Platinum recovery from dilute platinum solutions using activated carbon

Platinum adsorption on activated carbon,a common adsorbent,from dilute platinum-containing solution of 57.6 mg/L was investigated.The effects of different adsorption parameters on the platinum adsorption were reported in detail.The percentage of platinum adsorption increased with increasing the amount of adsorbent,as well as with increasing contact time and temperature.A platinum adsorption of 75% was obtained using 400 mg of activated carbon at a shaking rate of 200 r/min for 3 h at 25 ℃.A platinum adsorption of 88%,however,was obtained at 80 ℃ using 200 mg of activated carbon within only 1 h,which indicates that temperature plays a vital role in the adsorption process.A platinum adsorption of 99% or above was attained using 400 mg of activated carbon after contact for 3 h at 80 ℃.

Role of magnesium and aluminum substitution on the structural properties and bioactivity of bioglasses synthesized from biogenic silica

The objective of this study was to investigate the effect of magnesium(1 wt%)and aluminum(1 wt%)incorporation on the in vitro bioactivity and biodegradation behavior of 45S5 bioactive glasses synthesized from rice husk biogenic silica.The performance of biogenic silica-based samples was compared well with commercial silica-based counterparts.The in vitro biodegradation behavior of bioactive glasses was evaluated by the weight loss of samples and pH variation in the Tris buffer solution.Based on composition,bioglasses possessed different properties before and after simulated body fluid(SBF)immersion.The incorporation of magnesium(Mg)and aluminum(Al)enhanced the Vickers hardness of bioglasses.All the bioglasses showed the hydroxyapatite layer formation after SBF treatment as confirmed by the dissolution,FTIR,SEM and XRD analysis,however it was more prominent in the rice husk silica-based 45S5 bioglass.The biogenic silica seems to be a promising starting material for bioglass systems to be used in bone tissue engineering applications.

Stress Distribution in Composites with Co-Phase Periodically Curved Two Neighboring Hollow Fibers

In this paper,stress distribution is examined in the case where infinite length co-phase periodically curved two neighboring hollow fibers are contained by an infinite elastic body.The midline of the fibers is assumed to be in the same plane.Using the three-dimensional geometric linear exact equations of the elasticity theory,research is carried out by use of the piecewise homogeneous body model.Moreover,the body is assumed to be loaded at infinity by uniformly distributed normal forces along the hollow fibers.On the inter-medium between the hollow fibers and matrix surfaces,complete cohesion conditions are satisfied.The boundary form perturbation method is used to solve the boundary value problem.In this investigation,numerical results are obtained by considering the zeroth and first approximations to calculate the self-equilibrium shear stresses and normal stress at the contact surfaces between the hollow fibers and matrix.Numerous numerical results have been obtained and interpreted about the effects of the interactions between the hollow fibers on this distribution.