Selective Adsorption of Anionic Dye from Solutions by Modified Activated Carbon

A new adsorbent (AC–BP–V) was synthesized by activated carbon, which was used to remove anionic amaranth from aqueous solutions. The adsorption capability, adsorption isotherm and kinetics of the AC–BP–V were studied. X-ray photoelectron spectroscopy (XPS) and zeta potential were employed to characterize the adsorbent. Experimental results indicated that AC–BP–V adsorbent exhibited high-selectivity adsorption and efficiency for anionic dyes. Adsorption behavior of the modified activated carbon from aqueous solution was investigated by varying the parameters such as pH, contact time and amaranth concentration, and the optimum adsorption pH was 1. The equilibrium data fitted well with the Langmuir isotherm, and the obtained kinetic data obeyed the pseudo-second-order kinetic model. The maximum adsorption capacity was 216.92 mg/g. The new adsorbent (AC–BP–V) has obvious selectivity to anionic dyes. The results indicated that electrostatic interaction was the main mechanism for the adsorption of anionic amaranth.