Preparation and Characterization of Biodegradable Blend Membranes of PBS/CA

Asymmetric membranes of cellulose acetate/poly (butylene succinate) were prepared using immersion precipitation technique. The blended membranes were characterized by contact angle, scanning electron microscopy, thermogravimetric analysis, degradation test in compost and dynamic test of raisin wastewater treatment. Results demonstrated that hydrophilicity of cellulose acetate was enhanced by addition of poly (butylene succinate) up to 50 %. Furthermore, polymeric composition affects cross sectional structure of the membranes by controlling formation of macrovoids. Addition of poly (butylene succinate) improved the membranes thermal stability and obviously their degradation in compost. The prepared membranes were able to reject the wastewater pollutants properly.     

Probabilistic health risk assessment based on Monte Carlo simulation for pesticide residues in date fruits of Iran

Environmental Science and Pollution Research - The validation of an analytical procedure based on the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach is presented for...     

Investigation on diazinon and oxydemeton-methyl residues in cucumbers grown in Kerman greenhouses

Pesticides are considered as the most polluting substances. The residue of pesticides in agricultural crops, especially in greenhouse harvests, has been reported critical. Cucumber, considered as a vegetable, is an agricultural product which is commonly found in the Iranian food basket. The current study aims to assess the level of diazinon and oxydemeton-methyl existing in cucumbers sampled from Kerman greenhouses. The pesticide residue was extracted by acetone and dichloromethane. The extracts were cleaned up according to the solid-phase extraction method. The pesticide residues were then determined by capillary gas chromatography with nitrogen-phosphorus detection. The recoveries were 83 and 85 %, the limit of detection was 0.028 and 0.034 mg/kg, and the limits of qualification were 0.093 and 0.113 mg/kg for diazinon and oxydemeton-methyl in cucumber samples, respectively. The median of diazinon residue was detected 0.582 mg/kg, which was 11.64 times the national maximum residue limit (MRL) (0.05 mg/kg), and the median for oxydemeton-methyl was 1.910 mg/kg, being 1.91 times the MRL (1 mg/kg).     

Graphene quantum dots–eggshell nanocomposite to extract polycyclic aromatic hydrocarbons in water

In solid-phase extraction, the sorbent controls selectivity, affinity, and loading capacity. Many sorbents can be used, such as functionalized resin, naphthalene, activated carbon, molecular-imprinted polymers, and nanometer-sized materials. Here, we prepared a nanocomposite made of graphene quantum dots and eggshell to extract polycyclic aromatic hydrocarbons from aqueous solutions. We studied the effect of sample volume, solution pH, amount of nanosorbent, and sample loading flow rate on the extraction efficiency. We obtained a wide dynamic linear range from 0.1 to 200 ng m/L, good linearity with r ² higher than 0.99, and low-detection limits of 5–75 pg m/L. We measured PAH in spiked water samples.     

Evaluation of potentially toxic metals pollution in the sediments of the Kor river, southwest Iran

This study is carried out to evaluate potentially toxic metal concentrations (As, Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn) together with their spatial distribution, degree of pollution, and potential ecological risk in Kor river sediments (southwest Iran) using sediment quality guidelines, geoaccumulation index (I _geo), Hakanson potential ecological risk index (RI), and standard methods of statistical analysis. The study area stretches some 140 km from the Drodzan Dam to Bakhtegan Lake, a stretch of river where different industrial and domestic activities (e.g., petrochemical complex, oil refinery, industrial meat processing complex, Marvdasht city sewage) and ecological value overlap with each other. Calculated geoaccumulation index indicate that 50 % of the stations are moderately to very extremely polluted. The potential ecological risk for nine investigated metals in Kor river is Hg (948)?>?Mo (51.9)?>?Ni (37.8)?>?Cd (29.8)?>?As (22)?>?Cu (16.6)?>?Pb (13.3)?>?Zn (3.3)?>?Cr (1). Results show that sediments in parts of Kor river sediments are heavily affected by effluents discharged from industrial plants and other parts are affected by agriculture and urban runoff from nearby lands. These phenomena may cause a risk of secondary water pollution under sediment disturbance and/or changes in the physical–chemical characteristics of the aquatic system.