Adsorption of Ag+ by a surface molecular-imprinted biosorbent

Using the surface molecular imprinting technology, the Ag+-imprinted biosorbent for treatment of the wastewater contaminated by Ag+ was prepared, which showed higher adsorption affinity and selectivity for the imprinting ion (Ag+) than the other non-imprinting metal ions. Batch adsorption experiments were carried out as a function of imprinted Ag+ concentration, agitation time, temperature and initial Ag+ concentration. The optimal imprinted Ag+ concentration for preparing Ag+-imprinted biosorbent was 2.0 mg/g (biomass). The maximum adsorption capacity was 199.2 mg/g at the initial Ag+ concentration of 1200.0 mg/L and the biosorbent dosage of 3.0 g/L, which was much higher than that of previous work. The reaction temperature showed little effect on the adsorption process. The biosorbent could be easily desorbed by using 0.1 M Na2S2O3 solution as a desorbent at room temperature (25.0–27.0 °C). The SEM showed that noble metal silver could be well adsorbed by the biosorbent; the silver nanoparticles were of regular geometry shape and relatively uniform.