Evaluation of Marine Brown Laminaria japonica Algae as a Low-cost Adsorbent for the Removal of Malachite Green Dye from Aqueous Solution

Batch adsorption experiments were carried out using marine brown Laminaria japonica algae for the removal of the Basic dye Malachite Green from aqueous solution. The influence of process parameters such as the initial solution pH, the contact time, the adsorbent concentration, the particle size, the interaction temperature and the ionic strength were investigated. The adsorbent was characterized by FT-IR spectroscopy. The adsorption of Malachite Green was pH-dependent and attained equilibrium within 60 min for two particle size fractions. The kinetic data were tested using the pseudo-first-order equation and the second-order Ritchie equation. The results showed that the adsorption of Malachite Green onto Laminaria japonica followed the second-order Ritchie equation very well. The Langmuir and Freundlich equations were applied to the data relating to the adsorption isotherms and the observed maximum adsorption capacity (q(max)) for the particle size fraction < 150 mu m was 89.44 mg/g at 20 degrees C. The effects of adsorbent concentration and ionic strength on the adsorption of Malachite Green were very marked. The Laminaria japonica algae could serve as low-cost adsorbents for removing Malachite Green dye from aqueous solution.