Project founded by Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI
Host institution: Politehnica University Timişoara
Project No. 129 /01/10/2015
Project title: Synergic green technologies for treatment of hexavalent chromium polluted waters
Period: 01.10.2015 – 30.09.2017

Project team:

Gheju Marius Traian – Project manager
Moșoarcă Giannin Emanuel – Postdoctoral researcher
Vancea Cosmin Nicolae – Postdoctoral researcher
Balcu Ionel – Postdoctoral researcher
Bălășoiu-Flueraș Adriana Maria – PhD student
Enache Andreea – PhD student

Project description

The proposed theme is integrated in the thematic area of water and wastewater treatment, with the aim of water reuse, waste recovery and protection of environment quality. Metals environmental contaminants are particularly problematic because, unlike most organic contaminants, they are non-biodegradable and can accumulate in living tissues, thus becoming concentrated throughout the food chain. Chromium is an important metal which is used in a variety of industrial applications such as: preparation of chromium compounds, metallurgy, leather tanning and mordanting processes, textile dying, metal electroplating, wood preservation, production of colored glass and ceramics, corrosion control, refractory industry etc. All these applications are well represented in Europe (therefore, also in Romania) and, as a result, chromium has become a major heavy metal pollutant of ground and surface waters in industrial areas, due to unsuitable storage, accidental leakages or improper disposal practices. In natural aquatic environments, chromium compounds are thermodynamically stable only in the +3 and +6 states, which are characterized by different chemical and toxicological behavior. Under circumneutral pH conditions, Cr(III) is present mainly as relatively insoluble, immobile and non-toxic hydroxides and oxides; in contrast, Cr(VI) exists mainly as chromate anion, known to be toxic to humans, animals, plants and microorganisms, and characterized by a significant mobility in the environment. Thus, removal of chromium, and especially of Cr(VI), is an essential pollution abatement process that should be applied to all industrial effluents that contain this contaminant, before discharging them into aquatic environments, as well as to all Cr(VI) contaminated natural waters that are used as source of potable water.
During past two decades, there has been great interest in using metallic iron (Fe0) as cheap reagent for aqueous contaminant removal. Most of the papers dealing with the use of metallic iron technology for the reduction of Cr(VI) focused mainly on the in situ treatment of polluted groundwater, by using of permeable reactive barriers (PRBs). As a result, PRBs containing Fe0 as reactive medium have become an established technology for the treatment of Cr(VI) contaminated groundwater and, to date, several Fe0 PRBs have been installed worldwide with this purpose. In contrast, only few studies have investigated the use of above-ground filters packed with Fe0 for drinking water production or for wastewater treatment. Metallic iron is a reactive material and its oxidative dissolution by water is a volumetric expansive process. Due to the volumetric expansive nature of this process, the remediation of contaminated water necessarily results in the gradual clogging of the Fe0 PRB/filter, and thus in the deterioration of the PRB/filter hydraulic conductivity over time. Therefore, the major concern of Fe0 PRBs/filters is related to loss of permeability and reactivity with time. Accordingly, one major objective of this project will be to study the influence of co-presence of sand, MnO2 and sand coated with manganese oxides on Cr(VI) efficiency of removal with metallic iron. Another important question which rises in many water treatment technologies is what to do the wastes (the exhausted Fe0-based reactive mixtures, in our case) resulted from the treatment process? An alternative that responds to the ecological and sustainable development requirements is the vitrification, which reduces the waste volume, destroys residual organics, and immobilizes heavy metals. However, the development of rational solutions for waste immobilization in glass matrices requires a complex knowledge of the particularities of the vitreous state and a better understanding of the specific characteristics of the pollutant to be immobilized by vitrification. Therefore, the second major objective of this project is to study the immobilization of exhausted reactive mixtures containing Fe, Cr, sand and MnO2 in vitreous matrices. The Cr, Fe and Mn immobilization in the glass matrix will be analyzed in order to convert the resulting glasses into marketable glazes or bulk glass products.


Project objectives 2015

1. Ensuring the necessary conditions for the research activities.
2. Investigation of the effect of sand co-presence on Cr(VI) removal with Fe0
3. Investigation of the effect of MnO2 co-presence on Cr(VI) removal with Fe0
4. Dissemination of the obtained results
5. Project self-evaluation

Project activities 2015

1. Identification and preparation of the needed existent materials. Purchasing of other required materials. Selection and preparation of the analytical methods needed to support the research activities
2. Batch treatability experiments for Cr(VI) removal with Fe0 in the co-presence of sand
3. Batch treatability experiments for Cr(VI) removal with Fe0 in the co-presence of MnO2
4. Analysis and interpretation of experimental data. Writing of scientific articles
5. Analysis of the achievement degree of the 2015 stage objectives


Project objectives 2016

1. Ensuring the necessary conditions for the research activities
2. Investigation of the effect of sand co-presence on Cr(VI) removal with Fe0
3. Investigation of the effect of MnO2 co-presence on Cr(VI) removal with Fe0
4. Investigation of the effect of sand and MnO2 co-presence on Cr(VI) removal with Fe0
5. Investigation of the alternative to immobilize exhausted reactive mixtures in vitreous matrices
6. Dissemination of the obtained results
7. Project self-evaluation


Project activities 2016

1. Identification and preparation of the needed existent materials. Purchasing of other required materials. Selection and preparation of the analytical methods needed to support the research activities
2. Column treatability experiments for Cr(VI) removal with Fe0 in the co-presence of sand
3. Column treatability experiments for Cr(VI) removal with Fe0 in the co-presence of MnO2
4. Batch and column treatability experiments for Cr(VI) removal with Fe0 in the co-presence of sand and MnO2
5. Experiments for the synthesis and characterization of glasses from exhausted reactive mixtures
6. Analysis and interpretation of experimental data. Writing of scientific articles.
7. Analysis of the achievement degree of the 2016 stage objectives.

Disseminated results 2016
 
M. Gheju, I. Balcu, C. Vancea, An investigation of Cr(VI) removal with metallic iron in the co-presence of sand and/or MnO2, Journal of Environmental Management, 170, 2016, 145-151.
M. Gheju, I. Balcu, G. Mosoarca, Removal of Cr(VI) from aqueous solutions by adsorption on MnO2, Journal of Hazardous Materials, 310,  2016, 270-277.
M. Gheju, I. Balcu, Characteristics of hexavalent chromium removal in H2O-Fe(0) system, Proceedings of the 11th Conference on Sustainable Development of Energy, Water and Environment Systems, p. 196.1-196.16, 4-9 September 2016, Lisabon, ISSN 1847-7178.
M. Gheju, I. Balcu, Impact of anionic amendments on green remediation of Cr(VI) pollution, Proceedings of the 11th Conference on Sustainable Development of Energy, Water and Environment Systems, p. 198.1-198.17, 4-9 September 2016, Lisbon, ISSN 1847-7178.
M. Gheju, Treatment of water by means of metallic iron. A lost and recovered technology. Round table „Quality for results”, organized by Aquatim Company and The General Association of the Engineers in Romania, within the frame of the 16th ”Quality Week”, 9 November, Timișoara, 2016.

Project objectives 2017

1. Ensuring the necessary conditions for the research activities
2. Investigation of the effect of manganese oxide coated sand co-presence on Cr(VI) removal with Fe0
3. Investigation of the alternative to immobilize exhausted reactive mixtures in vitreous matrices
4. Dissemination of the obtained results
5. Project self-evaluation


Project activities 2017

1. Identification and preparation of the needed existent materials. Purchasing of other required materials. Selection and preparation of the analytical methods needed to support the research activities
2. Batch and column treatability experiments for Cr(VI) removal with Fe0 in the co-presence of manganese oxide coated sand
3. Experiments for the synthesis and characterization of glasses from exhausted reactive mixtures
4. Analysis and interpretation of experimental data. Writing of scientific articles. Patent application
5. Analysis of the achievement degree of the 2017 stage objectives.

Disseminated results 2017

M. Gheju, I. Balcu, A. Enache, A. Flueras, A kinetic approach on hexavalent chromium removal with metallic iron, Journal of Environmental Management, 203, 2017, 937-941.

M. Gheju, I. Balcu, Assisted green remediation of chromium pollution, Journal of Environmental Management, 203, 2017, 920-924.

C. Vancea, M. Gheju, G. Moșoarcă, Inertization in vitreous matrix of exhausted reactive mixtures resulted from the removal of Cr(VI) with Fe0 in continuous-flow system, Romanian Journal of Materials. Manuscript under review.
M. Gheju, I. Balcu, Mitigation of Cr(VI) aqueous pollution by reuse of iron-contaminated water treatment residues, ChemEngineering. Accepted manuscript.
 
M. Gheju, I. Balcu, Cheap metallic iron source for hexavalent chromium removal, 4th International Conference on Energy and Environment Research, ICEER 2017, 17-20 July 2017, Porto, Portugal. Manuscript accepted for publication in Energy Procedia.

M. Gheju, Treatment of waters with metallic iron. WORKSHOP: ”World water day”, 22 March, 2017, Timișoara.

M. Gheju, Decontamination of hexavalent chromium-polluted waters: significance of metallic iron technology, in N. Anjum, S. Gill, N. Tuteja (eds.), Enhancing Cleanup of Environmental Pollutants. Volume 2 Non Biological Approaches. Springer International Publishing, 2017, pp. 209-254. ISBN 978-3-319-55422-8.

M. Gheju, I. Balcu, G. Mosoarca, C. Vancea, Synergic composition for treatment of waters polluted with hexavalent chromium. OSIM patent application No. A/00260/2017. 

Scientific reports

Scientific report 2015

Scientific report 2016

Scientific report 2017