title: An inorganic-organic hybrid optical sensor for heavy metal ion detection based on immobilizing 4-(2-pyridylazo)-resorcinol on functionalized HMS.
abstract: A novel and low-cost optical sensor for heavy metal ion detection has been prepared by immobilizing 4-(2-pyridylazo)-resorcinol (PAR) on the functionalized hexagonal mesoporous silica (HMS) via N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMAC). The successful fabrication of this optical sensor is confirmed by extensive characterizations using FT-IR, low angle X-ray diffraction (XRD), UV-vis spectroscopy and N(2) sorption, meanwhile its colorimetric properties, selectivity, sensitivity and reversibility are also investigated. The optical sensor responds selectively to heavy metal ions, such as Fe(3+), Cd(2+), Ni(2+), Zn(2+), Pb(2+), Co(2+), Hg(2+) and Cu(2+) with a color change from yellow to orange or purple in alkaline solutions, while it shows a color change only for Cu(2+) under strongly acidic conditions. At pH 12.0, this optical sensor has a high sensitivity that makes it possible to detect Cu(2+) in aqueous solution with the detection limit as low as 40ppb by naked-eye. This optical sensor also shows excellent reversibility and regeneration by treatment with a solution of EDTA.
authors.affiliation: State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China.
authors.forename: Tongge
authors.initials: T
authors.lastname: Liu
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.forename: Yongying
authors.initials: Y
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003124:Colorimetry; D007477:Ions; D019216:Metals, Heavy / Q000032:analysis*; D015394:Molecular Structure; D055096:Optical Devices; D016062:Porosity; D012118:Resorcinols / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D007477:Ions; D019216:Metals, Heavy; D012118:Resorcinols; D012821:Silanes; D012996:Solutions; C040733:tetraethoxysilane; D012822:Silicon Dioxide; C028398:4-(2-pyridylazo)resorcinol