Adsorption of Malachite Green from Aqueous Solutions onto Rice Husks: Kinetic and Equilibrium Studies

Abstract

A study was done to evaluate the removal of a cationic dye from simulated waste water onto rice husks (RH). Spectroscopic methods such as FTIR and SEM/EDX were used for adsorbent characterization. Experimental dependency on solution pH, initial dye concentration, agitation speed, adsorbentparticle size, temperature of the solution and contact time was evaluated. The adsorption data was tested using both Langmuir and Freundlich isotherms. The data fitted well into Langmuir isotherm model with a monolayer adsorption capacity of 6.5 mg/g. Further, the separation factor (R L ) value was less than unity indicating a favorable adsorption process. Adsorption kinetics was determined using pseudo-first-order, pseudo-second-order and intra-particle diffusion models. The results showed that the adsorption of malachite green onto rice husks followed pseudo-second-order model with a determination coefficient of 0.986. This work has revealed that rice husks have a great potential to sequester cationic dyes from aqueous solutions and therefore it can be utilized to clean contaminated effluents.

Removal of Methylene Blue from Aqueous Solution by Bone Char

“…This is because the adsorption performance of bone char mainly depends on external diffusion. Similar results were reported in other literatures [28,37]. The errors of adsorption data listed in Table 1 were due to the existence of dynamic adsorption equilibrium.…”

Bioprocessing strategies for cost-effective simultaneous removal of chromium and malachite green by marine alga Enteromorpha intestinalis

“…The peaks at 2,923 and 2,855 cm –1 are related to (C–H stretching) 84 . The peaks ranged from 2014 to 2,162 cm −1 is due to C=C from alkynes and the peak at 2,149 cm −1 is related to alkynes 85 . Peak at 1653 cm −1 is due to carbonyl group as observed by Muinde et al .…”

“…Peak at 1653 cm −1 is due to carbonyl group as observed by Muinde et al . 85 . The peaks between 1629.45 and 1732.02 cm −1 are characteristic of carbonyl group.…”

“…The spectra of adsorbents before and after treatments were measured within the range of 400-4,000 cm −1 wave number" 82 .The spectrum of FTIR analysis 84 . The peaks ranged from 2014 to 2,162 cm −1 is due to C=C from alkynes and the peak at 2,149 cm −1 is related to alkynes 85 . Peak at 1653 cm −1 is due to carbonyl group as observed by Muinde et al 85 .…”

“…The peaks ranged from 2014 to 2,162 cm −1 is due to C=C from alkynes and the peak at 2,149 cm −1 is related to alkynes 85 . Peak at 1653 cm −1 is due to carbonyl group as observed by Muinde et al 85 . The peaks between 1629.45 and 1732.02 cm −1 are characteristic of carbonyl group.…”