Bio-synthesis of palladium nanoparticle using Spirulina platensis alga extract and its application as adsorbent

In this study, the potential of Spirulina platensis alga for the production of palladium nanoparticles and their application for lead removal from aqueous solution was studied. The synthesized palladium nanoparticle characteristics were identified UV–visible, XRD, SEM, TEM and FTIR analyses. The palladium nanoparticles have spherical shape and size within the range of 10–20 nm. The adsorption experiments were conducted in batch system. The effects of certain parameters such as contact time, pH, adsorbent dose, and initial lead concentration on the adsorption process were investigated. The highest adsorption efficiency was obtained at pH 6, contact time 60 min, adsorbent dose 0.5 g/L, and lead concentration 10 mg/L. With increase in initial lead concentration from 10–150 mg/L, the removal percentage decreased from 87% to 32%, while as the adsorbent dose increased from 0.02 to 0.5 g/L, the removal percentage increased from 12% to 90%. Freundlich model compared to Langmuir model can better describe the adsorption behavior of lead with palladium nanoparticle. According to R2 values (higher than 0.985), Freundlich isotherm model and pseudo-second-order kinetic model can better explain lead uptake by palladium nanoparticle than Langmuir isotherm model and pseudo-first-order kinetic model.