Functionalized moso bamboo powder adsorbent for Cd(II) complexes with citric acid/tartrate acid: characterization, adsorptive performance, and mechanism

A new amine group functionalized moso bamboo powder adsorbent (AMBP) was prepared using a facile procedure to remove Cd(II) complexes with citric acid (CA) and tartrate acid (TA). The properties of the AMBP were characterized using SEM, FTIR, XPS, BET, and an elemental analysis. The adsorptive performances of the AMBP toward Cd(II)-CA/TA were investigated. The results indicated that amine group was successfully introduced, and the AMBP with a BET specific surface area of 0.463 m2/g was effective in adsorbing Cd(II)-CA/TA under pH 4.0–10.0. The removal of Cd(II) increased significantly when the Cd(II)/ligand molar ratio changed from 1:0.5 to 1:2. The adsorption processes of Cd(II)-CA/TA were endothermic and fit well with the pseudo-second-order kinetic model (R2 > 0.999). The Langmuir model (qmax of 14.41 and 7.58 mg/g for Cd(II)-CA and Cd(II)-TA, respectively) fit the isotherms better than the Freundlich model. The AMBP could be regenerated by HCl and reused at least 4 times. The uptake mechanisms of Cd(II)-CA/TA were proposed to be physisorption and the chemisorption of the coordination between –NH2/–NH and the Cd(II). This work shows that the AMBP is an adsorbent with high practical value to remove Cd(II) in water or wastewater containing CA/TA.