Removal of Methyl Orange from Aqueous Solution by Mineral-based Porous Granulated Material

Sodium bentonite, graphite, light calcium carbonate and diatomite were used as parent minerals for the mineral-based porous granulated material(MPGM) which was tested for the removal of methyl orange(MO), a cationic dye, from aqueous solution. The adsorption capacity was evaluated under the conditions of varied initial p H, adsorbent dosage, dye concentration, temperature, reaction time, and static regeneration. Experimental results showed that the maximum capacity of MPGM adsorbing MO was more than 80 mg·g-1. The adsorption equilibrium and kinetics of MPGM followed typical pseudo-first-order and Langmuir adsorption models respectively. The thermodynamic parameters of ΔGo, ΔHo and ΔSo showed that the adsorption was an endothermic and spontaneous process without remarkable change. The spent MPGM was regenerated 5 times and probable pathway for the efficient and re-utilizing adsorbent has been proposed. The results indicate that MPGM has a structure of silicon-aluminium-calcium-carbon, and could be employed as porous, low density, and large specific surface area alternatives for the removal of cations dyes from industrial wastewater.