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The Sr-induced ordered superstructures on the Si(100)-2×1 surface have been studied using ultrahigh vacuum scanning tunneling microscopy and low-energy electron diffraction (LEED) for metal coverages (θ) below one monolayer (ML). At very low coverages (θ≤0.01 ML) Sr atoms adsorb as isolated atoms or small clusters. At submonolayer coverages of ∼θ≥0.12 ML we have observed the alkali-earth metal chains, even at room temperature, that run perpendicular to the substrate dimer rows. It is found that the Sr rows form areas of (2×3) order for coverages θ about 1/3 ML after annealing at 800 °C whereas a (1×3) phase grows on top of this with θ≥1.0 ML coverage in agreement with LEED data. It was also observed that the (2×3) phase formation is critical to the Sr coverage and to the annealing temperature as well. The relationship between the (2×3) and (1×3) ordered structures has been investigated as a function of Sr coverage and annealing temperature.

Lead (Pb) pollution is our water system is a major concern, as this metal is toxic even at low concentration. This study aim to fabricate a bio-nanocomposite (cyclodextrin-polycaprolactone titanium dioxide) that will be used as an adsorbent for the removal of lead in aqueous waste. In this study, titanium dioxide was synthesized via sol-gel technique then incorporated in a polymer blend (CD-PCL) via solution blending method. The resulting bio-nanocomposites were characterized using Scanning Electron Microscopy (SEM), transmission electron microscope (TEM) and Brunauer Emmett and Teller (BET). The effect of how factors such as pH, concentration and adsorbent dose affect the removal efficiency of the bio-nanocomposites were studies. Maximum adsorption of lead obtained was 98% at pH 9.7, 10 ppm with 0.005 g dosage. Kinetic studies and adsorption isotherms were also investigated. The adsorption data fit Langmuir isotherm. Pb (II) obeyed pseudo-second order kinetics.