J. Environ. Eng. Manage., 19(3), 165-172 (2009)
Wen-Tien Tsai, Huei-Ru Chen, Kuan-Chi Kuo, Chia-Ying Lai, Tu-Cian Su, Yuan-Ming Chang and Jwu-Maw Yang
Shellfish shell, methylene blue, adsorption, isotherm, kinetic modeling
Shellfish shell has become one of the most significant wastes in aquaculture. In this work, three ground shells derived from oyster, hard clam and short-neck clam were used as mineral adsorbents for removal of cationic dye (i.e., methylene blue) from aqueous solution at 25 °C and initial solution pH of 7.0. The shell adsorbents possessed mesoporous structure according to their type IV isotherms with the hysteresis loops corresponding to type H3, but they displayed poor pore properties. The equilibrium adsorption capacity of methylene blue onto the oyster shell is significantly larger than those onto the hard clam and short-neck clam shells, which are parallel to their pore properties. It was further found that both of the Langmuir and Freundlich models were useful for describing the equilibrium of adsorption system. The adsorption kinetics showed that the adsorption process can be
well described with a simple model, the pseudo-second order model. The parameters(amount of dye adsorbed at equilibrium) of the model obtained in the present work were significantly in line with the adsorption process parameter (i.e., initial dye concentration).