Environmental uses of zeolites in Ethiopia

Abstract

In the past six years we have been intensively collaborating with the Chemistry Department of Addis Ababa University as well as Haramaya University to bust scientific knowledge related to zeolites and zeolite applications. Initially, we teamed up with geologists and government actors in the mining sectors; as a result we got access to natural zeolites from the north of the country, as well as other industrial minerals such as kaolin. In parallel we developed research activities in the use of zeolites as adsorbents and in catalytic processes related to environmental applications of necessity in Ethiopia. In the first part of this paper I will describe two examples of adsorption processes using mineral resources: one is a natural stilbite used to develop an adsorbent to remove fluoride from drinking waters; and the second one uses virgin kaolin to prepare a synthetic zeolite 4A that we used to remove chromium from tannery wastewaters. Finally, two catalytic examples will be described: in the first one we tackled the photocatalytic degradation of dyes from textile industries using Ti-modified natural and synthetic zeolites, and in the second one we used modified mordenites, both natural and synthetic, for the conversion of glucose into 5-HMF.

Environmental Applications of Diatomite Minerals in Removing Heavy Metals from Water

“…More seriously, water polluted by heavy metals might be accessible to drinking water someday. 13 Therefore, removing heavy metals before discharge is necessary.…”

“…In general, adsorbents commonly used are metals oxides, 20,21 activated carbon, 22−25 zeolites, 13,26,27 polymers, 28−30 biomaterials, 31,32 clays, 33−39 and others. 40 Most commercial systems currently use activated carbon (AC) as adsorbent to purify metal-contaminated water because of its excellent adsorption capability.…”

Photocatalytic wet peroxide assisted degradation of Orange II dye by reduced graphene oxide and zeolites

“…3. In the last process (UV/Vis + catalyst), the behavior observed is because the catalysts employed show good absorption of radiation 40,41 …”

Photocatalytic and Adsorptional Removal of Heavy Metals from Contaminated Water using Nanohybrids

“…Secondly, migration of generated electron-hole pair arises on the surface of semiconductor where, electron jumps from valence band to the conduction band of photocatalyst. Thirdly, photogenerated holes oxidizes H2O molecule to produce hydroxyl radicals ( • OH) in the valence band and electrons reduces the O2 molecule to form superoxide radical anion (O2 • − ) in the conduction band, respectively as shown below in equation (1)(2)(3)(4) [41].…”