Phase 3 (2023) Short description / Phase 3 results indicators
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Phase 3 short description
In stage 3 (2023) of the project three scientific research activities were carried out. All activities were completed in full and on time, leading to the achievement of the objectives for the year 2023 and exceeding the project indicators.
The first research activity (A.3.1.) focused on the technical performance analysis of four innovative sorbents using wastewater from the municipal wastewater treatment plant in Iași. As the water samples did not contain significant amounts of heavy metals or sodium diclofenac (DCF-Na), precise quantities of lead ions and DCF-Na were added to these samples. The retention of Pb2+ ions and DCF-Na from wastewater on the composite material was studied using a static method, simultaneously. The materials exhibited a high affinity for retaining Pb2+ ions, achieving a retention rate between 92% and 96%, compared to the adsorption efficiency of DCF-Na (62-64%). Similar results were obtained in sequential sorption tests using the sorbent IS/(PEI-PMAA)r=1. All tested materials can be used for the retention of metal ions and DCF-Na from wastewater.
The second activity (A.3.2.) presented the results obtained from testing the innovative sorbents on synthetic and real wastewater in dynamic mode for the sequential and simultaneous removal of emerging pollutants. Highly reticulated materials showed significantly higher sorption capacities compared to ones with low reticulation degree, allowing for at least 10 cycles of sorption/desorption without significantly affecting the maximum sorption capacity. These materials were then tested in dynamic mode for the sequential removal of metal ions (Pb2+, Cd2+, and Ni2+) and DCF-Na. The experimental results demonstrated the effectiveness of all tested materials in removing pollutants, with higher sorption capacities observed for Pb2+ ions, in the following order: Pb2+ > Cd2+ > Ni2+. The composite material IS/(PEI-PMAA)r=0.1 exhibited the highest sorption capacities for metal ions. Despite having a lower reticulation degree compared to IS/(PEI-PMAA)r=1, its higher retention capacity could be attributed to its more porous structure, allowing heavy metal ions to form more bonds with a greater number of functional groups. The study on the influence of initial concentrations on the efficiency of the IS/(PEI-PMAA)r=0.1 material showed that with increasing initial concentrations, a decrease in breakthrough volume and time occurred due to a faster saturation of the sorbent’s active centers by pollutant molecules. Mathematical modeling of kinetic and equilibrium data indicated close sorption capacities derived from breakthrough curve analysis, indicating a better correlation between experimental and nonlinear Thomas and Yoon-Nelson models.
To assess the affinity and accessibility of functional groups on the surface, the composite materials were tested in dynamic conditions using an equimolar mixture (CCd2+ = CNi2+ = CPb2+ = 0.1 mM) continuously. Metal ions were completely retained under non-competitive conditions, with the total sorption capacity varying depending on the composite type. After depleting the column with metal ions, the materials were exposed to a solution of DCF-Na (148mg/L). Heavy metal ions interacted within the reticulated organic envelope of the composite with the active functional groups of PEI, PAA, and PMAA by forming coordinative bonds, while the DCF molecule, containing a carboxylic group, could electrostatically interact with the amine groups of PEI or through ionic exchange with the nitrogen counterion in the coordination sphere of each immobilized metal ion in the composite’s polyelectrolytic network.
Activity 3.3. presents the study evaluating the environmental performances of the materials tested in the previous activity, focusing on two directions:
i) identification and quantification of environmental impacts resulting from material testing in dynamic conditions,
ii) development, modeling, and interpretation of “What If” scenarios to evaluate various opportunities for improving environmental performances through ecological design.
The highest impact is generated by the removal of Ni2+ ions, followed by Cd2+ ions due to the lower efficiency in adsorption (for the same tested material) compared to the other two pollutants (Pb2+ ions and DCF-Na). The smallest environmental impacts for the removal of all four pollutants are generated by the material IS/(PEI-PAA)r=1, while the material IS/(PEI-PMAA)r=0.1 generated substantially higher impacts. These environmental impact values can be explained by the generally better affinity of the material IS/(PEI-PAA)r=1 for all four pollutants. In the eco-toxicity category, the most efficient material is still IS/(PEI-PMAA)r=1, followed by IS/(PEI-PMAA)r=0.1, while IS/(PEI-PAA)r=0.1 and IS/(PEI-PAA)r=1 show lower performance.
Activity 3.4 proposed three scenarios of ecological design to improve environmental performances. The main component of the environmental impact in most impact categories is electricity consumption, which is addressed from the perspective of developing eco-design scenarios. Three scenarios were modeled:
S1 – Optimizing electricity consumption by performing multiple simultaneous sorption/desorption tests;
S2 – Replacing electricity from the national grid with locally produced electricity through a photovoltaic panel system;
S3 – Treatment of resulted wastewater streams with conventional elimination of resulting pollutants.
By optimizing electricity consumption, significant reductions in impacts in most relevant categories (26-72% in categories related to electricity consumption) can be achieved. Transitioning from the national energy mix leads to additional significant reductions in impacts related to climate change, ionizing radiation, and fossil fuel consumption, but this also results in increased impacts in toxicity-related categories due to the production processes of photovoltaic panels. Regarding the implementation of scenario S3, it achieves an almost complete reduction of the environmental impact in the marine eutrophication category due to the purification of the effluent resulting from the washing and desorption processes of pollutants from the adsorbent material.
Phase 3 results indicators
Scientific articles
Bârjoveanu G., Teodosiu C*,Morosanu I., Ciobanu R., Bucatariu F., Mihai M., 2023. Life Cycle Assessment as Support Tool for Development of Novel Polyelectrolyte Materials Used for Wastewater Treatment, Nanomaterials, 13(5), 840, (Q1, IF = 5.3, ISI Web of Science), DOI: https://doi.org/10.3390/nano13050840.
Morosanu I., Bucatariu F., Fighir D., Paduraru C., Mihai M.*, Teodosiu C*, 2023. Optimization of Lead and Diclofenac Removal from Aqueous Media Using a Composite Sorbent of Silica Core and Polyelectrolyte Coacervate Shell, Polymers 2023, 15(8), 1948; (Q1, IF = 5.0, ISI Web of Science), DOI: https://doi.org/10.3390/polym15081948.
Fighir D., Paduraru C., Ciobanu R., Bucatariu F., Plavan O.A., Gherghel A., Barjoveanu G., Marcela M*., Teodosiu C*., Removal of diclofenac and heavy-metal ions from aqueous media using composite sorbents with silica core and polyelectrolyte coacervate shell in dynamic conditions, Nanomaterials, sent for publication, under review as of 29/11/2023 (Manuscript ID: nanomaterials-2757170).
Scientific communications
Mihai M., 2023. Polyelectrolyte-based composite materials for targeted environmental applications (key-note lecture as invited speaker ), 12th International Conference on Environmental Engineering and Management, ICEEM12, 13-16 September 2023, Iasi, Romania
Mihai M., 2023. (Multi)functional ionic polymers. Form synthesis to materials design (Conferinta invitata) 29th PolyChar Forum – Université Côte d’Azur, 25-29 September 2023, Nice, Franta
Mihai M., 2023. Porous polymeric materials for medical and environmental applications (prezentare orala), WORKSHOP Geo Milev Campus – Eco-friendly technologies and advanced functional polymeric materials, 29 May – 02 June 2023, Sofia, Bulgaria
Lupu A.M., Paduraru C., Ciobanu R., Plavan O., Gherghel A., Fighir D., Bucatariu F., Mihai M., Teodosiu C., 2023. Heavy metals removal from aqueous solution using a regenerated silica/polyelectrolyte multilayer core-shell composite sorbent, 12th International Conference on Environmental Engineering and Management, ICEEM12, 13-16 September 2023, Iasi, Romania (oral communication)
Petrila L.-M., Bucatariu F., Zaharia M.-M., Mihai M., Separation and water cleaning by composites of polyelectrolytes and inorganic microparticles, 12th International Conference on Environmental Engineering and Management, ICEEM12, 13-16 September 2023, Iasi, Romania ( oral communication ).
Ciobanu R., Fighir D., Paduraru C., Bucatariu F., Plavan O., Gherghel A., Mihai M., Teodosiu C., 2023. Fixed- bed column study for Pb(II) removal from aqueous solution using silica composite microparticles, Progress in Organic and Macromolecular Compounds Conference, MACRO Iasi 2023, 29th edition, 4-6 October 2023