SIMI 2020

The use of zero-valent iron nanoparticles (nZVI) as a reactive medium in permeable reactive barriers (PRBs) has often been used to remediate contaminated groundwater especially with oxo-anions such as nitrates and chromates, as well as chlorinated organics. Nitrates have received special attention because they can easily reach groundwater, the main source being agricultural activities. However, ZVI nanoparticles have some limitations in practical applications. The main drawback is that they are extremely small and can easily agglomerate due to their colloidal and magnetic characteristics. To solve the issue regarding the nZVI tendency to be agglomerated when used alone, a wide range of supporting materials were used to immobilize nZVI without decreasing its reactivity. In this respect, both organic materials (i.e. ion exchange resins, chelating resins, polymeric substrates, etc.), as well as inorganic materials (i.e. clay minerals, metal oxides, zeolites, etc.) were used. The physical-chemical characteristics of the materials used as support have a major influence on the size and distribution of nZVI particles immobilized on them. In addition, the support material has the role of concentrating the reactive phases by adsorption, which favors the redox reactions that take place in the system. Therefore, this paper tests the performance of a new reactive barrier, based on nZVI deposited on a strongly basic anion exchange resin for removing nitrates from a simulated groundwater.

Surface water and groundwater represent the main sources of drinking water in Romania. Ammonium, iron, manganese, and arsenic are the main potential pollutants that can be found in groundwater. In high concentrations or long-term consumption, they can have a dangerous effect on human health when present in drinking water. Ammonia can have a compromising effect on the disinfection process efficiency leading to taste and odour problems. Excess iron and manganese can modify the drinking water organoleptic characteristics (turbidity, colour) making it hardly acceptable for human consumption. Long term arsenic consumption can have a dangerous effect on the human body like skin cancer, cardiovascular diseases and dermal lesions. In Romania, drinking water is controlled by the National Drinking Water Quality Act no. 458/2002, republished in 2011. For this reason, the present study focused on determining drinking water quality according to the national legislation.

Inorganic pollutants represent a major risk to the health of the population and ecosystems because they are not biodegradable. Due to the mobility in the environment, they can get into the food chain and thus can seriously affect the health of the population. The most important source of pollution is anthropogenic nature and is mainly due to industrial activity. Mining and processing activities, metal coatings, tailings deposits, waste discharges have a special impact on surface water which is a vector for the transmission of contaminants at a distance (soil, groundwater). Monitoring them is a first utility activity. In this paper are presented the results obtained at the separation of some metallic cations: Zn2+, Cu2+ frequently found in wastewater or other industrial residues. The presence of high doses of these cations severely affects people’s health. Copper causes anemia and diseases of the liver and kidneys. Zinc intoxication in humans causes gastric irritation and other digestive phenomena with complex metabolic consequences. Zinc also causes respiratory disorders, but also nutritional disorders.

High coal consumption leads to both environmental pollution and the destruction of resources. Minimizing resource destruction and environmental pollution is the main direction of our research. The IGCC technology can increase the efficiency of coal use and in the same time reduces the intensity of pollution in the process of converting coal into electricity. Many researches has been done regarding the removal H2S, CS2, COS, mercaptan, thioethers, disulfide, thiophene from flue gases. The paper is part of the current concerns regarding the prevention of air pollution with sulfur compounds, these being the most important pollutants of the atmosphere. One of the main sources of air pollution with sulfur compounds is the burning of fuels, especially coal and petroleum fuels, in order to obtain energy. The need for advanced desulfurization is required by the existence in the flue gases of sulfur compounds: H2S, CS2, COS, mercaptan, thioethers, disulfide, thiophene. Current guidelines regarding the pollution of the atmosphere with sulfur compounds concern the desulfurization of sulfur raw materials or intermediate gases when the the predominant form of sulfur compounds is hydrogen sulfide. Many researchers have used as sorbents metal oxides used as monocomponent materials or in mixture, multicomponent material. The most efficient oxides proved to be the oxide of Fe, Zn, Mn, as monocomponents or in mixture with oxides of Ti, Al, Si, aiming to obtain stable sorbents over time, with high retention capacity. Since the amount of pyrite waste from the manufacture of H2SO4 is large, we tried to capitalize on this waste by trying to retain H2S.

Acetaminophen (paracetamol) is a pharmaceutical drug for curing fever, headaches and body aches. The main areas that pollute the environment with acetaminophen and its residues come from hospitals, domestic and veterinary effluents and the pharmaceutical industries. Pharmaceutical drugs have appeared in our environment and entered as residues in rivers, sewage effluents, surface, soil and drinking water. The adsorption method is economically and technically favourable for wastewater treatment. This technique consists in the ability of the adsorbent material to absorb on its surface’s pollutants and its residues from wastewater from the environment. Fe3O4 nanomaterial has been used as an adsorbent due to its high pollutant removal efficiency, small particle size and maximum internal surface area. The specific surface area of the adsorbent material is important because the removal efficiency generally increases with increasing surface area.

Structure of 2,6-bis((E)-2-(thiophen-2-yl)vinyl)-4-(5-isopropyl-3,8-dimethylazulen1-yl)pyridine (LV) was investigated by DFT method using computational tools, aiming to assess their molecular key parameters for reactivity and electrochemical behavior. Energetical levels of frontier molecular orbitals, the Highest Occupied Molecular Orbital (HOMO) and of the Lowest Unoccupied Molecular Orbital (LUMO) were calculated and used to obtain global reactivity descriptors and an assessment of oxidation and reduction potentials for electrochemical applications. Some studies report correlations between the molecular orbital energies and their reduction and oxidation potentials obtained from cyclic voltammetry. Consequently, we tried to verify this assumption using Density Functional Theory (DFT) in silico computations on the lowest energy conformer of the above-mentioned structure.