Study On Interaction Between Elemental Selenium Nanoparticles And Copper/Silver Ions

Selenium nanoparticles (nanoSe0) have been regarded as promising materials for many applications due to its unique properties, which include high biological activity, lower toxicity, high particle dispersion, large surface area, catalytic potential and high reactivity. This paper discussed the interaction between amorphous nanoSe0 and metal (copper, silver) ions which included two respects content. On one hand, nanoSe0 as adsorbent adsorb copper from aqueous solutions. On the other hand, nanoSe0 as selenium source prepare selenide nanoparticles (cuprous selenide and silver selenide) in mild conditions.The removal of copper from aqueous solutions using nanoSe0 by dialysing was presented. The effects of the concentration of vitamin C (Vc), adsorption equilibrium, the mass of nanoSe0, pH, initial CUSO4 concentration and temperature on the adsorption of copper were investigated. Divalent metal ions such as Zn2+, Cd2+, Pb2+, Ni2+ have no noticeable interference to adsorption. The adsorption kinetic was well described by the pseudo-second order equation which suggested that the model was indicative of a chemical adsorption mechanism. The rate constant k2 determined was 2.02 g-g-1·h-1. The adsorption isotherm was better fitted by the Langmuir equation. The maximum adsorption capacity of nanoSe0 for copper was found to be 0.89 g-g-1 at 298.15 K. The formation mechanism of adsorption product was discussed from the results of SEM, XRD and EDX, combined with the adsorption mode. The adsorption process include physical adsorption and chemical adsorption, and the process was maily controlled by chemical adsorption. The results indicated that the nanoSe0 coexisting with Vc (a proper reducer) was a green and efficient adsorbent for the removal of copper from aqueous solutions. Also, the semiconductor materials Cu2Se could be obtained in the copper removal process.Cu2Se nanoparticles were synthesis by the reaction of selenium nanoparticles (nanoSe0) sol with copper sulfate solution containing Vc at room temperature. The SEM, TEM, XRD results indicated that Cu2Se nanoparticles were spherical with cubic structure and well crystallized in the diameter about 75 nm. The UV-Vis and CV of Cu2Se nanoparticles were also investigated. The optical band gap energy of Cu2Se nanoparticles was 1.94 eV. On the basis of a series of experiments and characterizations, the formation mechanism of Cu2Se nanoparticles was discussed.Ag2Se nanoparticles were synthesized by the chemical reaction between silver ions and selenium nanoparticles (nanoSe0) in aqueous system at room temperature. The Ag2Se nanoparticles were spherical with orthorhombic crystal structure in the diameter about 100 nm. The optical band gap energy of Ag2Se nanoparticles was 1.34 eV. The CV of Ag2Se was investigated and the formation mechanism of Ag2Se nanoparticles was also discussed.This synthesis method was simple and rapid, no requirement for sophisticated instruments, nontoxic operation, low-cost, and the potential for large-scale production.