Synthesis And Application Of New Magnetic Composite

Pickling waste liquor and electroplating wastewater generated from theIndustrial processes. According to the disadvantages of the previous methods forheavy metal wastewater purification, the new idea which promoted the added valueof the products has become the focus of attention.As heavy metal ions can form the spinel ferrite and heavy metal-layered doublehydroxide which is usually observed in the product obtained from the heavy metalsolidification/stabilization, two kinds of new magnetic composites have beensuccessfully prepared via a two-step microwave hydrothermal method. We discussedthe relationship between the structure and the properties and applied this method toelectroplating wastewater and pickling waste liquor purification. The treatedwastewater was below the discharge limit regulated by the China EnvironmentProtection Ministry and the solid products potential application prospect in treatingthe dyeing wastewater.（1） The magnetic Fe₃O₄/Zn₂Cr-LDH composite was fabricated via optimizingpreparation method and conditions (n（Fe3+:Fe2+）=1:3.5, n(Zn²⁺:Cr³⁺)=2:1and pH=6).The characterization by XRD, FT-IR, TEM revealed the Fe₃O₄in size of20-30nmdistributed on the surface of Zn₂Cr-LDH （150-200nm）. In Fe₃O₄/Zn₂Cr-LDH, themass ratio of two constituent compounds was approximately3:1. The values ofsaturation magnetization and surface area of Fe₃O₄/Zn₂Cr-LDH are22.6emu/g and114m2/g, respectively. The composite adsorbed1.64mmol/g of methyl orange（MO）.（2） A well-defined Fe₃O₄/Cu（Ni）-Cr-LDH magnetic catalyst of was fabricated,associating it with PMS to degrade organic dye. The effects of the reactiontemperature, the PMS dosages, the initial concentration of AO7and the reactants ondegradation were also studied, as well as the reusability of the catalysts degradationpathway of AO7. Each factor will have an impact on the degradation. Catalyst recycling for5times still remained high degradation rate. The presence of LDH inFe₃O₄/Cu（Ni）-Cr-LDH had little effect on the degradation of AO7.（3） To realize the aim of reuse and resource of treatment, the magneticFerrite/Layered double hydroxide composite was produced from electroplatingwastewater and pickling waste liquor via a two-step microwave hydrothermalmethod in different reaction conditions. The pH value had a significant impact onheavy metal wastewater purification. Adsorption of methyl orange （MO） from waterwas studied using this material. The effects of three variables have been investigatedby a single-factor method. The response surface methodology （RSM） based onBox-Behnken design was successfully applied to the optimization of the preparationconditions. The maximum adsorption capacity of MO was found to be240.16mg/g,indicating that this material may be an effective adsorbent. It was shown that99%ofheavy metal ions (Fe²⁺, Fe³⁺, Cr³⁺and Zn²⁺) can be effectively removed intoprecipitates and released far less in the adsorption process. In addition, this materialwith adsorbed dye can be easily separated by a magnetic field and recycled aftercatalytic regeneration with advanced oxidation technology. Meanwhile, kineticmodels, FT-IR spectra and X-ray diffraction pattern were applied to theexperimental data to examine uptake mechanism. The boundary layer andintra-particle diffusion played important roles in the adsorption mechanisms.