Graduated PhD, Former PhD at University of Amsterdam
In developing countries, such as Egypt, sophisticated techniques for water purification are often not widely available, using natural low-cost local materials as sorbents are, therefore an important alternative approach. Pliocene clays from Egypt have unique physcio-chemical properties and these materials may be alternative scavengers for toxic HMs, although their potential application in wastewater treatment technology has not yet assessed because of a lack of information regarding their adsorption/regeneration characteristics.
The data presented in our current study forms a foundation for the potential removal of heavy metals from wastewater using the Pliocene clay material in Egypt. This research work fills some of the existing knowledge gaps on the adsorption mechanisms of Cu, Zn, and Ni by clay materials in the presence of DOM and their implications for wastewater treatment technology. The insight in the obtained present work provides new data about the impact of timing of addition of DOM on the wastewater treatment. Nevertheless, further work on the regeneration of exhausted sorbent materials and enhancement of the adsorption capacity of Pliocene clay has to be done to further develop this method.
Abstract: Infiltration of heavy metal (HM) polluted wastewater can seriously compromise soil and groundwater quality. Interactions between mineral soil components (e.g. clay minerals) and dissolved organic matter (DOM) play a crucial role in determining HM mobility in soils. In this study, the influence of the timing of addition of DOM, i.e. concurrent with or prior to HMs, on HM mobility was explored in a set of continuous flow column experiments using well defined natural soil samples amended with goethite, birnessite and/or smectite. The soils were subjected to concurrent and sequential additions of solutions of DOM, and Cu, Ni and Zn. The resulting breakthrough curves were fitted with a modified dose-response model to obtain the adsorption capacity (q0). Addition of DOM prior to HMs moderately enhanced q0 of Cu (8-25%) compared to a control without DOM, except for the goethite amended soil that exhibited a 10% reduction due to the blocking of binding sites. Meanwhile, for both Zn and Ni sequential addition of DOM reduced q0 by 1-36% for all tested soils due to preferential binding of Zn and Ni to mineral phases. In contrast, concurrent addition of DOM and HMs resulted in a strong increase of q0 for all tested metals and all tested soil compositions compared to the control: 141-299% for Cu, 29-102% for Zn and 32-144% for Ni. Our study shows that when assessing the impact of soil pollution through HM containing wastewater it is crucial to take into account the presence of DOM.
Pub.: 04 Dec '16, Pinned: 28 Jul '17