Schiff based ligand containing nano-composite adsorbent for optical copper(II) ions removal from aqueous solutions

A novel Schiff base ligand based nano-composite adsorbent (NCA) was prepared for the detection and removal of copper (Cu(II)) ions in wastewater samples. Upon the addition of Cu(II) ions to NCA at optimum conditions, the clear color was visible to the naked-eye in the detection system. This NCA exhibited an obvious color change from yellowish to dark green in the presence of Cu(II) ions in aqueous solution. The limit of detection was found to be 0.16 mu g/L by optical detection. The NCA could detect the Cu(II) ions over other foreign ions with high sensitivity and selectivity. For adsorption behavior, influences several factors such as solution pH, contact time, concentration for Cu(II) ion adsorption was investigated by batch experiment in detail. The results showed that neutral solution pH was suitable to get optimum Cu(II) ions adsorption. Also an extending contact time was favorable for improving adsorption efficiency. The adsorption process of Cu(II) ions by the NCA was followed the Langmuir adsorption isotherm model. The maximum adsorption capacity of Cu(II) ions by the NCA from the Langmuir isotherm model was 173.62 mg/g. The mesoporous NCA exhibited higher adsorption capacity compared with some other reported diverse materials. In the multi-component system, the competing ions did not significantly interfere in the adsorption of Cu(II) ions. The adsorbed Cu(II) ions was effectively eluted with 0.25 M HCl and remain the almost same functionality for many cycles use. Even in seven consecutive cycles, the NCA showed great potential in the optical Cu(II) ions removal from wastewater. Then the proposed NCA could be used a promising adsorbent for the clean-up of Cu(II) ions in wastewater treatment. (C) 2015 Elsevier B.V. All rights reserved.