fe reduction
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2022 ◽  
Vol 808 ◽  
pp. 151911
Author(s):  
Qi Liu ◽  
Yuhong Li ◽  
Shoulong Liu ◽  
Wei Gao ◽  
Jianlin Shen ◽  
...  
Keyword(s):  

2021 ◽  
Vol 9 (E) ◽  
pp. 1486-1490
Author(s):  
Dwi Sudiarto ◽  
Nurhayati Nurhayati ◽  
Fajriansyah Fajriansyah

BACKGROUND: It is known the effectiveness of a venturi aerator, deposition with a sand filter magnet and ion exchange in one unit to reduce Fe content, total dissolved solid (TDS) and saltiness (CL content) in clean water, and the ability of ion exchange to reduce CL content is known. AIM: This study aims to analyze the effectiveness of venturi aerator, magnetic sedimentation, filtration, and ion exchange in one unit against Fe, TDS, and CL well water. METHODS: The method used is a quasi-experimental method using aeration with a venturi system, deposition with magnets, filtration, and ion exchange. The population in this study was all water containing Fe and CL in the Darul Kamal sub-district, Aceh Besar. The sample in this study is part of the population following research needs. RESULTS: The results showed an effect of a venturi aerator, deposition with magnets, filtering sea sand, anion, and cation resins in one unit to decrease Fe content and did not affect decreasing TDS content and Salinity. Moreover, a venturi aerator has an effect, deposition with magnets, filtering sea sand, anion, and cation resins in one unit on the decrease in Fe content, TDS, and salinity at deposition time of 24 h. Venturi aerator’s effect on Fe reduction does not affect TDS and CL of well water. There is an effect of venturi aerator and precipitation with magnets, in one unit on Fe reduction, and does not affect TDS and CL of well water. There is an effect of venturi aerator, precipitation with magnets, filtration in one unit on Fe reduction, no effect on TDS, and CL of well water. CONCLUSION: This tool effectively reduces Fe content and effectively reduces Fe, TDS, and salinity at a 24 h deposition time.


2021 ◽  
pp. 105134
Author(s):  
Diego Barcellos ◽  
Hermano M. Queiroz ◽  
Amanda D. Ferreira ◽  
Angelo F. Bernardino ◽  
Gabriel Nuto Nóbrega ◽  
...  

2021 ◽  
Author(s):  
Bo Shan ◽  
Yuzhu Xiong

Abstract Developing the polymer-based thermal interface materials (TIMs) is one of the most promising approaches to address heat accumulation along with the functionalization, integration, and miniaturization of modern electronics, while it is still a great challenge to balance the thermal conductivity and mechanical properties. In this article, Fe ion-anchored graphene (FeG) is successfully fabricated by a facile in situ Fe reduction of graphene oxide (GO) approach, and then cellulose nanofiber (CNF)/FeG composites are prepared by vacuum-assisted filtration. FeG exhibits excellent dispersion and exfoliation in CNF/FeG composites, due to the strong interfacial interaction between CNF and FeG, such as hydrogen bonds and “Fe-O” complex binding. Thus, CNF/FeG composite has the largely improved thermal conductivity up to 30.2 W/mK at FeG content of 50 wt%, which is substantially increased by 1160% in comparison with that of pure CNF. In addition, the mechanical performances of CNF/FeG-50 are unexpectedly simultaneously enhanced to 244 MPa for tensile strength, 4.10% for elongation at break, and 9.5 GPa for Young’s modulus, outperforming pure CNF with increase of 137%, 33%, and 121%, respectively. This study provides a significant strategy for the design and construction of high thermal conductivity and high-performance polymeric TIMs in flexible and portable electronics.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1485
Author(s):  
Brady A. Ziegler ◽  
G.-H. Crystal Ng ◽  
Isabelle M. Cozzarelli ◽  
Aubrey J. Dunshee ◽  
Madeline E. Schreiber

We used a reactive transport model to investigate the cycling of geogenic arsenic (As) in a petroleum-contaminated aquifer. We simulated As mobilization and sequestration using surface complexation reactions with Fe(OH)3 during petroleum biodegradation coupled with Fe-reduction. Model results predict that dissolved As in the plume will exceed the U.S. and EU 10 µg/L drinking water standard for ~400 years. Non-volatile dissolved organic carbon (NVDOC) in the model promotes As mobilization by exerting oxygen demand, which maintains anoxic conditions in the aquifer. After NVDOC degrades, As re-associates with Fe(OH)3 as oxygenated conditions are re-established. Over the 400-year simulation, As transport resembles a “roll front” in which: (1) arsenic sorbed to Fe(OH)3 is released during Fe-reduction coupled to petroleum biodegradation; (2) dissolved As resorbs to Fe(OH)3 at the plume’s leading edge; and (3) over time, the plume expands, and resorbed As is re-released into groundwater. This “roll front” behavior underscores the transience of sorption as an As attenuation mechanism. Over the plume’s lifespan, simulations suggest that As will contaminate more groundwater than benzene from the oil spill. At its maximum, the model simulates that ~5.7× more groundwater will be contaminated by As than benzene, suggesting that As could pose a greater long-term water quality threat than benzene in this petroleum-contaminated aquifer.


2021 ◽  
Author(s):  
Anne-Christin Melcher ◽  
Susann Henkel ◽  
Thomas Pape ◽  
Anette Meixner ◽  
Simone A. Kasemann ◽  
...  

<p>The Argentina Continental Margin represents a unique geologic setting to study interactions between bottom currents and sediment deposition as well as their impact on (bio)geochemical processes, particularly the cycling of iron (Fe). Our aim was to determine (1) how different depositional conditions control post-depositional (bio)geochemical processes and (2) how stable Fe isotopes (δ<sup>56</sup>Fe) of pore water and solid phases are affected accordingly. Furthermore, we (3) evaluated the applicability of δ<sup>56</sup>Fe of solid Fe pools as a proxy to trace past diagenetic alteration of Fe, which might be decoupled from current redox conditions. Sediments from two different depositional environments were sampled during RV SONNE expedition SO260: a site dominated by contouritic deposition on a terrace (Contourite Site) and the lower continental slope (Slope Site) dominated by hemipelagic sedimentation. Sequentially extracted sedimentary Fe [1] and δ<sup>56</sup>Fe analyses of extracts and pore water [2,3] were combined with sedimentological, radioisotope, geochemical and magnetic data. Our study presents the first sedimentary δ<sup>56</sup>Fe dataset at the Argentina Continental Margin.</p><p>The depositional conditions differed between and within both sites as evidenced by variable grain sizes, organic carbon contents and sedimentation rates. At the Contourite Site, non-steady state pore-water conditions and diagenetic overprint occurs in the post-oxic zone and the sulfate-methane transition (SMT). In contrast, pore-water profiles at the Slope Site suggest that currently steady-state conditions prevail, leading to a strong diagenetic overprint of Fe oxides at the SMT. Pore-water δ<sup>56</sup>Fe values at the Slope Site are mostly negative, which is typical for on-going microbial Fe reduction. At the Contourite Site the pore-water δ<sup>56</sup>Fe values are mostly positive and range between -0.35‰ to 1.82‰. Positive δ<sup>56</sup>Fe values are related to high sulfate reduction rates that dominate over Fe reduction in the post-oxic zone. The HS<sup>- </sup>liberated during organoclastic sulfate reduction or sulfate-mediated anaerobic oxidation of methane (AOM) reacts with Fe<sup>2+</sup> to form Fe sulfides. Hereby, light Fe isotopes are preferentially removed from the dissolved pool. The isotopically light Fe sulfides drive the acetate-leached Fe pool towards negative values. Isotopic trends were absent in other extracted Fe pools, partly due to unintended dissolution of silicate Fe masking the composition of targeted Fe oxides. Significant amounts of reactive Fe phases are preserved below the SMT and are possibly available for reduction processes, such as Fe-mediated AOM [4]. Fe<sup>2+</sup> in the methanic zone is isotopically light at both sites, which is indicative for a microbial Fe reduction process.</p><p>Our results demonstrate that depositional conditions exert a significant control on geochemical conditions and dominant (bio)geochemical processes in the sediments of both contrasting sites. We conclude that the applicability of sedimentary δ<sup>56</sup>Fe signatures as a proxy to trace diagenetic Fe overprint is limited to distinct Fe pools. The development into a useful tool depends on the refining of extraction methods or other means to analyse δ<sup>56</sup>Fe in specific sedimentary Fe phases.</p><p> </p><p>References:</p><p>[1]Poulton and Canfield, 2005. Chemical Geology 214: 209-221.<br>[2]Henkel et al., 2016. Chemical Geology 421: 93-102.<br>[3]Homoky et al., 2013. Nature Communications 4: 1-10.<br>[4]Riedinger et al., 2014. Geobiology 12: 172-181.</p>


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Vera Viena ◽  
Elvitriana Elvitriana ◽  
Zulhaini Sartika ◽  
Diana Patra

Patchouli oil refinery in Gayo Lues Aceh Indonesia commonly used evaporation process in an old drums at high temperature which decreased the quality of oil produced. The research to enhance the quality of patchouli alcohol of Gayo Lues patchouli oil using Citrus hystrix absorber has been done.The juice from kaffir lime (1 – 10 % v/v) used as chelating agent, and the kaffir peels powder (2,5 - 7 gr) used as bio sorbent. The highest patchouli alcohol (P.A) both resulted at T=50 oC and 60 minutes heating. Kaffir bio sorbent at 7,5 gr usage, gave 40,37% P.A and Fe reduction of 77,67%; while kaffir lime juice at 4% v/v usage, gave P.A 39,90% and Fe reduction of 78,25%. Purified patchouli oil also characterized by its light yellow color, density and refractive index based on SNI.06-2385-2006. It’s concluded that kaffir peels bio sorbent purification has superior P.A quality than kaffir lime juice.


2020 ◽  
Vol 125 (12) ◽  
Author(s):  
Salvatore Calabrese ◽  
Diego Barcellos ◽  
Aaron Thompson ◽  
Amilcare Porporato
Keyword(s):  

2020 ◽  
Vol 30 (11) ◽  
pp. 2941-2951
Author(s):  
Dong-dong GU ◽  
Jia-wen WANG ◽  
Yu-bin CHEN ◽  
Jian PENG

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