Synthesis of zeolite A using raw kaolin from Ethiopia and its application in removal of Cr(III) from tannery wastewater

Abstract

[Background] The commercial production of zeolite A mainly involves costly synthetic chemicals. However, cheaper raw materials such as clay minerals, coal ashes, natural zeolites, solid wastes and industrial sludge have been tested. Based on this, the objective of the present study is synthesis of zeolite A from two sources of raw kaolins (Ansho and Bombowha) from Ethiopia and evaluation of its application in tannery wastewater treatment.

[Results] The synthesis result indicated high crystallinity (>90%) of zeolite A using Ansho kaolin. Lower grade Bombowha kaolin yielded zeolite A with crystallinity of 80%. In the tannery wastewater treatment study, a real sample having chromium concentration of 2036 mg L−1 was treated, obtaining 99.8% removal and about 200 mg g−1 adsorption capacity of Cr(III) using 100 g L−1 and 5 g L−1 adsorbent dose, respectively. This indicated that the synthesized zeolite A has great potential for Cr(III) removal from tannery wastewater.

[Conclusion] In this study, zeolite A has been synthesized from two sources of kaolin from Ethiopia and has been evaluated in tannery wastewater treatment. The synthesis result indicated the formation of crystals of zeolite A with optimum crystallinity of 91% and the material exhibited chromium removal efficiency of 99.8%. © 2017 Society of Chemical Industry