Ag2O/Sawdust nanocomposite as an efficient adsorbent for removal of hexavalent chromium ions from aqueous solutions

Ag2o/sawdust nanocomposite (ag2o/sd nc) as adsorbent of cr(vi) was prepared by precipitation method. the as-prepared sample was characterized by various techniques such as x-ray diffraction (xrd),scanning electron microscopy (sem) and fourier transform infrared spectroscopy (ft-ir). the sem micrographs show formation of ag2o nanoparticles within 50-60 nm in size which have been homogeneously dispersed on the sawdust surface. the as-prepared ag2o/sd nc were used to remove cr(vi) from aqueous solutions. to determine the optimal conditions for adsorption,the effect of important parameters such as ph,contact time,initial concentration of cr(vi),amount of adsorbent,temperature and ionic strength were investigated. it was found that the ag2o/sd nc showed a high cr(vi) removal capacity of 20.75 mg/g at 25 oc. the experimental data were well described by the pseudo-second-order kinetics and langmuir isotherm model. thermodynamic studies for the adsorption system were calculated and suggested that the adsorption process is spontaneous and exothermic. taking advantages of the high adsorption capacity,inexpensive adsorbent,fast removal and easy separation from treated water,the ag2o/sd nc can be used as an efficient for cr(vi) removal from aqueous solution. the exhausted adsorbent can be regenerated by simple alkaline treatment with high efficiency.