Journal of the Serbian Chemical Society

Pharmaceuticals in Belgrade’s wastewater: Impact on surface waters and environmental risk assessment

2025-12-02T10:22:25+01:00

In the Belgrade region, direct discharges of untreated wastewater into the Sava and Danube rivers have a detrimental impact on water quality. This study investigates this impact by examining the presence of pharmaceuticals in Belgrade’s wastewater and corresponding surface water, alongside the associated environmental risk. A highly sensitive and selective LC–MS/MS method was developed, validated and applied to the analysis of water samples. Thirteen out of seventeen target pharmaceuticals were detected in wastewater, while nine compounds were found in surface water, with diclofenac reaching the highest concentration (1.1 µg L^-1). Metoprolol, carbamazepine and diclofenac were the most prevalent in both wastewater and surface water samples. Risk assessment indicated that diclofenac and azithromycin posed a high environmental risk (RQ > 1), while a mixture toxicity assessment suggested a cumulative hazard at all sampling sites. Additionally, the study evaluated pharmaceutical removal efficiencies in two wastewater treatment plants in Serbia, revealing variable efficiencies and even negative removal rates for some compounds, highlighting the inadequacy of conventional treatment plants in effectively eliminating these substances. The results emphasize the urgency of regulatory actions and the need for adequate treatment technologies to reduce pharmaceutical pollution in aquatic environments.

Adsorption of clofibric acid on the activated carbon prepared from polyester cloth waste: Study of the operational parameters, kinetics and adsorptive equilibrium using the nοn-linear methοd

2025-08-01T11:25:31+02:00

The objective of this research work was to examine the feasibility of preparing adsorbent materials from textile waste (polyester) for the elimination of pharmaceutical products such as clofibric acid (CA). The results showed that the adsorbents prepared by chemical activation in the presence of phosphoric acid followed by pyrolysis at 600 °C led to microporous materials with large specific surfaces. Batch experiments were conducted to study the effect of contact time, initial CA concentration, solution pH and temperature. Elimination yields by adsorption of CA in aqueous solution greater than 95 % were obtained with dilute solutions (10 mg L^-1) at room temperature and at pH 3. The adsorption kinetics is perfectly described by the pseudo-second-order model and the isotherms are of the Freundlich types. The results indicate that this process is spontaneous, efficient and potentially applicable in the removal of CA from water.

Syntheses and computational analyses of selected macrolide derivatives derived from clarithromycin A

2026-03-12T10:17:08+01:00

This study presents the synthesis and experimental and computational analysis of novel macrolide derivatives obtained from clarithromycin A, with the aim of exploring their potential to address the growing problem of antimicrobial resistance. The compounds synthesized include 2′-O-acetyl-clarithromycin A, its phosphoramidite derivative, and the corresponding phosphonyl derivative. Special attention was paid to the optimization of phosphitylation conditions due to the inherent instability of phosphoramidite compounds. The purity of the phosphoramidite derivative was successfully confirmed using diffusion-ordered NMR spectroscopy (DOSY). Comprehensive conformational analyses were carried out using molecular modeling techniques, followed by molecular docking and MM-GBSA calculations with a target protein from Escherichia coli to evaluate the relative binding affinities of clarithromycin A and its derivatives. The results indicate that the phosphoramidite and phosphonyl derivatives exhibit comparable binding affinities relative to the parent antibiotic. In addition, complex mass spectrometric fragmentation patterns of the phosphorus-containing derivatives were analyzed and rationalized using the MS Fragmenter computational tool.

Investigation of morphological and mechanical properties of hardened and tempered AISI 4340 steel

2026-01-12T12:47:58+01:00

AISI 4340 steel is widely used in risk-intensive industries due to its excellent mechanical strength and impact resistance. The mechanical properties of AISI 4340 steel can be significantly enhanced through heat treatment, particularly tempering at controlled temperatures. This study investigates the effect of tempering on the microstructure and mechanical properties of AISI 4340 steel. The experimental analysis includes characterization before and after heat treatment to assess changes in strength, toughness and ductility. The results demonstrate that tempering at 450 °C for 45 min provides the optimum balance of impact energy and ductility while slightly reducing hardness and strength. Conversely, tempering at 550 °C results in a more pronounced increase in impact energy and ductility, but at the cost of a greater reduction in hardness and strength. Microstructural examination confirms the formation of tempered martensite, contributing to the observed mechanical behaviour. The findings provide valuable insights into optimizing heat treatment parameters for AISI 4340 steel to achieve a balanced combination of strength, toughness, and ductility for industrial applications.

Fabrication of chitosan membrane modified by vanillin and gelatin for crystal violet dye adsorption

2026-03-30T18:08:37+02:00

Crystal violet is a cationic dye that poses serious environmental risks when accumulated in aquatic ecosystems due to its high toxicity to living organisms. Therefore, effective treatment methods are required to remove this dye from wastewater. In this study, a chitosan (Cs)-based bioadsorbent membrane, cross-linked with vanillin (V) and modified with gelatin (G), was developed to adsorb crystal violet dye. The chitosan/vanillin membrane was mixed with gelatin at various concentrations of 0.5 (CsVG1), 0.75 (CsVG2) and 1 % (CsVG3). The adsorption process was examined as a function of pH, contact time, initial dye concentration and temperature. Physicochemical characterization of the membranes included porosity, swelling degree, water absorption, FTIR and SEM analysis. The results showed that the optimal parameters for dye adsorption were pH 6, contact time of 80 min, and temperature of 298 K, resulting in 88 % dye removal. The adsorption kinetics followed a pseudo-second-order model and the Freundlich model best described the adsorption isotherm. The thermodynamic analysis demonstrated that the adsorption process was spontaneous and exothermic. Thus, the CsVG membrane has the potential to serve as an effective alternative for removing crystal violet from textile industrial wastewater.

In silico modeling of selected phloroglucinol derivatives from Rhodomyrtus tomentosa: Mechanistic insights into their potential against cervical cancer

2026-03-12T15:57:35+01:00

Cervical cancer remains a major cause of morbidity and mortality worldwide, driven primarily by persistent infection with high-risk HPV types. Natural phloroglucinol derivatives from Rhodomyrtus tomentosa have demonstrated anti-cervical cancer potential; however, their apoptosis-related mechanisms remain insufficiently characterized. In this work, selected phloroglucinol derivatives were evaluated as potential inhibitors of the anti-apoptotic Bcl-2 protein (PDB: 6GL8) through an integrated in silico pipeline that combines molecular docking, 100 ns molecular dynamics simulations, MM/GBSA binding free-energy estimation, ADMET profiling, and DFT-based electronic analysis. Docking prioritized CPD1 as the most favorable ligand (–37.36 kJ/mol), outperforming Belzutifan (–25.73 kJ/mol) and engaging the conserved binding pocket. MD trajectories supported stable complex formation across 100 ns. MM/GBSA further indicated stronger binding for CPD1 (ΔTOTAL = –138.78±15.4 kJ/mol) relative to Belzutifan (–63.72±14.31 kJ/mol), primarily due to more favorable gas-phase interactions, while maintaining a comparable solvation term. ADMET predictions suggested similar solubility but higher intestinal absorption for CPD1, alongside a hERG II alert that warrants cardiotoxicity-oriented optimization. DFT descriptors were consistent with the enhanced electrophilic character of CPD1. Collectively, CPD1 is computationally prioritized as a candidate scaffold for follow-up experimental validation and structure-guided refinement.

Errata

2026-03-24T21:11:29+01:00

Adsorptive removal of Pb(II) from industrial effluent using nitric acid modified activated carbon: Optimization using Taguchi method

2025-10-22T11:05:33+02:00

The study aimed to examine the use of nitric-acid-modified granular activated carbon to treat the wastewater of a lead-acid battery recycling unit for lead removal. The adsorbent was characterized using FTIR, SEM and XRD analyses. Surface functional groups, surface morphology and crystallinity were altered due to the modification. The batch adsorption study was conducted to evaluate the effects of adsorbent dose, initial pH, and contact time on adsorption performance for lead removal. Experiments were performed according to the Taguchi design of experiment method and factors were optimized based on SNR analysis to maximize the response. The ideal factor values were found to be pH 6, an adsorbent dose of 0.05 g, and a time of 240 min for the adsorption of lead onto the adsorbent, with an adsorbent uptake capacity of 9.93 mg g^-1. According to the ANOVA analysis, pH was found to be the most significant factor with an F-value of 28.07. Isotherm and kinetic studies were also carried out to understand the mechanism of adsorption. Adsorption was found to follow the Langmuir isotherm and the second order kinetic model.