The effectiveness and mechanism of modified clinoptilolite in removing Cd2+ and Zn2+ from aqueous solutions and stabilizing Cd and Zn from contaminated sediment were investigated. It was found that the calcination-NaOH modified clinoptilolite with the particle sizes of 2–4 mm had the best effect on removing Cd2+ and Zn2+ from the aqueous solution. According to the Langmuir isotherm model, the maximum adsorption capacities of Cd2+ and Zn2+ would be 25.26 and 21.16 mg/g at 25°C, respectively. The Dubinin–Radushkevich adsorption model and the pseudo-second-order model indicated that the type of adsorption of Cd2+ and Zn2+ by modified clinoptilolite could be recognized as chemisorption. Toxicity characteristic leaching procedure showed that modified clinoptilolite could effectively reduce the leaching of Cd and Zn from the sediment. It was also observed that modified clinoptilolite could effectively lower the bioavailability and mobility of Cd and Zn in sediment using BCR sequential extraction. The results in this study showed that modified clinoptilolite could effectively remove Cd2+ and Zn2+ from water and stabilize Cd and Zn in the sediment.
All Science Journal Classification (ASJC) codes
- Water Science and Technology
- Ocean Engineering
- Heavy metal
- Modified clinoptilolite