Removal of Ni (II) and Cu (II) ions from aqueous solution using rambutan fruit peels (Nephelium lappaceum L.) as adsorbent

摘要

Rambutan fruit peels contain cellulose and hemicellulose compounds which are used in the heavy metal adsorption process. However, lignin compounds that bind cellulose and hemicellulose cause the active site to be covered. To make an adsorbent that has good performance, it is necessary to remove lignin from the material (delignification). This study aims to determine the activated adsorbent performance to remove Ni (II) and Cu (II) from the solution. The activation method using 0.1 M NaOH and 1% Formaldehyde mixture by soaking material for 2 hours at 80°C. The adsorption process was carried out a batch at 30°C by investigating the effect of initial pH, treatment time, and fitting model between Langmuir and Freundlich isotherm. Metal concentration in the solution was determined by Atomic Absorption Spectroscopy (AAS), identification of functional groups on the surface of the adsorbent by Fourier Transform Infra-Red (FTIR), and the adsorbent morphological structure was characterized by Scanning Electron Microscopy (SEM). The experimental results show that the lignin on the raw material has been lost which is indicated by the loss of peaks of 1716.81 and 1216.67 on the FTIR spectra. The surface morphology of the adsorbent becomes more porous on the results of SEM image. Freundlich isotherm models are more suitable for both Ni (II) and Cu (II) metals. Adsorption capacity from experimental was obtained 64.015 mg/g and 41.121 mg/g for Ni~(2+) and Cu~(2+), respectively.