Nutrient enhancement of bioremediation with nitrogen, namely biostimulation, increases process performance. Selection of a proper nitrogen source is critical for bioremediation applications. In this study, the effects of different nitrogen sources on biodegradation of C₁₀–C₂₅ n-alkane compounds in diesel fuel-spiked soil were revealed, and the most appropriate nitrogen source for biodegradation of semi- and non-volatile n-alkanes was investigated. Bioremediation of diesel fuel contaminated soil was monitored in lab-scale reactors for 15 days. Ammonium sulfate, potassium nitrate and urea were used as nitrogen sources. Carbon dioxide and oxygen levels in the reactors were recorded to monitor microbiological activity. Contaminant removal process was investigated by pH, heterotrophic plate count, total petroleum hydrocarbons (TPH) and C₁₀–C₂₅ n-alkane analyses. First-order kinetic constants were calculated via respirometric and contaminant concentration data. According to total C₁₀–C₂₅ n-alkane removal levels and degradation rate constants, ammonium sulfate addition resulted in the most efficient contaminant removal followed by potassium nitrate and urea. Simultaneous degradation of individual n-alkanes was observed for all of the nitrogen sources. Urea addition changed the distribution of individual n-alkane concentrations relative to the pre-experimental concentrations. Nitrogen source type had no differential effect on degradation rates of semi- (C₁₀–C₁₆) and non-volatile (C₁₇–C₂₅) fractions.

Assessing soil quality in industrial coal-mining regions is critical for ensuring environmental sustainability and public health. This study provides a comprehensive assessment of heavy metal (HM) contamination, ecological risk, and source apportionment in the Zonguldak province of Turkey. By utilizing systematic soil sampling, the research integrates statistical evaluation and spatial mapping with multiple contamination indices, including the Enrichment Factor (EF), Geo-accumulation Index (I _geo ), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI). Results revealed that mean concentrations of Co, Cu, Hg, Cd, Zn, and Ni significantly exceeded crustal and global soil averages. Furthermore, high coefficients of variation for elements such as Cu and Zn suggested significant anthropogenic influences. Spatial analysis, supported by I _geo and EF indices, identified critical pollution hotspots near the urban centers of Ereğli, Alaplı, and Zonguldak, as well as the Gülüç River basin. The overall ecological assessment indicated moderate ecological risk (PERI) across most of the study area, with Hg posing the highest individual risk based on average Er values. PMF analysis identified five potential sources contributing to heavy metal enrichment: coal mining and coal-based emissions, geogenic origins, industrial processes, agricultural activities, and mixed sources. This integrated approach establishes a robust scientific baseline for the effective management of heavy metal pollution in coal-dependent industrial landscapes.

In this study, a novel LFP–catalytic microfiltration membrane (LFP@PVDF) was fabricated by loading a lithium-ion battery material LiFePO₄ (LFP) onto polymeric micro-porous polyvinylidene fluoride (PVDF) using a filter press coating method. The successful loading of LFP material onto the LFP@PVDF catalytic membrane was confirmed by the characterization of the material using FTIR, SEM, EDX, and XRD analysis. To evaluate the catalytic performance of the LFP@PVDF membrane, the reactive black 5 (RB5) dye-containing solution was used with or without the peroxymonosulfate (PMS) activator in a dead-end filtration under room conditions. The influence of parameters such as LFP loading, initial RB5 dye concentration, persulfate dosage, and solution pH on the performance of the persulfate oxidation process was comprehensively examined. It was found that the LFP@PVDF membrane/persulfate activation system can effectively remove RB5 dye with an efficiency of 97.3%. The RB5 dye removal by LFP@PVDF membranes with varying experimental conditions was found to fit the pseudo-second-order kinetic model. Quenching experiments showed that the reactive species ${\mathrm{HO}}^{•}$, ${{\mathrm{SO}}_4}^{•-}$ and ¹O₂ were responsible for the dye removal. The LFP@PVDF membrane/persulfate activation system appeared to be a promising approach for the removal of organic contaminants.