Study On Decolorization Of The Wastewater Containing Anionic Dyes By Mg/Al Layer Double Hydroxides

Layered double hydroxides(LDHs) are prepared hydrothermal by perfect mixed spraying reactor using industrialization equipment and the stuff was industrial magnesium sulfate, aluminum sulfate, sodium hydroxide, sodium carbonate. Different instruments such as XRD,TG-DTA,IR et al were used to characterize the chemical component, crystal structure, thermal decomposition, specific surface area and particle distribution of the sample. The sample's specific surface area is 81.4 m2/g, pore volume is 0.47 mL/g, average particle diameter is 11.1μm. After the sample is calcined at 500℃, the specific surface area is 113 m2/g and pore volume is 0.85 mL/g, TG-DTA characterized that there are two stages in the process of thermal decomposition and the lost weight was consistent with the theoretic value.Decolorization of wastewater containing Reactive dark blue ST-2GLN or Weak acid brilliant blue RAWL using Mg/Al Layered double hydroxides(LDHs) and Calcined Mg/Al layered double hydroxides(LDO) is studied, Reactive dark blue ST-2GLN and Weak acid brilliant blue RAWL are representative anionic dyes. The effects of pH value, sorbent dosage, adsorption time and Calcined temperature, inorganic anions and anionic surfactant dodecyisulfate on adsorption dyes by LDHs/LDO are investigated. The recyclability and adsorption isotherms of LDHs/LDO are also studied. Some main results can be drawn as follow:Decolorization of wastewater containing anion dyes by LDHs/LDO are more valid because of anionic exchange of LDHs and structural reconstruction of LDO. Adsorption capacity of LDO is much higher than those of LDHs. LDHs may be used to remove anionic dyes of low concentrations, whereas LDO could possibly be used to remove anionic dyes of relative high concentrations.LDHs or LDO has an excellent performance in decolorization of the wastewater containing Reactive dark blue ST-2GLN or Weak acid brilliant blue RAWL with 1g/L LDH and 0.5g/L的LDO.The effect of initial pH on dyes adsorption by LDHs/LDO are small when the initial pH values are between 4～10.What,more,both LDHs and LDO have a good pH buffer action to Reactive and weak acid dyes and the time of adsorption equilibrium are 60min. The effects of...