The characteristics of aqueous lithium recovery by ion exchange were studied using three commercial cation exchange resins: CMP28 (porous type strong acid exchange resin), SCR-B (gel type strong acid exchange resin) and WK60L (porous type weak acid exchange resin). CMP28 was the most effective material for aqueous lithium recovery; its performance was even enhanced by modifying the cation with K+. A comparison to Na+ and H+ form resins demonstrated that the performance enhancement is reciprocally related to the electronegativity of the cation form. Further kinetic and equilibrium isotherm studies with the K+ form CMP28 showed that aqueous lithium recovery by ion exchange was well fitted with the pseudo-second-order rate equation and the Langmuir isotherm. The maximum ion exchange capacity of aqueous lithium recovery was found to be 14.28 mg/g and the optimal pH was in the region of 4-10.

The adsorption characteristics of the methylene blue (MB) were studied using three activated carbons such as ACA and ACB with similar specific surface area (1,185 and 1,105 m2/g), and ACC with relatively high specific surface area (1,760 m2/g). The surface chemical properties of these activated carbons were investigated by X-ray photoelectron spectroscopy (XPS). The results indicated that ACA had more functional groups (with phenol, carbonyl, and carboxyl etc.) than ACB (with carbonyl and carboxyl) and ACC (with carboxyl). The isotherm data were fitted well by Langmuir isotherm model. The adsorption capacities of ACA, ACB, and ACC for MB were 454.7 mg/g, 337.7 mg/g, and 414.0 mg/g, respectively. As phenol and carboxyl content of the surface on activated carbon increased, MB adsorption capacity was increased. Although ACA had a smaller specific surface area than ACC, the content of phenol and carboxyl group was abundant, so MB adsorption capacity was found to be higher than ACC.

Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time (t0.05), saturation time (t0.95), length of mass transfer zone (LMTZ), adsorptive capacity (W), and adsorption rate constant (Ka) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer LMTZ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.