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Molecularly imprinted polymers (MIPs) as materials with determined levels of selectivity and specificity for designated analytes have recently gained much attention in various application fields. However, with the growing adoption of green analytical chemistry (GAC) principles, it is essential to investigate the greenness of MIP synthesis and its subsequent application in sample preparation, as well as to evaluate the "green"nature of the developed analytical methodologies, such as dispersive solid-phase microextraction (DSPME). Accordingly, the main objective of this research was to evaluate the greenness of MIP-based glycidyl methacrylate synthesis and MIP use as a DSPME sorbent prior to high-performance liquid chromatography with mass spectrometry (HPLC-MS). The green perspective of MIP-DSPME prior to HPLC-MS was investigated using various analytical metric tools such as the Analytical Eco-Scale, the Green Analytical Procedure Index, and Analytical GREEnness (AGREE). Since these analytical tools are not fully implementable for the assessment of the greenness of the MIP synthesis, some alternative approaches were used to optimize the synthesis parameters to make the MIP DSPME sorbent as close as possible to the GAC principles. The calculated AGREE score (0.62) and 91 points in the Analytical Eco-Scale for the proposed DSPME technique using MIP indicated a high level of greenness.

This study investigated the occurrence and distribution of rare earth elements (REEs), including 14 lanthanoids, scandium (Sc), and yttrium (Y), in groundwater around a large coal-fired thermal power plant (TPP). The ICP-MS technique was used to analyze 16 REEs in groundwater samples collected from monitoring wells. REE concentrations ranged from 59.9 to 758 ng/L, with an average of 290 ng/L. The most abundant was Sc, followed by La, accounting for 54.2% and 21.4% of the total REE concentration, respectively. Geospatial analysis revealed the REE enrichment at several hotspots near the TPP. The highest REE concentrations were observed near the TPP and ash landfill, decreasing with the distance from the plant and the landfill. REE fractionation ratios and anomalies suggested the Light REE dominance, comprising over 78% of the total REEs. Correlation and principal component analyses indicated similar behavior and sources for most REEs. Health risk assessment found hazard indices (HI) of 1.36 × 10−3 and 1.98 × 10−3 for adults and children, respectively, which are far below the permissible limit (HI = 1). Likewise, incremental lifetime cancer risks (ILCR) were all below 1 × 10−6. Nevertheless, ongoing ash disposal and potential accumulation in the environment could elevate the REE exposure over time.

The occurrence and distribution of yttrium and rare earth elements (REYs), along with major elements and heavy metal(loid)s (HMs) in coal fly ash (CFA) from five coal-fired power plants (CFPPs), were analyzed, and the REY-associated ecological and health risks were assessed. The individual REYs in CFA were abundant in the following order: Ce > La > Nd > Y > Pr > Gd > Sm > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The total REY content ranged from 135 to 362 mg/kg, averaging 302 mg/kg. The mean light-to-heavy REY ratio was 4.1, indicating prevalent light REY enrichment in CFA. Significantly positive correlations between the REYs suggested that they coexist and share similar origins in CFA. REYs were estimated to pose low to moderate ecological risks, with risk index (RI) values ranging from 66 to 245. The hazard index (HI) and target cancer risk (TCR) of REYs from CFA, estimated to be higher for children (HIc = 0.15, TCRc = 8.4 × 10−16) than for adults (HIa = 0.017, TCRa = 3.6 × 10−16), were well below the safety limits (HI = 1, TCR = 1.0 × 10−6). However, the danger to human health posed by HMs in the same CFA samples (HIc = 5.74, TCRc = 2.6 × 10−4, TCRa = 1.1 × 10−4) exceeded the safe thresholds (excl. HIa = 0.63). The mean RI and HI attributed to REYs in CFA were 14% and 2.6%, respectively, of the total risks that include HMs.

In this work, removal of heavy metals (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) from fly ash has been studied using acid leaching and wet oxidation methods. In parallel, microwave-assisted acid digestion was applied for determination of pseudo-total concentrations of heavy metals to estimate the leaching efficiency. Multivariate statistics (Pearson correlation, principal component analysis, and hierarchical cluster analysis) have shown two dominant groups of elements, depending on their characteristics and affinity towards the ash solid phase. Thus, Cr, Zn, Mn, Co, and Ni belong to the group I, while Pb, As, Cd, and Cu belong to the group II. It was demonstrated that the wet oxidation method was more suitable than acid leaching since the reduction in metal concentration was 30 to 75 % compared to 12 to 25 % obtained by acid digestion. The influence of fly ash treatment on the residue characteristics was investigated by X-ray diffractometry and scanning electron microscopy. The analyses revealed surface and structure changes of fly ash after the wet oxidation treatment. Overall, wet oxidation could be an appropriate treatment for heavy metal removal from fly ash, providing a material that could be further used, thus reducing the risk of pollution caused by the disposal of coal combustion fly ash. © 2024, Association of the Chemical Engineers of Serbia., Uklanjanje teških metala (Cr, Mn, Co, Ni, Cu, Zn, As, Cd i Pb) iz elektrofilterskog pepela proučavano je korišćenjem metoda kiselog luženja i vlažne oksidacije. Paralelno je primenjena i kisela digestija uz pomoć mikrotalasne pećnice za određivanje pseudoukupnih koncentracija teških metala u cilju procene efikasnosti luženja. Multivarijantna statistika (Pearsonova korelacija, analiza glavnih komponenti i hijerarhijska klaster analiza) pokazala je dve dominantne grupe elemenata u zavisnosti od njihovih karakteristika i afiniteta prema čvrstoj fazi pepela. Grupe I (Cr, Zn, Mn, Co i Ni) i II (Pb, As, Cd i Cu) su međusobno diskriminisane. Pokazalo se da je metoda vlažne oksidacije prikladnija od kiselog luženja jer je smanjenje koncentracija metala bilo 30-75 % u poređenju sa 12-25 % dobijenih kiselom digestijom. Takođe je ispitan uticaj tretmana letećeg pepela na karakteristike čvrstog ostatka metodama rendgenske difrakcije i skenirajuće elektronske mikroskopije. Ovim metodama su otkrivene promene na površini i u strukturi letećeg pepela nakon tretmana vlažnom oksidacijom. Vlažna oksidacija se može smatrati kao moguća metoda za tretman u cilju uklanjanje teških metala iz letećeg pepela, obezbeđujući materijal koji bi se mogao dalje koristiti i smanjujući rizik od zagađenja izazvanog odlaganjem letećeg pepela.

The occurrence and distribution of yttrium and rare earth elements (REYs), along with major elements and heavy metal(loid)s (HMs) in coal fly ash (CFA) from five coal-fired power plants (CFPPs), were analyzed, and the REY-associated ecological and health risks were assessed. The individual REYs in CFA were abundant in the following order: Ce > La > Nd > Y > Pr > Gd > Sm > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The total REY content ranged from 135 to 362 mg/kg, averaging 302 mg/kg. The mean light-to-heavy REY ratio was 4.1, indicating prevalent light REY enrichment in CFA. Significantly positive correlations between the REYs suggested that they coexist and share similar origins in CFA. REYs were estimated to pose low to moderate ecological risks, with risk index (RI) values ranging from 66 to 245. The hazard index (HI) and target cancer risk (TCR) of REYs from CFA, estimated to be higher for children (HIc = 0.15, TCRc = 8.4 × 10−16) than for adults (HIa = 0.017, TCRa = 3.6 × 10−16), were well below the safety limits (HI = 1, TCR = 1.0 × 10−6). However, the danger to human health posed by HMs in the same CFA samples (HIc = 5.74, TCRc = 2.6 × 10−4, TCRa = 1.1 × 10−4) exceeded the safe thresholds (excl. HIa = 0.63). The mean RI and HI attributed to REYs in CFA were 14% and 2.6%, respectively, of the total risks that include HMs.

Considering the rising demand for rare earth elements (REEs), researchers are looking for new sources for their extraction, thereby fostering economic and environmentally justified processing solutions. Among potential industrial sources, coal fly ash emerges as one of the most promising. The recovery of REEs from coal fly and bottom ashes derived from different thermal power plants was the main focus of this study. A dual-step methodology was conducted on ash samples, which involved an ultrasonic roasting process to disintegrate the silica matrix, followed by a microwave-assisted acid leaching step to extract REEs. The roasting procedure was studied using the Plackett–Burman design, and the Box–Behnken design was subsequently implemented to optimize the leaching procedure. The optimized ultrasonic roasting procedure was set up at 95 °C for 10 min with an ash-to-roasting agent (3M NaOH) ratio of 0.5:1 (m/V). For acid leaching, the optimal conditions were obtained at 174 °C for 30 min with an HCl ÷ HNO3 mixture (1:1 V/V). The standard reference material (NIST 1633c) was used in the conclusive experiments to estimate the average recovery (80%) of REEs. The green aspects of this methodology were evaluated using several metrics (atom economy, E-factor, and energy consumption). The proposed process outperforms high-temperature roasting procedures in terms of greenness; however, the REE recovery rate is lower.

Podzemne vode su ključan izvor slatke vode neophodan za regionalni razvoj i očuvanje ekologije, što čini bezbednost njihovog korišćenja od presudnog značaja za dobrobit ljudi. U ovom radu je ispitivana pogodnost podzemnih voda za piće i navodnjavanje u dolini reke Jadar. Pogodnost podzemnih voda za piće procenjivana je korišćenjem entropijskog indeksa kvaliteta vode (EWQI), dok je pogodnost podzemnih voda za navodnjavanje procenjena korišćenjem koeficijenta adsorpcije natrijuma (SAR) i procenta natrijuma (%Na). Rezultati su pokazali da je 13,6% uzoraka imalo EWQI vrednost nižu od 100, što su podzemne vode pogodne za piće. Proračunate SAR i %Na vrednosti kretale su se u rasponu 0,2–744 i 4%–99,5%, pri čemu je većina uzoraka pripala kategorijama odličnog do dobrog kvaliteta vode. Voda najlošijeg kvaliteta primećena je u centralnom delu istraživanja područja, dok se kretajući ka obodu njen kvalitet poboljšavao., Groundwater is a vital freshwater resource crucial for regional development and ecological preservation, making its safety imperative for human well-being. This study investigated the suitability of groundwater for drinking and irrigation purposes in the Jadar River valley. The suitability of groundwater for drinking was assessed using the entropyweighted water quality index (EWQI), while the suitability of groundwater for irrigation was evaluated using the sodium adsorption ratio (SAR) and sodium percentage (%Na) indices. The results showed that 13.6% of the samples exhibited an EWQI value below 100, suggesting groundwater suitable for drinking. The SAR and %Na of the samples ranged from 0.2 to 744 and 4% to 99.5%, respectively, with the majority of the samples falling within the excellent to good water quality categories. The central portion of the study area exhibited the poorest water quality, which gradually improved towards the periphery.

Pesticides are extensively used in the cultivation and postharvest protection of citrus fruits, therefore continuous monitoring and health risk assessments of their residues are required. This study aimed to investigate the occurrence of pesticide residues on citrus fruits and to evaluate the acute and chronic risk for adults and children. The risk ranking of twenty-three detected pesticides was carried out according to a matrix ranking scheme. Multiple residues were detected in 83% of 76 analyzed samples. In addition, 28% contained pesticides at or above maximum residue levels (MRLs). The most frequently detected pesticides were imazalil, azoxystrobin, and dimethomorph. According to the risk ranking method, imazalil was classified in the high-risk group, followed by prochloraz, chlorpyrifos, azinphos-methyl, tebufenpyrad, and fenpiroximate, which were considered to pose a medium risk. The majority of detected pesticides (74%) posed a low risk. The health risk assessment indicated that imazalil and thiabendazole contribute to acute (HQa) and chronic (HQc) dietary risk, respectively. The HQc was negligible for the general population, while the HQa of imazalil and thiabendazole exceeded the acceptable level in the worst-case scenario. Cumulative chronic/acute risk (HIc/HIa) assessment showed that chronic risk was acceptable in all samples for children and adults, while the acute risk was unacceptable in 5.3% of citrus fruits for adults and 26% of citrus fruits for children. Sensitivity analyses indicated that the ingestion rate and individual body weight were the most influential risk factors.

Conventional wastewater treatment processes are increasingly difficult to fulfill strict standards of achieving the required quality. Therefore, it is necessary to apply processes that in an efficient and economically justified way reach the necessary limits in order to discharge wastewater into the recipient. The process of photolysis represents the degradation of the starting pollutant practically to water and carbon dioxide. The whole process takes place under the action of a UV lamp that imitated solar irradiation. The process is environmentally justified since, unlike some other advanced oxidation processes - AOPs, there is no use of additional, hazardous, chemicals which possibly results in the precipitates formation that are leading to further treatment. In this paper, photolytic degradation of pesticide thiophanate methyl was performed in doubled wall quartz reactor equipped with a thermoregulation system. Reaction was forced under Osram ULTRA VITALUX UV lamp (300W). Kinetics of photodecomposition process was followed by pseudo-first order. In certain time periods, specimens were sampled, filtered and monitored by UV spectrophotometer Shimadzu 1800 with an aim to determine the concentration of xenobiotic. Complete degradation of present xenobiotics was obtained after 240 min. With an aim to enhance the degradation process, hydrogen peroxide was added as a boosting agent which cause a shortening in demanded time (150 min) for complete degradation. Verification of the success of decomposition was confirmed by the obtained values of chemical oxygen demand (COD), which reveal that the established system has a basis for real application in industrial or municipal wastewater.