Kinetic studies on visible-light-switchable photochromic fluorophores based on diarylethenes

2011 ◽  
Vol 10 (9) ◽  
pp. 1488 ◽  
Author(s):  
Britta Seefeldt ◽  
Kai Altenhöner ◽  
Oliver Tosic ◽  
Thomas Geisler ◽  
Markus Sauer ◽  
...  
2008 ◽  
Vol 83 (1-2) ◽  
pp. 8-14 ◽  
Author(s):  
J. Madhavan ◽  
P. Maruthamuthu ◽  
S. Murugesan ◽  
S. Anandan

2014 ◽  
Vol 938 ◽  
pp. 257-262
Author(s):  
G.A. Suganya Josephine ◽  
Arumugam Sivasamy

Dyes are a source of serious pollutants from different industrial outlets and show a major contribution in polluting the environment. In the present study two dyes namely Orange G and Acid Blue 113 were compared for their photodegradation efficiency employing rare earth nanometal oxide as a visible active photocatalyst. The prepared catalyst was nanocrystalline form with particle size 70 nm and the surface of the catalyst was highly porous and rough which facilitates the absorption of the dye further enhance the photo degradation which were confirmed by various characterization techniques. Effect of pH, variation of catalyst dosage, variation of initial dye concentration and kinetic studies were conducted for both the dyes. The reaction followed a pseudo first order kinetics. The activity of the prepared catalyst was higher when compared to a commercially used metal oxide. Reusability studies proved that the catalyst prepared was very active even upto the third cycle. The degradation process was initiated by the attack of the OH radical generated in the in-situ process via visible light irradiation. EPR spin trapping technique was employed to confirm the presence of OH radicals. The prepared catalyst degraded the dye molecules of interest in lesser time duration by absorption of visible light, thereby reducing the cost of photodegradation.


Author(s):  
Mina Sharifi-Bonab ◽  
Soheil Aber ◽  
Dariush Salari ◽  
Fatemeh Khodam

Abstract CoZnAl-layered double hydroxide (LDH) was synthesized by homogeneous co-precipitation. CoZnAl-Mixed Metal Oxide (MMO) was prepared by calcining the LDH. The samples' structure and morphology were studied by analytical techniques including X-ray diffraction, N2 adsorption-desorption isotherm, scanning electron microscopy and UV–visible spectroscopy. Acid orange 7 (AO7) adsorption by as-prepared samples was studied. CoZnAl-MMO showed 526.32 mg/g adsorption capacity, higher than that of CoZnAl-LDH, 243.9 mg/g. Kinetic studies confirmed the pseudo-second-order and pseudo-first-order AO7 adsorption kinetics of the LDH and MMO, respectively. AO7 adsorption onto both LDH and MMO fitted the Langmuir isotherm model well. Band gap calculation confirmed the ability of this nano-MMO to operate in the visible light region. It displayed synergetic adsorption-photocatalytic performance under visible-light and the removal efficiency was about 97%.


2020 ◽  
Vol 9 (3) ◽  
pp. 1-8
Author(s):  
Hung Nguyen Van ◽  
Nguyet Bui Thi Minh ◽  
Linh Bui Thi Thuy ◽  
Nghi Nguyen Huu ◽  
Tuoi Nguyen Thanh ◽  
...  

In the present study, the synthesis of ZnO/LSAC through pyrolysis of the carbonized material prepared from longan seed, zinc acetate in alkaline medium. The obtained materials was characterized by means of XRD, SEM, TEM, BET and UV-Vis-DRS. The XRD patterns of ZnO/LSAC nanocomposites were assigned to wurtzite structure of ZnO with crystallite size about 15 to 30 nm. SEM and TEM observations showed the spherical ZnO particles formed on the activated carbon. The band gap energy and specific surface area of ZnO/LSAC were found to be 2.79 eV and 294.4 m2/g, respectively. The photocatalytic activities of the prepared materials were evaluated for the degradation of Rhodamine B (RhB) dye. The removal of RhB was found to be pH dependent, and the optimized removal efficiency reached to 93.75% and the mineralization level was over 84,09% at initial RhB concentration of 40 mg.L-1 andpH 7 following 120 min under visible-light illumination. The kinetic studies showed the decolorizationof RhB followed pseudo first-order kinetics with the rate constant were determined kapp= 1.67Í10-2 min−1


2017 ◽  
Vol 41 (23) ◽  
pp. 14334-14341 ◽  
Author(s):  
Ka Wai Kwong ◽  
Dharmesh Patel ◽  
Jonathan Malone ◽  
Ngo Fung Lee ◽  
Benjamin Kash ◽  
...  

Depending on the structure of the porphyrin ligands, the visible light photolysis of porphyrin–iron(iii) bromates produced iron(iv)-oxo radical cations or iron(iv)-oxo porphyrins, permitting direct kinetic studies of their oxidation reactions.


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