Determination of Trace Amounts of Zirconium by Flotation - Spectrophotometric Method

Pourreza, N.,Parham, H.,Shiri, S. Korean Chemical Society 2010 대한화학회지 Vol.54 No.3

지르코늄의 부유-분광 광도의 측정에 대한 감도가 좋고 재현성 있는 방법이 기록되었다. 그 방법은 지르코늄과 자일렌오렌지(XO)착물 형성에 기초하였고 그것은 격렬한 진탕에 의해 수용액 상과 n-헥산의 표면에 떠있게 된다. 수용액과 n-헥산을 폐기함에 따라 분리된 깔대기의 벽에 있던 흡착된 착물은 작은 부피의 메탄올 용액으로 해리되어진다. 그리고 그것의 흡광도는 429 nm에서 측정되었다. PH, HCl, XO의 농도, n-헥산 부유 용매의 부피, 지속시간과 진탕시간과 같은 다른 변수의 효과가 연구되었다. 보정곡선은 0.9991의 상관계수를 갖는 지르코늄의 7 ~ 120 ng/mL의 범위에서 선형이었다. 검출한계(LOD)는 58 ng/mL이었다. 지르코늄의 50과 110 ng/mL 의 7개의 분할척정에 대한 상대표준편차(RSD)는 4.4와 3.0%였다. 이 방법은 물샘플에서 지르코늄의 측정에 성공적으로 적용되었다. A sensitive and reproducible method for the flotation-spectrophotometric determination of zirconium is reported. The method is based on the complex formation zirconium and xylenol orange (XO) which is floated in the interface of aqueous phase and n-hexane by vigorous shaking. By discarding the aqueous solution and n-hexane, the adsorbed complex on to the wall of a separating funnel was dissolved in a small volume of methanol solvent and its absorbance was measured at 429 nm. The effect of different parameters such as pH, concentrations of HCl, and XO, and volume of n-hexane flotation dissolvent, standing and shaking time were studied. The calibration curve was linear in the range of 7-120 ng $mL^{-1}$ of zirconium with a correlation coefficient of 0.9991. The limit of detection (LOD) was 5.8 ng $mL^{-1}$. The relative standard deviation (RSD) for seven replicate measurements of 50 and 110 ng $mL^{-1}$ of zirconium were 4.4 and 3.0%, respectively. The method was successfully applied to the determination of zirconium in water samples.

Nonlinear vibration of nanosheets subjected to electromagnetic fields and electrical current

Pourreza, Tayyeb,Alijani, Ali,Maleki, Vahid A.,Kazemi, Admin Techno-Press 2021 Advances in nano research Vol.10 No.5

Graphene Nanosheets play an important role in nanosensors due to their proper surface to volume ratio. Therefore, the main purpose of this paper is to consider the nonlinear vibration behavior of graphene nanosheets (GSs) under the influence of electromagnetic fields and electrical current create forces. Considering more realistic assumptions, new equations have been proposed to study the nonlinear vibration behavior of the GSs carrying electrical current and placed in magnetic field. For this purpose, considering the influences of the magnetic tractions created by electrical and eddy currents, new relationships for electromagnetic interaction forces with these nanosheets have been proposed. Nonlinear coupled equations are discretized by Galerkin method, and then solved via Runge-Kutta method. The effect of different parameters such as size effect, electrical current magnitude and magnetic field intensity on the vibration characteristics of GSs is investigated. The results show that the magnetic field increases the linear natural frequency, and decreases the nonlinear natural frequency of the GSs. Excessive increase of the magnetic field causes instability in the GSs.

A highly efficient MIL-101(Cr)-Graphene-molybdenum oxide nano composite for selective oxidation of hydrogen sulfide into elemental sulfur

Alimohammad Pourreza,Saeed Askari,Alimorad Rashidi,Saeed Fakhraie,Mohammad Kooti,Marzieh Shafiei-Alavijeh 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.71 No.-

Hybrid composites of MIL-101(Cr) and Nanoporous Graphene with ratios in the range of 10-50% wereprepared via hydrothermal synthesis method. This study deals with an experimental investigation onselective oxidation of H2S into elemental sulfur in the range of 200-270 C, the catalyst activity andselectivity toward sulfur was studied. High-temperature reactor tests indicated that the MIL-101(Cr)-NPG50-Mo could be a promising candidate with conversion and selectivity of 100% and 99.5% at 200 C. The MIL-101(Cr)-NPG50-Mo stability showed there were not any significant changes in physicalproperties, the activity was evaluated after 20 h which was completely stable without any changes.

D-Limonene as a green bio-solvent for dispersive liquid–liquid microextraction of β-cyclodextrin followed by spectrophotometric determination

Nahid Pourreza,Tina Naghdi 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.51 No.-

In this paper D-limonene and b-carotene are introduced as two natural products in a dispersive liquid–liquid microextraction (DLLME) method for spectrophotometric determination of b-cyclodextrin (b-CD). Dissolved b-carotene in D-limonene exhibits strong absorption exhibits strong absorption intensity afterperforming. The absorption intensity of the extracted phase is increased in the presence of b-CD due to itsinteraction (complex formation) with b-carotene. This increase in the absorbance of the extracted phaseis related to the b-CD concentration and was utilized as an analytical signal for determination of b-CD. The effect of chemical variables such as pH of the sample solution, nature and volume of dispersivesolvent, volume of extraction solvent and extraction time on the DLLME method was studied andoptimum conditions were established. The calibration curve was linear in the range of 110 4–6 10 3 mol L 1 (r = 0.9956) with a limit of detection 410 5 mol L 1. The relative standard deviation foreight replicate determinations of 110 3 mol L 1 and 510 3 mol L 1 of b-CD was 1.82% and 0.88%respectively. The proposed method was successfully applied to the determination of b-CD in spikedwater and pharmaceutical samples and good recoveries in the range of 94.2–108.0% were obtained.

Simultaneous preconcentration of Cd(II), Cu(II) and Pb(II) on Nano-TiO2 modified with 2-mercaptobenzothiazole prior to flame atomic absorption spectrometric determination

N. Pourreza,S. Rastegarzadeh,A. Larki 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Nano-TiO2 modified with 2-mercaptobenzothiazole (MBT) was investigated as a new adsorbent for preconcentration of Cd(II), Cu(II) and Pb(II). The metal ions are adsorbed onto nano-TiO2-MBT, eluted by nitric acid and determined by flame atomic absorption spectrometry. The parameters affecting the adsorption were investigated. Under optimized conditions, the calibration curves were linear in the range of 0.2–25.0, 0.2–20.0, and 3.0–70.0 ng mL 1 for cadmium, copper and lead, respectively. The limits of detection for Cd(II), Cu(II) and Pb(II) were 0.12, 0.15 and 1.38 ng mL 1, respectively. The method was applied to determination of Cd(II), Cu(II) and Pb(II) in water and ore samples. 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V.

Silicon carbide nanoparticles as an adsorbent for solid phase extraction of lead and determination by flame atomic absorption spectrometry

Nahid Pourreza,Tina Naghdi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Silicon carbide nanoparticles were applied as a new solid phase adsorbent for preconcentration of lead ions. Pb(II) ions are adsorbed on silicon carbide nanoparticles, eluted with nitric acid and determined by flame atomic absorption spectrometry. The solid phase extraction conditions were optimized. The calibration graph was linear in the range of 2–150 ng mL-1 (r = 0.9995) with a detection limit of 0.4 ng mL-1. The relative standard deviation for eight measurements of 20 ng mL-1 of Pb(II) was 1.3%. The adsorption capacity was 156.2 mg g-1of Pb(II). The method was applied to determination of Pb(II) in different samples.

Fabrication of AuNPs into alginate biopolymer and functionalized by thiourea as a film shape probe for palladium(II) sensing

Nahid Pourreza,Parichehr Abasipanah,Matineh Ghomi 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.100 No.-

A simple process was developed for the fabrication of alginate biopolymerfilm embedded by thiourea-functionalized AuNPs (thiourea/AuNPs) for palladium(II) detection. A mixture of sodium alginate andHAuCl4 was prepared as the main matrix and the AuNPs were in situ synthesized in alkali media providedby borax. The AuNPs entrapped in the alginate network were functionalized by thiourea and fabricated asa transparentfilm. The characteristics of thiourea/AuNPs alginate biopolymerfilm were investigated byTransmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDX) and UV–visspectrophotometry. The UV–vis absorption spectrum showed the maximum wavelength of thiourea/AuNPs was at 530 nm. The effect of various parameters such as pH and thiourea concentration on thesensing of palladium(II) ions was investigated. The prepared alginate biopolymerfilm showed goodstability over the time. The calibration graph was linear in the range of 0.05 2.10 mg mL 1 with adetection limit of 0.038 mg mL 1. The relative standard deviation (n = 10) for 0.6 and 1.2 mg mL 1 ofpalladium(II) was 4.6% and 3.5%, respectively. The sensing system was successfully applied for thedetermination of palladium in walnut leaves, wastewater, dental amalgam, and ceramic capacitorsamples.

Nano-TiO2 modified with 2-mercaptobenzimidazole as an efficient adsorbent for removal of Ag(I) from aqueous solutions

N. Pourreza,S. Rastegarzadeh,A. Larki 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1

Nano-TiO2 was modified with 2-mercaptobenzimidazole via surfactant activation and used as anadsorbent for the removal of Ag(I) under optimum conditions. The adsorbent was characterized usingpowder X-ray diffraction and FT-IR spectroscopy. The equilibrium data were fitted to the Langmuir,Freundlich and Temkin isotherm models. Langmuir isotherm describes the adsorption data better thanFreundlich isotherm and Temkin. Kinetic studies showed that the pseudo second order kinetic model fitsthe adsorption kinetic processes well. Maximum adsorption capacity for Ag(I) was 128.2 mg g-1 of nano-TiO2. The method was successfully applied to the removal of silver from radiology film processingwastewater samples.

Extraction-Spectrophotometric Determination of Cimetidine in Pharmaceutical Samples as an Ion Pair with Bromothymol Blue

Zargar, B.,Pourreza, N.,Shahrouz, M. Korean Chemical Society 2011 대한화학회지 Vol.55 No.1

감도가 높고 선택적인 추출-분광광도법은 미량의 시메티딘의 측정을 위해 개발되어 왔다. 이 방법은 클로로포름안에 브로모티몰 블루(BTB)와 함께 이온 쌍으로 시메티딘의 추출에 기초했다. 그리고 417 nm에서 흡광도를 측정하고 있다. pH, BTB의 농도, 클로로포름의 부피, 섞는 시간과 같은 다른 변수들의 효과를 연구하였다. 또한, 추출에서 간섭이온의 효과도 연구하였다. 보정곡선은 0.9997의 상관계수와 함께 0.25~8 ug/mL의 범위에서 선형이다. 3Sb에 기초한 검출한계는 0.14 ug/mL이고 시메티딘의 0.1과 4.0 ug/mL의 10번 측정에 대한 상대표준편차는 3.2와 1.49%이었다. 제안된 방법은 좋은 회수와 함께 약제 샘플에서 시메티딘의 측정에 적용되었다. A highly sensitive and selective extraction-spectrophotometric method has been developed for determination of trace amounts of cimetidine. This method is based on the extraction of cimetidine as an ion pair with bromothymol blue (BTB) into chloroform and measuring its absorbance at 417 nm. The effect of different variables such as pH, concentration of BTB, volume of chloroform and shaking time was investigated. The effect of interfering ions on the extraction was also studied. The calibration curve was linear in the range of 0.25-8 ${\mu}gmL^{-1}$ with correlation coefficient of 0.9997. The detection limit based on 3Sb was 0.14 ${\mu}gmL^{-1}$ and relative standard deviation for 10 replicated measurements of 1.0 and 4.0 ${\mu}gmL^{-1}$ of cimetidine was 3.2 and 1.49%, respectively. The proposed method was applied to the determination of cimetidine in pharmaceutical samples with good recoveries.

Extraction-Spectrophotometric Determination of Cimetidine in Pharmaceutical Samples as an Ion Pair with Bromothymol Blue

B. Zargar,N. Pourreza,M. Shahrouz 대한화학회 2011 대한화학회지 Vol.55 No.1

A highly sensitive and selective extraction-spectrophotometric method has been developed for determination of trace amounts of cimetidine. This method is based on the extraction of cimetidine as an ion pair with bromothymol blue (BTB) into chloroform and measuring its absorbance at 417 nm. The effect of different variables such as pH, concentration of BTB, volume of chloroform and shaking time was investigated. The effect of interfering ions on the extraction was also studied. The calibration curve was linear in the range of 0.25-8 μg mL^(-1) with correlation coefficient of 0.9997. The detection limit based on 3S_b was 0.14 μg mL^(-1) and relative standard deviation for 10 replicated measurements of 1.0 and 4.0 μg mL^(-1) of cimetidine was 3.2 and 1.49%, respectively. The proposed method was applied to the determination of cimetidine in pharmaceutical samples with good recoveries.