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12 pages, 2312 KiB

Open AccessArticle

Bioavailability, Sources, and Transfer Behavior of Heavy Metals in Soil–Crop Systems from a High Geological Background Area Impacted by Artisanal Zn Smelting in Guizhou Province, Southwest China

by Honghong Ma, Chen Zhao, Li Zhang, Zhizhuo Liu, Fugui Zhang, Huiyan Wang, Fei Guo, Shiqi Tang, Zheng Yang and Min Peng

Processes 2023, 11(9), 2538; https://doi.org/10.3390/pr11092538 - 24 Aug 2023

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Abstract

The environmental risk posed by heavy metals in agricultural soil is primarily influenced by their sources, bioavailability, and geochemical transfer behavior. This study focused on Weining County, a region in Guizhou province, Southwest China, with a high geological background and long-term impact from [...] Read more.

The environmental risk posed by heavy metals in agricultural soil is primarily influenced by their sources, bioavailability, and geochemical transfer behavior. This study focused on Weining County, a region in Guizhou province, Southwest China, with a high geological background and long-term impact from artisanal Zn smelting. Vertical soil profiles, crop, and rhizospheric soil samples were collected and analyzed for heavy metal concentration (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, and Zn) including the total concentration and chemical fraction. The results revealed elevated concentrations of Cd (range: 0.7–6.9 mg·kg⁻¹), Co (range: 19.3–120.0 mg·kg⁻¹), Cu (range: 71.6–386.0 mg·kg⁻¹), Ni (range: 51.0–121.0 mg·kg⁻¹), and V (range: 310.0–721.0 mg·kg⁻¹) in all soil samples compared to the background values of Guizhou Province. Chemical fractionation analysis indicated that Cr, Ni, As, Cu, and Zn were predominantly present in the residual fraction, while Hg and Pb were predominantly found in the potentially bioavailable fraction. Cd exhibited the highest bioavailability, accounting for 58.5% of its total concentration. Enrichment factor analysis suggested that artisanal Zn smelting activities were the main sources of Cd, Pb, and Zn contamination. Furthermore, Cd, Pb, and Zn were found to be highly accumulated in the surface soil layer (0–20 cm). Notably, 90.0% of potato and 9.4% of maize grain samples exceeded the food hygiene standards for Cd concentration, posing potential health risks to consumers. The bioconcentration factor (soil-to-root) and translocation factor (root-to-grain) analyses indicated that maize roots had a higher tendency to accumulate Cd from the soil, while Zn and Cu showed a significant transferability from roots to maize grains. These findings offer valuable insights for devising heavy metal remediation strategies in similar areas. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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14 pages, 3593 KiB

Open AccessFeature PaperArticle

Effects of Calcination Temperature and Calcination Atmosphere on the Performance of Co₃O₄ Catalysts for the Catalytic Oxidation of Toluene

by Sicheng Jiang, Zhimin You and Ning Tang

Processes 2023, 11(7), 2087; https://doi.org/10.3390/pr11072087 - 13 Jul 2023

Cited by 1 | Viewed by 1620

Abstract

A series of Co₃O₄ catalysts were synthesized and derived from Co-BTC (BTC = 1,3,5-benzenetricarboxylic acid). The effects of different calcination temperatures and calcination atmospheres on the catalytic activity of the materials were investigated. The characteristics of the catalysts were investigated [...] Read more.

A series of Co₃O₄ catalysts were synthesized and derived from Co-BTC (BTC = 1,3,5-benzenetricarboxylic acid). The effects of different calcination temperatures and calcination atmospheres on the catalytic activity of the materials were investigated. The characteristics of the catalysts were investigated by using various techniques, including X-ray diffraction, N₂ adsorption–desorption measurements, scanning electron microscopy, X-ray photoelectron spectroscopy, and H₂ temperature-programmed reduction. The findings demonstrated that an increase in calcination temperature caused a higher agglomeration of grains, reduced the specific surface area, and influenced the contents of the active substance Co³⁺ and surface-adsorbed oxygen of the catalyst. The catalyst pretreated under the N₂ atmosphere showed a more uniform particle distribution, better low-temperature reducibility, and the highest catalytic activity. The in situ DRIFTS results indicated that toluene was decomposed successively to benzaldehyde, benzoic acid, bicarbonate, and carbonate species and was eventually broken down into small molecules of CO₂ and H₂O as the temperature increased. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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22 pages, 7182 KiB

Open AccessArticle

A CFD-Based Methodology for Impact Assessment of Industrial Emissions and Evaluation of Mitigation Measures for Regulatory Purposes

by Elena Antuña-Yudego, Víctor Manuel Fernández-Pacheco, Eduardo Álvarez-Álvarez, Juan Luis Carús-Candás and María José Suárez-López

Processes 2023, 11(7), 2039; https://doi.org/10.3390/pr11072039 - 7 Jul 2023

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Abstract

In a context where air quality has become a global concern, modelling techniques are becoming very popular for analysing pollutant dispersion conditions. While models based on empirical formulations are most widely used for industrial scenarios, singular cases involving complex terrain or large obstacles [...] Read more.

In a context where air quality has become a global concern, modelling techniques are becoming very popular for analysing pollutant dispersion conditions. While models based on empirical formulations are most widely used for industrial scenarios, singular cases involving complex terrain or large obstacles in the vicinity of emission sources require a more robust approach to evaluate the dispersion conditions. In this research, a computational fluid dynamics (CFD) model is developed to analyse the dispersion of pollutants from an industrial facility whose location and characteristics suggest the occurrence of complex flow features that affect the dispersion patterns. In addition, the variation of the gas exit temperatures of waste heat recovery systems is proposed as a measure to mitigate the impact of the plume. The simulation results show unexpected deviations in the plume path affecting vulnerable areas in a nearby mountainside, but increasing the gas exit temperature is useful to prevent this event. Therefore, the proposed methodology can be considered a decision support tool to find a compromise between the environmental impact and the fuel consumption of the plant. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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13 pages, 9344 KiB

Open AccessArticle

Effects of Varied Forms of Arsenic Stress on Seedling Growth and Arsenic Distribution in Honeysuckle Plants

by Xin Yuan, Juntong Zhou, Congnan Peng, Jiaqi Qiao, Shengqi Xia, Yilin Fan, Li Yao, Kailin Qi, Dongliang Chen, Zhiying Guo, Xiaolong Gan, Yaxuan Sun, Xueling Dai, Liangyu Lv, Yizhi Ji and Qing Huo

Processes 2023, 11(7), 1980; https://doi.org/10.3390/pr11071980 - 30 Jun 2023

Viewed by 884

Abstract

At present, soil arsenic contamination is one of the prominent environmental problems. The arsenic concentration in honeysuckle exceeds the standard levels, thus affecting the quality of traditional Chinese medicine. In this study, the hydroponic method was employed to explore the effect of organic [...] Read more.

At present, soil arsenic contamination is one of the prominent environmental problems. The arsenic concentration in honeysuckle exceeds the standard levels, thus affecting the quality of traditional Chinese medicine. In this study, the hydroponic method was employed to explore the effect of organic arsenic (dimethyl arsenic) and trivalent inorganic arsenic (NaAsO₂) on the growth of honeysuckle plants. The study demonstrated that low concentrations of inorganic arsenic (10–20 mg/L) and 10–50 mg/L organic arsenic had a stimulating effect on the growth of honeysuckle plants. The activities of antioxidant enzymes (peroxidase and catalase) increased correspondingly. However, the antioxidant system in honeysuckle plants was damaged under high concentrations of inorganic arsenic (20–40 mg/L) and 50–70 mg/L organic arsenic. On exposure to 30 mg/L NaAsO₂ or 50 mg/L dimethyl arsenic acid for 10 days, the activities of peroxidase and catalase, as well as the malondialdehyde content, increased with prolonged exposure. The micro X-ray fluorescence analysis revealed that the accumulated arsenic in the roots was transported from the central vascular cylinders to the outer part of the root with the increase in concentration and exposure duration of inorganic arsenic. However, organic arsenic stress did not result in significant variations in the distribution of arsenic with increasing concentrations of arsenic. The arsenic element was predominantly located in the middle woody part of the root. The distributions of arsenic in the stems and leaves, in terms of organic and inorganic arsenic stresses, were similar, with accumulation primarily in the cortex of the stem and veins of the leaves. As a commonly used bulk traditional Chinese medicine, honeysuckle has a wide range of product quality issues. Hence, exploring the absorption, distribution, and transport trends of heavy metals such as arsenic in the plant body is of great significance for scientifically evaluating the impact of heavy metal pollution on the quality of medicinal materials and exploring ways to reduce the accumulation of heavy metals in the medicinal parts of plants. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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16 pages, 7769 KiB

Open AccessArticle

Adsorptive Removal of Dye (Methylene Blue) Organic Pollutant from Water by Pine Tree Leaf Biomass Adsorbent

by Tushar Kanti Sen

Processes 2023, 11(7), 1877; https://doi.org/10.3390/pr11071877 - 22 Jun 2023

Cited by 11 | Viewed by 1735

Abstract

In this laboratory batch adsorption study, the raw pine tree leaf biomass solid waste adsorbent material was used for the removal of methylene blue (MB) dye from water at different physicochemical process conditions. The characteristics of adsorbents were determined for particle size, surface [...] Read more.

In this laboratory batch adsorption study, the raw pine tree leaf biomass solid waste adsorbent material was used for the removal of methylene blue (MB) dye from water at different physicochemical process conditions. The characteristics of adsorbents were determined for particle size, surface area, the existence of functional group identification, and the morphology of the adsorbent surface. The adsorption was performed at different process conditions, which include solution pH, dye concentrations, adsorbent doses, and temperature, respectively. In this study, it was found that MB dye adsorption increased with increases in solution pH and adsorbate MB dye concentration but decreased with adsorbent doses and temperature at fixed process conditions. The Langmuir isotherm model was best fitted with the experimental equilibrium data, with a higher linear regression coefficient (R²) value of 99.9% among the two widely used Langmuir and Freundlich adsorption isotherm model equations. The maximum Langmuir monolayer adsorption capacity of raw pine leaf was found to be 36.88 mg/g, which was comparable with other reported adsorbent capacities towards methylene blue (MB) dye adsorption. The value of the separation factor, R_L, from the Langmuir isotherm model equation gives an indication of favorable adsorption. Thermodynamic parameters such as standard Gibbs free energy change (ΔG⁰), standard enthalpy change (ΔH⁰), and standard entropy change (ΔS⁰) indicated that the methylene blue (MB) dye adsorption by pine tree leaf biomass was spontaneous and exothermic in nature and that the mechanism of adsorption was mainly physical adsorption. Finally, limitations and future studies are also discussed here. The outcome of this batch adsorption study may result in the valorization of locally available large pine tree leaf residue waste, which could be used in water purification. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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12 pages, 2214 KiB

Open AccessArticle

Preliminary Study on the Feasibility of Radiation Technique for Mural Protection

by Zesheng Wang, Min Luo, Yang Shao, Lingling Ma and Minghong Wu

Processes 2023, 11(6), 1710; https://doi.org/10.3390/pr11061710 - 2 Jun 2023

Viewed by 803

Abstract

Murals are a significant cultural heritage of humanity, and one of the conservation studies is to control the growth of microorganisms. General biocide agents can be used to preserve murals while also providing new organic carbon sources and increasing environmental pollution. In recent [...] Read more.

Murals are a significant cultural heritage of humanity, and one of the conservation studies is to control the growth of microorganisms. General biocide agents can be used to preserve murals while also providing new organic carbon sources and increasing environmental pollution. In recent years, radiation technology has shown promising prospects for use in heritage protection. Five microorganisms often found in murals were irradiated with an electron beam in this study, and six mineral pigments were tested for color change, Raman spectra and pigment layer cohesion after irradiation. The result showed that irradiation at 20 kGy can basically eliminate Pseudomonas citronellolis, Bacillus sporothermodurans, Streptomyces vinaceus, and Streptomyces griseolus from the culture medium, but only inhibited the growth of Penicillium flavigenum. Lead white pigment showed a color difference of 5.56 (∆E*₉₇) after irradiation, but lead tetroxide, azurite, malachite, ferrous oxide, and cinnabar showed no visible changes. The Raman spectra of the irradiated and unirradiated samples were basically the same. E-beam radiation did not affect the surface cohesion of the pigment layer. This preliminary work shows the potential of electron-beam technology in mural protection and provides basic research and relevant experience for the subsequent in situ mural protection work. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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18 pages, 5644 KiB

Open AccessArticle

Multi-Factor Coupling Analysis of Porous Leakage in Underwater Gas Pipelines

by Hong Ji, Jie Guo, Gao Zhang, Ke Yang, Juncheng Jiang, Yaxin Wang, Zhixiang Xing and Haipu Bi

Processes 2023, 11(4), 1259; https://doi.org/10.3390/pr11041259 - 19 Apr 2023

Cited by 2 | Viewed by 1202

Abstract

Natural gas pipeline leaks under the sea will have a significant negative effect on the marine ecosystem, result in significant financial losses, and possibly even harm marine floating objects. The VOF (Volume of Fluid) multi-phase flow model is used to numerically simulate and [...] Read more.

Natural gas pipeline leaks under the sea will have a significant negative effect on the marine ecosystem, result in significant financial losses, and possibly even harm marine floating objects. The VOF (Volume of Fluid) multi-phase flow model is used to numerically simulate and study the diffusion process of porous leakage in submarine gas pipelines. Experiments confirmed the model’s correctness and dependability. Based on this, the coupling effect and the porous effect of the leakage velocity, the size of the leaked pore, and water velocity of the natural gas pipelines on the diffusion of porous leakage in the submarine gas pipelines are analyzed with the test scheme designed by the orthogonal test method. The similarity principle is used to connect the leakage model with the actual application. The results show that three factors, namely, the leakage velocity, the size of leaked pore, and the water velocity, influence the shape of the air mass, the time when the gas reaches the sea surface, and the diffusion range. The size of the leakage hole and the leakage velocity have a substantial impact on the form of the air mass and the amount of time it takes for the gas to reach the sea surface, while the water velocity has no effect. Additionally, while there is essentially little impact from the leakage velocity, the size of the leaky pore and the water velocity have a significant impact on the diffusion range. Furthermore, the porous effect between leaky pores has a significant impact on the gas diffusion range. This study can serve as a guide for risk assessment and emergency decision-making regarding a submarine gas pipeline leak. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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Review

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19 pages, 4883 KiB

Open AccessReview

Research Progress in the Analysis of Chemical Forms of Mercury in Traditional Chinese Medicine

by Congnan Peng, Liping Kang, Xin Yuan, Jiaqi Qiao, Yilin Fan, Li Yao, Kailin Qi, Yaxuan Sun, Xueling Dai, Yuan Zhang and Qing Huo

Processes 2023, 11(10), 2821; https://doi.org/10.3390/pr11102821 - 24 Sep 2023

Viewed by 1326

Abstract

A comprehensive evaluation of the chemical forms of heavy metals, rather than their total amount of elements, is the basis of the scientific and objective evaluation of safety in heavy metals. As mercury, the most toxic heavy metal in the environment (such as [...] Read more.

A comprehensive evaluation of the chemical forms of heavy metals, rather than their total amount of elements, is the basis of the scientific and objective evaluation of safety in heavy metals. As mercury, the most toxic heavy metal in the environment (such as in water, soil, and air), accumulates in medicinal plants, chemical forms of mercury in medicinal plants and their preparation need to be clearly understood. This study aims to summarize the chemical status of mercury in bulk Chinese medicinal herbs and traditional Chinese medicine preparations and to discuss research methods for their analysis. Further, widespread high-performance liquid chromatography–inductively coupled plasma mass spectrometry, advanced synchrotron X-ray absorption fine structure spectroscopy, and X-ray fluorescence were used for the in situ analysis of the chemical state of mercury. The results were then analyzed to improve the analytical methods and evaluation standards for the chemical state of mercury in Chinese herbal medicines. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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21 pages, 2268 KiB

Open AccessFeature PaperReview

Progress of the Analytical Methods and Application of Plutonium Isotopes in the Environment

by Xidong Liu, Yang Shao, Min Luo, Lingling Ma, Gang Xu and Minghong Wu

Processes 2023, 11(5), 1430; https://doi.org/10.3390/pr11051430 - 8 May 2023

Cited by 1 | Viewed by 2165

Abstract

Since the beginning of the use of nuclear energy in the twentieth century, atmospheric nuclear weapons testing, nuclear accidents, and spent fuel reprocessing have released large amounts of radioisotopes into the environment, especially plutonium isotopes. As an important anthropogenic radionuclide, plutonium is mainly [...] Read more.

Since the beginning of the use of nuclear energy in the twentieth century, atmospheric nuclear weapons testing, nuclear accidents, and spent fuel reprocessing have released large amounts of radioisotopes into the environment, especially plutonium isotopes. As an important anthropogenic radionuclide, plutonium is mainly produced by neutron irradiation of uranium. Plutonium isotopes and their ratios from different sources have a specific ‘fingerprint’, which is determined by irradiation time and intensity. Accordingly, several methods have been developed for the analysis of plutonium isotopes. As a popular new tracer in recent years, plutonium isotopes could be used for environmental tracer applications and source identification of regional environmental contamination sources. This paper summarizes and compares the pretreatment of plutonium isotopes in various samples and the detection and analysis methods in recent years. Plutonium isotopes in various environmental samples were enriched by chemical treatments, such as ashing, acid digestion, and alkali fusion. Then it was purified and separated by extraction resins to remove interfering nuclides for the subsequent mass spectrometry. The practical applications of plutonium isotopes and their related ratios in the environment are summarized, such as the determination of plutonium isotopes and their related ratios in the environment near two representative nuclear power plant accidents and the monitoring of the safe operation of nuclear power plants; the establishment of a plutonium isotope database in the vicinity of Chinese waters; and the traceability of plutonium isotopes in environmental regions through the global atmosphere and sand and dust. Finally, the outlook for subsequent research in plutonium isotope detection and applications is presented. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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18 pages, 1446 KiB

Open AccessFeature PaperReview

Single Particle Inductively Coupled Plasma Time-of-Flight Mass Spectrometry—A Powerful Tool for the Analysis of Nanoparticles in the Environment

by Ziwei Meng, Lingna Zheng, Hao Fang, Pu Yang, Bing Wang, Liang Li, Meng Wang and Weiyue Feng

Processes 2023, 11(4), 1237; https://doi.org/10.3390/pr11041237 - 17 Apr 2023

Cited by 2 | Viewed by 2719

Abstract

Single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) has emerged as an important tool for the characterization of inorganic nanoparticles (NPs) in the environment. Although most SP-ICP-MS applications rely on the quadrupole ICP-MS (ICP-QMS), it is limited by the slow scanning speed of the quadrupole. [...] Read more.

Single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) has emerged as an important tool for the characterization of inorganic nanoparticles (NPs) in the environment. Although most SP-ICP-MS applications rely on the quadrupole ICP-MS (ICP-QMS), it is limited by the slow scanning speed of the quadrupole. Recent advancements in instrumentation have led to the development of inductively coupled plasma time-of-flight mass spectrometry (ICP-TOF-MS) which offers a viable solution. In this review, we discuss the recent advances in instrumentation and methodology of ICP-TOF-MS, followed by a detailed discussion of the applications of SP-ICP-TOFMS in analyzing NPs in the environment. SP-ICP-TOFMS has the potential to identify and quantify both anthropogenic and natural NPs in the environment, providing valuable insights into their occurrence, fate, behavior, and potential environmental risks. Full article

(This article belongs to the Special Issue Advances in Environmental Pollution and Control Processes)

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