Zbigniew Suchorab, Danuta Barnat-Hunek, Małgorzata Franus, Grzegorz Łagód and Zbyšek Pavlík
The article presents the laboratory investigations of the basic thermal and hygric parameters of standard lightweight aggregate-concrete and lightweight aggregate-concrete supplemented with municipal sewage sludge. Both types of concrete are based on light aggregates, commonly used in the Polish building market. In order to improve the hygric parameters of the material, such as water absorptivity, the admixture of water emulsion of reactive polisiloxanes was applied. Within the presented research, together with basic moisture parameters estimation, capillary rise process was monitored using Time Domain Reflectometry (TDR) modified sensors. Hygric parameters were supplemented with the estimation of thermal conductivity coefficient λ determined using stationary method. The analysis of thermal and hygric properties of concrete confirmed the applicability of lightweight aggregate-concrete with sewage sludge supplementation for further production.
The main source of usable water supply in Poland is surface water. The most frequently used methods of surface water treatment are coagulation and filtration processes. During these processes post-coagulation sludge is generated, which is the main waste produced in water treatment plants. This sludge is characterized by an amorphous structure with a strongly developed specific surface, similar to sewage sludge. Dried and crushed post-coagulation sludge was used in the studies as an adsorbent of two acid dyes: Acid Red 18 (AR 18) and Acid Green 16 (AG 16). The most favourable pH of process and contact time as well as sorption isotherm were established. For both dyes the most favourable pH value was equal 2. The tests showed that in the case of AR 18 (180 min) a longer contact time was necessary to reach the equilibrium than for AG 16 (120 min). Moreover, based on the different isotherm two-parameter models, the sorption capacity, type of sorption and energy of sorption were calculated based on linear and non-linear regression. The tests showed that in the case of dye AG 16 monolayer sorption occurred - the analysis showed better fitting the results to Langmuir model. Moreover, for both dyes, physical adsorption took place - it was indicated by the values of parameter 1/n (computed from the Freundlich model).
The paper studies the influence of industrial pollution on bio-ecological characteristics of the one-year shoot of Robinia pseudoacacia L. in the conditions of the city of Dnipro, Ukraine. It analyses the state of biometric parameters of the shoot and anatomic indices of the stem of the studied species exposed to toxic gases. It was found that there are adaptive changes in the histological structure of the stem of R. pseudoacacia under the conditions of technogenesis. The study revealed that bio-ecological characteristics of the black locust are highly resistant to industrial emissions with big shares of SO2 and NO2. It was suggested to use R. pseudoacacia for greening of the technogenic territories.
For the third time since 2005 atmospheric deposition of trace elements in Belarus was monitored by the moss technique widely used in Europe for air pollution studies. Samples of moss species of Hylocomium splendens and Pleurozium schreberi were collected at 86 sites over the Gomel, Vitebsk and Minsk Regions in the summer of 2015. A total of 30 elements were determined by epithermal neutron activation analysis. Studying of the temporal trends in Belarus was undertaken with the results obtained in previous moss surveys in 2005/2006 and 2010/2011. Comparison with the analogous data from the neighbouring countries showed relatively low contamination levels in Belarus for the most heavy and toxic elements. The results of survey 2010/2011 showed that, except Cr, other element concentrations reduce or are at the same levels.
The influence of ions of heavy metals (copper, cadmium, nickel, zinc, cobalt and manganese) was investigated on the basis of trophic characteristics: the average daily ration (ADR), and duration of food passage (DFP) of the Lymnaea stagnalis L. in various concentrations of toxicants in vivisection experiment. In addition to these indicators, the total amount of food consumed in the solutions with various concentrations of pollutants was found out during the chronic experiment and it was calculated for an individual (average monthly ration – AMR). It leads to the conclusions about the intensity of food consuming considering different levels of intoxication. In solutions with lethal concentrations, the death of animals occurs during the first day of its impact due to the damage of tissues and organ systems. Chronic lethal concentrations of toxicants inhibit the nutrition of pond snails dramatically. At the beginning of the experiment, solutions of heavy metals with sublethal concentrations give some stimulatory effect on the digestive system of molluscs that is replaced by its suppression in case of longer being in the toxic environment. The influence of toxicants within a subthreshold limit cannot be considered safe because of the cumulative properties of heavy metals – they become sublethal with prolonged exposure time.
Tanja Maksimović, Srđan Rončević and Biljana Kukavica
Paper deals with seasonal changes in heavy metal bioaccumulation (Fe, Mn, Cu, Zn and Pb) in Utricularia vulgaris L. and Salvinia natans (L.) All. of two localities (Necik and Sinjak – active fishpond basins) in the area of Bardača fishpond. According to our results, the better accumulator of Fe (3035 mg/kg) and Zn was S. natans (163.55 mg/kg), whereas Utricularia vulgaris better accumulates Mn (620 mg/kg) and Cu (10.18 mg/kg). Amounts of Pb in both investigated macrophyte were below the detection level (<0.51 mg/kg). The values of the bioaccumulation factor (BAC) of the tested metals were >1 or ~1 for both species, and the BAC values decreased in the following order in both investigated species: Fe > Mn > Cu > Zn. The results obtained indicated that tested macrophyte show very good characteristics as bioaccumulators and, thanks to this fact, they could be used in phytoremediation technique successfully in water-polluted ecosystem.
Abbas Rahdar, Somayeh Rahdar, Shahin Ahmadi and Jie Fu
Antibiotics are widely detected emerging contaminants in water environments and possess high potential risks to human health and aquatic life. However, conventional water treatment processes cannot remove them sufficiently. To develop innovative nanoadsorbents for effectively remove antibiotic contaminants from water environment, nanoceria were prepared via in situ precipitation method, and evaluated their adsorption capacity for a model antibiotic, ciprofloxacin (CIP). The properties of the prepared nanoceria were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and vibration sample magnetization (VSM). The effect of various operating parameters such as pH, initial CIP concentration, contact time, and adsorbent dosage on adsorptions of CIP were studied in batch experiments. Maximum adsorption capacity of the nanoceria was 49.38 mg/g at the conditions of pH 5, initial CIP concentration of 200 mg/dm3 and adsorbent dosage of 0.2 g/dm3, when 95.43 % of the CIP was removed. For adsorption kinetics, both pseudo-first-order and pseudo-second-order models can well describe the experimental data, indicating that the adsorption process was controlled by both physical diffusion and chemical interaction. For adsorption isotherms, the Freundlich model could fit the experimental data better than the Langmuir and Temkin models, suggesting a multilayer adsorption process. The thermal dynamics study showed the absorption process was spontaneity, exothermic, and irreversible. Finally it was concluded that the nanoceria can be used effectively for CIP removal.
Ágnes Keresztesi, Réka Boga, Zsolt Bodor, Katalin Bodor, Szende Tonk, György Deák and Ion-Andrei Nita
In order to investigate the precipitation chemistry, studies were carried out from January 2013 to December 2013 in Odorheiu Secuiesc and Miercurea Ciuc, Eastern Carpathians, Romania. During a period of eleven years (2006 – 2016), 2013 was the driest year. The rainwater samples were analyzed for pH, major anions and cations. HCO3− concentrations were calculated based on the empirical relationship between pH and HCO3−. NH4+, Ca2+, SO42− were the dominant ions in precipitation at both sites. The pH values varied from 6.75 to 7.46 Miercurea Ciuc, and from 6.69 to 7.67 in Odorheiu Secuiesc. The neutralization was mainly brought by Ca2+ and NH4+. Estimated ratios of sea-salt fraction (SSF), non-sea-salt fraction (NSSF), and results from Spearman’s rank correlation and Principal Component Analysis (PCA), showed that the acidic ions (SO42−, NO3−) were derived from anthropogenic activities, NH4+ from soil fertilization, while Ca2+, Mg2+, K+ originated from terrestrial source. These influence the precipitations ionic content, especially during droughts. Spatial variations and the rim effect of the Eastern Carpathians on precipitation chemistry is also shown.