Hydrogen sulfide is a very dangerous, toxic and corrosive gas. It can diffuse into drilling fluid from formations during drilling of gas and oil wells. Hydrogen sulfide should be removed from this fluid to reduce the environmental pollution, protect the health of drilling workers and prevent corrosion of pipelines and equipments. In this research nano zinc oxide with 14-25 nm particle size and 44-56 m 2 /g specific surface area was synthesized by spray pyrolysis method. The synthesized nanoparticles were used to remove hydrogen sulfide from water based drilling fluid. The efficiency of these nanoparticles in the removal of hydrogen sulfide from drilling mud were evaluated and compared with that of bulk zinc oxide. The obtained results show that synthesized zinc oxide nanoparticles are completely able to remove hydrogen sulfide from water based drilling mud in just 15 min., whereas bulk zinc oxide is able to remove 2.5% of hydrogen sulfide in as long as 90 min. under the same operating conditions.
A novel magnetic mesoporous silica material was synthesized and used as the sorbent for the magnetic solid-phase microextraction of diazinon and malathion before their quantification by high-performance liquid chromatography with UV detection. The sorbent was synthesized by a surfactant-templated one-pot sol-gel procedure using SiO -coated Fe O as the magnetic support, cetyltrimethylammonium bromide as the template and tetraethyl orthosilicate as the silicon source. The characteristics of the prepared sorbent were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The sorbent exhibited a high maximum adsorption capacity of 19.2 and 9.4 mg/g for diazinon and malathion, respectively. The parameters affecting the microextraction were optimized by the MultiSimplex method. Under the optimized conditions, the calibration graphs were linear in the concentration ranges of 0.3-50.0 and 0.5-50 μg/L with the limits of detection of 0.09 and 0.14 μg/L for diazinon and malathion, respectively. The relative standard deviations (n = 5) at a concentration level of 10.0 μg/L of analytes were less than 2.5 and 4% for intra and interday, respectively. The developed method was successfully used for the determination of diazinon and malathion in apple, tomato, cucumber, tap water, and well water samples.
A new reagent 2-(2,3-dihydroxy-4-oxocyclobut-2-enylidene) hydrozinecarbothiamide has been synthesized and used for developing a simple spectrophotometric method for the determination of Fe(III) which is based on a 2 : 1 complex formation between Fe(III) and new reagent in aqueous solution. e method is optimized in terms of the pH value, amount of reagent required, ionic strength, and stability of the complex, sensitivity, linearity, and tolerance limits of various foreign ions. e complex is a redbrown chelate, with max = 465 nm at pH = 3 (= 5 3 L⋅mol − ⋅cm −). e ionic strength was kept constant at 0.02 by adding appropriate amounts of NaCl solution. e calibration curve is linear in the concentration range from 0.27-33.50 g⋅mL −. e effects of foreign ions on the determination of Fe(III) were investigated in order to assess the selectivity of the method. e method was applied in determination of Fe(III) in tap water, cow milk, and human serum.
A simple, environmentally benign, and rapid method based on temperature-controlled liquid-liquid microextraction using a deep eutectic solvent was developed for the simultaneous extraction/preconcentration of diazinon and fenitrothion. The method involved the addition of deep eutectic solvent to the aqueous sample followed by heating the mixture in a 75°C water bath until the solvent was completely dissolved in the aqueous phase. Then, the resultant solution was cooled in an ice bath and a cloudy solution was formed. Afterward, the mixture was centrifuged and the enriched deep eutectic solvent phase was analyzed by high-performance liquid chromatography with ultraviolet detection for quantification of the analytes. The factors affecting the extraction efficiency were optimized. Under the optimized extraction conditions, the limits of detection for diazinon and fenitrothion were 0.3 and 0.15 μg/L, respectively. The calibration curves for diazinon and fenitrothion exhibited linearity in the concentration range of 1-100 and 0.5-100 μg/L, respectively. The relative standard deviations for five replicate measurements at 10.0 μg/L level of analytes were less than 2.8 and 4.5% for intra- and interday assays, respectively. The developed method was successfully applied to the determination of diazinon and fenitrothion in water and fruit juice samples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.