Removal of Bound PAH Residues in Contaminated Soils by Fenton Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 619 ◽  
Author(s):  
Xuqiang Zhao ◽  
Li Qin ◽  
Michael Gatheru Waigi ◽  
Pengfei Cheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Contaminated Soils ◽  
Chelating Agent ◽  
Fenton Oxidation ◽  
Valuable Insight ◽  
First Order Kinetics ◽  
Bound Residues ◽  
Polycyclic Aromatic ◽  
Insight Into

The availability of bound residues of polycyclic aromatic hydrocarbons (PAHs), in reference to their parent compounds, can be enhanced by microbial activity and chemical reactions, which pose severe risks for the ecosystems encompassing contaminated soils. Considerable attention has been raised on how to remove these bound residues from PAH-contaminated soils. This paper provides a novel application of Fenton oxidation in the removal of bound residues of model PAHs, such as naphthalene (NAP), acenaphthene (ACP), fluorene (FLU) and anthracene (ANT), from naturally contaminated soils. The citric acid-enhanced Fenton treatment resulted in the degradation of bound PAH residues that followed pseudo-first-order kinetics, with rate constants within 4.22 × 10−2, 1.25 × 10−1 and 2.72 × 10−1 h−1 for NAP, FLU, and ANT, respectively. The reactivity of bound PAH residues showed a correlation with their ionization potential (IP) values. Moreover, the degradation rate of bound PAH residues was significantly correlated with H2O2-Fe2+ ratio (m/m) and H2O2 concentrations. The highest removal efficiencies of bound PAH residues was up to 89.5% with the treatment of chelating agent oxalic acid, which was demonstrated to be superior to other acids, such as citric acid and hydrochloric acid. This study provides valuable insight into the feasibility of citric acid-Fenton and oxalic acid-Fenton treatments in rehabilitating bound PAH residues in contaminated soils.

Remediation of Arsenic Contaminated Soils and Treatment of Washing Effluent Using Calcined Mn-Fe Layered Double Hydroxide

2014 ◽  
Vol 955-959 ◽  
pp. 2014-2021 ◽  
Author(s):  
Pei Ya Liu ◽  
Huan Liu ◽  
Yu Jiao Li ◽  
Chang Xun Dong
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Layered Double Hydroxide ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Pure Water ◽  
Soil Washing ◽  
Extraction Rate ◽  
Effective Capacity ◽  
Double Hydroxide

Arsenic contaminated soil is a serious worldwide problem nowadays, and soil washing technique is one of hottest topics in the area of remediating arsenic contaminated soils, while treatment of the washing effluent is still an urgent problem. In this study, in order to select the best washing extractants for arsenic contaminated soil of the Xiangxi Autonomous Prefecture, nine kinds of extractants (citric acid, oxalic acid, malic acid, tartaric acid, H3PO4, KH2PO4, KOH, NH4Ac and ultra-pure water) were studied. Innovatively, a new material (calcined Mn-Fe Layered double hydroxide) was firstly introduced and fully applied to the adsorption of arsenic washing effluents. Results showed citric acid, oxalic acid and KH2PO4 were the optimal extractants for arsenic contaminated soil, considering the extraction rate and environmental perspective. When the concentrations were 200, 300, 300 mmol/ L , solution soil ratios were 10, 10, 20 mL/g , extraction times were 12,12,12 h, the citric acid, oxalic acid and KH2PO4, respectively, achieved the maximum extraction rate of 39%, 65% and 29%. Calcined Mn-Fe LDH used in this work was characterized by SEM and FT-IR, indicating the unique structure and high phase purity of the synthetic samples. For the 28mg/L arsenic effluent washing by citric acid, calcined Mn-Fe LDH showed the most effective capacity as adsorbent under neutral or weak base condition as well as 2 h absorption time.

scholarly journals Removal of Chromium from a Contaminated Soil Using Oxalic Acid, Citric Acid, and Hydrochloric Acid: Dynamics, Mechanisms, and Concomitant Removal of Non-Targeted Metals

2019 ◽  
Vol 16 (15) ◽  
pp. 2771 ◽  
Author(s):  
Sun ◽  
Guan ◽  
Yang ◽  
Wang
Keyword(s):  
Citric Acid ◽  
Hydrochloric Acid ◽  
Oxalic Acid ◽  
Contaminated Soil ◽  
Photoelectron Spectroscopy ◽  
Contaminated Soils ◽  
Acid Leaching ◽  
Morphological Properties ◽  
X Ray ◽  
Fe And Mn

Soil leaching is an effective remediation technique using agents to leach the target pollutants from the soil. However, the dynamics and mechanisms for leaching of Cr and other non-pollutant metals from Cr-contaminated soils are not yet well understood. Here, column leaching experiments were conducted to determine the effect of hydrochloric acid (HCl), citric acid (CA), and oxalic acid (OX) on the leaching of Cr, as well as of Ca, Mg, Fe, and Mn, from a soil contaminated by a Cr slag heap. Acid leaching decreased soil pH and enhanced the mobility of all the surveyed metals. Leaching dynamics varied with both metals and acids. OX had the highest removal rates for Cr, Fe, Mn, and Mg, but had the poorest ability to leach Ca. HCl leached the largest amount of Ca, while CA leached similar amounts of Mg and Mn to OX, and similar amounts of Fe and Cr to HCl. Cr in the leachates was correlated with Ca, Mg, Fe, and Mn. Cr mainly interacted with soil mineral components and showed a punctate distribution in soil particles. The X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) analyses showed soil mineralogical and morphological properties were differently altered after leaching by different acids. Complexation of Cr(III), competitive desorption, and reduction of Cr(VI) make significant contribution to Cr leaching by organic acids. In conclusion, OX can be applied in leaching remediation of Cr-contaminated soil, but the concomitant removal of other non-targeted metals should be taken into account because of the loss of soil minerals and fertility.

Effects of Acid on the Performance of Polishing Process

2016 ◽  
Vol 700 ◽  
pp. 50-59 ◽  
Author(s):  
Nurul Syafiqah Hasni ◽  
Noorina Hidayu Jamil ◽  
Abdullah Chik ◽  
Wi Wan Mohd Arif ◽  
Hong Eng Seong
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Chelating Agent ◽  
Polishing Process ◽  
Quality Problem ◽  
Difference Type ◽  
Magnetic Substrate ◽  
Lapping Machine

The serious quality problem in the magnetic substrate during polishing process by using conventional lapping machine had generate the idea to develop a doubled-sided lapping machine of polishing stone manufactured of an abrasive and resin. After certain parameter of polishing process, the polishing stone starts to clog because of debris agglomeration from the polishing substrate, thus lead to the scratches on the magnetic substrate which will affect its performance. Three difference type of acid were used as to dissolve the debris agglomeration in the polishing stone. The influence of oxalic, phosphoric and citric acid at three different times were examined. It was found that oxalic acid is the best chelating agent in dissolving the debris in the polishing stone.

scholarly journals Negative Correlations Between Cultivable Pyrene-degrading Sphingomonas and Active Soil Pyrene Degraders Explain Bioaugmentation Postpone or Failure

2021 ◽  
Author(s):  
Bo Jiang ◽  
Yating Chen ◽  
Yi Xing ◽  
Luning Lian ◽  
Yaoxin Shen ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Magnetic Nanoparticle ◽  
Degradation Efficiency ◽  
Degradation Pathways ◽  
Pyrene Degradation ◽  
Polycyclic Aromatic ◽  
Underlying Mechanisms ◽  
Engineering Practices ◽  
Encoding Genes ◽  
Insight Into

Abstract Background: Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbon (PAHs), but suffers from unsatisfactory performance in engineering practices. It is hypothetically explained by the complicated interactions between indigenous microbes and introduced degrading consortium. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium consisting of Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira by magnetic-nanoparticle mediated isolation (MMI) from soils.Results: Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, explained by its negative correlations with the active pyrene degraders. In contrast, amendment with the active pyrene degrading consortium, pyrene degradation efficiency increased by 30.17%. In addition, pyrene degradation efficiency was positively correlated with the abundance of pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP), which significantly increased in MMI-isolated consortium. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas the MMI-isolated pyrene degrading consortium exhibited both phthalate and salicylate pathways. The results indicated that Sphingomonas sp. YT1005 was not the actual pyrene degrader in soils, and MMI could successfully isolate the active pyrene degraders that were suitable for bioaugmentation.Conclusion: This work revealed the microbial intra-correlations during the bioaugmentation process, uncovered the underlying mechanisms of bioaugmentation postpone with cultivable degraders, and provided a deeper insight into the actual pyrene degraders and degradation pathways in PAHs contaminated soils. Our findings gave new explanations for bioaugmentation postpone or failure, and offered clues to enhance bioaugmentation performance by the active degraders using MMI.

scholarly journals Effectiveness of chelating agent-assisted Fenton-like processes on remediation of glucocorticoid contaminated soil using chemical and biological assessment: performance comparison of CaO2 and H2O2

2021 ◽  
Author(s):  
Yanan Liu ◽  
Quan Zhou ◽  
Zhenyu Li ◽  
Ai Zhang ◽  
Jiaxun Zhan ◽  
...  
Keyword(s):  
Citric Acid ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Treatment Time ◽  
Chelating Agent ◽  
Performance Comparison ◽  
Biological Assessment ◽  
Modified Fenton ◽  
Assessment Performance ◽  
Biological Assessments

Abstract Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. Most studies on GC removal mainly focused on aquatic environment, while GC behaviors in soil were less mentioned. In this study, degradation of three selected GCs in soil have been investigated using citric acid (CA)-modified Fenton-like processes (H2O2/Fe(III)/CA and CaO2/Fe(III)/CA treatments). The results showed that GCs in soil can be removed by modified Fenton-like processes (removal efficiency > 70% for 24 h). CaO2/Fe(III)/CA was more efficient than H2O2/Fe(III)/CA at low oxidant dosage (< 0.28–0.69 mmol/g) for long treatment time (> 4 h). Besides the chemical assessment with GC removal, effects of Fenton-like processes were also evaluated by biological assessments with bacteria and plants. CaO2/Fe(III)/CA was less harmful to the richness and diversity of microorganisms in soil compared to H2O2/Fe(III)/CA. Weaker phytotoxic effects were observed on GC-contaminated soil treated by CaO2/Fe(III)/CA than H2O2/Fe(III)/CA. This study therefore, recommends CaO2 based treatments to remediate GC-contaminated soils.

Study of the resistor material of an automotive spark plug by use of the charge-up effect along with elemental mapping in an electron microprobe

1991 ◽  
Vol 49 ◽  
pp. 742-743
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
J. S. Park ◽  
B. N. Juterbock
Keyword(s):  
Electron Microprobe ◽  
Present Report ◽  
Coated Sample ◽  
Valuable Insight ◽  
Elemental Mapping ◽  
Spark Plug ◽  
Carbon Coated ◽  
Electron Image ◽  
Electron Imaging ◽  
Insight Into

The electric and thermal properties of the resistor material in an automotive spark plug should be stable during its service lifetime. Containing many elements and many phases, this material has a very complex microstructure. Elemental mapping with an electron microprobe can reveal the distribution of all relevant elements throughout the sample. In this work, it is demonstrated that the charge-up effect, which would distort an electron image and, therefore, is normally to be avoided in an electron imaging work, could be used to advantage to reveal conductive and resistive zones in a sample. Its combination with elemental mapping can provide valuable insight into the underlying conductivity mechanism of the resistor.This work was performed in a CAMECA SX-50 microprobe. The spark plug used in the present report was a commercial product taken from the shelf. It was sectioned to expose the cross section of the resistor. The resistor was known not to contain the precious metal Au as checked on the carbon coated sample. The sample was then stripped of carbon coating and re-coated with Au.

Quantum Mechanical Interpretation of the Ultra-Low Energy Methyl-Rotation Dynamics in Porous Metal-Organic Frameworks Probed by Low-Frequency Vibrational Spectroscopy and ab initio Simulations

2018 ◽  
Author(s):  
Qi Li ◽  
Adam J. Zaczek ◽  
Timothy M. Korter ◽  
J. Axel Zeitler ◽  
Michael T. Ruggiero
Keyword(s):  
Ab Initio ◽  
Metal Organic Frameworks ◽  
Low Frequency ◽  
Rotor Dynamics ◽  
Quantum Mechanical ◽  
Valuable Insight ◽  
Void Space ◽  
Ab Initio Simulations ◽  
Metal Organic ◽  
Insight Into

<div>Understanding the nature of the interatomic interactions present within the pores of metal-organic frameworks</div><div>is critical in order to design and utilize advanced materials</div><div>with desirable applications. In ZIF-8 and its cobalt analogue</div><div>ZIF-67, the imidazolate methyl-groups, which point directly</div><div>into the void space, have been shown to freely rotate - even</div><div>down to cryogenic temperatures. Using a combination of ex-</div><div>perimental terahertz time-domain spectroscopy, low-frequency</div><div>Raman spectroscopy, and state-of-the-art ab initio simulations,</div><div>the methyl-rotor dynamics in ZIF-8 and ZIF-67 are fully charac-</div><div>terized within the context of a quantum-mechanical hindered-</div><div>rotor model. The results lend insight into the fundamental</div><div>origins of the experimentally observed methyl-rotor dynamics,</div><div>and provide valuable insight into the nature of the weak inter-</div><div>actions present within this important class of materials.</div>

An Insight into Oligopeptide Transporter 3 (OPT3) family proteins

2020 ◽  
Vol 27 ◽  
Author(s):  
Fırat Kurt
Keyword(s):  
Stress Responses ◽  
Chelating Agent ◽  
Biological Processes ◽  
Biotic And Abiotic Stress ◽  
Oligopeptide Transporter ◽  
Binding Residues ◽  
Fe Homeostasis ◽  
Proteins Interactions ◽  
Insight Into ◽  
Selection Of

: Oligopeptide transporter 3 (OPT3) proteins are one of the subsets of OPT clade, yet little is known about these transporters. Therefore, homolog OPT3 proteins in several plant species were investigated and characterized using bioinformatical tools. Motif and co-expression analyses showed that OPT3 proteins may be involved in both biotic and abiotic stress responses as well as growth and developmental processes. AtOPT3 usually seemed to take part in Fe homeostasis whereas ZmOPT3 putatively interacted with proteins involved in various biological processes from plant defense system to stress responses. Glutathione (GSH), as a putative alternative chelating agent, was used in the AtOPT3 and ZmOPT3 docking analyses to identify their putative binding residues. The information given in this study will contribute to the understanding of OPT3 proteins’ interactions in various pathways and to the selection of potential ligands for OPT3s.

A Review of Phytochemical and Pharmacological Studies of Inula Species

2020 ◽  
Vol 16 (5) ◽  
pp. 557-567
Author(s):  
Aparoop Das ◽  
Anshul Shakya ◽  
Surajit Kumar Ghosh ◽  
Udaya P. Singh ◽  
Hans R. Bhat
Keyword(s):  
Bacterial Infections ◽  
Chemical Constituents ◽  
Valuable Insight ◽  
Important Ingredient ◽  
Pharmacological Activities ◽  
Medicinal Uses ◽  
The Family ◽  
Pharmacological Studies ◽  
Perennial Herbs ◽  
Insight Into

Background: Plants of the genus Inula are perennial herbs of the family Asteraceae. This genus includes more than 100 species, widely distributed throughout Europe, Africa and Asia including India. Many of them are indicated in traditional medicine, e.g., in Ayurveda. This review explores chemical constituents, medicinal uses and pharmacological actions of Inula species. Methods: Major databases and research and review articles retrieved through Scopus, Web of Science, and Medline were consulted to obtain information on the pharmacological activities of the genus Inula published from 1994 to 2017. Results: Inula species are used either alone or as an important ingredient of various formulations to cure dysfunctions of the cardiovascular system, respiratory system, urinary system, central nervous system and digestive system, and for the treatment of asthma, diabetes, cancers, skin disorders, hepatic disease, fungal and bacterial infections. A range of phytochemicals including alkaloids, essential and volatile oils, flavonoids, terpenes, and lactones has been isolated from herbs of the genus Inula, which might possibly explain traditional uses of these plants. Conclusion: The present review is focused on chemical constituents, medicinal uses and pharmacological actions of Inula species and provides valuable insight into its medicinal potential.

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