This work focuses on investigating the conversion of olive stone waste into porous, graphitic carbon materials using a sequence of thermal and catalytic treatments. Three distinct processing strategies were investigated: (i) chemical activation with potassium hydroxide (AC-OS-KOH), (ii) thermal pyrolysis in an inert atmosphere yielding biochar (C-OS), and (iii) catalytic graphitization using transition metals (Ni or Fe) either in combination with KOH activation (AC-OS-KOH-Ni, AC-OS-KOH-Fe) or applied directly to biochar (C-OS-Ni). The structural, morphological, and textural properties of the resulting carbon materials were characterized using X-ray diffraction, scanning electron microscopy, and carbon dioxide (CO 2 ) physisorption at 0°C. Among all synthesized materials, AC-OS-KOH and AC-OS-KOH-Fe displayed superior microporosity and well-developed pore architectures, leading to enhanced CO 2 adsorption capacities compared with nonactivated and nickel-catalyzed samples. Notably, the dual strategy of chemical activation and nickel catalysis facilitated the transformation of olive stone precursors into graphitic-like porous carbon with a crystallinity index reaching 61%, indicating successful partial graphitization. CO 2 adsorption–desorption experiments were conducted at 25°C and 50°C under two CO 2 concentrations (90% and 10%, balanced with N 2 ). The KOH-activated carbons, with or without metal doping, exhibited fast adsorption–desorption kinetics, in contrast to the sluggish performance of the C-OS-Ni sample. This behavior underscores the critical role of micropore size and volume in governing CO 2 molecular diffusion and access to active sites. At elevated CO 2 concentration (90%), AC-OS-KOH demonstrated the greatest adsorption capacity, achieving 13.64 wt.% at 25°C and 8.98 wt.% at 50°C. In contrast, under diluted CO 2 conditions (10%), the AC-OS-KOH-Fe sample showed superior performance, indicating a strong link between pore size distribution and selective gas adsorption. Furthermore, the KOH-activated carbons maintained consistent adsorption performance across six consecutive adsorption–desorption cycles, confirming their stability and regeneration potential for practical CO 2 capture applications.

The primary objective of this study is to develop a modified trickling filter (MTF) mathematical model that addresses limitations of conventional biofilm models, including their inability to capture microbial stratification, simultaneous nitrification–denitrification, and diffusion effects in porous sponge media. Under fixed-bed circumstances, the MTF uses a polyurethane sponge medium to promote biomass adhesion and proliferation. The two main zones of the MTF are aerobic and anoxic. Heterotrophic organic carbon oxidation and nitrification are both carried out concurrently in the aerobic zone. The two main zones of the MTF are aerobic and anoxic: heterotrophic organic carbon oxidation and nitrification occur in the aerobic zone, whereas denitrification proceeds in the anoxic zone. The model integrates three components: a compartmental reactor flow model (axial plug-flow representation of completely mixed biofilm reactors), a biofilm kinetics module (substrate conversion by heterotrophs, nitrifiers, and denitrifiers), and a porous-media diffusion module (effective diffusion via the Millington–Quirk relationship). Within the biofilm, both bilayer distributions (heterotrophs outer, nitrifiers inner) and homogeneous distributions were evaluated. Model predictions were validated against experimental data (influent COD = 119–161 mg L −1 , NH 3 -N = 29–35 mg L −1 , hydraulic residence times = 2–4 h, with/without recycle) using parity charts and statistical indices. The bilayer biofilm with pore diffusion provided the most accurate results, with Willmott’s index of agreement (d) = 0.95 for COD, 0.95 for Ammoniacal Nitrogen (NH3-N), and 0.94 for Nitrate Nitrogen (NO 3 -N) and relative errors (RE) of 0.05–0.07, compared with d ≤ 0.47 and RE ≥ 0.24 for the homogeneous model. These findings confirm that incorporating stratification and pore diffusion significantly improves model performance. The framework not only clarifies COD, NH 3 , and NO 3 removal mechanisms in sponge-based MTFs but also offers design guidance on recycle ratios and porosity thresholds for enhanced operation.

Estimates as of July 2025 report that as much as 90% of the water and sanitation infrastructure in Gaza has been destroyed. Civil and environmental engineers are committed to holding paramount the safety, health, and welfare of the public. As members of this community, we are appalled by the near-total destruction of the water and sanitation systems in Gaza. This letter is a call to members of our profession to draw attention to the water scarcity and water infrastructure destruction in Gaza. The expertise in the field of civil and environmental engineering provides a platform to speak authoritatively about the extent of the water problems and the severity of the threat to public health.

Environmental engineering plays a critical role in managing air quality services, which are of daily concern to the public, particularly as climate change alters the factors affecting air quality. Within this context, our study introduces a comprehensive approach that emphasizes predictive models relying on multivariate time-series data. By integrating data from various sources and modalities, we propose a multimodal deep learning method to enhance traditional unimodal models. This study includes a review of existing literature, the preparation of relevant datasets, the development of robust models, and extensive evaluations. The experiments feature a case study focused on air quality services in a subtropical city, aiming to provide insights for improving prediction models. The integrated multimodal approach offers a better understanding of environmental conditions by combining data from automatic air quality monitors, meteorological stations, the European Centre for Medium-Range Weather Forecasts reanalysis data, as well as public welfare information and societal disruption reports. The analysis also considers weather-related alerts, such as typhoon and rainstorm warnings, which lead to school closures and city-wide suspensions. The model incorporates emission sources and upwind areas. Preliminary causality tests confirm that augmented feature space to encompass upstream areas enhances the model analytical capability. Downstream pollution and environmental conditions are significantly influenced by socio-economic activities in upwind areas. Granger causality and Diebold-Mariano tests highlight the importance of public welfare information and societal disruption reports, addressing a critical gap in this field.

Biological activated carbon (BAC), an alternative water treatment, has emerged as an effective technology in water treatment plants (WTPs) for removing organic compounds and micropollutants. It integrates granular activated carbon (GAC) with biofiltration, improving taste and odor removal, prolonging carbon lifespan, and reducing chemical use. Microbial biofilms established on the carbon bed contribute to these processes, as characterizing their microbiota supports the optimization of contaminant removal. However, most studies employ a limited range of techniques, which constrains a comprehensive understanding of microbial colonization and functional roles within GAC filters. This study evaluated the ability of a WTP-derived microbiome to inoculate a GAC bed by applying, for the first time, a multimodal analytical framework. The approach combined scanning electron microscopy, energy-dispersive X-ray spectroscopy, metagenomic analyses (16S, 18S, and internal transcribed spacer [ITS]), flow cytometry, and adenosine triphosphate (ATP) quantification. Results confirmed successful microbial transfer from the inoculum to the GAC through imaging and genetic sequencing. Specifically, the inoculum microbiome yielded 116,526 sequences for 16S rRNA, 115,170 for 18S rRNA, and 432,578 for ITS. BAC samples produced 107,095 sequences for 16S rRNA and 267,057 for ITS, with no 18S sequences detected, indicating diminished eukaryotic presence. Flow cytometry detected nucleic acids in both samples, while ATP quantification showed higher ATP concentrations in the inoculum compared with BAC samples, suggesting reduced microbial viability postinoculation. This multitechnique engineering study advanced understanding of biofilm colonization dynamics on BAC filters by demonstrating microbial inoculation using raw water sources and established a methodological framework for optimizing BAC operation in drinking water treatment.

Avian species, as part of the higher-order vertebrates and situated at the upper trophic levels of the food chain, are particularly vulnerable to environmental pollutants owing to their potential for bioenrichment. This physiological characteristic renders birds as sensitive indicators of ecosystem health and contaminant exposure. In this study, sampling was done in the Saunders’s Gulls nesting grounds and feeding regions in the Lijin Field of the Yellow River Delta Nature Reserve in May 2018 and April 2019. Deceased individuals of Saunders’s Gulls were collected, totaling 15 nestlings (8 females and 7 males) and 3 adult female Saunders’s Gulls. We determined the concentrations of cadmium (Cd), iron (Fe), nickel (Ni), manganese (Mn), copper (Cu), chromium (Cr), and lead (Pb) in various tissues—including the heart, sternum, muscles, kidneys, lungs, intestines, and liver—of Saunders’s Gulls across different age and sex groups. Tissues were processed by drying and grinding, hydrogen peroxide digestion, and metal concentrations in different tissues were compared using atomic absorption spectrometry. Pearson correlation analysis and principal component analysis were used to understand the effects of different metals on gulls of different ages and sexes. Our findings indicated that, on average, Fe was the most abundant metal in all tissues of Saunders’s Gulls. The content of Fe in all tissues of female Saunders’s Gull nestlings ranged from 625.919 to 1,352.175 mg/kg, and in female adult Saunders’s Gulls, the content of Fe in the tissues confined 1,167.484–2,969.771 mg/kg. Notably, Ni was the least abundant in the intestines of adult birds, ranging from 0.926 to 1.572 mg/kg. We observed higher Fe concentrations in adult birds compared with nestlings, with the liver being the primary site of Fe accumulation in both female nestlings and adults. The study revealed that different tissues of Saunders’s Gulls have varying capacities for metal accumulation, with the liver, kidneys, and muscles showing the highest levels. Additionally, we found that different age and sex groups exhibit distinct metal concentration profiles in their tissues. Juvenile gulls were more likely to accumulate metals such as Mn, Cu, and Fe, whereas adult gulls were more affected by Cr and Pb. This research contributes valuable insights into metal pollution assessment in the Yellow River Delta wetlands, aiding in the ecological monitoring and management of metal pollution in this region.

Algal blooms not only lead to significant water pollution but also produce algal organic matter (AOM) from algal cells, which serves as precursors for disinfection byproducts. To address the inefficiency of existing algae removal technologies in eliminating AOM, this study investigates the feasibility of a combined technique utilizing chitosan quaternary ammonium salt (HTCC) and activated carbon (AC) for simultaneous algae removal and AOM elimination. First, the release of AOM during algae removal by standalone HTCC was examined. Second, AC with optimal AOM removal efficiency was selected, followed by evaluating the performance of the HTCC–AC combined technique in algae removal and AOM elimination. The disinfection byproduct formation potential before and after treatment was analyzed. Mechanism insights were elucidated through characterization techniques including Zeta potential, scanning electron microscope, Brunauer–Emmett–Teller, and FT-IR. Results indicated that standalone HTCC treatment poses a risk of AOM release, with released AOM originating from both intracellular and extracellular algal components. Wood-based activated carbon exhibited the highest AOM adsorption capacity at 6.43 mg/g. The HTCC–AC combined technique achieved removal efficiencies of 97.32%, 96.11%, and 91.13% for algal density, turbidity, and dissolved organic carbon, respectively. Notably, trihalomethane formation decreased by 94.56% compared with the control group, resulting in a posttreatment THM ratio of 0.15, significantly below the 1.0 limit specified in drinking water standards. The mechanisms of algal removal through the combined technique involve adsorption bridging and charge neutralization, while the removal of AOM occurs via π–π conjugation and hydrogen bonding interactions.

The effective removal of phenols from coking wastewater) in the pretreatment process is crucial for reducing the burden on biological unit and enhancing biodegradability. Although adsorption strategy has attracted widespread attention, the high-efficiency and low-cost adsorbents must be developed and proposed in order for the strategy to be competitive. Herein, powdery activated carbon (PAC) and various industrial residues [coal gangue (CG), granulated blast furnace slag (GBFS), and fly ash (FA)] were selected as adsorbents, and results showed that chemical oxygen demand (COD) removal efficiencies of PAC, CG, GBFS, and FA were 47.9%, 30.84%, 27.83%, and 44.15%, respectively. In comparison, FA and PAC had high adsorption capacity for high concentrations of organics, and FA exhibited higher adsorption efficiency for total phenols (52.53%). Moreover, the biodegradability of the wastewater was significantly improved (B/C ratio: 0.35), and the acute toxicity was greatly reduced to 8.3 after FA adsorption. The pseudo-second-order kinetic model and the Sips model could better describe the adsorption process of FA for COD removal. The adsorption mechanism of organics involved hydrogen bonding adsorption and surface complexation. During this adsorption process, FA exhibited a significant effect on the adsorption of organic substances, especially phenols, and the humification degree of wastewater was considerably diminished. Finally, the cost of removing COD per kilogram of FA is only 0.6 ¥. This work presents new idea and strategy for resource recycling and environmental protection, with the aim of providing theoretical support for the effective utilization of FA.

Accurately identifying microplastics (MPs) poses a challenge because environmental and human activities, like thermal oxidation (common in wildfires, urban fires, and waste burning) and mechanical abrasion (common in riverine and marine environments), chemically modify the plastic structure. Conventional Fourier transform infrared (FTIR) libraries lack the accuracy to identify these plastics because degradation alters their spectra-thermal oxidation adds new peaks, and abrasion causes characteristic peaks to fade. This creates a knowledge gap, leading to MP misidentification and flawed risk assessments for plastic pollution. To address this, we developed a new, environmentally relevant spectral library that significantly improved identification, increasing match rates by 7.3% for thermally oxidized plastics and by 23.8% for mechanically abraded plastics. We did this by subjecting seven commercial polymers (polypropylene [PP], polystyrene, rayon, low-density polyethylene [LDPE], linear low-density polyethylene, high-density polyethylene, and polyethylene terephthalate) to controlled thermal oxidation (100-200°C for 1-24 h) and by exposing PP and LDPE preproduction pellets to 40 days of mechanical abrasion (33 rpm; 3.41 rad s - 1). We then collected attenuated total reflectance (ATR)-FTIR spectra from these altered plastics and incorporated them into two newly developed spectral libraries. We tested these new libraries on 62 environmental MP samples (thermally oxidized) and 15 lab-generated particles (abraded), confirming a significant improvement in identification accuracy. Our findings underscore the importance of incorporating spectra obtained from plastics exposed to environmentally weathering processes into FTIR libraries, which represent a scientific advancement and a practical tool for more accurate MP identification and monitoring in environmental research.