Thermal characterization of methylene blue intercalated montmorillonites by photoacoustic technique

Abstract

Thermal diffusivity (TD) measurement on commercial K-10 and KSF montmorillonites was carried out by photoacoustic technique. The TD of the montmorillonites after methylene blue adsorption changed with the dye concentration. The repeatedly adsorbed samples showed a lesser TD than the single adsorbed samples. After methylene blue adsorption the acid leached K-10 samples showed well defined changes in TD when compared to the ordered KSF samples.

Thermal characterisation of dye-intercalated K-10 montmorillonite ceramics using photoacoustic technique

“…Consequently, the solid matrix-dye interaction also brings about the broadening of the absorption bands [44]. The PA amplitude spectrum of the pellets, in accordance with the RG theory [12], characterised by the slope change is similar to that given in our previous paper [14]. The measured TD values of the samples under investigation are shown in Tables 1 and 2.…”

“…The presence of air in the porous network contributes towards a TD value of 0.676 Â 10 À4 m 2 s À1 [14]. The TD of the dye-intercalated samples increases with increase in dye concentration.…”

“…The measured TD values of the samples under investigation are shown in Tables 1 and 2. Clay and soil samples possess TD values of the order of 10 À7 to 10 À4 m 2 s À1 [8,14,[45][46][47]. However, TD is a transient thermo-physical parameter that measures how effectively phonons carry heat through the sample.…”

“…This technique enables study if the modification of optical, structural and thermal properties of the sample are due to dye adsorption. Previously, we reported the thermal characterisation of methylene blue (MB)-intercalated montmorillonites (K-10 and KSF) and found that K-10 samples have well-defined changes compared with KSF samples [14]. Hence, the present study is an attempt to understand the changes in TD of various dye-adsorbed K-10 montmorillonites and to fabricate appropriate materials with tuneable thermal characteristics.…”

“…This non-radiative relaxation produces temperature fluctuations in the sample. These temperature fluctuations facilitate an indirect measurement of the thermal and optical properties of the sample [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In photoacoustics (PA), the pressure variations produced within the cell are detected using a sensitive microphone.…”