[Adsorption of Methylene Blue and Cu(Ⅱ) by Activated Carbon/Macromolecule Composite Hydrogel]

Activated carbon/alginate/poly(vinyl alcohol) composite macromolecule hydrogels (CAP) were prepared as adsorbents to study their adsorption performance for methylene blue (MB) and Cu²⁺ in aqueous solution. The effect of dosage, pH, temperature, contact time, and initial concentrations of MB and Cu²⁺ on the adsorption process was investigated. SEM, FTIR, and BET analyses were conducted to identify the physicochemical properties of CAP. The results indicated that activated carbon was successfully loaded into the interconnected 3D porous network and CAP had rich -COOH and -OH groups. The surface area of the composite hydrogel was 112.7 m²·g^-1. With the dosage and temperature increase, the adsorbed amount of MB and Cu²⁺ on CAP decreased, while with the increase in pH, the adsorbed amount increased. The adsorption isotherm was fitted to the Langmuir equation and the maximum monolayer adsorption capacities of MB and Cu²⁺ on CAP were 1940.75 and 190.48 mg·g^-1, respectively. The adsorption was a fast process and 90% of the maximum adsorption capacity could be reached in 5 h. The kinetic data were fitted to the pseudo-second-order kinetic model reasonably well. CAP had excellent adsorption properties after five times of regeneration.