Cloud point extraction (CPE) has been used for the pre-concentration of lead, after the
formation of a complex with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-
PADAP), and later analysis by graphite furnace atomic absorption spectrometry (GFAAS)
using octylphenoxypolyethoxyethanol (TritonX-114) as surfactant. The chemical variables
affecting the separation phase were optimized. Separation of the two phases was
accomplished by centrifugation for 15min at 4000rpm. Under the optimum conditions ie, pH …

Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer TiO2) was
prepared by sol–gel method and characterized using X-ray diffraction (XRD) and scanning
electron microscope (SEM). The adsorptive capability of immobilized nanometer TiO2 for
lead was assessed in this work using column method. It was found that lead can be
quantitatively retained by immobilized nanometer TiO2 in the pH range 4–7, then eluted
completely with 1.0 molL− 1 HCl. The adsorption capacity of immobilized nanometer TiO2 …