Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at -196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H(+). The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.

Central European Institute of Technology Brno University of Technology Czech Republic; Textile Research Division National Research Center Dokki P O 12622 Giza 12522 Egypt

Chemistry Department College of Science King Saud University P O Box 2455 Riyadh 11451 Saudi Arabia; Textile Research Division National Research Center Dokki P O 12622 Giza 12522 Egypt

Chemistry Department Faculty of Science Damanhour University Damanhour Egypt

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