Search

Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composition, which can vary considerably. Ash is mainly disposed of in landfills, which creates a risk for air, soil and groundwater contamination by trace elements. In order for wood biomass ash to be used as a secondary raw material, it is necessary to perform leaching tests, to determine which microelements it contains, and which of them could be released into the environment during the ash disposal. Sequential extraction (SE) showed that in the exchangeable and carbonate fraction, the most volatile metals As, Cd, Zn and Pb are released the most from the ash of deciduous trees, while the leaching of ash from coniferous trees is significantly lower. The evaluation of risk assessment code (RAC) for the tested biomass ash samples, indicates that Pb is a high-risk leaching element due to its condensation on the ash particles. By performing toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) tests, it was established that the released concentrations of tested metals are below the maximum allowable concentration, given by the regulation. The leaching tests of composites, prepared from wood ash in combination with cement, indicate that the leaching of ash is reduced to a minimum, and that all heavy metals are bound in a cement matrix, which indicates the possibility of using wood ash for construction purposes.

This paper presents two Machine Learning models that classify time series data given from smartwatch accelerometer of observed subjects. For the purpose of classification we use Deep Neural Network and Random Forest classifier algorithms. The comparison of both models shows that they have similar performance with regard to recognition of subject's activities that are used in the test group of the dataset. Training accuracy reaches approximately 95% and 100% for Deep Learning and Random Forest model respectively. Since the validation and recognition, reached about 81% and 75% respectively, a tendency for improving accuracy as a function of number of participants is considered. The influence of data sample precision to the accuracy of the models is examined since the input data could be given from various wearable devices.

This work presents results from a pilot-scale drinking water treatment plant used to investigate the performance of ozone oxidation and granulated activated carbon (GAC) adsorption in removing natural organic matter (NOM) and specific organic micropollutants from groundwater. The investigated groundwater has a relatively low NOM content (1.83±1.01 mg C/L total organic carbon, TOC). Using gas chromatography/mass spectrometry (GC/MS) screening analysis, a variety of different organic compounds were identified, including benzophenone, 2-phenoxyethanol, butylated hydroxytoluene and benzoic acid, all contaminants of emerging concern (CEC) identified by NORMAN. The application of the ozonation process resulted in a 4-20% NOM reduction, based on the TOC values. Estimated removal of CECs by ozone increased with increasing ozone dose (up to 1.0 g O3/m3) and was in the range 24-70%. Adsorption on GAC further improves total NOM and CECs removal compared to the ozonation alone. Combined use of ozone and GAC provides up to 16-33% TOC reduction as well as 70-82% CECs removal. UV absorbance values at 254 nm can serve as an indicator of aromatic carbon content in water, and were significantly reduced after ozonation and GAC filtration (by up to 50%). Among the CECs investigated, benzophenone was the most prone to oxidation/adsorption treatment. In addition to the naturally present organic matter, CECs detected can serve as indicators of anthropogenic pollution which may alter drinking water quality. Tracking their behaviour during treatment allows assessment of the efficiency of the technological line and optimization of the oxidation process in the case of groundwater pollution by infiltration.

In this study, fly ash (FA) with different chemical compositions was converted into zeolites by a fusion method, as confirmed by Fourier-transform infrared spectroscopy (FTIR). FA was obtained from three different thermal power plants in Bosnia and Herzegovina: Ugljevik, Stanari and Gacko. In the FA spectrum, a quite wide absorption band was observed at 1097 cm-1, while in those of the synthesized zeolites, this absorption band is narrowed and elongated and displaced toward 972 cm-1. These characteristic bands can be attributed to substitution of Si4+ with Al3+ in the tetrahedron, during the formation of alumosilicate and their interaction with Na+ ions. Chemical analysis has shown that the dominant component was SiO2 in the FA Ugljevik (UF) and FA Stanari (SF) with mass fractions of - 36.43 and 48.18 %, respectively and CaO in the FA Gacko (GF) with the mass fraction of 65.89 %. In studies of ammonium ion adsorption equilibrium was achieved after 24 h in zeolites of UF and SF, while for the GF sample it was necessary 48 h to reach the equilibrium. Kinetic studies of have shown that the adsorption process on all zeolites followed the Elovich model with high values of the coefficient of determination. The largest amounts of adsorbed ammonium ions were measured at the pH 8 amounting to 5.98, 6.54 and 4.23 mg NH₄+/g zeolite for UF, SF and GF, respectively. Examination of adsorption isotherms have shown the better agreement of the obtained results with the Langmuir model for the SF zeolite sample, and the Tempkin model for the UF and GF zeolite samples. Regenerated zeolites have shown similar adsorption capacities for ammonium ions (for UFr 10.3 mg/g; for SF 12.0 mg/g; for GFr 7.8 mg/g) as initial zeolites (for UF 12.2 mg/g; for SF 12.1 mg/g; for GF 14.3 mg/g). Examination of adsorption isotherms of regenerated samples has also shown the best agreement with the Langmuir model for all regenerated samples. The obtained similar and even higher removal percentages of ammonium ions from a real sample of wastewater by using regenerated zeolites (for UFr 60.7 %; for SFr 55.2%; and for GFr 30.7 %) as compared to the initial ones (for UF 45.1 %; for SF 60.6%; for GF 26.0 %) show potentials of the synthesized zeolites from fly ash for ammonium ion removal from wastewaters.

This paper investigates the removal of arsenic from water using an environmentally friendly modified biosorbent, chitosan coated with Fe–Mn binary oxide (Chit-FeMn), simply prepared with an one-pot low-cost procedure by simultaneous oxidation and coprecipitation. The sorbent was characterized by SEM, EDS, XRD, FTIR, BET specific surface area, and point of zero charge (pHpzc) measurements. The kinetic data fitted a pseudo-second order model for both As(III) and As(V), suggesting chemical adsorption on the sorbent surface and that intra-particle diffusion is not the only rate-limiting step during adsorption. The adsorption isotherms were best fit to the Freundlich model, and the non-monolayer adsorption model for arsenic on Chit-FeMn is therefore proposed. Below pH 9, the effect of pH on As(III) and As(V) removal by Chit-FeMn was insignificant, with As removals remaining above 85 %. Cl- and NO3 - had negligible influences on As(III) and As(V) removal, whereas PO4 3-, SiO3 2-, CO3 2- and SO4 2- were observed to compete with arsenic species for adsorption sites. The adsorbent was successfully applied to remove arsenic from real arsenic contaminated groundwater samples to below 10 μg L-1 suggesting that Chit-FeMn is a promising candidate for the low cost removal of both As(V) and As(III) during drinking water treatment. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43005 and Grant no. TR37004]

In this study, the effects of doping by 3d (V, Mn, Fe, Ni) and 4f (Nd, Sm, Er) ions on dielectric and infrared properties of SrTiO3 (STO) single crystals are investigated. It is well known that doping of the SrTiO3 can change the dielectric properties of the STO from an insulator to an n-type semiconductor, and even to a metallic conductor. Dielectric and infrared (IR) properties of the undoped STO and doped STO single crystals are analyzed using dielectric spectroscopy (80 kHz-5 MHz), transmission (200 cm−1–4000 cm−1), and reflection spectroscopy (50 cm−1–2000 cm−1). It is found that doping by the 3d ions reduces the value of dielectric permittivity, but the trend of temperature dependence of the dielectric permittivity remains almost unchanged. On the other hand, dielectric spectroscopy measurements for samples doped by 4f ions show the anomalous behaviors of the dielectric permittivity at temperatures around the temperature of the structural phase transition. There are two fractures of temperature dependences of inverse dielectric permittivity εr−1(T). Transmittance spectroscopy measurements show that there are differences in the shape of the spectrum in the mid-IR region between the undoped STO and the one doped by 4f ions. The differences in the reflectance spectrum between the STO:Nd and STO are analyzed in detail. [ABSTRACT FROM AUTHOR]

Abstract: The frequency and temperature dependences of dielectric properties of SrTiO3:Sm were investigated over the frequency range from 80kHz to 10MHz and temperature range from 30K to 300K. The Raman spectroscopic investigations of SrTiO3:Sm were performed in a wide temperature (25K to RT) and frequency range (30–150cm−1). The T-behavior of the broad band has been studied in detail. Surface of SrTiO3:Sm single crystal was treated by quasistationary compression plasma flow produced by magnetoplasma compressor. To investigate the microstructure and morphology of treated samples SEM techniques were used both with XRD analysis. It was observed that quasi-ordered structures were formed on the surface about 1μm in size. [Copyright &y& Elsevier]

One of the key stages of the process of preparing management plans for the river basin is the analysis of pressures and impacts, as well as the risk assessment of failing to achieve the environmental objectives. DPSIR framework (Driving Forces-Pressure-State-Impact-Response) was developed by the European Agency for the environmental protection, and makes the conceptual basis for the pressures and impacts analysis, taking into account the complexity of the interactions in the environment and represents the tool for their analysis. Impact assessment of the water body requires some quantitative information to describe the condition of the water body and/or the pressures that act on it. The aim of the study was to determine the effect of wastewater discharge on Krivaja watercourse. Impact assessment is carried out based on data of polluters’ wastewater and monitoring information for water in Krivaja. For each site at which sampling was performed, the specific risk quotients for surface water were calculated, as the ratio of the each pollutant concentration in surface water at the sampling point and environmental quality standards for pollutants, as well as their sum that represents the risk index. In order to have the integrated perceive of processes in the Krivaja River, taking into account cumulative effects from point sources, the concept of total maximum daily load was applied, using which the pollution amount, that can be discharged daily in a water body without degrading his prescribed/required quality, was calculated. Comparison of emitted loads from pollution point sources with maximum allowable ones was performed. Wastewaters of different polluters located on Krivaja are, due to insufficient treatment, very loaded with organic matter and nutrients. Krivaja receives daily 1332 m3 of wastewater, 999 kg COD, 722 kg BOD, 144 kg of nitrogen, 4.3 kg of phosphorus and 627 kg of suspended solids. Of the total wastewater volume, the majority (69%) originates from municipal wastewater, 81% of the total amount of organic matter comes from the industry, while nutrients mostly originate from municipal wastewater. Loading of Krivaja with wastewater is major, uneven and unbalanced. Water quality of Krivaja is unsatisfactory. According to national legislation there is the exceedance of maximum permissible values for Class II for watercourse (good status) for most parameters, in all sampling locations and in both sampling periods. Parameters that exceeded the value for the Class II are dissolved oxygen, organic matter content, suspended solids, nutrients. Water flow in the river is not sufficient to receive the total amount of the pollutant load from point sources. Risk assessment, based on the monitoring results, indicates that the river Krivaja is possibly at risk of failing to meet the required water quality because the most of the values exceeded the limit values. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR37004]

The photocatalytic elimination of the herbicide mesotrione from the commercial formulation Callisto® in environmental and synthetic waters by means of heterogeneous advanced oxidation processes was investigated. The activities of the commercial photocatalyst TiO2 Degussa P25 (TiO2) and ZnO in the degradation of mesotrione under UVA and simulated sunlight in doubly distilled, ground and in river water was compared. Environmental waters as the matrix significantly lowered the removal rate (by about 4 and 1.5 times for TiO2 and ZnO, respectively) under UVA irradiation. Besides, the organic additives from Callisto® also reduced the degradation rate of mesotrione. The effects of inorganic anions (Cl-, SO4 2- and HCO3 -) and humic acid (HA), which were identified as major species in ground and river water, was evaluated. It was found that Cl−(pH ≈4 and ≈8) and HCO3 - (pH ≈8) using TiO2 mainly accelerated the degradation rate of mesotrione, while SO4 2- had the opposite effect at pH ≈4 and did not affect the degradation rate at pH ≈8. Furthermore, HA mainly did not significantly affect the degradation rate of mesotrione at pH ≈4 and ≈8. Moreover, almost all anions, and HA slightly inhibited the degradation rate of mesotrione in synthetic water using ZnO. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172042]

Landfarming bioremediation was performed over 2 years on soil heavily polluted with weathered oil and oil derivatives: 23200 mg kg-1 of mineral oil, 35300 mg kg-1 total hydrocarbons, and 8.65 mg kg-1 of total PAHs. During the experiment, mineral oil, total hydrocarbon and PAH concentrations decreased by approximately 53%, 27% and 72%, respectively. A GC/MS-Scan was used to identify the crude oil components that persist after bioremediation treatment of contaminated soil and the metabolites generated during this process. The data shows that in weathered-hydrocarbons contaminated soil, the number of initially detected compounds after the bioremediation process further decreased over a 2 year period, and at the same time several new compounds were observed at the end of experiment. Higher persistence was also shown for heavier n-alkanes and branched alkanes, which could be detected over a longer period of time. The analysis highlights the importance of n-alkanes, their substituted derivatives and polycyclic aromatic hydrocarbons as the most significant pollutants.

Paper and cardboard factory sludges are generated by various processes during pulp, cardboard and paper production, and the increasing quantities produced make the disposal of this sludge a problem. This study investigates the use of cardboard factory sludge as a stabilizing agent in the solidification/stabilization (S/S) treatment of zinc polluted sediment. Semidynamic and toxicity leaching tests were conducted to assess the effectiveness of the solidification/stabilization treatment and long-term zinc leaching behaviour. A diffusion-based model was used to elucidate the controlling leaching mechanisms. The applied S/S treatment was effective in immobilizing zinc, and the controlling leaching mechanism appeared to be diffusion, which indicates that a slow leaching of zinc could be expected when cardboard mill sludge is applied as a S/S agent.

The influence of acute hypoxia on glucose, pyruvate, lipid peroxide (LP) reduced glutathione (GSH) concentrations and lactate level in the whole blood of carp (Cyprinus carpio L) under aquarium conditions were studied. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), the concentrations of ATP and ADP and ATP/ADP ratio in the red blood cells (RBCs) were analyzed. Glutathione-S-transferase (GST) activity was determined in the plasma. Our experiments showed that short-term and long-term hypoxia causes significant changes of all examined haema-tological parameters. Increased concentration of LP and increased SOD CAT and GST activities, as well as a decreased GSH-Px activity showed that under hypoxic conditions oxidative stress and RBCs damage were produced.

Objectives: To assess and compare the cell viability and ion release profiles of two conventional glass ionomer cements (GICs), Fuji IX and Ketac Molar EasyMix, modified with TiO 2 and Mg-doped-HAp nanoparticles (NPs)., Methods: TiO 2 NPs, synthesized via a sol-gel method, and Mg-doped hydroxyapatite, synthesized via a hydrothermal process, were incorporated into GICs at a concentration of 5 wt.%. The biocompatibility of prepared materials was assessed by evaluating their effects on the viability of dental pulp stem cells (DPSCs), together with monitoring ion release profiles. Statistical analysis was performed using One-way analysis of variance, with significance level p < 0.05., Results: The addition of NPs did not significantly affect the biocompatibility of GICs, as evidenced by comparable decreased levels in cell viability to their original formulations. Distinct variations in cell viability were observed among Fuji IX and Ketac Molar, including their respective modifications. FUJI IX and its modification with TiO 2 exhibited moderate decrease in cell viability, while other groups exhibited severe negative effects. While slight differences in ion release profiles were observed among the groups, significant variations compared to original cements were not achieved. Fluoride release exhibited an initial "burst release" within the initial 24 h in all samples, stabilizing over subsequent days., Conclusions: The addition of NPs did not compromise biocompatibility, nor anticariogenic potential of tested GICs. However, observed differences among FUJI IX and Ketac Molar, including their respective modifications, as well as induced low viability of DPSC by all tested groups, suggest the need for careful consideration of cement composition in their biological assessments., Clinical Significance: The findings contribute to understanding the complex interaction between NPs and GIC matrices. However, the results should be interpreted recognizing the inherent limitations associated with in vitro studies. Further research avenues could explore long-term effects, in vivo performance, and potential clinical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Shell from the seafood processing industry is an under-utilised waste resource worldwide. Calcite, the major component of shell is commonly used in wastewater treatment for the removal of phosphorus (P). Here, mussel and oyster shell-based adsorbents (MSB and OSB) were used for removal of P as phosphate (PO 4 3- ) from aqueous solution and secondary wastewater, following preparation through chemical calcination at 700 °C. Batch adsorption experiments were carried out to identify the effects of various operating parameters (e.g., pH, dosage, contact time, initial concentration of P ions, co-existing ions), while a desorption study helped to understand the availability of the bonded P. The optimal contact time for PO 4 3- removal was 120 min using both adsorbents with the dose at 200 mg. Characterisation of the adsorbent was performed using SEM-EDX, pH pzc , BET, FTIR and XRD. The XRD analysis showed that both calcite and lime were present on the surface of the shell particles. P was adsorbed effectively through inner-sphere complexation and surface microprecipitation mechanisms, while an enhanced maximum P adsorption capacity of 12.44 mg/g for MSB and 8.25 mg/g for OSB was reached. The Redlich-Peterson isotherm model fitted well with the equilibrium isotherm data (R 2  ≥ 0.97) which also suggested a heterogenic surface. The desorption study (on the saturated adsorbent) found that ~97% of bonded P could be plant available in soil. These results suggest that a shell-based adsorbent can serve as a promising material for P removal from real wastewater effluent and subsequently could be used as a soil conditioner., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Here, Box-Behnken design (BBD) approaches were utilised to optimise synthesis methodology for the chitosan-calcite rich adsorbent (CCM) made from fishery-food waste material (crab carapace), using low-temperature activation and potassium hydroxide (KOH). The effect of activation temperature, activation time and impregnation ratio was studied. The final adsorbent material was evaluated for its phosphorus (P) removal efficiency from liquid phase. Results showed that impregnation ratio was the most significant individual factor as this acted to increase surface deacetylation of the chitin (to chitosan) and increased the number of amine groups (-NH 2 ) in the chitosan chain. P removal efficiency approached 75.89% (at initial P concentration of 20 mg/L) under optimised experimental conditions, i.e. where the impregnation ratio for KOH:carapace (g/g) was 1:1, the activation temperature was 105 °C and the activation time was 150 min. Predicted responses were in good agreement with the experimental data. Additionally, the pristine and CCM material were further analysed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), Brunauer-Emmett-Teller technique (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Characterisation showed enhancements in surface chemistry (introducing positively charged amine groups), textural properties and thermal stability of the CCM.

Functionalised biochar (WpOH) was prepared from wild plum kernels using simultaneous pyrolysis and microwave potassium hydroxide (KOH) functionalisation. This was then applied to the removal (from water) of an ionisable pharmaceutical - naproxen (NPX). Characterization of the WpOH was carried out using pH pzc , SEM/EDX, BET, FTIR, XRD, and the principle adsorption mechanisms were thoroughly studied. A pseudo-second order kinetic model best described the reaction kinetic behaviour, and the Langmuir isotherm provided the best fit to the results. The maximum adsorptive interaction (73.14 mg/g) occurred between pH 5 and 7 through electrostatic attraction (the main interaction mechanism) between the negatively charged NPX and the positively charged WpOH functional groups. In addition, hydrogen-bonding and electron-donor-acceptor (EDA) interactions were important. In a competitive study, using NPX and carbamazepine (a basic/amphoteric drug), the different nature/structure of the two compounds resulted in slight competitive adsorption. The results demonstrate the potential for wild plum kernel biochar to be used in the efficient removal of emerging contaminants such as pharmaceuticals from water., (Copyright © 2019 Elsevier Inc. All rights reserved.)

It is known that nitric oxide (NO) influences the activities of glycolytic enzymes, resulting in alteration of glycolysis rate. We investigated the effect of NO donors on the energy metabolism of rat erythrocytes. Rat erythrocyterich blood suspensions were aerobically incubated for 2 hours (1) as controls or (2) with different concentrations of NO donors: nitroglycerin (NTG), isosorbide dinitrate (ISDN), molsidomine (MO), and sodium nitroprusside (SNP). NTG, ISDN, MO, and SNP significantly (p < 0.05) increased glucose consumption and lactate accumulation in rat erythrocytes in a dose-dependent manner, indicating stimulation of glycolysis. The increased rate of glycolysis was accompanied by elevation of energy production (p < 0.05), but no changes in ATP levels were observed. The dose-dependent increase of glycolytic ATP production and the unaltered levels of ATP resulted in considerably shortened ATP-turnover time with the maximal experimental doses of NO donors used, indicating the stimulation of the ATP-consuming process in rat erythrocytes. The metabolic effects of NTG, ISDN, MO, and SNP were not mimicked by exogenous 8-Br-cGMP, NaNO2, or NaNO3, suggesting that the NO donor-induced stimulation of glycolysis and abbreviation of ATP-turnover time in rat erythrocytes was mediated by NO as an effector molecule, irrespective of the irreversible scavenger effect of hemoglobin. The implications of the NO effect on energy metabolism of erythrocytes is discussed.