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18 pages, 2908 KiB

Open AccessArticle

Tungsten Accumulation in Hot Spring Sediments Resulting from Preferred Sorption of Aqueous Polytungstates to Goethite

by Qian Zhao, Qinghai Guo, Li Luo and Ketao Yan

Int. J. Environ. Res. Public Health 2021, 18(23), 12629; https://doi.org/10.3390/ijerph182312629 - 30 Nov 2021

Cited by 5 | Viewed by 2021

Abstract

Geothermal waters usually have elevated tungsten concentrations, making geothermal systems important sources of tungsten in the environment. To study the transport of tungsten in hot springs to hot spring sediment, which is one of the key processes for the release of geothermally derived [...] Read more.

Geothermal waters usually have elevated tungsten concentrations, making geothermal systems important sources of tungsten in the environment. To study the transport of tungsten in hot springs to hot spring sediment, which is one of the key processes for the release of geothermally derived tungsten to the surface environment, geochemical investigations of the hot springs and their corresponding sediments in Rehai (a representative hydrothermal area in southwestern China) and systematic laboratory experiments of tungstate and polytungstate adsorption onto typical iron-bearing minerals in hot spring sediments (i.e., pyrite and goethite) were conducted. The results demonstrate that considerable tungsten concentrations (i.e., not much less than 10 µg/L), formation of polytungstates under acidic conditions, and enrichment of iron oxide minerals represented by goethite are the prerequisites for extreme enrichment of tungsten in hot spring sediments (e.g., 991 µg/g in the ZZQ spring outflow channel). The absence of any of these conditions would weaken the immobilization of aqueous tungsten and result in higher mobility of tungsten in the hot springs and its further transport downstream, possibly polluting the other natural waters in and around Rehai that serve as local drinking water sources. This study provides an insight for identifying the key geochemical processes controlling the transport and fate of undesirable elements (in this case, tungsten) in geothermal systems. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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12 pages, 2451 KiB

Open AccessArticle

Measuring Responses of Dicyandiamide-, 3,4-Dimethylpyrazole Phosphate-, and Allylthiourea-Induced Nitrification Inhibition to Soil Abiotic and Biotic Factors

by Yu-Pin Lin, Andrianto Ansari, Lien-Chieh Cheng, Chiao-Ming Lin, Rainer-Ferdinand Wunderlich, Thanh-Ngoc-Dan Cao and Hussnain Mukhtar

Int. J. Environ. Res. Public Health 2021, 18(13), 7130; https://doi.org/10.3390/ijerph18137130 - 3 Jul 2021

Cited by 5 | Viewed by 3094

Abstract

Nitrification inhibitors (NIs) such as dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP), and allylthiourea (AT) are commonly used to suppress ammonia oxidization at different time scales varying from a few hours to several months. Although the responses of NIs to edaphic and temperature conditions have [...] Read more.

Nitrification inhibitors (NIs) such as dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP), and allylthiourea (AT) are commonly used to suppress ammonia oxidization at different time scales varying from a few hours to several months. Although the responses of NIs to edaphic and temperature conditions have been studied, the influence of the aforementioned factors on their inhibitory effect remains unknown. In this study, laboratory-scale experiments were conducted to assess the short-term (24 h) influence of eight abiotic and biotic factors on the inhibitory effects of DCD, DMPP, and AT across six cropped and non-cropped soils at two temperature conditions with three covariates of soil texture. Simultaneously, the dominant contributions of ammonia-oxidizing archaea (AOA) and bacteria (AOB) to potential ammonia oxidization (PAO) were distinguished using the specific inhibitor 2 phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Our results revealed that AT demonstrated a considerably greater inhibitory effect (up to 94.9% for an application rate of 75 mg of NI/kg of dry soil) than DCD and DMPP. The inhibitory effect of AT was considerably affected by the relative proportions of silt, sand, and clay in the soil and total PAO. In contrast to previous studies, the inhibitory effects of all three NIs remained largely unaffected by the landcover type and temperature conditions for the incubation period of 24 h. Furthermore, the efficacy of all three tested NIs was not affected by the differential contributions of AOA and AOB to PAO. Collectively, our results suggested a limited influence of temperature on the inhibitory effects of all three NIs but a moderate dependence of AT on the soil texture and PAO. Our findings can enhance the estimation of the inhibitory effect in soil, and pure cultures targeting the AOA and AOB supported ammonia oxidization and, hence, nitrogen dynamics under NI applications. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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18 pages, 3464 KiB

Open AccessArticle

Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment

by Haiyan Song, Wei Liu, Fansheng Meng, Qi Yang and Niandong Guo

Int. J. Environ. Res. Public Health 2021, 18(11), 5921; https://doi.org/10.3390/ijerph18115921 - 31 May 2021

Cited by 10 | Viewed by 2824

Abstract

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI [...] Read more.

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO₄²⁻, NO₃⁻, and Cl⁻ had a strong inhibitory effect on this process, while the presence of SO₄²⁻ promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe²⁺ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe⁰ core was exposed, which improved the reactivity of the composites. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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14 pages, 1156 KiB

Open AccessArticle

The Impact of Environmental Regulation on the Location of Pollution-Intensive Industries in China under Agglomeration Effect

by Yinhao Wu, Shumin Yu and Xiangdong Duan

Int. J. Environ. Res. Public Health 2021, 18(8), 4045; https://doi.org/10.3390/ijerph18084045 - 12 Apr 2021

Cited by 6 | Viewed by 2780

Abstract

Pollution-intensive industries (PIIs) have both scale effect and environmental sensitivity. Therefore, this paper studies how environmental regulation (ER) affects the location dynamics of PIIs under the agglomeration effect. Our results show that, ER can increase the production costs of pollution-intensive firms (PIFs) by [...] Read more.

Pollution-intensive industries (PIIs) have both scale effect and environmental sensitivity. Therefore, this paper studies how environmental regulation (ER) affects the location dynamics of PIIs under the agglomeration effect. Our results show that, ER can increase the production costs of pollution-intensive firms (PIFs) by internalizing the negative impact of pollutant discharge in a region, and thus, directly reduces the region’s attractiveness to PIFs. Meanwhile, ER can indirectly reduce the attractiveness of a region to PIFs by reducing the externality of the regional agglomeration effect. Moreover, these influences are regulated by the level of local economic development. Based on the moderated mediating effect model, we find evidence from the site selection activities of newly built chemical firms in cities across China. The empirical test shows that compared with 2014, the proportion of the direct effect of ER to the total effects significantly decreased in 2018, while the proportion of indirect effects under the agglomeration effect increased significantly. Our findings provide reference for the government to design effective environmental policies to guide the location choice of new PIFs. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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18 pages, 5930 KiB

Open AccessArticle

Fly Ash Waste Recycling by Pt/TiO₂ Incorporation for Industrial Dye Removal

by Maria Visa, Mihaela Cosnita, Macedon Moldovan, Cosmina Andreea Marin and Maria Mihaly

Int. J. Environ. Res. Public Health 2021, 18(8), 3887; https://doi.org/10.3390/ijerph18083887 - 7 Apr 2021

Cited by 4 | Viewed by 2877

Abstract

New materials are obtained by transforming fly ash wastes into a valuable composite, with tandem adsorption and photodegradation properties. Mild hydrothermal synthesis, from titanium dioxide, platinum nanoparticles and zeolite materials obtained from a waste, fly ash, as support, was involved in the composite [...] Read more.

New materials are obtained by transforming fly ash wastes into a valuable composite, with tandem adsorption and photodegradation properties. Mild hydrothermal synthesis, from titanium dioxide, platinum nanoparticles and zeolite materials obtained from a waste, fly ash, as support, was involved in the composite preparation. The platinum nanoparticles extended the photocatalytic activity of the composite in visible range (Eg = 2.1 eV). The efficiency of tandem adsorption and photocatalytic activity of the new composite were determined to be 25% for Bemacid Blau and 43.89% for Bemacid Rot after 360 min, the irradiation time. The addition of H₂O₂ improves the process efficiency up to 80.70% and 93.43%, respectively. The Pt nanoparticle (PtNP) contribution led to the band gap energy change to Vis light (400 nm), thus suggesting the possibility of photocatalysis under the action of a fraction of natural light. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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24 pages, 1697 KiB

Open AccessArticle

Insights Gained from an Approximate Analytical Solution of the Evaporation Model Used by ConsExpo Web

by Thomas Schendel and Eva Charlotte Rogasch

Int. J. Environ. Res. Public Health 2021, 18(6), 2829; https://doi.org/10.3390/ijerph18062829 - 10 Mar 2021

Cited by 3 | Viewed by 1987

Abstract

Evaporation of chemicals is an important source of inhalative exposure. We analyzed here the ConsExpo evaporation model, which is characterized by a set of nonlinear differential equations only solvable by numerical means. It shows qualitatively different behavior for different parameters, but the exact [...] Read more.

Evaporation of chemicals is an important source of inhalative exposure. We analyzed here the ConsExpo evaporation model, which is characterized by a set of nonlinear differential equations only solvable by numerical means. It shows qualitatively different behavior for different parameters, but the exact conditions remain unclear. This article presents an approximate analytical solution of the ConsExpo evaporation model, derived by using a specific linearization of the nonlinear equations valid for small concentrations. From this solution, three different boundary cases or regimes are found: quick release, near equilibrium, and ventilation driven regime. Depending on the evaporation regime, different parameters influence peak substance air concentration: Quick release regime: total substance amount and room volume; near equilibrium regime: vapor pressure, substance concentration in the product, and molecular weight of the product matrix; ventilation driven regime: vapor pressure, substance concentration in the product, room volume, surface area, mass transfer coefficient, ventilation rate, and molecular weight of the product matrix. A graphical method is developed to display the position of a given scenario in relation to the three regimes. Thus, the approximate analytical solution allows for a given situation to prioritize research for reducing uncertainty of the most sensitive parameters and helps to identify promising risk management measures. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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11 pages, 4927 KiB

Open AccessArticle

Groundwater Quality in Agricultural Lands Near a Rapidly Urbanized Area, South China

by Lingxia Liu, Shihua Qi and Wenzhong Wang

Int. J. Environ. Res. Public Health 2021, 18(4), 1783; https://doi.org/10.3390/ijerph18041783 - 12 Feb 2021

Cited by 7 | Viewed by 2920

Abstract

Understanding the groundwater quality and its factors is a key issue in the context of the use and protection of groundwater resources in agricultural areas near urbanized areas. This study assessed the groundwater quality in agricultural areas in the Pearl River Delta (PRD) [...] Read more.

Understanding the groundwater quality and its factors is a key issue in the context of the use and protection of groundwater resources in agricultural areas near urbanized areas. This study assessed the groundwater quality in agricultural areas in the Pearl River Delta (PRD) by a fuzzy synthetic evaluation method and determined the main factors controlling the groundwater quality by principal component analysis (PCA). Results showed that approximately 85% of groundwater sites in agricultural lands in the PRD were good-quality (drinkable). Drinkable groundwater was 95% and 80% in fissured aquifers and porous aquifers, respectively. Poor-quality groundwater in porous aquifers was controlled by four factors according to the PCA, including the seawater intrusion; the lateral recharge and irrigation of surface water and geogenic sources for As, Fe, NH₄⁺, and Mn; the wastewater infiltration; and the geogenic sources for iodide. By contrast, another four factors, including the infiltration of wastewater and agricultural fertilizers, the geogenic sources for heavy metals, the geogenic sources for iodide, and the irrigation of contaminated river water, were responsible for the poor-quality groundwater in fissured aquifers. Therefore, in the future, the groundwater protection in agricultural lands in the PRD should be strengthened because the majority of groundwater in these areas was good-quality and suitable for drinking and agricultural purposes. In addition, poor-quality groundwater in agricultural lands in the PRD was a small proportion and negligible because the factors for poor-quality groundwater are complicated. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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16 pages, 3277 KiB

Open AccessArticle

Microbial Diversity Dynamics in a Methanogenic-Sulfidogenic UASB Reactor

by E. Fernández-Palacios, Xudong Zhou, Mabel Mora and David Gabriel

Int. J. Environ. Res. Public Health 2021, 18(3), 1305; https://doi.org/10.3390/ijerph18031305 - 1 Feb 2021

Cited by 10 | Viewed by 2880

Abstract

In this study, the long-term performance and microbial dynamics of an Upflow Anaerobic Sludge Blanket (UASB) reactor targeting sulfate reduction in a SOx emissions treatment system were assessed using crude glycerol as organic carbon source and electron donor under constant S and C [...] Read more.

In this study, the long-term performance and microbial dynamics of an Upflow Anaerobic Sludge Blanket (UASB) reactor targeting sulfate reduction in a SOx emissions treatment system were assessed using crude glycerol as organic carbon source and electron donor under constant S and C loading rates. The reactor was inoculated with granular sludge obtained from a pulp and paper industry and fed at a constant inlet sulfate concentration of 250 mg S-SO₄²⁻L⁻¹ and a constant C/S ratio of 1.5 ± 0.3 g Cg⁻¹ S for over 500 days. Apart from the regular analysis of chemical species, Illumina analyses of the 16S rRNA gene were used to study the dynamics of the bacterial community along with the whole operation. The reactor was sampled along the operation to monitor its diversity and the changes in targeted species to gain insight into the performance of the sulfidogenic UASB. Moreover, studies on the stratification of the sludge bed were performed by sampling at different reactor heights. Shifts in the UASB performance correlated well with the main shifts in microbial communities of interest. A progressive loss of the methanogenic capacity towards a fully sulfidogenic UASB was explained by a progressive wash-out of methanogenic Archaea, which were outcompeted by sulfate-reducing bacteria. Desulfovibrio was found as the main sulfate-reducing genus in the reactor along time. A progressive reduction in the sulfidogenic capacity of the UASB was found in the long run due to the accumulation of a slime-like substance in the UASB. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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16 pages, 18288 KiB

Open AccessArticle

Development and Validation of Green UV Derivative Spectrophotometric Methods for Simultaneous Determination Metformin and Remogliflozin from Formulation: Evaluation of Greenness

by Mahesh Attimarad, Anroop B. Nair, Nagaraja Sreeharsha, Bandar E. Al-Dhubiab, Katharigatta N. Venugopala and Pottathil Shinu

Int. J. Environ. Res. Public Health 2021, 18(2), 448; https://doi.org/10.3390/ijerph18020448 - 8 Jan 2021

Cited by 26 | Viewed by 5236

Abstract

The recent trend in green analytical chemistry is the development of green analytical methods using environmentally friendly solvents. Therefore, three ecofriendly manipulated UV spectroscopic techniques have been validated for the concurrent quantification of newly approved remogliflozin etabonate (REM) and metformin HCl (MET) tablets [...] Read more.

The recent trend in green analytical chemistry is the development of green analytical methods using environmentally friendly solvents. Therefore, three ecofriendly manipulated UV spectroscopic techniques have been validated for the concurrent quantification of newly approved remogliflozin etabonate (REM) and metformin HCl (MET) tablets using water as a solvent. The first method was established using first derivative absorption spectroscopic method by determining the peak amplitude at 233.0 nm for REM and 252.2 nm for MET, a zero crossing of one the component. The second and third methods were based on the peak amplitude difference and first-order derivative absorption of the ratio spectra developed by the manipulation of scanned UV spectra. REM and MET showed good linearity in the series of 1–20 µg ml⁻¹ and 2.5–35 µg ml⁻¹, respectively, by all three methods with an excellent correlation coefficient (r² ≥ 0.998). Further, the proposed UV spectroscopic techniques were validated as per International Council for Harmonization guidelines. The methods showed good sensitivity, accuracy, and precision. Anticipated procedures were effectively utilized for the concurrent quantification of REM and MET in laboratory prepared mixtures and tablets. The high percent recovery with low standard deviation found for both analytes by all three methods confirms the accuracy and precision of the procedures. Finally, the greenness of the proposed spectroscopic methods, evaluated by semi-quantitative and quantitative methods, showed the eco-friendly nature of the methods. Furthermore, the proposed approaches were simple, accurate, sensitive, economic, and environmentally friendly and hence can be utilized for regular quality control of REM and MET formulation. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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23 pages, 3082 KiB

Open AccessArticle

Comparative Study of Hydrochemical Classification Based on Different Hierarchical Cluster Analysis Methods

by Jianwei Bu, Wei Liu, Zhao Pan and Kang Ling

Int. J. Environ. Res. Public Health 2020, 17(24), 9515; https://doi.org/10.3390/ijerph17249515 - 18 Dec 2020

Cited by 42 | Viewed by 4019

Abstract

Traditional methods for hydrochemical analyses are effective but less diversified, and are constrained to limited objects and conditions. Given their poor accuracy and reliability, they are often used in complement or combined with other methods to solve practical problems. Cluster analysis is a [...] Read more.

Traditional methods for hydrochemical analyses are effective but less diversified, and are constrained to limited objects and conditions. Given their poor accuracy and reliability, they are often used in complement or combined with other methods to solve practical problems. Cluster analysis is a multivariate statistical technique that extracts useful information from complex data. It provides new ideas and approaches to hydrogeochemical analysis, especially for groundwater hydrochemical classification. Hierarchical cluster analysis is the most widely used method in cluster analysis. This study compared the advantages and disadvantages of six hierarchical cluster analysis methods and analyzed their objects, conditions, and scope of application. The six methods are: The single linkage, complete linkage, median linkage, centroid linkage, average linkage (including between-group linkage and within-group linkage), and Ward’s minimum-variance. Results showed that single linkage and complete linkage are unsuitable for complex practical conditions. Median and centroid linkages likely cause reversals in dendrograms. Average linkage is generally suitable for classification tasks with multiple samples and big data. However, Ward’s minimum-variance achieved better results for fewer samples and variables. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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15 pages, 2956 KiB

Open AccessArticle

Glucocorticoids in Freshwaters: Degradation by Solar Light and Environmental Toxicity of the Photoproducts

by Alice Cantalupi, Federica Maraschi, Luca Pretali, Angelo Albini, Stefania Nicolis, Elida Nora Ferri, Antonella Profumo, Andrea Speltini and Michela Sturini

Int. J. Environ. Res. Public Health 2020, 17(23), 8717; https://doi.org/10.3390/ijerph17238717 - 24 Nov 2020

Cited by 15 | Viewed by 3610

Abstract

The photodegradation process of seven glucocorticoids (GCs), cortisone (CORT), hydrocortisone (HCORT), betamethasone (BETA), dexamethasone (DEXA), prednisone (PRED), prednisolone (PREDLO) and triamcinolone (TRIAM) was studied in tap and river water at a concentration close to the environmental ones. All drugs underwent sunlight degradation according [...] Read more.

The photodegradation process of seven glucocorticoids (GCs), cortisone (CORT), hydrocortisone (HCORT), betamethasone (BETA), dexamethasone (DEXA), prednisone (PRED), prednisolone (PREDLO) and triamcinolone (TRIAM) was studied in tap and river water at a concentration close to the environmental ones. All drugs underwent sunlight degradation according to a pseudo-first-order decay. The kinetic constants ranged from 0.00082 min⁻¹ for CORT to 0.024 min⁻¹ for PRED and PREDLO. The photo-generated products were identified by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The main steps of the degradation pathways were the oxidative cleavage of the chain 17 for CORT, HCORT and the rearrangement of the cyclohexadiene moiety for the other GCs. The acute and chronic toxicity of GCs and of their photoproducts was assessed by the V. fischeri and P.subcapitata inhibition assays. The bioassays revealed no significant differences in toxicity between the parent compounds and their photoproducts, but the two organisms showed different responses. All samples produced a moderate acute toxic effect on V. fisheri and no one in the chronic tests. On the contrary, evident hormesis or eutrophic effect was produced on the algae, especially for long-term contact. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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10 pages, 2656 KiB

Open AccessArticle

Determination of the Optimum Removal Efficiency of Fine Particulate Matter Using Activated Carbon Fiber (ACF)

by Min-Kyeong Kim, Yelim Jang and Duckshin Park

Int. J. Environ. Res. Public Health 2020, 17(21), 8230; https://doi.org/10.3390/ijerph17218230 - 7 Nov 2020

Cited by 3 | Viewed by 2719

Abstract

In Korea, concentrations of particulate matter (PM₁₀) are significantly higher in urban railway tunnels (178.1 μg/m³) than in metropolitan areas (49 μg/m³). In railway tunnels in Korea, it was maintained at 3–4 times higher concentration than general [...] Read more.

In Korea, concentrations of particulate matter (PM₁₀) are significantly higher in urban railway tunnels (178.1 μg/m³) than in metropolitan areas (49 μg/m³). In railway tunnels in Korea, it was maintained at 3–4 times higher concentration than general atmosphere and platform. Dust generated by trains is scattered at high speed in these tunnels, making filtration difficult; therefore, the development of filters that can be maintained in tunnels is required. In the present study, we examined PM adsorption in the laboratory scale using activated carbon fiber (ACF), which has high adsorption and capacity. The ACF depth, velocity of flow, and fine PM concentration in the tunnel were the experimental variables. We compared PM concentrations before and after the filter experiments, and calculated removal efficiency to determine the optimal conditions. Comprehensive examination of the experimental variables and differential pressure showed that the optimal conditions for an ACF specimen were a wind speed of 3.0 m/s and the ACF depth of 400 mm. The average removal efficiency of PM₁₀ was 55.5%, and that of PM_2.5 was 36.6%. The reproducibility tests showed that the ACF filter could be washed and reused and is suitable for various places because it is easily maintained. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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24 pages, 8035 KiB

Open AccessArticle

Formation and In Situ Treatment of High Fluoride Concentrations in Shallow Groundwater of a Semi-Arid Region: Jiaolai Basin, China

by Zongjun Gao, Mengjie Shi, Hongying Zhang, Jianguo Feng, Shaoyan Fang and Yechen Cui

Int. J. Environ. Res. Public Health 2020, 17(21), 8075; https://doi.org/10.3390/ijerph17218075 - 2 Nov 2020

Cited by 17 | Viewed by 3235

Abstract

Fluorine is an essential nutrient, and excessive or deficient fluoride contents in water can be harmful to human health. The shallow groundwater of the Jiaolai Basin, China has a high fluoride content. This study aimed to (1) investigate the processes responsible for the [...] Read more.

Fluorine is an essential nutrient, and excessive or deficient fluoride contents in water can be harmful to human health. The shallow groundwater of the Jiaolai Basin, China has a high fluoride content. This study aimed to (1) investigate the processes responsible for the formation of shallow high-fluoride groundwater (SHFGW); (2) identify appropriate methods for in situ treatment of SHFGW. A field investigation into the formation of SHFGW was conducted, and the results of experiments using soils from high-fluoride areas were examined to investigate the leaching and migration of fluoride. The results showed that the formation of SHFGW in the Jiaolai Basin is due to long-term geological and evaporation processes in the region. Stratums around and inside the basin act as the source of fluoride whereas the terrain promotes groundwater convergence. The hydrodynamic and hydrochemical conditions resulting from slow groundwater flow along with high evaporation and low rainfall all contribute to the enrichment of fluoride in groundwater. In situ treatment of SHFGW may be an effective approach to manage high SHFGW in the Jiaolai Basin. Since soil fluoride in high-fluoride areas can leach into groundwater and migrate with runoff, the construction of ditches can shorten the runoff of shallow groundwater and accelerate groundwater loss, resulting in the loss of SHFGW from high-fluoride areas through river outflow. The groundwater level will be reduced, thereby lowering the influence of evaporation on fluoride enrichment in shallow groundwater. The results of this study can act a reference for further research on in situ treatment for high-fluoride groundwater. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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12 pages, 2119 KiB

Open AccessArticle

Is It Possible to Predict the Concentration of Natural Volatile Organic Compounds in Forest Atmosphere?

by Geonwoo Kim, Sujin Park and Dooahn Kwak

Int. J. Environ. Res. Public Health 2020, 17(21), 7875; https://doi.org/10.3390/ijerph17217875 - 27 Oct 2020

Cited by 13 | Viewed by 3236

Abstract

We aimed to understand the correlation between the microclimate environment within a forest and NVOC (Natural volatile organic compounds) concentration and the concentration of NVOC more efficiently through the prediction model method. In this study, 380 samples were collected and analyzed to examine [...] Read more.

We aimed to understand the correlation between the microclimate environment within a forest and NVOC (Natural volatile organic compounds) concentration and the concentration of NVOC more efficiently through the prediction model method. In this study, 380 samples were collected and analyzed to examine the characteristics of NVOC emitted from a birch forest. NVOC were analyzed in May and July 2019, and measurements were performed at three different locations. Using a pump and stainless-steel tube filled with Tenax-TA, 9 L of NVOC was collected at a speed of 150 mL/h. The analysis of NVOC composition in the forest showed that it comprised α-pinene 27% and camphor 10%. Evaluation of the correlation between the NVOC concentration and the microclimate in the forests showed that the concentration increased markedly with the increase in temperature and humidity, and the concentration decreased with the increase in wind velocity. Nineteen substances in total including α-pinene and β-pinene were detected at high concentrations during the sunset. The results of the study site analysis presented a significant regression model with a R² as high as 60.1%, confirming that the regression model of the concentration prediction of NVOC in birch forest has significant explanatory power. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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18 pages, 4206 KiB

Open AccessCommunication

Graphene Oxide–ZnO Nanocomposites for Removal of Aluminum and Copper Ions from Acid Mine Drainage Wastewater

by Carolina Rodríguez, Camila Tapia, Enzo Leiva-Aravena and Eduardo Leiva

Int. J. Environ. Res. Public Health 2020, 17(18), 6911; https://doi.org/10.3390/ijerph17186911 - 21 Sep 2020

Cited by 63 | Viewed by 4780

Abstract

Adsorption technologies are a focus of interest for the removal of pollutants in water treatment systems. These removal methods offer several design, operation and efficiency advantages over other wastewater remediation technologies. Particularly, graphene oxide (GO) has attracted great attention due to its high [...] Read more.

Adsorption technologies are a focus of interest for the removal of pollutants in water treatment systems. These removal methods offer several design, operation and efficiency advantages over other wastewater remediation technologies. Particularly, graphene oxide (GO) has attracted great attention due to its high surface area and its effectiveness in removing heavy metals. In this work, we study the functionalization of GO with zinc oxide nanoparticles (ZnO) to improve the removal capacity of aluminum (Al) and copper (Cu) in acidic waters. Experiments were performed at different pH conditions (with and without pH adjustment). In both cases, decorated GO (GO/ZnO) nanocomposites showed an improvement in the removal capacity compared with non-functionalized GO, even when the pH of zero charge (pH_PZC) was higher for GO/ZnO (5.57) than for GO (3.98). In adsorption experiments without pH adjustment, the maximum removal capacities for Al and Cu were 29.1 mg/g and 45.5 mg/g, respectively. The maximum removal percentages of the studied cations (Al and Cu) were higher than 88%. Further, under more acidic conditions (pH 4), the maximum sorption capacities using GO/ZnO as adsorbent were 19.9 mg/g and 33.5 mg/g for Al and Cu, respectively. Moreover, the removal percentages reach 95.6% for Al and 92.9% for Cu. This shows that decoration with ZnO nanoparticles is a good option for improving the sorption capacity of GO for Cu removal and to a lesser extent for Al, even when the pH was not favorable in terms of electrostatic affinity for cations. These findings contribute to a better understanding of the potential and effectiveness of GO functionalization with ZnO nanoparticles to treat acidic waters contaminated with heavy metals and its applicability for wastewater remediation. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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14 pages, 3326 KiB

Open AccessArticle

Estimation on Fixed-Bed Column Parameters of Breakthrough Behaviors for Gold Recovery by Adsorption onto Modified/Functionalized Amberlite XAD7

by Adina Negrea, Maria Mihailescu, Giannin Mosoarca, Mihaela Ciopec, Narcis Duteanu, Petru Negrea and Vasile Minzatu

Int. J. Environ. Res. Public Health 2020, 17(18), 6868; https://doi.org/10.3390/ijerph17186868 - 20 Sep 2020

Cited by 34 | Viewed by 3698

Abstract

The objective of this paper was to evaluate the potential of a new adsorbent material to recover Au (III) from real wastewater, in a column with a fixed bed in a dynamic regime. The material was obtained through functionalization, by impregnation of the [...] Read more.

The objective of this paper was to evaluate the potential of a new adsorbent material to recover Au (III) from real wastewater, in a column with a fixed bed in a dynamic regime. The material was obtained through functionalization, by impregnation of the commercial resin, Amberlite XAD 7 type, with L-glutamic acid, which has active groups –NH₂ and –COOH. The goal of the experiments was to follow the correlation of fixed-bed column specific adsorption parameters (the effluent volume, the amounts of adsorbent, heights of the adsorbent layer in column) with the time necessary to cross the column. The experimental data obtained were modeled, using the Bohart–Adams, Yoon–Nelson Thomas and Clark models, to establish the mechanism of the Au (III) recovery process, in a dynamic regime. Also, we established the number of cycles for adsorption–desorption for which the new material can be used. We used 5% HNO₃ (5%) as desorption agent in five adsorption–desorption cycles, until the process was no longer efficient. The degree of desorption varied between 84% and 34% from cycle 1 to cycle 5. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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27 pages, 4533 KiB

Open AccessReview

Evolution of Singlet Oxygen by Activating Peroxydisulfate and Peroxymonosulfate: A Review

by Guangfeng Xiao, Tiantian Xu, Muhammad Faheem, Yanxing Xi, Ting Zhou, Haseeb Tufail Moryani, Jianguo Bao and Jiangkun Du

Int. J. Environ. Res. Public Health 2021, 18(7), 3344; https://doi.org/10.3390/ijerph18073344 - 24 Mar 2021

Cited by 87 | Viewed by 8685

Abstract

Advanced oxidation processes (AOPs) based on peroxydisulfate (PDS) or peroxymonosulfate (PMS) activation have attracted much research attention in the last decade for the degradation of recalcitrant organic contaminants. Sulfate (SO₄^•−) and hydroxyl (^•OH) radicals are most frequently generated [...] Read more.

Advanced oxidation processes (AOPs) based on peroxydisulfate (PDS) or peroxymonosulfate (PMS) activation have attracted much research attention in the last decade for the degradation of recalcitrant organic contaminants. Sulfate (SO₄^•−) and hydroxyl (^•OH) radicals are most frequently generated from catalytic PDS/PMS decomposition by thermal, base, irradiation, transition metals and carbon materials. In addition, increasingly more recent studies have reported the involvement of singlet oxygen (¹O₂) during PDS/PMS-based AOPs. Typically, ¹O₂ can be produced either along with SO₄^•− and ^•OH or discovered as the dominant reactive oxygen species (ROSs) for pollutants degradation. This paper reviews recent advances in ¹O₂ generation during PDS/PMS activation. First, it introduces the basic chemistry of ¹O₂, its oxidation properties and detection methodologies. Furthermore, it elaborates different activation strategies/techniques, including homogeneous and heterogeneous systems, and discusses the possible reaction mechanisms to give an overview of the principle of ¹O₂ production by activating PDS/PMS. Moreover, although ¹O₂ has shown promising features such as high degradation selectivity and anti-interference capability, its production pathways and mechanisms remain controversial in the present literatures. Therefore, this study identifies the research gaps and proposes future perspectives in the aspects of novel catalysts and related mechanisms. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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17 pages, 1517 KiB

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Marine Waste—Sources, Fate, Risks, Challenges and Research Needs

by Jolanta Dąbrowska, Marcin Sobota, Małgorzata Świąder, Paweł Borowski, Andrzej Moryl, Radosław Stodolak, Ewa Kucharczak, Zofia Zięba and Jan K. Kazak

Int. J. Environ. Res. Public Health 2021, 18(2), 433; https://doi.org/10.3390/ijerph18020433 - 7 Jan 2021

Cited by 30 | Viewed by 11391

Abstract

The article presents a comprehensive and cross-cutting review of key marine waste issues, taking into account: sources, fate, risks, transport pathways, threats, legislation, current challenges, and knowledge gaps. The growing amount of both human-created waste in seas and oceans and waste reaching marine [...] Read more.

The article presents a comprehensive and cross-cutting review of key marine waste issues, taking into account: sources, fate, risks, transport pathways, threats, legislation, current challenges, and knowledge gaps. The growing amount of both human-created waste in seas and oceans and waste reaching marine ecosystems from land is one of today’s challenges for the global economy and the European Union. It is predicted that if no decisive steps are taken to limit the amount of this type of waste, there may be more plastic waste than fish in the oceans after 2050. The influence of microplastics and nanoplastics on living organisms remains undiagnosed. Within the international and EU law, solutions are being developed to properly manage waste on board ships and to reduce the impact of processes related to the recycling of the vessels on the environment. Currently, over 80% of ships are dismantled in the countries of South Asia, in conditions that threaten the environment and the safety of workers. After World War 2, large quantities of chemical weapons were deposited in the seas. Steel containers with dangerous substances residing in the sea for over 70 years have begun leaking, thus polluting water. For many years, radioactive waste had also been dumped into marine ecosystems, although since 1993 there has been a total ban on such disposal of radionuclides. The impact of the COVID-19 pandemic on marine waste generation has also been presented as a significant factor influencing marine waste generation and management. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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23 pages, 6398 KiB

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Disposable and Low-Cost Colorimetric Sensors for Environmental Analysis

by Giancarla Alberti, Camilla Zanoni, Lisa Rita Magnaghi and Raffaela Biesuz

Int. J. Environ. Res. Public Health 2020, 17(22), 8331; https://doi.org/10.3390/ijerph17228331 - 11 Nov 2020

Cited by 56 | Viewed by 6610

Abstract

Environmental contamination affects human health and reduces the quality of life. Therefore, the monitoring of water and air quality is important, ensuring that all areas are acquiescent with the current legislation. Colorimetric sensors deliver quick, naked-eye detection, low-cost, and adequate determination of environmental [...] Read more.

Environmental contamination affects human health and reduces the quality of life. Therefore, the monitoring of water and air quality is important, ensuring that all areas are acquiescent with the current legislation. Colorimetric sensors deliver quick, naked-eye detection, low-cost, and adequate determination of environmental analytes. In particular, disposable sensors are cheap and easy-to-use devices for single-shot measurements. Due to increasing requests for in situ analysis or resource-limited zones, disposable sensors’ development has increased. This review provides a brief insight into low-cost and disposable colorimetric sensors currently used for environmental analysis. The advantages and disadvantages of different colorimetric devices for environmental analysis are discussed. Full article

(This article belongs to the Special Issue Environmental Chemistry and Technology)

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