The removal of reactive dyes using high-ash char

Abstract

The thermodynamics and kinetics of adsorption of reactive dyes on high-ash char was studied. Equilibrium data were obtained using the static method with controlled agitation at temperatures in the range of 30 to 60ºC. The Langmuir isotherm model was used to describe the equilibrium of adsorption, and the equilibrium parameters, R L, in the range of 0 to 1 indicate favorable adsorption. The amount of dye adsorbed increased as temperature increased from 30 to 40ºC, but above 40ºC the increase in temperature resulted in a decrease in the amount of dye adsorbed. The kinetic data presented are for controlled agitation at 50 rpm and constant temperature with dye concentrations in the range of 10 ppm to50 ppm. The film mass transfer coefficient, Kf, and the effective diffusivity inside the particle, De, were fitted to the experimental data. The results indicate that internal diffusion governs the adsorption rate

Use of montmorillonite clays as adsorbents of hazardous polluants

“…At temperatures higher than 40°C, however, it was observed that the adsorption capacity decreased in a behaviour typical of exothermic adsorption. Similar results were found by Moreira et al [14].…”

Biosorption of reactive dye using acid-treated rice husk: Factorial design analysis

“…This in an unexpected behavior, but it has been reported by some authors when studying the adsorption of different type of dyes and other organic compounds over several adsorbents McKay et al [31, Moreira et al [32][33][34], Ravikumar et al [27], Asfour et al [19]. McKay et al [31] suggested that this behavior is due to the possibility of an increase in the porosity and total pore volume of the adsorbent with the increase of the temperature.…”

Physiochemical Modification and Characterization of Bentonite Clay and Its Application for the Removal of Reactive Dyes

“…The band at 1045.42 cm -1 shows the stretching of alkene bonds (Sathorn et al, 2008). The bands at about 524.64 show the stretching of alkyl halides and slightly shifted to 466.77 due to the adsorption of RR 223 Dye (Moreira et al, 2001). After adsorption of RR 223, the spectrum shows that the transmittance bands are considered at different frequencies range.…”

“…Therefore, the peaks due to the KBr were appeared at 3452.58, 2372.44 cm -1 and 1645.28 cm -1 and were slightly shifted in the both the spectrums due to the adsorption process of RR 223 dye. In the spectrum of MBC before adsorption of dye a broad transmittance band at 3415.93 cm -1 is due to the stretching frequency of hydroxyl group (-OH) (Moreira et al, 2001). The band at 1045.42 cm -1 shows the stretching of alkene bonds (Sathorn et al, 2008).…”