LALA CLAM (ORBICULARIA ORBICULATA) SHELL AS AN ADSORBENT FOR ANIONIC AND CATIONIC DYES FROM AQUEOUS SOLUTION

In this work, lala clam shell was utilised as an alternative low-cost adsorbent for the remediation of water contaminated by two classes of dyes, namely anionic (Congo red (CR) and Methyl orange (MO)) and cationic (Methylene blue (MB) and Rhodamine B (RB)) dyes from aqueous solution. Batch adsorption experiments were performed to assess the effects of various experimental parameters such as solution pH, adsorbent dosage and initial adsorbate concentration. The applicability of lala clam shell to remove dyes from aqueous solution was evaluated in both single- and mix-systems. The optimum pH for CR, MO and RB removal was found at pH 2.0, while pH 8.0 was the optimum value for MB adsorption. At an initial concentration of 2.5 to 100 mg/L, the amount of four dyes adsorbed onto lala clam shell was in the order of CR> MB> RB> MO, in a single dye adsorption system. Whereas, in the case of a mix-dye adsorption system, the amount of four dyes adsorbed was found in the order MB> RB> MO> CR. The adsorption equilibrium data were correlated with both Langmuir and Freundlich isotherm models. The results showed that the equilibrium data were perfectly represented by the Freundlich isotherm model. The biomass adsorbent was characterised using the Field Emission Scanning Electron Microscope (FESEM) and Fourier Transform Infrared (FTIR) Spectrometer. Overall, outcomes from this study suggested that lala clam shell, a fishery waste, can be beneficial and efficient instead of expensive adsorbents for water treatment.