Water, Air, & Soil Pollution最新文献

Carbon neutrality is an important goal of global energy conservation and emission reduction, and achieving the green and low-carbon technological revolution. The straw biomass in Northeast China is a potential green resource, and its pyrolysis into biochar (BC) is of great significance for carbon neutrality. This study is based on bibliometrics to conduct network co-occurrence analysis on recent BC and carbon neutrality aspects, and uses the AHP + GRA dual evaluation model for index optimization evaluation. The research direction of BC in carbon neutrality in 2023 is more focused on its carbon fixation performance for carbonaceous substances. The carbon fixation index of BC accounts for 0.314 of this layer, which exceeds 30%. GRA is used to evaluate the performance of BC, with the highest correlation between η and C₀-η (1.0), followed by pore diameter, (O + N)/C, O/C, H/C, ash, SA, pore volume, C, and pH_pzc (0.696). In the process of assisting carbon neutrality with straw BC, the focus should be on carbon sequestration performance, while also considering various factors used for preparation. The aim of this study is to optimize the carbon neutrality indicators for evaluating the resource utilization process of solid waste such as straw, in order to provide a fundamental reference for decision-makers in preparing high-value products.

Poor waste management of the products and products used in water sources becomes a problem for living organisms’ health. Using biosorbent from agro-waste materials becomes the solution for waste management and wastewater treatment. This study investigated the removal of progesterone from aqueous solutions using a biochar adsorbent derived from mixed banana and mango peels. The biosorbent shows high progesterone removal of 97.8 ± 0.02% at 700℃ preparation temperature at an optimal biosorbent concentration of 0.50 g and pH of 8. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Isotherm analysis revealed that the adsorption data best fitted the Freundlich model (R² = 0.96), with a maximum adsorption capacity (q_max) of 307 mg g⁻¹, indicating multilayer adsorption with a heterogeneous surface. The Brunauer–Emmett–Teller (BET) surface area was 652 m²g⁻¹ with abundant functional groups verified by Fourier Transform Infrared Spectroscopy (FTIR). The Scanning Electron Microscopy image (SEM) indicated that the biochar is porous, contributing to its effectiveness as an adsorbent. Thermodynamics results indicate that the spontaneous nature of adsorption reveals the process. The findings proved the potential of using agricultural mixed waste-derived biochar containing various chemical and physical characteristics as an effective and sustainable adsorbent to remove endocrine disruptors. This technique addresses environmental concerns about water hormone pollution and promotes sustainable waste management practices, but the gradual decrease in adsorption efficiency highlights the importance of optimizing the biochar's chemical composition and structural reliability to maximize its performance.

Microplastics (MPs) pollution is one of the most pressing environmental problems. Rivers are important conduits for land-sea transport of materials and greatly influence the behaviour of MPs into the ocean. The Pearl River is the second largest river in China in terms of water flow and has a prosperous transport industry. Meanwhile, a large amount of MPs are transported into the South China Sea through the Pearl River. We collected water samples from the origin to the estuary of the Pearl River and studied the abundance, characteristics, ecological risks, and possible impacting factors of MPs. The results showed that the abundance of MPs in the surface water of the Pearl River Basin ranged from 0.7 to 4.5 items/L, and the distribution of abundance showed the order of: origin > estuary > downstream > midstream > upstream. MPs with sizes of 1–1000 µm were the most widely distributed, and fragments and fibers were the most prevalent MPs. The distribution of MPs showed strong spatial heterogeneity, with Polymethyl methacrylate (PMMA) dominating at the origin and upstream, polyethylene terephthalate (PET) dominating in the midstream, while polyethylene (PE) was most abundant in the downstream and estuary of the Pearl River Basin. Compared with the literature data, the concentration of MPs in the Pearl River Basin was overall low, and the pollution load index indicates that the Pearl River is at a low pollution level. However, the highly toxic PMMA could lead to significant ecological risks in the Pearl River, especially at the origin and upstream watersheds. Natural factors such as hydrological conditions, gravity, and topography can affect the migration trajectory of this MPs. Reservoirs and the concave banks of curved rivers may become new"sinks"for MPs.

Graphical Abstract

Tea (Camellia sinensis) is a perennial plant and a strong fluoride (F⁻) hyperaccumulator, requiring acidic soil for optimal growth and quality. Tea plants readily absorb F⁻ from the growing medium because the soil in which tea is grown is acidic. Environmental factors (soil pH, geological sources, temperature, and rain fall) and human activities are the main contributors to F⁻ in tea. We investigated the total F⁻ content in 100 samples each of CTC and orthodox teas collected from the tea-growing regions of Northeast India. Comparatively, CTC (119.7 µg/g) tea showed higher F⁻ content than orthodox tea (76.39 µg/g), with mean fluoride concentrations below European Commission Maximum Residue Limit (400 mg/kg). The non-carcinogenic anthropogenic risk from F⁻ in tea was evaluated using Hazard Quotient (HQ) and Monte Carlo Simulation (MCS) values, which were found to be < 1 for men, women, and children, with children showing higher F⁻ intake from tea than adults. Positive Matrix Factorization (PMF) identified geogenic sources and industrial drilling as the main contributors to increased F⁻ in tea. Additionally, a geostatistical tool using Inverse Distance Weighting (IDW) and hot-spot analysis was developed to predict the spatial distribution and hot and cold spot patterns of F⁻ in tea. This study significantly enhances the understanding of F⁻ in tea from the Northeast region, indicating that contemporary Northeast Indian tea does not pose any F⁻ related health hazards, though regular monitoring for any elemental contamination remains important for tea quality and production.

The concentration problem represents a significant challenge for membrane processes, necessitating supplementary treatment and management strategies. This study assesses the efficiency of a vacuum-assisted air gap membrane distillation/crystallization (VAGMD-C) system to addressing this issue, specifically focusing on the removal and recovery of boron, a critical raw material. Synthetic boron solutions were employed to optimize key parameters such as concentration, pH, and membrane type. Following this, real reverse osmosis (RO) concentrate was treated under optimized conditions using both commercial and custom-fabricated membranes. The experimental analyses included flux measurements, boron concentration assessments, and boron rejection rates, along with scanning electron microscope-energy dispersive spectrometry (SEM–EDS) and X-ray fluorescence (XRF) analysis of the resulting crystals. The results demonstrated that achieving up to 44.6% boron content in the crystals is feasible by utilizing the fabricated nanofiber membrane (NF) within the VAGMD-C system.

This study examines the adsorption capabilities of six types of biochars, prepared via pyrolysis of biomass materials sourced from Xinjiang, for removing pollutants from water. The results demonstrate that higher pyrolysis temperatures facilitate more complete decomposition of organic components within the feedstock, leading to increased pore size and specific surface area of the biochars. This enhancement significantly boosts the adsorption efficiency of methylene blue (MB) by the biochars. Efficient and well-structured porous biochars can be obtained at 700 °C; notably, biochars produced at 900 °C achieve MB removal efficiencies exceeding 99.5%. Furthermore, cyclic adsorption performance tests targeting MB indicate that, with the exception of corn cob biochar pyrolyzed at 900 °C, all other biochars maintain a removal rate of at least 71.4% after four cycles. The rich internal porous structure of the biochars and the presence of oxygen-containing functional groups on their surfaces enable those synthesized at 900 °C to achieve high equilibrium adsorption capacities for lead ions (Pb²⁺) in water within 30 min, averaging or surpassing 102.2 mg/g. Notably, cotton stalk biochar, which is abundant in oxygen-containing functional groups, exhibits a maximum equilibrium adsorption capacity for Pb²⁺ of up to 196.0 mg/g. Importantly, during the four cycles of reuse, both cotton stalk biochar and bamboo biochar pyrolyzed at 900 °C display relatively stable adsorption characteristics for Pb²⁺. Kinetic model analysis reveals that the adsorption processes of MB and Pb²⁺ by these biochars conform to both pseudo-first-order and pseudo-second-order kinetic models. These findings provide valuable guidance for the application of biochars in water treatment fields.

This study investigated the contents, spatial distribution, and ecological and health risks of nine metals in 19 coastal sediments from Sharm El Luli area, Red Sea. Metals followed a decreasing pattern: Fe > Ba > V > Cr > Zn > Pb > Cu > Ni > Co. Pb, Cr, and V exceeding the Canadian soil quality guidelines and earth crust backgrounds. Levels of Pb, Cr, Ni, and Zn in Sharm El Luli’s sediments have surpassed their respective Effect Range Median (ERM) values, suggesting potential adverse effects on local biota. Factor analysis results showed significant loads of Ba, Co, V, pH, and TOM% (F1: 21.3%), Cu, Cr, Sand%, and Mud% (F2: 18.6%), and Pb, Ni, Zn, Fe, and Gravel% (F3: 18%). Contamination factor values indicated low (Ba and Fe), moderate (Co, Cu, Cr, Ni, and V), considerable (Pb), and high (Zn) contamination. Geo-accumulation index of all metals indicated extremely contaminated sediments (I_geo > 5). The Potential ecological risk index of metals examined showed low risk (PERI < 150). Mean effects range median quotient (MERMQ) value (1.08) showed medium–high priority risk (0.51 < MERMQ ≤ 1.5), and Toxic risk index showed moderate toxicity risk. Non-carcinogenic risk index (HI) values indicated no chronic risk (HI < 1), and total carcinogenic risk (TCR) values were below the safe limit (1 × 10⁻⁴). The distribution of natural radioactive elements in sediments was also assessed. Mean ⁴⁰ K, ²²⁶Ra, and ²³²Th activity of sediments were 23.32, 24.57, and 241.83 Bq/kg, respectively, being lower than the recommended global limits. The heavy minerals detected are pyrite, ilmenite, and beryl. The study underscores the urgent need for comprehensive management strategies to mitigate environmental hazards from heavy metal pollution in coastal sediments, requiring ongoing scientific investigation and cooperation, which will play a crucial role in protecting the Red Sea's marine ecosystem.

Microplastics (MPs) are omnipresent in all ecosystems, and sediments are considered as their ultimate sink in marine environment. This study focused on the occurrence, characteristics, and risk of MPs in the beach sediments of Cox’s Bazar, Bangladesh. Sediment samples were collected from a total of 17 sites from four study areas hosting various types of aquacultural, agricultural, animal agricultural, and tourism activities during the peak tourist season. Stereomicroscopy, micro-Fourier transform infrared spectroscopy (μ-FTIR), and scanning electron microscopy (SEM) were used for qualitative and quantitative characterization of MPs. MPs were detected in all beach sediment samples, with abundance ranging from 280 to 1060 items/kg. Overall, small sizes (< 250 μm), fibrous and granular shapes, white and transparent color were the major characteristics for MPs in the beach sediments. The dominant polymer types for the MPs were PP (24.89%), LDPE (21.85%), and HDPE (18.06%). The risk of MPs in the beach sediments was quantitatively assessed with the pollution load index (PLI, 1.0–3.78), polymeric hazard index (PHI, 49.5–70.0), and ecological risk index (ERI, 54.3–232). MPs in the sediments of Kolatoli sea beach had the highest average PLI (2.32), which is indicative of significant pollution, while those in the sediments of Darianagar beach point had the lowest average PLI (1.07). The average PHI values of MPs in the four study areas (57.2 to 63.4) were within the medium range, while the average ERI values (61.1 to 135) were indicative of low to medium ecological risk. While the ecological risk of MPs in the beach sediments of Cox’s Bazar is relatively low due to the dominance of polymers with low risk scores, efforts devoted to the management of plastic waste should be made to prevent further accumulation of MPs.

The monitoring of ions in natural water provides valuable insights into environmental processes and impacts. Liquid ion chromatography (LIC) is a widely utilised method for the analysis of ionic species in water, facilitating the identification of pollution and environmental assessment. Despite its accuracy and reliability, LIC methods are not widely adopted, with outdated methods such as flame photometry and titrimetry still being prevalent. In this study, we employed LIC to assess the concentrations of cations (Na⁺, K⁺, Mg²⁺, Ca²⁺) and anions (Cl⁻, SO₄²⁻) in the surface water of the Styr river, Ukraine. The LIC measurements were conducted using Dionex ICS- 1500 and ICS- 2000 devices, with anion and cation exchange columns and appropriate eluents. Samples were collected on a weekly basis throughout 2023, subsequently stored and handled in accordance with standardised protocols. The analysis of the data was conducted using Pearson's correlation and principal component analysis (PCA), with the objective of identifying underlying relationships between parameters. The greenness of the LIC method was then compared with that of traditional methods using the AGREE software metric. The ion concentrations present in the Styr river exhibited a specific order of abundance: Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ for cations and SO₄²⁻ > Cl⁻ for anions. Pearson's correlation and PCA identified five principal components representing different aspects of the water's ionic composition. The greenness assessment using AGREE indicated that the LIC method is more sustainable compared to traditional methods. The comprehensive evaluation of irrigation suitability, based on various indices, confirmed that the water of the Styr river is suitable for irrigation. The adoption of LIC, coupled with green analytical practices, can significantly enhance water quality assessment, promoting sustainable environmental management.

Graphic Abstract

Extracellular polymeric substances (EPS) are a collection of organic molecules from microbial metabolism, secreted outside the cell to counteract effects of harsh environment, a process that has enabled the application of the biopolymer for wastewater treatment. Reduction in concentration of lead II (Pb²⁺) and chromium VI (Cr⁶⁺) together with other physicochemical parameters from tannery wastewater by EPS from Penicillium expansum was studied. The maximum removal of Pb²⁺ and Cr⁶⁺ were 23.13% and 17.83% respectively under optimized removal conditions of 180 rpm agitation, 90 mg/L EPS concentration, 5.0 pH at  40 °C using a 2-h residence time. However, this low percentage removal of Pb²⁺ and Cr⁶⁺ in the tannery wastewater called for more batches of removal process under optimized conditions. After subjecting the EPS to four batches of removal process, 100% and 89.75% removal of Pb²⁺ and Cr⁶⁺ respectively were achieved in less than 8 h. Based on this, FTIR Analyses showed frequency shifts in alkenyl (C = C), hydroxyl (OH) and carbonyl (C = O) functional groups, and molecular overlapping in the EPS was observed on scanning electron micrograph. Physicochemical parameters in the tannery wastewater were significantly (p < 0.05) reduced by 50% or more with the exception of pH after the duration of the biosorption process. The findings in this study showed that EPS produced by P. expansum could significantly (p < 0.05) decrease the concentrations of Pb²⁺, Cr⁶⁺ and other heavy metals as well as other tannery wastewater physicochemical properties that contributed to its polluting effect.