Modification of pineapple peel fibre with succinic anhydride for Cu²⁺, Cd²⁺ and Pb²⁺ removal from aqueous solutions

Abstract

Research on chemical modification of pineapple peel fibre with succinic anhydride was carried out to create a novel adsorbent for Cu²⁺, Cd²⁺ and Pb²⁺ removal from aqueous solution. After pretreatment with iso‐propyl alcohol and NaOH, pineapple peel fibre was modified via reaction with succinic anhydride for introduction of carboxylic functional groups. The modified pineapple peel fibre was characterized with Fourier transform infrared (FTIR) spectroscopy and evaluated for its adsorptive ability for Cu²⁺, Cd²⁺ and Pb²⁺ from synthetic metal solutions. The FTIR analysis proved the introduction of carboxylic functional groups in the backbone of the modified pineapple peel fibre. The modified pineapple peel fibre showed higher adsorptive capacity for Cu²⁺, Cd²⁺ and Pb²⁺ compared with raw pineapple peel and pineapple peel fibre pretreated with iso‐propyl alcohol. The adsorption of Cu²⁺, Cd²⁺ and Pb²⁺ on the modified pineapple peel fibre depended on solution pH value, adsorption time and initial metal concentration. The maximum adsorption capacities of the modified fibre were observed at pH 5.4 for Cu²⁺ (27.68 ± 0.83 mg g⁻¹ or 0.44 mmol g⁻¹), at pH 7.5 for Cd²⁺ (34.18 ± 1.02 mg g⁻¹ or 0.30 mmol g⁻¹) and at pH 5.6 for Pb²⁺ (70.29 ± 2.11 mg g⁻¹ or 0.34 mmol g⁻¹) respectively. The adsorption followed the pseudo‐second‐order kinetics model and the experimental data coincided well with the Langmuir model.

Keywords:

• pineapple peel fibre
• succinylation
• modification
• adsorption
• metal ion

Acknowledgement

The authors are grateful for the financial support from the Department of Science and Technology of Guangdong Province, China (Grant No. 2007A020901003, 2007B090100009, 2008A024200003) and the Ministry of Science and Technology of PRC (Grant No. 2007EA780005).