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Environmental pollution poses significant risks to human health and ecosystems, necessitating costly and time-consuming remediation efforts. Consequently, there's a growing interest among researchers in developing and utilizing next-generation materials. Carbon-based materials have emerged as promising candidates due to their environmentally friendly nature, although their application presents both positive and negative aspects, as evidenced by existing literature. A diverse range of low-cost carbonaceous sorbents, like biochars, have been investigated for their suitability in water treatment. Given the substantial volume of agricultural waste biomass generated globally, the cost-effective production of these materials from residual biomass holds promise for addressing additional environmental challenges, such as biomass waste management. Various biochars derived from corn, hemp, and straw were studied to evaluate the adsorption potential for removing a commonly used organic UV filter 3-(4′-methylbenzylidene)-camphor (4-MBC). The adsorption isotherms obtained were well-described by the Freundlich model, with nonlinearity values below 0.9. Generally, all investigated adsorbents exhibited a higher affinity for 4-MBC, underscoring the importance of such research in identifying safe adsorbents for water remediation purposes. Moreover, this paper also tackles the interactions between 4-MBC and microplastics as polymer carbon-based materials, indicating the highest adsorption capacity of polyethylene terephthalate. [ABSTRACT FROM AUTHOR]

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 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]

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]

Polycyclic aromatic hydrocarbons (PAHs) belong to the persistent organic pollutant class and are ubiquitously present in the environment. As a consequence of their high hydrophobicity, PAHs in aquatic environments tend to rapidly sink down to the bottom sediments which are the most important reservoirs of PAHs in the aquatic environment. This paper presents the validation and further performance evaluation of a method modified in-house for PAHs' sample preparation and analysis in sediment using gas chromatography-mass spectrometry (GC-MS). The method validation covers determining the calibration linear range, method detection and quantitation limits, method recovery and precision, method uncertainty and further internal and external quality control steps. Principal component analysis was used to identify the influence of different variables on method performance and indicated main clustering by PAH molecule size. The results of a two-year quality control programme show that the variations in method performance were not statistically significant in comparison to the parameters set during the validation experiments. Trueness expressed as recovery was very similar for spiked sediment samples and the analysed certified reference material (CRM) (70.6–113%). Expanded uncertainty ranged from 40.4% to 50.9% with higher values noted for the highly hydrophobic PAHs benzo(a)pyrene and benzo(g,h,i)perylene. [ABSTRACT FROM AUTHOR]