scholarly journals Modified Red Muds and Slag Based Hydraulic Binders for Zn Removal: A Matrix-Spiking Approach Applied on Clayey Sediments

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1189
Author(s):  
Adoum Mahamat Ahmat ◽  
Walid Maherzi ◽  
Claude Le Milbeau ◽  
Mahfoud Benzerzour ◽  
Nor-Edine Abriak

Dredging sediments can be implemented as primary resources in several civil engineering applications, on the condition that the release of anthropogenic compounds meets environmental requirements. The remediation of sedimentary wastes constitutes therefore, a key step before valorization consideration in circular economy schemes. This study focused on Zn removal from clayey river sediments dredged in northern France (Lille, Saint-Omer and Aire-Sur-La Lys) using a Thermo-Evolved Red Mud (TERM) and a Slag Based Hydraulic Binder (SBHB). The first step consisted in investigating Zn-trapping mechanisms prior to TERM and SBHB application as Zn-stabilizers. Results underlined poorer metal retention within the most organic sediment (high fatty acids and polycyclic aromatic molecules concentrations), emphasizing the minor role of the organic fraction typology during Zn-trapping. The pollutant displayed its best binding yields within the sediment with the highest interstitial pH and specific areas, which stressed out the preponderant influence of alkalinization ability and particles size distribution. In a second step, the spiked sediments were treated with TERM and SBHB, which resulted in a substantial lowering of Zn release at 12% of stabilizer/sediment ratio. Even though the organic content role was not preeminent during the pollutant trapping, it appeared here influential as delays in removal efficiencies were observed for the most endowed sediment. Two preferential geochemical pathways were adopted during the remediation operations with significant promotive roles of basic background pH. Indeed, Zn removal with TERM consisted mainly in sorptive mechanisms involving exchanges with Ca and Mg ions, whereas binding onto SBHB was principally achieved through precipitation phenomena.

1983 ◽  
Vol 105 (21) ◽  
pp. 6383-6389 ◽  
Author(s):  
K. Chandrasekaran ◽  
J. K. Thomas

1974 ◽  
Vol 27 (4) ◽  
pp. 556-561 ◽  
Author(s):  
Richard H. Clarke ◽  
John M. Hayes

2021 ◽  
Author(s):  
Rahul Kumar Kushwaha ◽  
Ambresh Mallya ◽  
Dipen Sahu ◽  
Jaya Krishna Meka ◽  
Sheng-Lung Chou ◽  
...  

<p>Benzene (C<sub>6</sub>H<sub>6</sub>) ice has been observed in the Titan’s stratosphere [1], and benzonitrile (C<sub>6</sub>H<sub>5</sub>CN) is a possible constituent in the benzene and nitrogen-rich environment of Titan’s atmosphere [2]. The energetic processing of such aromatic molecules can synthesize large and complex aromatic molecules such as the Polycyclic Aromatic Hydrocarbons (PAHs). To-date a number of laboratory experiments have reported the formation of complex organics from the energetic processing of aromatic molecules [3-6]. In particular, Scanning Electron Microscopy (SEM) micrographs of the residues resulting from irradiated benzene ices are found to contain geometrically shaped particles [6]. Therefore, by employing electron microscopes, we can understand the physical nature of the dust leftover from the aromatic molecule irradiation.</p> <p>In the present investigation, we subjected benzonitrile ice made at 4 K to vacuum ultraviolet (9 eV) radiation at two beamlines, BL03 and BL21A2 of Taiwan Light Source at NSRRC, Taiwan. After irradiation, the ice was warmed to room temperature, which left a brownish residue on the Potassium Bromide (KBr) substrate. The VUV spectrum of the residue is observed to have characteristic aromatic signatures. The residue is then transferred to a quantifoil grid for High-Resolution Transmission Electron Microscope (HR- TEM) imaging. HR-TEM micrographs revealed the presence of graphene in the residue. This result suggests that N-graphene could be present in benzene and nitrogen-rich icy clouds of Titan. The high masses observed by the Cassini plasma spectrometer in Titan’s atmosphere could then be attributed to the presence of N-graphene along with the more common tholins [7].</p> <p><strong>References</strong></p> <p>[1] Vinatier S. et al. (2018) <em>Icarus, 310,</em> 89.</p> <p>[2] Loison J. C. et al. (2019) <em>Icarus 329,</em> 55.</p> <p>[3] Strazzulla G. et al. (1991) <em>A&A, 241</em>, 310.</p> <p>[4] Callahan M. P. et al. (2013) <em>Icarus, 226</em>, 1201.</p> <p>[5] James R. et al. (2019) <em>RSC Adv. 9</em> (10), 5453.</p> <p>[6] Rahul K. K. et al. (2020) <em>Spectrochim. Acta A, 231, </em>117797.</p> <p>[7] Rahul K. K. et al. (2020) <em>arXiv:2008.10011</em>.</p>


1986 ◽  
Vol 17 (1) ◽  
pp. 31-46 ◽  
Author(s):  
K. B. Kronvang ◽  
C. Christiansen

The nverine supply of suspended inorganic and organic sediment, its temporal and spatial distribution and its exchange with the bay, were estimated for an urban estuary (Aarhus Harbour Estuary, Denmark) during 1983-84. The river supplies high levels of particulate matter to the estuary. Export from the estuary averages one fifth of the river introduced particulate matter resulting in the accumulation of terrigenous material in the estuary. River discharge determines whether the high depletion of particulate matter in the upper estuary follows an exponential(flocculation) or a lineary curve (dilution). Preferential deposition of organic as opposed to inorganic matter in the upper estuary depletes the particulate matter of organic matter and associated pollutants. The estuary is divided into three depositional zones identified on the basis of sediment activity, grain-size and organic content. A sediment budget is precented for the estuary. Good agreement is shown between the actually dredged sediment quantity and the mass to sedimentation from the budget.


1967 ◽  
Vol 47 (5) ◽  
pp. 1609-1619 ◽  
Author(s):  
Mark W. Dowley ◽  
Kenneth B. Eisenthal ◽  
Warner L. Peticolas

2013 ◽  
Vol 69 (3) ◽  
pp. 672-679 ◽  
Author(s):  
I. Seco ◽  
M. Gómez Valentín ◽  
A. Schellart ◽  
S. Tait

Reliable prediction of time-varying pollutant loads in combined sewer systems during storm periods can aid better management of the release of pollution into natural environments as well as enhancing storage tank design. Better understanding of the behaviour of sewer sediments is crucial for the development of models that adequately describe the transport of in-sewer solids and accurately predict the changes in pollutant concentration within combined sewers during storm events. This paper reports on the results of a test programme to examine the erosion of highly organic sewer sediment under the application of time-varying shear stress. The tests were carried out with and without supplying oxygen, and varying simulated dry-weather periods. The aim was to investigate the behaviour of real in-sewer sediment with a high organic content (around 80%) in an attempt to improve prediction of the transport rates under the particular Mediterranean conditions of long dry-period/build-up and intense rainfall/wash-off, and understand how this environment affects the erosional resistance and subsequent sediment release. Results have been compared with previous work on lower organic content sewer sediments and artificial organic sediment.


ChemNanoMat ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 68-72
Author(s):  
Gijo Raj ◽  
Yoshihiro Kikkawa ◽  
Luca Catalano ◽  
Renu Pasricha ◽  
Yasuo Norikane ◽  
...  

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