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Characterization of Solid Waste Incineration Fly Ashes and their Heavy Metal Leaching Behavior
2023
Li, Yonglun | Chen, Weifang | Hu, Mingzhu
Two fly ashes from municipal solid waste incineration were selected to study their heavy metal leaching behavior. The main purpose of this research is to investigate the characteristics of fly ashes and compare the leaching of heavy metals in different leaching environment. pH and acid neutralization capacity analysis showed that fly ashes were highly alkaline. Fly ashes also contained a variety of heavy metals including Pb, Cu, Cr, Zn, Cd and Ni etc. Leaching studies showed that the alkalinity of fly ashes raised the pH of leaching solution from acidic to basic. Ni, Cu and Zn were strongly bound to ashes and manifested low leaching. In contrast, Cr and Cd had high mobility but their leaching was inhibited by the low solubility of carbonate Cr and Cd. Pb was highly leachable in the alkaline environment with concentration in the leaching solution reached as high as 9.74 mg/L. In addition, the presence of EDTA in the environment also increased leaching. Pb concentration was raised to 16.63 mg/L. This could be attributed to the chelating capacity of EDTA which means that the presence of organics in natural environment should be taken into consideration.
Показать больше [+] Меньше [-]Batch and Column Studies on Nickle and Cadmium Removal Using Iranian Clay-based Geopolymer
2021
Bakhtiari, Somayeh | Zeidabadinejad, Asma | Abbaslou, Hanieh | Ghanizadeh, Alireza
The production rate of industrial and agricultural waste is increasing due to population growth. Soil is the most important receiver of industrial and agricultural waste. Contaminants such as heavy metals in various waste after reception by the soil, immediately become part of the cycle that has different impacts on the environment. Geopolymer, as a chemical stabilizer has the potential to stabilize heavy metals in the soil. In this research, several geopolymers for the stabilization of heavy metals in soil were synthesized. Silicon dioxide (SiO2) and aluminosilicate (Al2SiO4) must be used to produce the geopolymers. Rice husk ash was used as the SiO2 source. Also, Iranian zeolite and sepiolite, and red clay soil were utilized as the source of Al2SiO4. The synthesized geopolymers were investigated for the adsorption of nickel and cadmium. Also, batch and column studies of using geopolymers for the chemical stabilization of heavy metals in soil were conducted. The results revealed a high adsorption capacity of the geopolymers. The zeolite, sepiolite, and red clay geopolymer-soil samples adsorbed 100% of the heavy metals (i.e., Ni and Cd) at a concentration of 100 ppm. The zeolite geopolymer adsorbent adsorbed 57% and 96% of Ni and Cd at a concentration of 1000 ppm, respectively. In general, it was concluded that the use of geopolymer compounds in soils with high heavy metal adsorption capacity could be an efficient approach to prevent groundwater resource pollution.
Показать больше [+] Меньше [-]Combined use of open-air and indoor fumigation systems to study effects of SO<sub(2)> on leaching processes in Scots pine litter.
1991
Wookey P.A. | Ineson P.
Factors influencing nitrogen retention in forest soils.
1991
Duckworth C.M.S. | Cresser M.S.
Foliar leaching and root uptake of Ca, Mg and K in relation to acid fog effects on Douglas-fir.
1990
Turner D.P. | Tingey D.T.
Ion leaching from a sugar maple forest in response to acidic deposition and nitrification.
1989
Foster N.W. | Hazlett P.W. | Nicolson J.A. | Morrison I.K.
Evaluation of fate and exposure models - Pesticides and groundwater quality protection - Calibrating a simple model for ranking the contamination potential.
1994
Bacci E. | Franchi A. | Bensi L. | Gaggi C.
A simple approach for ranking the leaching of pesticides from surface soil presented and tentatively calibrated with field data from an agricultural a The approach is based on the calculation of a leaching index indicating the proportion of active ingredient, with respect to the quantity applied, leac from a soil model in a given time interval (one year). In the selected area wells tapping an unconfined aquifer were sampled for groundwater pesticide residue analysis, in order to explore the index region between leachers and nonleachers.
Показать больше [+] Меньше [-]Effect of grass cover on water and pesticide transport through undisturbed soil columns, comparison with field study (Morcille watershed, Beaujolais)
2010
Dousset, S. | Thevenot, M. | Schrack, D. | Gouy, V. | Carluer, N. | Laboratoire des Interactions Microorganismes-Minéraux-Matière Organique dans les sols (LIMOS) ; Université Henri Poincaré - Nancy 1 (UHP)-Centre National de la Recherche Scientifique (CNRS) | Université de Lille, Sciences et Technologies | Unité expérimentale SAD - Station de Mirecourt (MIRECOURT) ; Institut National de la Recherche Agronomique (INRA) | Milieux aquatiques, écologie et pollutions (UR MALY) ; Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)
[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU | The purpose of this work is to assess the effectiveness of two grass covers (buffer zone and grass-covered inter-row), to reduce pesticide leaching, and subsequently to preserve groundwater quality. Lower amounts of pesticides leached through grass-cover soil columns (2.7e24.3% of the initial amount) than the bare soil columns (8.0e55.1%), in correspondence with their sorption coefficients. Diuron was recovered in higher amounts in leachates (8.9e32.2%) than tebuconazole (2.7e12.9%), in agreement with their sorption coefficients. However, despite having a sorption coefficient similar to that of diuron, more procymidone was recovered in the leachates (10.2e55.1%), probably due to its facilitated transport by dissolved organic matter. Thus even in this very permeable soil, higher organic matter contents associated with grass-cover reduce the amount of pesticide leaching and limit the risk of groundwater contamination by the pesticides. The results of diuron and tebuconazole transfer through undisturbed buffer zone soil columns are in agreement with field observations on the buffer zone.
Показать больше [+] Меньше [-]Leaching of microplastic-associated additives in aquatic environments: A critical review
2022
Do, Anh TNgoc | Ha, Yeonjeong | Kwon, Jung-Hwan
Microplastic pollution has attracted significant attention as an emerging global environmental problem. One of the most important issues with microplastics is the leaching of harmful additives. This review summarizes the recent advances in the understanding of the leaching phenomena in the context of the phase equilibrium between microplastics and water, and the release kinetics. Organic additives, which are widely used in plastic products, have been introduced because they have diverse physicochemical properties and mass fractions in plastics. Many theoretical and empirical models have been utilized in laboratory and field studies. However, the partition or distribution constant between microplastics and water (Kₚ) and the diffusivity of an additive in microplastics (D) are the two key properties explaining the leaching equilibrium and kinetics of hydrophobic organic additives. Because microplastics in aquatic environments undergo dynamic weathering, leaching of organic additives with high Kₚ and/or low D cannot be described by a leaching model that only considers microplastic and water phases with a fixed boundary. Surface modifications of microplastics as well as biofilms colonizing microplastic surfaces can alter the leaching equilibrium and kinetics and transform additives. Further studies on the release of hydrophobic organic additives and their transformation products under various conditions are required to extend our understanding of the environmental fate and transport of these additives in aquatic environments.
Показать больше [+] Меньше [-]Nanoanalysis of the leaching process simulation of Pb in agricultural soil
2022
Liu, Shuyu | Min, Xin | Xiang, Minghui | Wang, Jiangli | Tang, Lei | Liu, Li
Using the Spectral characteristics of gold nanorods to investigate heavy metals Pb in agricultural soils. Studied included: (1) The effects of humic acid on Pb transformation and its formation changing were explored. The laboratory model was established to simulate Pb leaching process in the soil and investigated the change of total Pb content at different layers. (2) The migration and transformation of different forms Pb were studied by the nano system. The effect of humic acid and pH were analyzed based on the nano-analysis method. (3) The relationship between various forms Pb irons were analyzed. (4) The data showed that ion exchange state and iron-manganese oxidation state Pb were more likely to enriched at 0 cm depth, and organic bound state was more likely to enriched at 10 cm depth. Humic acid increased the solidify ability of different forms of Pb in agricultural soil, and the analysis system was efficient to supply the exactly transition process.
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