Gheju Marius Traian – Project manager

Moșoarcă Giannin Emanuel – Postdoctoral researcher

Vancea Cosmin Nicolae – Postdoctoral researcher

Balcu Ionel – Postdoctoral researcher

Bălășoiu Adriana Maria – PhD student

Enache Andreea – PhD student

 

 

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.

 

 

 

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. Disemination of the obtained results

5. Project self-evaluation

 

  

 

 

1. Ensuring the necesary 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. Disemination of the obtained results

7. Project self-evaluation

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.

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.