Chemical Engineering Journal, Vol.307, 85-94, 2017
New type mesoporous conjugate material for selective optical copper(II) ions monitoring & removal from polluted waters
The main objective of this work is to evaluate the effectiveness of the ligand supported mesoporous silica as conjugate nanomaterials for the copper (Cu(II)) ions detection and removal from environmental samples. The ligand synthesization, characterization, silica substrate preparation and their conjugation were presented. The absorbance spectra of the conjugate nanomaterials was changed when it was corroded by Cu(II) ions. The prepared nanomaterials was exhibited an obvious color change from yellowish to dark red in the presence of Cu(II) ions, which was visualized through naked-eye. The concentration dependent colorimetric response with the nanomaterials was matched well with the exponential linear curve under color optimization conditions, where the linear range was observed in the low level of Cu(II) ions, and the detection limit were measured to be 0.37 mu g/L. The solution pH, adsorption isotherms, initial concentration, contact time and foreign ions were investigated. The pH-dependent adsorption capability of the nanomaterials was much higher efficiency under weak acidic pH conditions. More attractively, the adsorption equilibrium was achieved within a short-time, which showed superior properties among various materials. The modification of silica by functional ligand not only increase the adsorption sites, but also cause chelation with Cu(II) ions for improving the adsorption capacity. The adsorption isotherm results showed that the maximum adsorption capacity of Cu(II) ion was 183.81 mg/g with monolayer coverage as judged from the Langmuir adsorption model. Continuous adsorption-elution-regeneration cyclic results demonstrated that Cu(II)-loaded conjugate nanomaterials was effectively regenerated by HCl acid, and the regenerated nanomaterials was employed for repeated use without significant capacity loss, indicating the good stability of the materials. Therefore, the fabricated conjugate nanomaterials could be readily applied to environmental samples for Cu(II) ions remediation. (C) 2016 Elsevier B.V. All rights reserved.