Removal of sulfate and phosphate by Zn-Al layered double hydroxides
Küçük, Mehmet Emin (2017)
Diplomityö
Küçük, Mehmet Emin
2017
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe201710048883
https://urn.fi/URN:NBN:fi-fe201710048883
Tiivistelmä
Sulfate and phosphate are irreplaceable nutrients for living mechanisms. If not present in excessive levels, these compounds are not toxic for humans. However, waters highly concentrated in terms of sulfate and phosphate cause extraordinary taste and odor in water. Sulfate is responsible for water hardness, gastrointestinal problems for humans and corrosion in metals. Excessive phosphate amount leads to eutrophication in water sources. Furthermore, phosphate is widely used as a fertilizer; therefore, removal and recovery studies of both nutrients have accelerated in last decades.
Zn-Al Layered Double Hydroxides (LDH) with different Zn-Al rates were synthesized and characterized, their sulfate (SO42-) and phosphate (PO43-) removal performances from aqueous solutions by adsorptive methods were investigated as a comparative study. The results showed that the synthesized adsorbent exhibits outstanding removal performances for both sulfate (>80%) and phosphate (>90%). High nutrient uptake was observed in a wide pH range.
The kinetic data followed the pseudo-second-order model for both compounds suggesting that the adsorption processes were controlled by the surface reactions. The Sips isotherm model was found to be the best model to define the adsorption equilibrium conditions. Moreover, the slight positive effect of temperature increase was observed which confirmed that the adsorption process was endothermic. For regeneration of the adsorbents NaCl solution was found to be suitable for the regeneration cycle.
Zn-Al Layered Double Hydroxides (LDH) with different Zn-Al rates were synthesized and characterized, their sulfate (SO42-) and phosphate (PO43-) removal performances from aqueous solutions by adsorptive methods were investigated as a comparative study. The results showed that the synthesized adsorbent exhibits outstanding removal performances for both sulfate (>80%) and phosphate (>90%). High nutrient uptake was observed in a wide pH range.
The kinetic data followed the pseudo-second-order model for both compounds suggesting that the adsorption processes were controlled by the surface reactions. The Sips isotherm model was found to be the best model to define the adsorption equilibrium conditions. Moreover, the slight positive effect of temperature increase was observed which confirmed that the adsorption process was endothermic. For regeneration of the adsorbents NaCl solution was found to be suitable for the regeneration cycle.