Structural analysis and the effect of the chromium on LTA (Na) zeolite synthesized from kaolin

Official URL: https://dx.doi.org/10.1016/j.matchemphys.2021.124957

The release of heavy metals ions into water resources is an environmental issue due to their high toxicity, long-lasting stability, and bioaccumulation in the food chain. Currently, the discharge of Mayan leather manufacturing plants’ wastewater into the Aji Chai River in East Azerbaijan (Iran) has increased the concentration of heavy elements such as chromium, copper, and zinc, so that the upper free aquifer of the Mayan Plain has become salty due to the feeding from this River. To overcome such a problem, we synthesized a highly functional Linde Type A (LTA) Na-zeolite from Kaolin as the raw material. In this regard, the impact of parameters such as synthetic temperature, adsorption temperature, and pH on the Cr adsorption capacity of zeolite on wastewater solutions obtained from this area was investigated. The structural analysis through XRD, SEM, BET, and FTIR, coupled with the Rietveld refinement method demonstrated that upon adsorption of Cr ions into the LTA zeolite structure, the lattice parameter decreases. Additionally, the results of this study suggest that the synthesized LTA zeolite has a very high adsorption rate in both acidic and alkaline environments in a way that a 100% removal rate was recorded at pH = 3. The as-synthesized zeolite has efficiently removed chromium from industrial waste waters flowing into this area.