0.015]. The MIC [50 and 90 percentiles] for each antibiotic was as fallow: Ampicillin [256, 256], Amikacin [1/5, 4/8], Gentamycin [0.38, 32], Nalidixic Acid [1/5, 256], Ceftriaxon [0.023, 32], Cefixim [0.19, 256] and Trimethoprim-Sulfamethoxazole [32, 32]. The antibiotic susceptibility rate for each antibiotic was as fallow: Ampicillin [21.8%], Amikacin [92%], Gentamycin [75.5%], Nalidixic Acid [64/4%], Ceftriaxon [72/4%], Cefixim [65/5%] and Trimethoprim- Sulfamethoxazole [41/4%]. This study showed that the antibiotic resistance of E.coli was very high. Due to increasing rate of E.coli resistance to Ampicillin and Cotrimoxasole in children, it is better to reconsider the empirical therapy with these antibiotics. Since in this study a lower resistance rate of E.coli was observed for Amikacin and Gentamycin therefore, we could suggest these antibiotics as alternatives in the treatment of children with urinary tract infection

Two cases of disseminated TB due to BCG vaccination and review of the related articles

Although BCG vaccination has many benefits, it can cause multiple complications. Disseminated TB is the most severe but rare complication of BCG vaccination. Osteomyelitis is another important complication. Usually these complications are due to a defect in immune system. Rapid diagnosis and treatment can be life saving. The first case was a 3 month old boy that was admitted in hospital because of fever, lethargy and fistula in the right axillary area at the site of BCG vaccination. The second one was a 7 month old boy with an ulcer and a fistula at the site of BCG vaccination and chest wall. Diagnosis of disseminated TB was made by biopsy and culture. All immunologic investigations, except interleukin 12-gamma interferon pathway, were normal. When a child presents with lymphadenopathy and ulcer near the site of BCG vaccination, the physician must perform a complete physical examination to exclude diagnosis of disseminated TB, especially in the presence of long term low grade fever, organomegally, skin lesions and lack of weight gain