Fabrication Of Millimeter-scale Composite Adsorbents For High Efficient Cr(?) And As(?)Removal In Aqueous System

Possessing generous free surface energy,large surface area and numerous active sites,the nanomaterials often manifest a noticeable performance of pollutant adsorption in aqueous systems.Reasoning from that,the nanoadsorbents were considered as a competing solution to address the water pollution challenges occured in recent years.However.the increased surface energy may simultaneously cause some problems including low stability of the nanomaterial.secondary pollution and low hydraulic conductivity,leading to the restraint of practical application of these nanosized adsorbents.In this work,phase inversion route was employed to fabricate a nano-composite adsorbent material with enhanced stability,excellent mechanical strength and easy recyclability.The as-obtained millimeter-scale polymeric adsorbent and its adsorption capacity on Cr(?),As(?)was clearly investigated.Specific contents were as follow:The millimeter-sized amine-rich polymer spheres(APSs)embedded PES beads(APSs-PES)were manufactured via phase inversion process for an efficient chromium removal.The as-obtained APSs-PES beads possess an asymmetric and hierarchical structure:numerous interpenetrating finger-like channels interior and a porous surface dense layer exterior,which can efficiently promote molecule transportation.Meanwhile,the thermal stability,the tolerance of acid-base and the distribution of APSs were significantly improved after a compositing procedure with polyethersulfone(PES).The Cr adsorption result demonstrated the abundant adsorption sites on the material surface which provided by nitrogen-containing functional groups of nanomaterials were retained during the embedding process.Besides,the maximum adsorption capacity of APSs-PES beads for Cr was 243.9 mg/g at the pH=2 and the desorption efficiency of Cr reached at about 85%after 5 times recycle process,indicating a strong support for APSs-PES during practical application.For proving the applicability of this method,another millimeter-sized inorganic MgO particles embedded PES beads(MgO-PES)were also fabricated via phase inversion process.The produced MgO-PES beads successfully acquired a similar hierarchical asymmetric structure contrasted with APSs-PES beads.The As(V)adsorption result demonstrated that during the embedding process,the adsorption capacity of MgO-PES beads was 69.0 mg/g at 298 K.After several times recycle process,no obvious adsorbents loss was detected during regeneration,indicating an excellent stability.