Biosorption of copper, zinc and cadmium using sodium hydroxide immersed Cymbopogon schoenanthus L. Spreng (lemon grass)

Studies were conducted to evaluate the performance of sodium hydroxide solution (NaOH) immersed lemon grass (ILG) adsorbing copper (Cu), zinc (Zn) and cadmium (Cd) in single-metal and multi-metal solutions, respectively. Parameters included pH, sorbent dosage and contact time. Fourier transform infrared (FTIR) spectrophotometer was used to elucidate ILG sorption mechanisms. Results indicated that sorption isotherms of ILG for all three metals were well described by Langmuir equation, with a maximum uptake at 13.93 mg Cu, 15.87 mg Zn and 39.53 mg Cd per g ILG. The change of peaks in FTIR spectrum were observed after being immersed by 0.2 M sodium hydroxide solutions (NaOH), which was likely to increase the number of sorption sites for metal uptake. Obtained results implied that ILG had a great potential for the removal of heavy metals in aqueous solutions.