Study On The Removal Of Heavy Metal And Organics For Magnesium Silicate-Based Nano-composite

Now some researches often focused on the removal of organic substances in wastewater with poor biochemical degradability and degradation-resistant characters,such as Bisphenol A(BPA)and Decabromodiphenyl ether(BDE209).However for the inorganic substances in wastewater,the main research issues included the removal of toxic metal ions and the recovery of valuable ions,for example the rare earth elements.The removal of pollutants in wastewater involved many methods,including precipitation,adsorption,membrane technology,biological process et al.Among known methods,the adsorption had been concerned because of the simplicity and effectiveness.At present,nano-adsorbent had been widely applied into the removal of pollutions in wastewater,due to the large specific surface area,high surface activity,and numerous active sites.However,the aggregation of nano-materials decreased the specific surface area and the number of active sites,inducing the poor adsorption performance.Studies indicated that constructing the micro-nano composite materials can effectively overcome above shortcoming.In this dissertation,we should make magnesium silicate deposited on the surface of oxidized grapheme(GO)and polystyrene sphere(PS)to design the composite materials.Then the composite materials were used to studied on the concentration of rare earth elements and the removal of BPA,the main contents are shown as following.(1)Magnesium silicate nanoparticles had been successfully synthesized under alcohol-water systems(T-MS).A series of characterization,including XRD,SEM,TEM and Zeta potentials,had been used to describe feature of the as-prepared samples.Then methylene blue(MB)was used as the model pollutant to evaluate the adsorption performance and selectiveness of magnesium silicate nanoparticles.Some experiments,such as the screen of experiment conditions,adsorption kinetic,adsorption thermodynamics and competitive adsorption,are conducted.The results showed the adsorption equilibrium can reach within 120 min and the the maximum adsorption capacities are 135.14 mg/g for T-MS samples.(2)The magnesium silicate@graphene oxide nanocomposite(MgSi@GO)were synthesized by hydrothermal approach.XRD,SEM,and Zeta potentials had been adopted to characterize the MgSi@GO nanocomposites.Then the nanocomposites were used to collect the Eu3+ from the simulated wastewater.We conducted adsorption kinetic,adsorption thermodynamics,competitive adsorption and et al.The MgSi@GO nanocomposite appeared high adsorption capacities of 344.82 mg/g.In addition,the adsorption capacities can still remain 204 mg/g after four recycling.(3)A novel hybrid nanomaterial MgSi@SPS was fabricated by loading MgSi nanoparticles on sulfonated polystyrene balls(SPS).Many characterizations involved XRD,SEM,and Zeta potentials had been conducted.And the MgSi@SPS nanocomposite present superior adsorption performance and selectiveness for BPA.The maximum adsorption capacities are 357.14 mg/g,and can maintain 298.2 mg/g after being regenerated by NaOH solution for four recycling.