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Activated carbon is an effective sorbent for removing organic and inorganic contaminants from aqueous solutions. In conducted experiments, granulated activated carbon (GAC) was used to examine the adsorption processes of heavy metals (Cd, Cu, Ni, Pb and Zn). Studies (performed in batch system) were carried out as a function of time, heavy metals concentration and pH values. The obtained results show that GAC effectively removes mentioned metals. Numerous kinetic models were used to investigate the mechanism of adsorption processes. Using the Langmuir isotherm, the maximum adsorption capacities were calculated to be 3.010, 3.662, 4.430, 3.800 and 4.169 mg·g–1 for Cd, Cu, Ni, Pb and Zn, respectively, in neutral conditions and 2.684, 2.578, 3.482, 2.592 and 2.253 mg·g -1 in acidic conditions.
The hydraulic conductivity of zero-valent iron treatment zone of permeable reactive barriers (PRBs) may be decreased by reducing the porosity caused by gas production and solids precipitation. The study was undertaken in order to evaluate the influence of chloride and heavy metals on the hydraulic conductivity of ZVI and nZVI using hydraulic conductivity tests as well as continuous column tests. Results show that the lead retention in the solution had no impact for hydraulic conductivity in ZVI sample, on the other hand the calculated hydraulic conductivity losses in nZVI sample (from 4.10·10–5 to 2.30·10–5 m·s–1) were observed. Results also indicate that liquids containing the mixture of heavy metals may cause signifi cant decrease in hydraulic conductivity (from 1.03·10–4 to 1.51·10–6 m·s–1). During the column tests, several number of clogging of the reactive material caused by iron hydroxides precipitation was observed over the course of injection of heavy metals solution. In contrast, the hydraulic conductivity of ZVI and nZVI is unaffected when they are permeated with chloride ions solution (k = 1.03·10–4 m·s–1). Finally, the results indicate the need to take account of changes in the hydraulic conductivity of reactive materials for successful implementation of PRBs technology.
Recently a numerous methods were designed for the in-situ treatment of contaminated groundwater, among them a versatile technology – Permeable Reactive Barriers (PRB). This environmentally safe technology requires the application of reactive materials with high specific surface areas (zeolite, activated carbon, zero-valent iron particles, etc.). This paper presents the review of laboratory methods commonly used for determination of specific surface area. More detailed description was included for the methylene blue sorption (MBS) method recommended for application in geotechnical practice. According to the test results obtained for zeolite and zeolite-sand mixtures it can be concluded that simple MBS method gives results comparable to more sophisticated methods.
Permeable reactive barriers (PRB) are treatment technology based on the inserting into the subsoil specific reactive material – for example zeolite. Designing the PRB’s requires taking into account three criteria of selection of the reactive materials: hydraulic, sorptional and mechanical. Mechanical criterion, concerning shear strength characteristics is very important due to stability and technology of realization of the barrier. In this paper results of the shear strength tests performed on pure zeolite and zeolite-sand mixtures are presented. The tests were made in the direct shear and triaxial apparatus on the samples with various proportions of mixtures and moisture contents of pure zeolite.
Wybrane parametry fizyko-chemiczne gleb wzdłuż trasy komunikacyjnej zlokalizowanej na obszarach cennych ekologicznie. Celem badań, których wyniki przedstawiono w niniejszym artykule, było zbadania wpływu tras komunikacyjnych na zanieczyszczenie gleb. W ramach prac badawczych na poletku badawczym przy ul. Czecha w warszawskim Wawrze pobrano próbki gleb do laboratoryjnych analiz chemicznych (stężenia chlorków, przewodności elektrycznej i pH), jak również właściwości fizycznych (uziarnienia i zawartości części organicznych wyrażonej stratami przy prażeniu). Dodatkowo w warunkach terenowych wykonano pomiary techniką profilowania elektrooporowego. Wyniki badań wskazały, że gleby i grunty w bezpośrednim sąsiedztwie tras komunikacyjnych charakteryzują się podwyższonym zasoleniem. Przeprowadzone badania potwierdziły również możliwość zastosowania metody elektrooporowej do oceny stopnia degradacji gruntów na obszarach cennych ekologiczne.
The effects of increasing nickel contamination of soil on selected macroelement uptake byIndian mustard (Brassica junceaL. Czern) and application of natural zeolite, raw and modified halloysite were investigated in this experiments. In a vegetative-pot experiment, four different level of nickel contamination, i.e., 0 (control), 80, 160, 240, 320 mg · kg–1were applied in an analytical grade NiSO4·7H2O solution mixed thoroughly with the soil. The content of nitrogen, phosphorus, sodium, calcium, potassium and magnesium in Indian mustard depended on the dose of nickel and type of neutralizing substance. The average accumulation of tested elements in Indian mustardgrown in nickel contaminated soil were found to follow the decreasing order Na>P>Ca>Mg>K>N.The application of MH turned out to be most advantageous, resulting in a small increase in the average content of Na and Mg. Addition of RH and NZ led to the highest increase in the average content of the P
One of the most critical sources of pollutants are road run-offs. Road run-off is a complex mixture of toxicants e.g. heavy metals, de-icing agents, organic compounds and water suspensions of solid substances. One of the most negative impact on the environment has sodium chloride which is used as de-icing agent. In the case of incorrect environment protection in the vicinity of roads pollutants may migrate to groundwater causing hazard to sources of potable water. One of the methods to prevent the migration of pollutants to groundwater is imposing the flow of polluted water through a reactive material filling a permeable reactive barrier (PRB). This paper examines the feasibility of selected reactive materials for the reduction chlorides concentration in road run-offs. Four different reactive materials: zero valent-iron, activated carbon, zeolite and geza rock have been chosen for studies. The tests results indicated that the most popular reactive materials used in PRB technology, activated carbon and zero-valent iron, removed exhibited the highest efficiency in chloride ions removal. Moreover, the composition of road run-off in samples collected along roads in Warsaw was determinated.
The paper presents results of laboratory research on the zeolite and zeolite-sand blends using the electrical conductivity measurements to verify the sorption capacity of materials proposed to performance of the Permeable Reactive Barriers. First part of paper contains the characteristics of mathematical models commonly used to simulate the flowing of groundwater and liquid contaminants. In the second paper the test method proposed to assess an environmental attenuation was described. Analysis of dynamic test results obtained with application of electrical conductivity measurements has proven the efficiency of proposed method. Finally, an electrical tomography or electrical measurements using electrodes installed inside of barriers was recommended to control of sorption capacity fulfi llment. However, the field investigations are required to validate the proposed procedure.
Obecnie beton jest najczęściej wykorzystywanym materiałem kompozytowym spośród wytworzonych przez człowieka, a drugim po wodzie w całym kompleksie stosowanych materiałów. To ekologiczny materiał wytworzony z miejscowych surowców – kruszywa, cementu, wody, domieszki i dodatku mineralnego, charakteryzujący się najmniejszym śladem węglowym. W artykule przedstawiono wyniki badań betonów klasy C20/25 na bazie CEM I 42,5R, kruszywa otoczakowego oraz popiołu lotnego z termicznego przekształcania osadów ściekowych w ilościach 5, 10, 15 i 20% masy cementu. W toku prac eksperymentalnych wykonano pomiary wytrzymałości na ściskanie po dwóch okresach dojrzewania oraz mrozoodporność F150. Zebrane wyniki badań umożliwiły porównanie właściwości betonów wytworzonych z popiołem pochodzącym z dwóch oczyszczalni ścieków. Uzyskane wyniki badań potwierdzają możliwość wytwarzania betonu zwykłego, modyfikowanego popiołem lotnym z termicznego przekształcania osadów ściekowych. Średnią wytrzymałość na ściskanie dla betonu zawierającego 20% popiołu z Krakowa ustalono na 50,1 i 50,6 MPa po 28 i 56 dniach dojrzewania, a dla popiołu z Warszawy na 42,6 i 45,7 MPa.
Research of the biodegradability of degradable/biodegradable plastic material in various types of environments. Research was carried out in order to assess biodegradability of degradable/biodegradable materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive) or made of polyethylene (PE) with the addition of pro-oxidant additive (d2w additive), advertised as 100% degradable or certified as compostable within various types of environments. Research conditions were: (i) controlled composting environment – laboratory-scale, (ii) real composting conditions – domestic compost bin, (iii) real composting conditions – industrial composting plant and (iv) landfill conditions. The results demonstrate that the materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive) or made of polyethylene (PE) with the addition of pro- -oxidant additive (d2w additive) or advertised as 100% degradable did not biodegrade in any of the above-described conditions and remained completely intact at the end of the tests. Biodegradation of the certified compostable plastic bags proceeded very well in laboratory-scale conditions and in real composting conditions – industrial composting plant, however, these materials did not biodegrade in real composting conditions – domestic compost bin and landfill conditions.
Soil parameters in agricultural areas play an important role in the migration of nitrogen compounds to groundwater. Nitrogen loss from subsoil depends on soil permeability, organic content, and soil saturation. Our study evaluates the parameters controlling the migration of nitrogen compounds through selected fine and sandy soils that may affect the quality of groundwater in agricultural areas. The results of this study indicate that denitrification processes that substantially affect ammonium (NH₄⁺) and nitrate (NO₃⁻) concentrations take place in fine soils. These processes decrease the flow of nitrogen into groundwater and are indicated by the production of a gashouse phase, a decrease in hydraulic conductivity, and a nitrogen compound concentration in the filtrate that is lower than the maximum concentration. Column tests have shown that the dominant transport process for silt loam and sand samples was advection, and the dominant transport process for loam was dispersion. Moreover, the velocities of NH₄⁺ ion transport were lower than the velocities of water flow by approximately seven and five times for loam and sand, respectively. The estimated values of the retardation factor and dynamic sorption capacity for NO₃⁻ were lower than those for NH₄⁺ ions. Finally, groundwater located below the silt loam and loam soil layers can effectively be protected against the infiltration of nitrogen compounds from agricultural sources.
Selected monitoring properties of agricultural soil from the Imielin experimental site. The effects of two types of agricultural practice: variable rate application (VRA) and uniform (UNI) N dose on selected chemical properties of soil were compared in a fi eld fertilization experiment. Nitrogen, in doses 60 or 80 kg·haˉ¹ (UNI) and 55–105 kg·haˉ¹ (VRA), was applied to soil farmed with winter wheat (Triticum aestivum L.). The research was conducted in the 2012/2013 growing season in Poland on 22 ha of production fi elds located in the Imielin countryside (central Poland). The soil samples were taken from three depths: 0.0–0.3, 0.3–0.6, and 0.6–0.9 m, and the pH, HAC, TEB, CEC, and BS were determined. The application of the nitrogen fertilizer in the two types of agricultural practice – variable rate application (VRA) and uniform (UNI) N dose modified the basic physical and chemical properties of soil. The highest values of pH and hydrolytic acidity were observed at the soil depth of 0.6–0.9 m after the first rate of nitrogen fertilizer was applied. Cation exchange capacity of soils collected after uniform nitrogen rates were characterized by values decreasing with the increasing depth of the soil profile.
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