New cyclopentadiene derivatives as novel pH indicators

Nourmohammadian, Farahnaz; Davoodzadeh, Mahnaz; Alizadeh, Abdolali

doi:10.1016/j.dyepig.2006.05.011

Cited by 8 publications

(2 citation statements)

References 9 publications

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“…There is an acid-base balance in PNP solution, which presents in its acidic form at a wavelength~315.0 nm, whereas the alkaline form has a wavelength~400.0 nm. According to the observed absorbance values, the adsorption of PNP into peat is not significant at acidic pH values (1-6) (10.20-25.52 %), because an ion-dipole interaction occurs between the peat and PNP, whereas hydrogen bonds occur between the hydroxyl group of PNP and the carboxyl groups present in the peat (Nourmohammadian et al 2007). At pH values of 8-9, there was increased removal of PNP (40.58-56.76 %), which may be attributed to the exchange of electrons between peat and p-nitrophenolate ions (Erdem et al 2009).…”

Section: Adsorption Parametersmentioning

confidence: 93%

Removal of p-Nitrophenol from Aqueous Solution Using Brazilian Peat: Kinetic and Thermodynamic Studies

Jaerger

Santos

Fernandes

et al. 2015

Water Air Soil Pollut

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Removal of p-nitrophenol (PNP) from aqueous solutions using fibrous peat has been investigated in this study by batch adsorption experiments. Factors that can affect the adsorption process, such as pH, temperature, initial PNP concentration and contact time, have been investigated. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) measurements have also been obtained in order to study the adsorption mechanism of PNP by peat. The Langmuir and Freundlich equations have been applied to investigate the equilibrium. The data fitted the Langmuir isotherm well, with the maximum adsorption capacity decreasing with temperature from 23.4 to 16.1 mg g −1 . In general, the adsorption equilibrium was attained within 100 min. For the kinetics study, the best fit was obtained by the pseudo-second-order model instead of the pseudo-firstorder model, both of which applied to the experimental data, whereas the results of intraparticle diffusion show a two-step adsorption process. The activation energy value of 70.31 kJ mol −1 , calculated from the Arrhenius equation, indicated a predominantly chemical adsorption, whereas the thermodynamic parameters, obtained by the van't Hoff equation, were exothermic and spontaneous in nature.

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Section: Adsorption Parametersmentioning

confidence: 93%

Removal of p-Nitrophenol from Aqueous Solution Using Brazilian Peat: Kinetic and Thermodynamic Studies

Jaerger

Santos

Fernandes

et al. 2015

Water Air Soil Pollut

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“…Various synthetic reagents have been utilised as pH indicators. However, there are not many indicators in the pH range of 10-14 [1]. In this study, curcumin was chosen as a pH indicator and given a linear response at pH 8-12. Curcumin [1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] is a natural yellow dye obtainable from ISSN…”

Section: Introductionmentioning

confidence: 99%

SOL-GEL/CHITOSAN HYBRID THIN FILM IMMOBILISED WITH CURCUMIN AS pH INDICATOR FOR pH SENSOR FABRICATION

2019

MJAS

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An optical pH sensor based on the immobilisation of curcumin in sol-gel/chitosan hybrid thin films was fabricated on a cellulose acetate sheet as solid support for preparing a thin film. The thin film was prepared using the dip coating method. This sensor gave a range of linear pH responses at pH 9-13 (R 2 = 0.9821). The relative standard deviation (RSD) values of repeatability of this sensor were 7.03% (pH 10) and 3.34% (pH 11), while the RSD values of reproducibility were 7.46% (pH 10) and 8.66% (pH 11). The photostability of immobilised curcumin gave an RSD value of 2.37% for a study period of 15 weeks. This sensor had a response time between 10-20 s, and no hysteresis effect was observed when the pH in a cycle of pH 2-12-2 was measured. This sensor was applied in the determination of pH in real samples, and the results were comparable to a conventional pH meter. AbstrakSensor optik pH berdasarkan pemegunan kurkumin dalam filem nipis hibrid sol-gel / kitosan difabrikasi di atas kepingan selulosa asetat sebagai penyokong untuk penyediaan filem nipis. Filem nipis telah disediakan menggunakan kaedah penyalutan celup. Sensor ini memberikan julat rangsangan linear pH pada pH 9-13 (R 2 = 0.9821). Nilai sisihan piawai relatif (RSD) bagi kebolehasilan sensor ini adalah 7.03% (pH 10) dan 3.34% (pH 11), manakala nilai RSD kebolehulangan ialah 7.46% (pH 10) dan 8.66% (pH 11). Kestabilanfoto reagen kurkumin terpegun memberikan nilai RSD 2.37% untuk tempoh kajian selama 15 minggu. Sensor ini mempunyai masa tindak balas antara 10-20 s dan tiada kesan histerisis diperhatikan apabila sensor digunakan untuk mengukur pH dalam kitaran pH 2-12-2. Sensor ini digunakan untuk penentuan pH dalam sampel sebenar dan hasilnya dapat dibandingkan dengan meter pH konvensional.Kata kunci: sensor pH optik, sol-gel hibrid / kitosan, kurkumin, filem nipis

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A New pH Indicator Based on 2,5‐Diaryl‐1‐salicylideneamino‐1,3,4‐triazole Derivative

et al. 2008

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2-Phenyl-5-p-tolyl-1-salicylideneamino-1,3,4-triazole (PTST) was studied among 2,5-diaryl-1-salicylidene amino-1,3,4-triazole derivatives as a novel potential pH indicator. In terms of absorption intensity coming from the acid-base reactions, PTST showed strong yellow-green colour with high extinction coefficient in the pH range 7.0-9.5. In addition, the corresponding colour development at the transition point can be attributed to the resonance structures of PTST, which were caused by the hydrogen ion dissociation from the acidic form of the compound in the presence of alkali. The full geometric optimization and achievement of the electronic structure of the molecule were performed by an AM1 semiempirical method. The triazole compound was compared with phenolphthalein (PT), which is widely used as an acid-base indicator in titrimetry, for accuracy test.

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New cyclopentadiene derivatives as novel pH indicators

Cited by 8 publications

References 9 publications

Removal of p-Nitrophenol from Aqueous Solution Using Brazilian Peat: Kinetic and Thermodynamic Studies

Removal of p-Nitrophenol from Aqueous Solution Using Brazilian Peat: Kinetic and Thermodynamic Studies

SOL-GEL/CHITOSAN HYBRID THIN FILM IMMOBILISED WITH CURCUMIN AS pH INDICATOR FOR pH SENSOR FABRICATION

A New pH Indicator Based on 2,5‐Diaryl‐1‐salicylideneamino‐1,3,4‐triazole Derivative

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