scholarly journals Promoting mechanism of electronic shuttle for bioavailability of Fe(III) oxide and its environmental significance

2020 ◽  
Vol 20 (4) ◽  
pp. 1157-1166
Author(s):  
Yuning Yang ◽  
Lei Chen ◽  
Yu Jiang ◽  
Zheng Xu ◽  
Shaobo Gao ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Reduction Process ◽  
Accelerate Electron ◽  
Limiting Factors ◽  
Redox Activity ◽  
Electron Shuttle ◽  
Environmental Significance ◽  
Promoting Effect ◽  
Biological Reduction ◽  
Removal Of Heavy Metals

Abstract The biological reduction process of Fe(III) not only strongly affects the circulation of C, N, O, P and other elements in the environment, but also plays an important role in the transformation and degradation of organic and inorganic pollutants. Most Fe(III) oxides existing in nature have low bioavailability due to their poor solubility or strongly crystalline form with stable chemical properties. Addition of a substance having redox activity can form an electron shuttle cycle between Fe(III) oxide and the microorganism, which can not only enhance the bioavailability of Fe(III) and accelerate electron transfer, but also improve the removal efficiency of contaminants. This paper compares and analyzes several common redox active substances, for their promoting effect and limiting factors of Fe(III) bioavailability. Moreover, the mechanism by which the electron shuttle promotes the bioavailability of Fe(III) oxide is discussed. This review demonstrates that the electron shuttle promotes the Fe(III) bioreaction process for the degradation and removal of heavy metals, polycyclic aromatic hydrocarbons, azo dyes and other pollutants, which is of great environmental significance.

A Critical Review of the Biological Processes in the Chemical Absorption-biological Reduction Integrated System for NO Removal

2021 ◽  
Vol 07 ◽  
Author(s):  
Wei Li
Keyword(s):  
Catalytic Reduction ◽  
Low Cost ◽  
Reduction Process ◽  
Integrated System ◽  
Future Research ◽  
Small Scale ◽  
Biological Processes ◽  
Chemical Absorption ◽  
Biological Reduction ◽  
Biological Reaction

: Exploring low-cost, green and safe technologies to provide an alternative to the conventional selective catalytic reduction process is key to the control of NOx emitted from small-scale boilers and other industrial processes. To meet the demand, the chemical absorption-biological reduction integrated system has been developing recently. chemical absorption-biological reduction integrated system applies Fe(II)EDTA for NO absorption and iron-reducing and denitrifying bacteria for absorbent regeneration. Many studies have focused on the enhancements of mass transfer and biological reaction, among which the biological processes were the rate-limiting steps. This review summarizes the current researches on the biological processes in the CABR system, which focuses on the mechanism and enhancement of biochemical reactions, and provides the possible directions of future research.

scholarly journals Changes in some chemical properties of saline-sodic soils over time as affected by organic residues: An incubation study

2020 ◽  
Vol 53 (1) ◽  
pp. 1
Author(s):  
Mohsen Jalali ◽  
Maryam Saeedi Lotf ◽  
Faranak Ranjbar
Keyword(s):  
Crop Production ◽  
Positive Impact ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Limiting Factors ◽  
Plant Residues ◽  
Organic Residues ◽  
Sodic Soils ◽  
Treated Soil ◽  
Incubation Study

<p>Salinization and sodification of agricultural lands in arid and semi-arid regions of the world are two limiting factors in the crop production. This study was conducted to evaluate the effect of readily available agricultural residues on changing some chemical properties of saline-sodic soils. Wheat, potato, sunflower, and canola residues were separately added into three saline-sodic soils at a rate of 2% by weight and thoroughly mixed with soils. Control and treated soils were incubated for 168 days at a constant moisture and temperature. The pH, electrical conductivity (EC), soluble cations, available nitrate (NO3-) and phosphorous (P), cation exchange capacity (CEC), and exchangeable sodium percentage (ESP) were measured during the incubation. The EC increased in the response to the incorporation of plant residues, whereas the pH was reduced. The application of organic components in soils increased CEC and decreased ESP. The results showed that the maximum reduction in ESP was observed in the potato treatment because of the highest Ca2+ concentration. The average reduction in ESP of treated soil samples at the end of incubation followed this order: 16.1% (potato residue-treated soil) &gt;12.7% (canola residue-treated soil) &gt;11.1% (wheat residue-treated soil) &gt;9.6% (sunflwer residue-treated soil). The potato residue was the most effective amendment in changing the chemical properties of saline-sodic soils in comparison with other organic residues. The results indicated that the application of organic residues had a positive impact on reducing the soil sodicity and improving the soil fertility depending on their chemical composition.</p>

Structural Defect Formation in Inorganic Sol-Gel Derived Oxides

2005 ◽  
Vol 242-244 ◽  
pp. 143-158 ◽  
Author(s):  
Elena V. Frolova ◽  
Mariya I. Ivanoskaya
Keyword(s):  
Defect Formation ◽  
Complex Structure ◽  
Sol Gel ◽  
Chemical Properties ◽  
Reduction Process ◽  
Molar Ratios ◽  
Glass Forming ◽  
Structural Peculiarities ◽  
Complex Metal Oxides ◽  
Physical And Chemical

The advantages and uniqueness of the Inorganic modification of the Sol-Gel method have already been described. Homogeneous nano-composites as well as some exotic glasses, complex-metal-oxides systems with little glass-forming ability, can be produced by this method. Thus, the obtained materials are characterized by a complex structure that leads to the wide variety of physical and chemical properties. Zirconia-containing materials are of utmost interest because of the mechanical toughness and chemical resistance provided by the presence of ZrO2. In the present work, we report on unusual structural peculiarities of the Zr-O, two types of Zr-Ge-O systems (with Zr>Ge and Zr<Ge molar ratios) and Zr-Ce-Al-O glassy samples, successfully prepared by inorganic modification of the Sol-Gel technique. We tried to elucidate the cause of a self-reduction process in those oxides systems under thermal treatment in air and the way in which structural imperfections impact upon some properties of the materials obtained.

Influence of pH on hexavalent chromium reduction by Fe(II) and sulfide compounds

2015 ◽  
Vol 72 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Juan Chen ◽  
Ri Chen ◽  
Mei Hong
Keyword(s):  
Reduction Process ◽  
Single Species ◽  
Batch Experiments ◽  
Chromium Reduction ◽  
Promoting Effect ◽  
Ph Values ◽  
Ph Dependent ◽  
Ph Range ◽  
Influence Of Ph ◽  
Sulfide Species

Abstract Batch experiments were conducted to investigate the influence of pH on Cr(VI) reduction with Fe(II), sulfide and mixtures of Fe(II) and sulfide at pH 3.0–12.0. The results showed that Fe(II) could reduce Cr(VI) with a high removal of nearly 100% in the pH range of 3.0–9.0, while the reduction of Cr(VI) decreased to approximately 60% considering the oxygenation of Fe(II) at pH 12.0. The reaction between Cr(VI) and sulfide, however, was largely pH dependent. H2S was the main sulfide species with the Cr(VI) removal of ∼80% at pH &lt; 7.0, while sulfide mainly existed in the forms as HS− or S2− at pH ≥ 7.0, which had very limited removal of Cr(VI) (no more than 10%). The Cr(VI) removal by the mixtures of Fe(II) and sulfide was also compared with the sum of separate ones at different pH values. The sum of Cr(VI) removal by single Fe(II) and S(-II) was similar to that by the mixtures at pH 3.0–5.0 and pH 12.0, while the removal of Cr(VI) by the mixtures was observed to be more effective than the sum of the single-species removals at pH 7.0–9.0; the promoting effect was primarily attributed to the catalysis of ferric ion generated during the reduction process.

scholarly journals Design and characterization of 2D MXene-based electrode with high-rate capability

MRS Bulletin ◽  
2021 ◽  
Author(s):  
Xuehang Wang ◽  
Lars Bannenberg
Keyword(s):  
Energy Storage ◽  
Interlayer Space ◽  
Rate Capability ◽  
Chemical Properties ◽  
Active Surface ◽  
High Rate ◽  
Limiting Factors ◽  
Redox Active ◽  
Systematic Understanding ◽  
The Impact

AbstractMXenes, two-dimensional transition metal carbides and nitrides, are promising materials for electrochemical energy storage application due to their redox-active surface and flexible interlayer space. Among all reported MXene-based electrodes, some have shown significantly better high-rate energy storage capabilities. Hence, it is crucial to have a systematic understanding on the decisive factors of the rate capability in the MXene family. This article discusses the impact of material properties at three levels, including intralayer composition, interlayer space and morphology, on the charge transfer and ion transport, revealing all the possible rate-limiting factors of MXene-based electrodes. We also describe systematic methods to characterize MXene electrodes as a detailed fundamental understanding of the structural and chemical properties, and the charge storage mechanisms crucial for rationally designing MXene-based electrodes. Graphic abstract

scholarly journals Kajian Metode Evaluasi Kesesuaian Lahan untuk Kakao di Kabupaten Bantaeng

2019 ◽  
Vol 3 (2) ◽  
pp. 85
Author(s):  
Anwar Anwar ◽  
Muliati Galib ◽  
Wahyuni M
Keyword(s):  
Soil Fertility ◽  
Physical Properties ◽  
Soil Depth ◽  
Chemical Properties ◽  
Land Suitability ◽  
Land Evaluation ◽  
Limiting Factors ◽  
Limiting Factor ◽  
Suitability Analysis ◽  
Effective Depth

Land evaluation is an assessment of the potential of land resources. The results of land evaluation will provide information on the best use of it which will lead to expected value of production. This study aimed to determine the level of suitability of the cocoa plantations in Bantaeng Regency using the FAO and Sys methods; make a map of the actual and potential land suitability. The results of the analysis showed that the actual cocoa land suitability of the FAO method was presented in distribution points according to marginal (S3rn) with limiting factor of rooting media and nutrients availability. While the actual land suitability analysis of the cocoa Sys method was not suitable (N1cSf) with climate limiting factors, the soil physical properties and soil fertility. Based on the limiting factors the physical properties of the two methods, there were similarities in effective depth (FAO) and soil depth (Sys), S3 parameters according to FAO and N1 according to Sys. The limiting factor for the soil chemical properties of the two methods was also the same, the availability of S3 (FAO) nutrients, while the (Sys) method was the soil fertility N1.

Influence of Limiting Factors on Phytoplankton and Coliform Population in an Inundated, Isolated Wetland

2009 ◽  
Vol 3 ◽  
pp. 43-56 ◽  
Author(s):  
JI Nirmal Kumar ◽  
Cini Oommen
Keyword(s):  
Chemical Properties ◽  
Correlation Coefficients ◽  
Single Species ◽  
Total Coliform ◽  
Fecal Coliforms ◽  
Limiting Factors ◽  
Phytoplankton Species ◽  
Isolated Wetland ◽  
Total Phytoplankton ◽  
Study Sites

The relationships of phytoplankton with physical (temperature, pH), chemical (dissolved oxygen, phosphate, sulphate and nitrate) and biotic (total and fecal coliforms) parameters were analysed for the year September 2007 to August 2008 in a seasonally inundated, isolated wetland - Malwar which is situated between 22° 36'55.78" N and 72°54'58.01" E; about 7 kilometres from Anand, near Kanjari- Boriyavi railway station, Central Gujarat, India. Phytoplankton species belonged to Cyanophyceae, Chlorophyceae, Bacillariophyceae and Euglenophyceae. Cyanophyceae members accounted for 68% of the total phytoplankton population, followed by Chlorophyceae which accounted for 23% and the rest 9% were the members of Bacillariophyceae and a single species of Euglenophyceae. ANOVA indicated significant variation in phytoplankton species richness between the two study sites (P ≤ 0.001). Significant temporal variation for Cyanophyceae density (P ≤ 0.05) was also recorded. Correlation coefficients (r) among the various hydro-chemical properties and different phytoplankton groups (densities) were calculated (correlation matrix). Key words: Phytoplankton; total coliform; fecal coliform; hydro-chemical parameters DOI: 10.3126/jowe.v3i0.2225 Journal of Wetlands Ecology, (2009) Vol. 3, pp 43-55

Bioleaching of heavy metals from contaminated aquatic sediments using indigenous sulfur-oxidizing bacteria: a feasibility study

1998 ◽  
Vol 37 (6-7) ◽  
pp. 387-394 ◽  
Author(s):  
H. Seidel ◽  
J. Ondruschka ◽  
P. Morgenstern ◽  
U. Stottmeister
Keyword(s):  
Heavy Metals ◽  
Pilot Plant ◽  
River Sediments ◽  
Chemical Properties ◽  
Leaching Potential ◽  
Removal Of Heavy Metals ◽  
Sulfur Oxidizing ◽  
Physical And Chemical ◽  
Better Than ◽  
Sulfur Oxidizing Bacteria

The removal of heavy metals from contaminated river sediments was studied using suspension leaching under laboratory conditions and percolation leaching in a pilot plant. The leaching potential of indigenous sulfur-oxidizing bacteria was compared with acid treatment. Bioleaching with elemental sulfur as substrate was found to be better than treatment with sulfuric acid for the solubilization of all metals tested. The physical and chemical properties of the sediments used in this study did not affect leaching capacity under optimum conditions in the laboratory. Under the practical conditions in the pilot plant, the redox state of sludge had a considerable influence on leaching efficiency. In a deposited oxic sediment with good permeability, about 62% of the metals tested were removed by percolation leaching after 120 days. Zn, Cd, Ni, Co and Mn were sufficiently leached to enable treated sediments to be reused as soil. In a freshly dredged anoxic sediment, only a total of 9 % of metals were removed. The results indicate that freshly dredged sediments need to undergo pretreatment before percolation leaching to improve mass transfer and to activate the leaching active bacteria.

scholarly journals Assessing soil fertility status and land suitability for patchouli plants (Pogostemon cablin Benth.) in Lamala District, Banggai Regency

2021 ◽  
Vol 2 (1) ◽  
pp. 50-58
Author(s):  
Yulinda Karundeng ◽  
Hertasning Yatim ◽  
Hidayat Arismunandar Katili ◽  
Lina Lathifah Nurazizah
Keyword(s):  
Soil Fertility ◽  
Nutrient Deficiency ◽  
Chemical Properties ◽  
Base Cations ◽  
Soil Nutrient ◽  
Land Suitability ◽  
Limiting Factors ◽  
Organic C ◽  
Fertility Status ◽  
Soil Fertility Status

Besides influenced by genotype, the quality and quantity of patchouli essential oil were controlled by soil as a growing medium. The development of patchouli plantation in Lamala District is still hampered by negative stigma from the community. It is believed, the strong absorption rate from patchouli could lead to soil nutrient deficiency. The purpose of this study was to determine soil fertility status and evaluate its suitability for patchouli plant in 3 land units (e.g., uncultivated, cultivated with fertilization, and cultivated without fertilization). The method used is an Exploratory-Descriptive Survey. The determination of soil properties was based on physical properties such as texture, and chemical properties such as pH, organic-C and nitrogen, P2O5 and K2O, base cations and cation exchange capacity/CEC, and Fe. The data then matched to Soil Fertility and Land Suitability Criteria for the patchouli plant. The result showed that the chemical properties in 3 land units had slightly acidic, high CEC, medium base saturation, moderate P2O5 content, and moderate organic-C content. Meanwhile, the K2O content of the land without patchouli was very low and the patchouli with and without fertilizer was low. Soil fertility status in 3 land units was classified as marginally suitable (S3-rc,na), this is due to the limiting factors; soil texture (rc) and P2O5 (na).

Biogenic gold nanoparticles-reduced graphene oxide nanohybrid: synthesis, characterization and application in chemical and biological reduction of nitroaromatics

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97798-97806 ◽  
Author(s):  
Bin Dong ◽  
Guangfei Liu ◽  
Jiti Zhou ◽  
Aijie Wang ◽  
Jing Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Accelerate Electron ◽  
Biological Reduction ◽  
Reduced Graphene

The biogenic AuNPs/rGO can participate in and accelerate electron transfer, and catalyze both chemical and biological reduction of nitroaromatics efficiently.

Sign in / Sign up

Export Citation Format

Share Document