Preparation, Characterization and Adsorption Mechanism of Cu(II) onto Protonated Rubber Leaf Powder

The adsorption of Cu(II) onto HCl treated rubber leaf powder (HHBL) was investigated in batch and column studies. The adsorbent was characterized by spectroscopic and quantitative analyses in order to understand the mechanism of copper adsorption. HHBL is mesoporous in nature as indicated by Bruneuer, Emmett and Teller (BET) analysis, and has various kinds of functional groups such as Si-OH, ROH, RCOOH, RCOO-, RNH2, C-O-C and aromatic rings as detected by Fourier transform infrared (FTIR) spectroscopy. Copper adsorption was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The equilibrium process was described well by the Langmuir isotherm model, and a maximum adsorption capacity of 8.39 mg/g was recorded for the smallest adsorbent size (<180 mu m). The two main adsorption mechanisms involved were ion exchange and complexation. The fixed bed column study demonstrated satisfactory applicability of HHBL in removing Cu(II) from aqueous solutions.