Functionalized novel mesoporous adsorbent for selective lead(II) ions monitoring and removal from wastewater

An efficient material is needed to develop selective and effective sensing/removal systems with highflexibility, and low capital cost for control the capturing of toxic ions. In this study, we designed ligandimmobilized mesoporous adsorbent for ultra-trace Pb(II) monitoring and removal from wastewater. Theadsorbent was synthesized by indirect immobilization of 4-tert-octyl-4-((phenyl) diazenyl) phenol ontoinorganic mesoporous silica. This adsorbent exhibited the large surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Pb(II). Theapplicability of the adsorbent for Pb(II) detection and removal was assessed, and the efficient parameterssuch as solution pH, contacting time, initial Pb(II) concentration and ionic strength of competing ionswere measured. The effective pH range for detection and removal systems was at the neutral region. The data revealed that the adsorbent was able to detect the ultra-trace Pb(II) ions with high sensitivityand selectivity by charge transfer (intense pi-pi transition) transduction mechanism. Then the adsorbent proved to have an efficient ability for continuous Pb(II) monitoring and removal even on-site andin situ chemical analyses. The maximum sorption capacity and limit of detection were 200.80 mg/g and0.12 mu g/L, respectively. The adsorbent was reused in several cycles without significant deterioration afterelution with a suitable eluent (0.10 M HCl). Therefore, the design of mesoporous adsorbent has a greatpotentiality to be used in selective Pb(II) detection/removal from wastewater. Large-scale studies arerecommended to confirm these promising results from the laboratory scale. (C) 2014 Elsevier B. V. All rights reserved.