Synthesis of high capacity adsorbents from low-cost materials, with atomic layer deposition, for mine water treatment

Abstract

Mining waste water with all its harmful effects is an ongoing problem for the ecosystem, hence methods are proposed to bring this issue to an end. Among these methods are trying out a number of low cost adsorbents, potentially industrial wastes, which can be altered somehow to get better adsorption properties. The aim of this thesis work is to improve the adsorbent capacities of certain low cost adsorbents, by some modification done by atomic layer deposition. ZnO, TiO2 and Al2O3 films were deposited on granules and fine powders of these adsorbents and tested on synthetic and real AMD water for the removal of Cu2+, Fe3+, Zn2+, Ni2+, SO42- and CN- ions. Modified industrial solid waste (iron sand) was used to remove metallic ions from real mine water and the percentage removed was 50%, 75%, 80%, 99% and 90 for SO42-, Ni2+, Zn2+, Fe3+ and Cu2+ respectively. Modified sulfate tailings were used to remove cyanide from synthetic mine water, removal efficiency of around 97% was achieved, selectively removing cyanide ions from synthetic mine water.