Water, Air, & Soil Pollution最新文献

This study investigated the treatment efficiency of Moringa oleifera Lam. vegetated constructed wetlands (CWs) to treat domestic wastewater with a case study of real wastewater from Al-Habil wastewater treatment plant, Luxor governate, Egypt. A total of four CW systems were designed using different types of media: sand (S-CWs), gravel (G-CWs), pottery waste-based (PW-CWs), and ceramic waste-based (CW-CWs). The systems were tested at different hydraulic retention times (HRTs) of 15, 7, 5, and 1 day to study the influence of media type and HRT on the pollutant removal efficiency, in addition to the growth of plants. The results revealed that CW-CWs demonstrated the highest treatment efficiency. In addition, decreasing HRT from 15 to 1 day consistently declined pollutant removal across all systems. The treatment efficiencies of CW-CWs with the longest HRT of 15 days were found to be the highest for COD removal of 95.4 ± 3.2%, BOD removal of 95.3 ± 1.7%, TN removal of 96.2 ± 1.9%, and TP removal of 91.7 ± 1.7%. The excellent performance of CW-CWs could be ascribed to their improved porosity and adsorption capacity, which promoted nutrient uptake, organic matter degradation, and microbial activities. Furthermore, the findings demonstrated that plants grew remarkably longer over time, and CW-CWs showed the greatest growth. Beginning at 10 cm at the start of the experimental work, they grew to a maximum length of > 5 m in 250 days, demonstrating their superior support for Moringa oleifera Lam. development. This study provides valuable insights into optimizing CW design for wastewater treatment, with implications for resource recovery and environmental sustainability.

Microplastics (MPs) are now widespread contaminants in aquatic environments, acting not only as long-lasting pollutants but also as surfaces that interact with many chemical and biological species. This review brings together recent advances in understanding the dual roles of MPs—their ability to transport pollutants and their potential use as engineered materials for contaminant removal. The discussion examines the physicochemical processes that control adsorption, desorption, and surface reactivity, showing how polymer type, particle size, oxidation, and biofilm growth shape their environmental behaviour. Special attention is given to developments in engineered and biofunctionalized MPs, including materials modified with catalytic, magnetic, or enzymatic components to improve pollutant capture and breakdown. Despite notable progress, major gaps remain: standardized testing protocols are still lacking, long-term environmental studies are limited, and the ecological impacts of engineered MPs are not well understood. This review highlights these gaps and identifies priorities such as developing harmonized testing methods, improving understanding of transformation pathways, and designing biodegradable or recyclable alternatives aligned with sustainability goals. By presenting a framework that clarifies when MPs act as pollutant carriers and when they can serve as functional materials, the review outlines the mechanisms behind their dual behaviour and the risk–benefit considerations needed for their responsible use in water treatment.

Graphical Abstract

This study integrated an air flotation and settling (AFS) tank, anaerobic/oxic (A/O) tank, moving bed biofilm reactor (MBBR) with a constructed wetland (CW) for removing high levels of COD (834–1981 mg/L), BOD₅ (302–886 mg/L), TN (102.4–398.2 mg/L) and coliforms (2.1 × 10⁵–4.5 × 10⁵ CFU/100 mL) from the effluent of a biogas digester processing piggery wastewater. The plants Eichhornia crassipes and Ipomoea aquatica were used in the CW to improve the pollutant removal effiency. From April 18 to July 30, 2024, the experiment was conducted, during which the integrated AFS–A/O–CW system achieved removal efficiencies of 74.2 ± 5.9% for TSS, 82.6 ± 8.2% for COD, 86.7 ± 5.3% for BOD₅, 79.1 ± 8.6% for NH₄⁺, 65.2 ± 10.7% for TN, and 94.5 ± 3.2% for coliforms. Through 16S rRNA gene metabarcoding analysis, 14 genes and 16 phyla were detected in the mixture of sludge and wastewater in the aerobic zone of A/O tanks that contributed to the reduction of NH₄⁺, TN, COD and BOD₅ in the piggery wastewater. The weight of Eichhornia crassipes (n = 7) after a 3-month period increased from 17.5 ± 2.3 g to 86.3 ± 9.7 g, while the average weight of Ipomoea aquatica (n = 7) after a period of one month increased from 6.3 ± 0.6 g to 17.4 ± 3.6–22.7 ± 4.7 g. Following the treatment by the integrated AFS tank, A/O tanks, MBBR and CW system, the final treated water quality met the specifications set out by the Vietnam National Technical Regulation on livestock effluent discharge [QCVN62-MT:2016/BTNMT].

Removal of lead ions from drinking water is one of the biggest global issues. In this study, green modification of multi-walled carbon nanotubes (MWCNTs) was performed by calcium ferrite (CNT@CaF) and magnesium ferrite (CNT@MgF). Taxus wallichiana (T.W) was used as green template. For comparison, bare CNTs were also studied to evaluate the effect of surface functionalization. The morphology, composition, functional groups analysis, surface area and charge characteristics were performed by Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Energy-Dispersive X-ray Spectroscopy (EDX), Barrett-Joyner-Halenda (BJH), Point of Zero Charge (PZC) and zeta potential. BET surface area of CNTs, CNT@CaF and CNT@MgF calculated as 98 m²/g, 186 m²/g, and 206 m²/g respectively. The adsorption behavior of Pb²⁺ ion was determined under the influence of contact time, pH, temperature, concentration, and dose. The results manifested that functionalized adsorbents showed incredible removal efficiency of Pb²⁺ ions (81–85%). Langmuir and Pseudo second order (PSO) models were found suitable for data fitting. The maximum adsorption capacities of 58.5 mg/g, 371.7 mg/g, and 210.9 mg/g were calculated for CNTs, CNT@CaF and CNT@MgF respectively. Separation factor (R_L) values further supports the favorable sorption on the sorbent’s surface. The desorption and thermodynamic studies support chemisorption as a dominating mechanism. However, spectroscopic studies revealed the mixed sorption mechanisms i.e., inner sphere complexation and electrostatic interactions are simultaneously taking place.

Graphical Abstract

Substandard irrigation water impacts the chemical characteristics of soil, which may subsequently modify the shape of soil bacterial communities. Five categories of water, including the river water (RW), acid mine drainage (AMD), untreated wastewater (UTWW), treated wastewater (TWW), and tap water (TW), were utilized as irrigation water samples. Soil and water samples were examined for heavy metals, such as Chromium (Cr), Cobalt (Co), Zinc (Zn), Arsenic (As), Cadmium (Cd), and Lead (Pb), using ICP-MS. The V1-9 region of bacterial 16S rRNA was PCR-amplified to evaluate the effects of heavy metals in low-quality irrigated soil on bacterial diversity and abundance in the rhizosphere of Swiss chard seedlings. Approximately 88.9% of heavy metals in water, with concentrations ranging from 0.03 to 432.8 mg/L, were detected at low levels in TW. Conversely, about 83.3% of heavy metals, with the concentrations between 0.38 and 553.78 mg/kg, were detected at low levels in TW irrigated soil (TS1). The electrical conductivity (EC), pH, and organic matter (OM) fluctuated based on the irrigation water and soil samples. Bacterial diversity and abundance in soils differed according on the quality of irrigation water samples. Blastoccus, Microlunatus, Nocardioides, Solirubrobacter, and Streptomyces exhibited higher relative abundance in soil subjected to low-quality water compared to soil irrigated with TW (TS1). Redundancy analysis (RDA) demonstrated that bacterial community structure in the rhizosphere of Swiss chard seedlings were influenced by heavy metals, EC, pH and OM. This indicates that the introduction of heavy metals into the soil can select sensitive bacteria, whereas soil OM can supply nutrients that enhances resistant/tolerant bacterial multiplication, thereby influencing seedling growth.

Pharmaceutical manufacturing generates wastewater with unusual contaminant profiles including extraordinarily high ammoniacal nitrogen concentrations (> 12,000 mg/L) and stream-dependent heavy metal speciation patterns not typically documented in literature. This study documents scientific contributions of segregated treatment effectiveness for high-strength pharmaceutical wastewater, providing novel insights into treatment technology selection mechanisms for diverse contaminant profiles. Three segregated wastewater streams (high-COD, high-TDS, and low-TDS) from an active pharmaceutical ingredient manufacturing facility (100–150 KLD capacity) were comprehensively characterized for 42 physicochemical parameters following IS:3025 and APHA 24th Edition standards. Heavy metal speciation across stream types was analyzed using ICP-OES/ICP-MS (IS:3025 Part-65:2022). Segregated multi-train treatment performance was systematically evaluated to quantify removal effectiveness and elucidate mechanistic pathways for contaminant fate across thermal-oxidative and biological treatment processes. Wastewater characterization reveals unusual pharmaceutical manufacturing signatures: ammoniacal nitrogen of 12,272 mg/L constituting 79% of total nitrogen in high-COD stream (indicating ammonia-based process chemistry), stream-dependent heavy metal speciation (nickel concentration 31-fold higher in low-TDS versus high-COD stream), and extreme phosphorus concentrations (1,251 mg/L in high-TDS stream). Segregated treatment investigation demonstrates differential pathway effectiveness: 90% COD removal in high-TDS streams via thermal-oxidative pathways (35,358 to 3,536 mg/L) versus 85% COD removal in low-TDS streams via biological pathways (2,241 to 336 mg/L). All heavy metals remained within CPCB discharge limits with substantial safety margins. Treatment analysis enables pharmaceutical synthesis pathway attribution for observed heavy metal and nitrogen speciation patterns, providing mechanistic understanding of contaminant fate. This case study documents novel scientific contributions to pharmaceutical wastewater treatment science through systematic characterization of unusual high-strength effluent profiles and investigation of segregated treatment effectiveness for technology selection. Findings advance understanding of contaminant-specific treatment design principles and provide baseline data for segregated treatment optimization in pharmaceutical manufacturing under water scarcity constraints.

The use of biochar (BC) for remediating soils contaminated with metalloids like arsenic (As) and antimony (Sb) is promising, yet its efficacy and the underlying dose–response relationships remain poorly understood and often contradictory. This study specifically investigates the link between BC-induced changes in soil properties and the subsequent bioavailability and plant uptake of As and Sb. A pot experiment was conducted with Pennisetum purpureum grown in tailings-contaminated soil amended with BC at mass ratios of 0, 1.5%, 3%, 4.5%, 6%, and 7.5%. We found that BC amendment significantly elevated soil pH, organic matter, and phosphorus content. Crucially, these chemical shifts were directly linked to a marked increase in the water-soluble fraction of both As and Sb, which rose from 0.059 ± 0.011% and 8.89 ± 2.75% in the control to 0.216 ± 0.041% and 16.21 ± 2.41% in the 7.5% BC treatment, respectively. However, this elevated solubility did not translate directly into increased plant uptake. Instead, a more complex dynamic was uncovered: BC addition reduced root uptake and the overall bioconcentration factor (BCF) for As, particularly at higher doses, while simultaneously enhancing the translocation factor (TF) from roots to shoots. A similar, though less pronounced, trend was observed for Sb. This critical divergence between soil bioavailability and plant internal transport highlights that BC's impact extends beyond simple immobilization, influencing plant physiological pathways. Our findings therefore establish a dose-dependent framework for BC application and underscore the need to consider plant translocation mechanisms, not just soil solubility, when assessing the long-term efficacy and risks of BC-assisted phytoremediation for As- and Sb-contaminated soils.

To efficiently separate Co (II) from aqueous solutions and address the issues of difficult recycling and insufficient adsorption performance of traditional adsorbents, this study used polyacrylonitrile nanofibers (PAN/NFs) as the matrix and prepared an amino-functionalized adsorbent (PAN/NFs@NH₂) via graft modification with triethylenetetramine (TETA). The structural characteristics and Co (II) adsorption performance of PAN/NFs@NH₂ were investigated, and the material was characterized via SEM, EDS, FTIR, BET, XPS, and CA. PAN/NFs@NH₂ exhibits advantages of easy recyclability, excellent physicochemical stability, and good hydrophilicity. Static adsorption experiments showed that the optimal conditions for Co(II) adsorption by PAN/NFs@NH₂ are pH = 8 and a contact time of 12 h; under these circumstances, the equilibrium adsorption capacity reaches 48.30 mg/g, and the highest measured adsorption capacity is 158.29 mg/g (the Langmuir-fitted theoretical maximum capacity qm = 173.9 mg/g). The adsorption process follows the Langmuir monolayer adsorption model and is an endothermic and spontaneous process. PAN/NFs@NH₂ exhibits selective adsorption for Co(II), with selectivity coefficients of 1.73, 156.5, and 194.1 for Ni(II), Li(I), and Mn(II). Following 5 adsorption–desorption cycles, its adsorption capacity still retains around 70% of the initial value. XPS analysis confirmed that the adsorption mechanism involves the formation of coordination bonds between Co (II) and nitrogen atoms in amino groups (-NH₂, -NH-), where nitrogen atoms donate their lone pairs of electrons to Co (II). In conclusion, PAN/NFs@NH₂ provides an efficient, stable, and easily recyclable fiber-based adsorbent for the treatment of Co (II)-containing wastewater.

Water pollution incidents are often characterized by domain-specific knowledge that is inherently contradictory and uncertain, posing considerable challenges for informed decision-making. This paper presents a novel methodology to address these contradictions by leveraging Extenics-Conjugate Analysis, with a particular focus on its application to water pollution events. Initially, we construct Extenics sets and knowledge element models to systematically identify and reveal the contradictory elements within the domain of water pollution. The Extenics-Conjugate Analysis framework is then employed to systematically analyze and resolve these contradictions, thereby enabling the construction and evolution of more coherent, realistic, and scientifically robust scenarios. The ultimate goal is to improve the scientific rigor and operational efficiency in the management of water pollution incidents, contributing to more effective decision-making processes. The proposed framework was applied to a river segment in Region A. Results demonstrate that the Extenics-Conjugate Analysis effectively identifies and resolves domain-knowledge contradictions, thereby improving scenario robustness and decision quality in water contamination events.

Mn²⁺-doped Ni–Al layered double oxide (LDO) nanoplates were synthesized via co-precipitation and calcination, aiming to develop an efficient adsorbent for fluoride removal from aqueous solutions. Comprehensive characterization using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), High-resolution transmission electron microscopy (HRTEM), Energy-dispersive X-ray spectroscopy (EDS), and Brunauer–Emmett–Teller (BET) confirmed the successful incorporation of Mn²⁺, formation of well-defined crystalline structures, plate-like morphology, and high surface area with mesoporosity. The adsorption performance of MNAOs was evaluated under varying conditions, including pH, initial fluoride concentration, adsorbent dose, contact time, temperature, and agitation speed. MNAO-20 exhibited the highest adsorption capacity, reaching a maximum modeled value of 411.97 mg/g, with rapid adsorption kinetics and equilibrium achieved within 30 min. The introduction of Mn²⁺ dopant represented the key innovation of this study, as it significantly enhanced the surface area, mesoporosity, and density of active sites, thereby improving fluoride adsorption efficiency compared with undoped Ni–Al LDO. Kinetic studies indicated that adsorption was governed by a combination of mass transfer and chemical reaction mechanisms, while isotherm analyses suggested heterogeneous, multi-layer adsorption. Thermodynamic parameters revealed spontaneous, exothermic adsorption accompanied by decreased system randomness, consistent with the formation of ordered fluoride–adsorbent complexes. Regeneration experiments showed that MNAO retained 73.82% of its capacity after five adsorption–desorption cycles, demonstrating structural stability and reusability. The presence of coexisting anions (Cl⁻, SO₄²⁻, NO₃⁻) moderately reduced fluoride removal efficiency. Although the removal efficiency at neutral pH limits direct applicability to drinking water, the study provided important insights into the role of Mn²⁺ doping in enhancing adsorption performance. These findings highlight MNAOs as a promising adsorbent for further surface modifications and development of scalable fluoride adsorbents for water treatment.