Nanoparticles of perovskite-type LaCo0.5Fe0.5O3 (LCFO) were fabricated by sol–gel method.Thermal decomposition process of the complex precursor was examined by means of differentialthermal analysis–thermal gravimetric analysis (DTA/TGA). X-ray diffraction (XRD) resultsshowed that single perovskite phase has been completely formed after calcination at 750 °C. Inaddition, the surface morphology and composition of these nanopowders were also investigatedusing SEM and EDX. These nanoparticles showed the excellent adsorption efficiency towardsTrypan Blue (TB) as a reactive dye in aqueous solution. The adsorption studies were carried outat different pH values, dye concentrations, various adsorbent dosages and contact time in a batchexperiments. LCFO exhibited good dye removal efficiency at acidic pH specially pH 2.Experimental results indicated that the adsorption kinetic data follow a pseudo-second-order ratefor tested dye. The isotherm evaluations revealed that the Freundlich model better fits to theexperimental equilibrium data than Langmuir the model. تفاصيل المقالة

A highly selective copper (II) coated graphite sensor was prepared by 1,13-bis(8-quinolyl)- 1,4,7,10,13-pentaoxatridecane (kryptofix 5) as a supramolecule ionophore into plasticized polyvinyl chloride (PVC) membrane. The best response characteristic was observed using the membrane composition of PVC = 30.0 mg, dioctyl sebacate (DOS) = 63.5 mg, palmitic acid (PA) = 3.0 mg and kryptofix 5 = 3.5 mg. The sensor exhibits a nernstian slope (30.0±0.2 mV/ decade) in a wide linear concentration range of 1.0×10-5 to 1.0×10-1 M with detection limit of 8.7×10-6 M. The electrode has a fast response time of 15 s with a satisfactory reproducibility and relatively long life time of about 16 weeks without significant drift in potential. The sensor operates in the wide pH range of 2.0-10.0. This sensor reveals a good selectivity towards Cu2+ ion over a wide range of alkali, transition and heavy metal cations. The electrode was used as an indicator electrode for potentiometric titration of Cu2+ using EDTA solutions. The proposed sensor was applied for the direct determination of Cu2+ cation and the results were compared with those obtained from atomic absorption spectrometric analysis and were found in good agreement. Also this sensor was successfully used for determination of copper (II) in real samples تفاصيل المقالة

In present study a chromium (III) selective sensor based on dibenzo-18-crown-6 as a macrocyclic ionophore was fabricated. The best operation obtained in the membrane including: 5.0 mg dibenzo-18-crown-6 (DB-18C6), 4.0 mg sodium tetraphenylborate (NaTPB), 61.0 mg dioctyl sabacate (DOS) and 30.0 mg polyvinyl chloride (PVC). This electrode has a good selectivity respect to Cr3+ cation, with a nernstian slope of 19.6±0.1 mV/decade in a linear concentration range of 1.0×10-5 M-1.0×10-1 M. The detection limit of the electrode is 8.8×10-6 M. The porposed sensor has a fast response time of 5 s and good reproducibility. It can be used for a period of 63 days without any significant changes in its potential. The effects of the pH and possible interfering ions were investigated. This electrode was employed as an indicator electrode in potentiometric titrations of chromium cation with EDTA solutions and a sharp break in titration curves around the equivalent point was observed. This sensor was successfully used for the determination of chromium (III) in real samples. تفاصيل المقالة

A new polyvinyl choloride (PVC) membrane sensor for cerium(III) was prepared based on 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (kryptofix22DD) as an ionophore. The sensorexhibites a linear concentration range of 1.0×10-6 to 1.0×10-1 M, with aNernstian slope of 18.0±1.0 mV/decade, and a detection limit of 9.7×10-7M. It has a fast response time (5 s) and can be used for two monthswithout any considerable divergence in its potential. The proposedsensor revealed high selectivity toward Ce3+ ion with respect to somealkali, alkaline earth and transition metal cations. It could be used in awide pH range of 2.0-11.0. The sensor was successfully used as anindicator electrode in potentiometric titration of Ce3+ ion withethylenediaminetetraacetic acid (EDTA) and sodium iodide (NaI)solutions, and in determination of Ce (III) concentration in real samples. تفاصيل المقالة

A new polyvinyl choloride (PVC) membrane sensor for cerium (III) was prepared based on 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (kryptofix22DD) as an ionophore. The sensor exhibites a linear concentration range of 1.0×10-6to 1.0×10-1M, with a Nernstian slope of 18.0±1.0 mV/decade, and a detection limit of 9.7×10-7M. It has a fast response time (5 s) and can be used for two months without any considerable divergence in its potential. The proposed sensor revealed high selectivity toward Ce3+ion with respect to some alkali, alkaline earth and transition metal cations. It could be used in a wide pH range of 2.0-11.0. The sensor was successfully used as an indicator electrode in potentiometric titration of Ce3+ion with ethylenediaminetetraacetic acid (EDTA) and sodium iodide (NaI) solutions, and in determination of Ce (III) concentration in real samples. تفاصيل المقالة

A new polyvinyl choloride (PVC) membrane sensor for cerium (III) was prepared based on 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (kryptofix22DD) as an ionophore. The sensor exhibites a linear concentration range of 1.0×10-6 to 1.0×10-1 M, with a Nernstian slope of 18.0±1.0 mV/decade, and a detection limit of 9.7×10-7 M. It has a fast response time (5 s) and can be used for two months without any considerable divergence in its potential. The proposed sensor revealed high selectivity toward Ce3+ ion with respect to some alkali, alkaline earth and transition metal cations. It could be used in a wide pH range of 2.0-11.0. The sensor was successfully used as an indicator electrode in potentiometric titration of Ce3+ ion with ethylenediaminetetraacetic acid (EDTA) and sodium iodide (NaI) solutions, and in determination of Ce (III) concentration in real samples. تفاصيل المقالة

Two new oxo-centered trinuclear complexes, one of them a mixed-valence complex [Mn2MnO(CCl3CO2)6(Py)3] (1) and the other, mixed-metal complex of [Fe2MnO(CCl3CO2)6(H2O)3].NO3 (2) were synthesized by the direct reaction between metal nitrates and trichloroacetic acid. These complexes were characterized by elemental analyses (CHN), atomic absorption spectroscopy and spectral (IR, electronic) studies. These are new type of oxo-bridged mixed-metal complexes in which the carboxylate ligand is trichloroacetic acid. The UV spectra of the complexes exhibited a strong band in the region 213 and 257 nm which is related to the (π → π*) and (n → π*) transitions of the pyridine and H2O ligands, respectively. The IR spectra of these compounds showed two strong stretching vibrations bands, indicating a bridging coordination mode of the carboxylic group of the ligand in the complexes. تفاصيل المقالة

A new polyvinyl choloride (PVC) membrane sensor for cerium (III) was prepared based on 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (kryptofix22DD) as an ionophore. The sensor exhibites a linear concentration range of 1.0×10-6 to 1.0×10-1 M, with a Nernstian slope of 18.0±1.0 mV/decade, and a detection limit of 9.7×10-7 M. It has a fast response time (5 s) and can be used for two months without any considerable divergence in its potential. The proposed sensor revealed high selectivity toward Ce3+ ion with respect to some alkali, alkaline earth and transition metal cations. It could be used in a wide pH range of 2.0-11.0. The sensor was successfully used as an indicator electrode in potentiometric titration of Ce3+ ion with ethylenediaminetetraacetic acid (EDTA) and sodium iodide (NaI) solutions, and in determination of Ce (III) concentration in real samples تفاصيل المقالة

A new PVC based membrane using benzo-18-crown-6 as an ionophore has been developed as a calcium ion selective electrode. The electrode comprises of ionophore (4%), PVC (30%) and plasticizer (63%). The electrode shows a linear dynamic response in the concentration range of 1×10−5 M to 1×10−1 M with a Nernstian slope of 29.8 mV/decade and detection limit is 4.0×10−6 M. The proposed sensor shows reasonably good selectivity with respect to alkali, alkaline earth and transition metal ions. It can be used in the pH range of 5 to 12. The proposed electrode also was applied for the direct determination of Ca2+ cation in doubly distilled deionized water samples spiked with different concentrations of calcium. This electrode was also used for determination of Ca2+ in real samples with a very good recovery. تفاصيل المقالة

در این تحقیق یک نانو پودر اکسید مضاعف از نوع اسپینل با فرمول LiMn0.5Co1.5O4 به روش سل-ژل تهیه گردید. برای مشخصه یابی بلوری، ریختی، سطح ویژه و اندازه دانه ای نانوذرات از یک سری آنالیزهای تجزیه ای مانند XRD, TGA،SEM ،FT-IR استفاده گردید. الگو پراش اشعه ایکس نشان داد که بعد از عملیات تکلیس ، تنها فاز اسپینل با ساختار مورد نظر تشکیل شده است. پس از شناسایی و مشخصه یابی اسپینل رشد داده شده به بررسی حذف فسفات از محلول آبی پرداخته شد. برای حذف آلاینده پارامترهای مختلفی از جمله: زمان، غلظت جاذب، غلظت رنگ و pH مورد مطالعه قرار گرفتند. تفاصيل المقالة