Comparative study on the adsorption capacity of raw and modified litchi pericarp for removing Cu(II) from solutions

• Published in: Journal of environmental management 2014-02, Vol.134, p.109-116
• Main Authors: Kong, Zhenglei, Li, Xiaochen, Tian, Jiyu, Yang, Jili, Sun, Shujuan
• Format: Article
• Language: English
• Subjects: Adsorption; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Carbon - analysis; Comparative analysis; Conservation, protection and management of environment and wildlife; Copper - chemistry; Copper ions; Fruit; Fundamental and applied biological sciences. Psychology; General aspects; Leaching; Litchi; Litchi pericarp; Mechanism; Nitrogen - analysis; Phosphorus - analysis; Potential risk; Risk assessment; Thermodynamics; Waste Products; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2014.01.007

The adsorption of Cu(II) onto raw litchi pericarp (LP) and modified litchi pericarp (MLP) as a function of pH, adsorbent dose and contact time, were investigated. Adsorption equilibrium isotherms, kinetics, and thermodynamics were studied to characterize the adsorption process. Leaching assays were also conducted to evaluate the potential contamination risk of LP and MLP to aqueous systems. The maximum adsorption of Cu(II) onto MLP was occurred at the pH of 6.0, adsorbent dose of 10.0 g/L, and contact time of 60 min, respectively. The adsorption process of Cu(II) onto LP and MLP were described well by both Langmuir and Freundlich isotherms, and the adsorption kinetics of Cu(II) on MLP was pseudo-second-order. Cu(II) adsorption onto LP and MLP are both exothermic, while it is spontaneous for MLP, and non-spontaneous for LP. The maximum adsorption capacity of Cu(II) onto MLP was 23.70 mg/g, which was about 2.7 times higher than that of LP. Additionally, as compared to LP, the leaching amounts of TOC, TN, and TP from MLP were significantly reduced by a percentage of 27.0%, 90.3%, and 35.3%, respectively. •Raw and modified litchi pericarp were employed as new adsorbents for removing Cu(II).•Mechanisms of raw and modified litchi pericarp for removing Cu(II) were discussed.•Contamination risk of agro-waste-based adsorbents was evaluated by leaching assay.