Rhodamine B removal from aqueous solutions using loofah sponge and activated carbon prepared from loofah sponge

Loofah sponge and activated carbon (AC) made from it were used to adsorb rhodamine B (RhB) onto aqueous solutions. Scanning electron microscopy of the two materials revealed they possessed rough surfaces; loofah sponge featured a high surface area of 132.6m(2)/g, which increased to 842.3m(2)/g for AC. Fourier transform infrared spectroscopy indicated that the surface of both materials was abundant in O-H, C-H, and C=O groups, which may increase their adsorption capacities. The kinetics, isotherms, and optimum conditions for RhB removal were studied. RhB adsorption by the adsorbents was consistent with pseudo-second-order equations. The adsorption isotherms revealed that the adsorption process of loofah sponge involved multilayer adsorption, while that of AC was monolayer adsorption. The optimal performance of AC (removal ratio of 99.20% and equilibrium adsorption of 191.43mg/g) was achieved using a temperature of 313K, AC content of 0.6mg/L, and initial RhB concentration of 120mg/L. AC displayed an increased adsorption capacity for RhB compared with that of loofah sponge; the maximum equilibrium adsorption of AC reached 333.33mg/L, which is 14 times that of loofah sponge. AC derived from loofah sponge is a promising adsorbent for RhB removal from aqueous wastewater.