Novel application of nanoscale zero valent iron (nZVI) for sustainable water production
The aim of the reseach is to develop materials and a related water treatment process for extracted ground water based on nanoscale zero-valent-iron(nZVI) as a chemical reducing agent for pollutants which are not treatable by biological or chemical oxidation. Emphasis is on solving the well-known problems of nZVI application being ineffective delivery, short active lifetime and separation from treated water. Immobilization of nZVI combined with a protective surface coating is utilized to achieve this through combining granular activated carbon with an advanced synthetic polymer coating which provided a synergistic effect of the polymers’ adsorption capacity with nZVI reducing activity. The polymer protect nZVI from oxidation by oxygen and nitrate and leaching into water.
Nano-composite materials for selective adsorption of contaminants
Contamination by heavy metal ions, such as cadmium, lead, copper, and zinc, has been a persistent problem to the environment and humans for several millennia, and yet considerable amounts of heavy metals still originate from industrial operations, for example mining, stormwater runoff and even agriculture. The demand for new adsorbents, which not only have a high surface area, but also are selective, continues to drive research into efficient and functionalized sorbent materials. We are studying to develop nanomaterials having specific affinity towards desired heavy metal ions to be used as water treatment operation. However, nanomaterials are not considered to be practical materials for water treatment due to its small size. We are trying to make nano-composite materials to be used as water treatment column or filtration system, which can provide practical applicability for nanomaterials while nano effect can be expected. Currently, surfur based organic polymer for cadmium adsorption and prussian blue based composite materials for cesium uptake are studying.
Sensing techniques for determining redox reactivity of nanomaterials
We adapted colorimetric assays for determining reductive activity of nZVI and its composites with other metals. The assay quantifies reduction products to avoid interfering reactions, such as sorption and volatilization. Three different reaction products, ammonium, phenol, and aniline, generated as the result of reduction of nitrate, p-halophenols, and nitrobenzene, respectively, could be quantified using the same reagent for all reactions. The colorimetric assays were further adapted to the 96-well microplate format, thus minimizing sample and reagent use, as well as lowering color development time to 2 h. The substrates showed graduated reactivity and thus reduction potency and kinetics of different materials and reaction mechanism was distinguished. The applicability was successfully proven by determining the reactivity of a commercial nZVI sample, and investigating the effect of nickel content on dehalogenation. Therefore, the suggested reactivity test with different compounds, combined with the use of a multi-well microplate based color assay, promises to be a useful and simple tool in various nZVI related research topics.