Magnetite nanoparticles have become a promising material for scientific research. Among numerous technologies of their synthesis, co-precipitation seems to be the most convenient, less time-consuming and cheap method which produces fine and pure iron oxide particles applicable to environmental issues. The aim of the work was to investigate how the co-precipitation synthesis parameters, such as temperature and base volume, influence the magnetite nanoparticles ability to separate heavy metal ions. The synthesis were conducted at nine combinations of different ammonia volumes - 8 cm3, 10 cm3, 15 cm3 and temperatures - 30°C, 60°C, 90°C for each ammonia volume. Iron oxides synthesized at each combination were examined as an adsorbent of seven heavy metals: Cr(VI), Pb(II), Cr(III), Cu(II), Zn(II), Ni(II) and Cd(II). The representative sample of magnetite was characterized using XRD, SEM and BET methods. It was observed that more effective sorbent for majority of ions was produced at 30°C using 10 cm3 of ammonia. The characterization of the sample produced at these reaction conditions indicate that pure magnetite with an average crystallite size of 23.2 nm was obtained (XRD), the nanosized crystallites in the sample were agglomerated (SEM) and the specific surface area of the aggregates was estimated to be 55.64 m2·g-1 (BET). The general conclusion of the work is the evidence that magnetite nanoparticles have the ability to adsorb heavy metal ions from the aqueous solutions. The effectiveness of the process depends on many factors such as kind of heavy metal ion or the synthesis parameters of the sorbent.
Environmental risks associated with Co, Cr, Cu, Mn, Ni, Pb, V and Zn in street dust collected from Baotou, a medium-sized industrial city in a semi-arid area of northwest China, were assessed by using enrichment factor and the potential ecological index. Their spatial distributions and sources in the dust were analyzed on the basis of geostatistical methods and multivariate statistical analysis, respectively. The results indicate that street dust in Baotou has elevated heavy metal concentrations, especially of Co, Cr, Cu, Pb and Zn. Co in the dust was significantly enriched. Cr and Pb were from moderate to significant enrichment. Cu and Zn were from minimal to moderate enrichment, whereas Mn, Ni and V in the dust were from deficient to minimal enrichment. The ecological risk levels of Co and Pb in the dust were moderate to considerable and low to moderate, respectively, whereas those of other heavy metals studied in the dust presented low ecological risk. Different distribution patterns were found among the analyzed heavy metals. Three main sources of these heavy metals were identified. Cr, Mn, Ni and V originated from nature and industrial activities. Cu, Pb and Zn derived mainly from traffic sources, and Co was mainly from construction sources.
The aim of this research was to assess the content and composition of the pollutants emitted by domestic central heating boilers equipped with an automatic underfeed fuel delivery system for the combustion chamber. The comparative research was conducted. It concerned fuel properties, flue gas parameters, contents of dust (fl y ash) and gaseous substances polluting the air in the flue gases emitted from a domestic CH boiler burning bituminous coal, pellets from coniferous wood, cereal straw, miscanthus, and sunflower husks, coniferous tree bark, and oats and barley grain. The emission factors for dust and gaseous air pollutants were established as they are helpful to assess the contribution of such boilers in the atmospheric air pollution. When assessing the researched boiler, it was found out that despite the development in design and construction, flue gases contained fly ash with a significant EC content, which affected the air quality.
The heavy metal release experiments were conducted in the laboratory to examine the effects of 3 factors - pH, dissolved oxygen (DO), and temperature on the metal release from sediments taken from the Huangpu River. The metal concentrations in the dry sediments ranged from 0.030 to 0.296 mg g-1 for Cr, 0.021 to 0.097 mg g-1 for Ni, 0.014 to 0.219 mg g-1 for Cu, 0.035 mg to 0.521 mg g-1 for Zn, 0.0002 to 0.001 mg g-1 for Cd and 0.023 to 0.089 mg g-1 for Pb. Most of the metals found in the sediments were in the form of residual fraction, the exchangeable fraction consisted of only a small portion of total metals. The average dissolved metal concentrations in the overlying water during the 13-day period under different conditions were ranging from 0.82 to 1.93 μg L-1 for Cr, 1.08 to 4.19 μg L-1 for Ni, 40.79 to 82.28 μg L-1 for Cu, 20.30 to 29.96 μg L-1 for Zn, 1.57 to 4.07 μg L-1 for Cd, and 22.26 to 75.50 μg L-1 for Pb, respectively. Statistical interpretation of the data indicated that pH (7, 8, 9), dissolved oxygen DO (1.0 and 5.0 mg L-1) and temperature (4, 16, 25°C) had no significant effects on the heavy metal release under the studied conditions. Cu and Pb had the highest release flux, while Cd, Pb and Cu had higher mobility. The main factors controlling the metals release might be the inherent characters of metals and sediments.
Removal of mercury(II) (Hg(II)) from aqueous media by a new biosorbent was carried out. Natural Polyporus squamosus fungus, which according to the literature has not been used for the purpose of Hg(II) biosorption before, was utilized as a low-cost biosorbent, and the biosorption conditions were analyzed by response surface methodology (RSM). Medium parameters which were expected to affect the biosorption of Hg(II) were determined to be initial pH, initial Hg(II) concentration (Co), temperature (T (°C)), and contact time (min). All experiments were carried out in a batch system using 250 mL fl asks containing 100 mL solution with a magnetic stirrer. The Hg(II) concentrations remaining in fi ltration solutions after biosorption were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Based on the RSM results, the optimal conditions were found to be 5.30, 47.39 mg/L, 20°C and 254.9 min for pH, Co, T (°C), and contact time, respectively. Under these optimal conditions, the maximum biosorbed amount and the biosorption yield were calculated to be 3.54 mg/g and 35.37%, respectively. This result was confi rmed by experiments. This result shows that Polyporus squamosus has a specifi c affi nity for Hg ions. Under optimal conditions, by increasing the amount of Polyporus squamosus used, it can be concluded that all Hg ions will be removed
The study presents the results of the research into different phosphorus forms in the bottom sediments of anthropogenic limnic ecosystems i.e. the reservoirs of Pławniowice, Rybnik and Goczałkowice (SP). The bottom sediments of dam reservoirs were investigated by chemical extraction procedure for phosphorus forms. The lowest value of the mean AAP form percentage in the Pławniowice bottom sediments reflected the effect of reclamation with the hypolimnetic removal that had been conducted in the reservoir since 2003. The highest percentage of the RDP form (2%) was found in the Goczałkowice bottom sediments. The order of the specific speciation forms in the bottom sediments of the examined reservoirs was:
Rybnik: AAP > EP > WDP > RDP; 4,630> 3,740 > 117 > 65 > 3.5 mgP/kg
Pławniowice: AAP > EP > WDP > RDP; 916 > 783 > 107 > 15 > 1.4 mgP/kg
Goczałkowice: AAP > WDP > EP > RDP; 686 > 628 > 51 > 7 > 0.14 mgP/kg
The mutual correlations between the phosphorus speciation forms (AAP : EP : WDP : RDP) were as follows:
Rybnik: 1,323 : 1,068 : 33 : 18 : 1;
Pławniowice: 654 : 559 : 76 : 11 : 1;
Goczałkowice: 4,900 : 4,485 : 364 : 50 : 1.
The comparison of the mean concentration values for specific phosphorus forms in the bottom sediments of the three investigated reservoirs demonstrated that the Rybnik sediments had the highest contents of phosphorus. The contents in Pławniowice and Goczałkowice were 5-7 times lower
There is often a need to improve the taste of mineral water by reducing the sulphate ion content. It was found that for such an effect, nanofiltration (NF) process can be used. In the case, the proposed formula was assumed obtaining a mineral water with reduction of H2S and SO42- content through the following processes: stripping - UF/MF or rapid fi ltration - nanofiltration - mixing with raw water or filtration through calcium bed. The paper shows the results of the tests, with use of mineral waters and nanofiltration. Commercial nanofiltration membranes NF-270 Dow Filmtec and NF-DK GE Infrastructure Water&Process Technologies were applied. NF was carried out for mixed water from both water intakes (1 and 2), recovery of 50%, at transmembrane pressure of 0.8-1.2 MPa in the dead-end fi ltration mode. In addition, the permeate obtained in NF was filtered through a column fi lled with 1.0-3.0 mm limestone rock, in order to improve the composition of mineral water. The tested mineral water is the sulphate-chloride-sodium-calcium-magnesium in nature and contains 991 mg/L of SO42- and 2398 mg/L of TDS, while the permeate after NF showed the chloride - sodium hydrogeochemical type (TDS: 780-1470 mg/L, sulfate 10-202.7 mg/L, calcium 23-39.7 mg/L, magnesium 11-28 mg/L). As a result of water treatment in the NF process, high reduction of SO42- ions was obtained (79-98.7%), while the TDS was reduced in 51-64%. Because the process of NF allows for relatively high reduction of bivalent ions, a significant reduction in calcium ion content (84-88%) and magnesium (84-89%) has been also obtained. Monovalent ions were reduced to a lesser extent, i.e. sodium in 46% and bicarbonates in 39-64.1%. Despite obtaining the positive effect of the sulphate ions content reduction, the NF process significantly changed the mineralogy composition of water. The permeate filtration (DK-NF membrane) on the CaCO3 deposit led to a correction of the hydrogeochemical type of water from chloridesodium to chloride-bicarbonate-sodium. The concentration of calcium ions was increased by 60.5% and was 28.2 mg/L, and bicarbonate ions by 7.78% (increased to 195 mg/L). Based on a morphological assessment of the deposits in the SEM image and their chemical composition, the presence of gypsum crystals was detected on the surface of the NF-270 membrane. The deposits formed on the NF-DK membrane were of a completely different character as aggregations of iron and aluminium oxides/hydroxides were found. Such significant mineralogical differences between the secondary deposits crystallising on the surface of the membranes point to the impact of several factors, including membrane characteristics, concentration polarisation, mass transport mechanisms, etc.
High intake of over-the-counter, non-steroidal anti-inflammatory drugs, such as ibuprofen, has resulted in their presence in wastewaters and surface waters. The potentially harmful effect of ibuprofen present in the waters has led to a search for new methods of drugs’ removal from the environment. One of the most important technological and economical solutions comprises microbiological degradation of these resistant pollutants. Searching for new strains able to degrade ibuprofen could be one of the answers for increasing the detection of pharmaceuticals in the waters. In this study, the ability of bacterial strain Bacillus thuringiensis B1(2015b) to remove ibuprofen is described. Bacteria were cultured in both monosubstrate and cometabolic systems with 1, 3, 5, 7 and 9 mg L-1 ibuprofen and 1 g L-1 glucose as a carbon source. Bacillus thuringiensis B1(2015b) removed ibuprofen up to 9 mg L-1 in 232 hours in the monosubstrate culture, whereas in the cometabolic culture the removal of the drug was over 6 times faster. That is why the examined strain could be used to enhance the bioremediation of ibuprofen.
Five cosmetics wastewater samples were treated by Dissolved Air Flotation (DAF) assisted by coagulation. Different aluminum based coagulants were used: (Al2(SO4)3, Al 1019, Al 3010, Al 3030, Al 3035, PAX 16 and PAX 19). The raw wastewater COD values were in the range 285-2124 mg/l. The efficiency of DAF depended on different coagulants and production profi le of factory. COD removal was varied from 11.1 to 77.7%. The efficiency of coagulants was similar during treatment of particular sample. The best results were obtained with Al2(SO4)3 and for sample 5 - lotions and shampoos production. The wastewater from UV fi lter creams production (sample 4) was resistant to treatment by DAF regardless of used coagulant. HS-SPME-GC-MS analysis can be a confirmation of DAF effectiveness
The variation law of dissolved silica (DSi), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and nutrition structure after the Three Gorges Project (TGP) impounding as well as their ecological effect were analyzed according to monitoring survey of the Yangtze River Estuary in spring (May) and summer (August) from 2004-2009. The results showed that after impounding, DSi and DIN concentration decreased and increased, respectively. During the study period, DSi decreased by about 63%, while DIN almost tripled. DIP concentration fluctuated slightly. With respect to nutrition structure, N:P increased, whereas Si:P and Si:N declined. According to chemometry standard of nutrient limits, nutrition structure tended to be imbalanced and the limiting factor of phytoplankton growth (P) was studied. Changes of nutrition structure have largely decreased diatom and caused different composition of dominant phytoplankton species. This may change ecosystem structure of the Yangtze River Estuary.