Synergistic process using calcium peroxide and ferrous iron for enhanced ultrafiltration of Microcystis aeruginosa-laden water

Abstract The chlorobenzene (CB) degradation performances by various oxidants, including hydrogen peroxide (H2O2), nanoscale calcium peroxide (nCaO2) and sodium percarbonate (SPC), activated with ferrous iron (Fe(II)) were investigated and thoroughly compared. The results showed that all tested systems had strong abilities to degrade CB. The CB removal rate increased with increasing dosages of oxidants or Fe(II) because the generation of reactive oxygen species could be promoted with the chemical dosages' increase. Response surface and contour plots showed that CB could achieve a better removal performance at the same H2O2 and Fe(II) molar content, but the Fe(II) dosage was higher than that of oxidants in the nCaO2 and SPC systems. The optimal molar ratios of H2O2/Fe(II)/CB, nCaO2/Fe(II)/CB and SPC /Fe(II)/CB were 5.2/7.6/1, 8/8/1, and 4.5/8/1, respectively, in which 98.1%, 98%, and 96.4% CB removals could be obtained in 30 min reaction. The optimal pH condition was around 3, while CB removal rates were less than 20% in all three systems when the initial pH was adjusted to 9. The oxidative hydroxyl radicals (HO•) and singlet oxygen (1O2) had been detected by the electron paramagnetic resonance test. Based upon the results of liquid chromatograph-mass spectrometer analysis, the pathways of CB degradation were proposed, in which 1O2 roles were elaborated innovatively in the CB degradation mechanism. The CB degradation performance was significantly affected in actual groundwater, while increasing the molar ratio of oxidant/Fe(II)/CB was an effective way to overcome the adverse effects caused by the complex of actual groundwater matrix.

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Characteristics of the Freshwater Cyanobacterium Microcystis aeruginosa Grown in Iron-Limited Continuous Culture

Applied and Environmental Microbiology ◽

10.1128/aem.06908-11 ◽

2011 ◽

Vol 78 (5) ◽

pp. 1574-1583 ◽

Cited By ~ 33

Author(s):

T. C. Dang ◽

M. Fujii ◽

A. L. Rose ◽

M. Bligh ◽

T. D. Waite

Keyword(s):

Microcystis Aeruginosa ◽

Ferrous Iron ◽

Growth Characteristics ◽

Edta Complex ◽

Short Term ◽

Content Type ◽

Absorption Of Light ◽

Biological Uptake ◽

Fe Uptake ◽

Good Agreement

ABSTRACTA continuous culturing system (chemostat) made of metal-free materials was successfully developed and used to maintain Fe-limited cultures ofMicrocystis aeruginosaPCC7806 at nanomolar iron (Fe) concentrations (20 to 50 nM total Fe). EDTA was used to maintain Fe in solution, with bioavailable Fe controlled by absorption of light by the ferric EDTA complex and resultant reduction of Fe(III) to Fe(II). A kinetic model describing Fe transformations and biological uptake was applied to determine the biologically available form of Fe (i.e., unchelated ferrous iron) that is produced by photoreductive dissociation of the ferric EDTA complex. Prediction by chemostat theory modified to account for the light-mediated formation of bioavailable Fe rather than total Fe was in good agreement with growth characteristics ofM. aeruginosaunder Fe limitation. The cellular Fe quota increased with increasing dilution rates in a manner consistent with the Droop theory. Short-term Fe uptake assays using cells maintained at steady state indicated thatM. aeruginosacells vary their maximum Fe uptake rate (ρmax) depending on the degree of Fe stress. The rate of Fe uptake was lower for cells grown under conditions of lower Fe availability (i.e., lower dilution rate), suggesting that cells in the continuous cultures adjusted to Fe limitation by decreasing ρmaxwhile maintaining a constant affinity for Fe.

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Mechanisms and performance of calcium peroxide-enhanced Fe(ii) coagulation for treatment of Microcystis aeruginosa-laden water

Environmental Science Water Research & Technology ◽

10.1039/d0ew00005a ◽

2020 ◽

Vol 6 (5) ◽

pp. 1272-1285

Author(s):

Huaijia Xin ◽

Shu Yang ◽

Yulin Tang ◽

Mengyi Wu ◽

Yang Deng ◽

...

Keyword(s):

Microcystis Aeruginosa ◽

Calcium Peroxide ◽

Pre Treatment ◽

And Performance

Pre-oxidation has been extensively studied as a pre-treatment for enhancement of algae-laden water coagulation.

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Influence of increased nutrient supply on Microcystis aeruginosa at cellular and proteomic levels

Aquatic Microbial Ecology ◽

10.3354/ame01939 ◽

2020 ◽

Vol 85 ◽

pp. 47-58

Author(s):

Y Jiang ◽

Y Liu

Keyword(s):

Microcystis Aeruginosa ◽

Regulatory Protein ◽

Acid Synthesis ◽

Nutrient Supply ◽

Nitrogen Supply ◽

Nitrogen And Phosphorus ◽

Comprehensive Description ◽

Amino Acid Synthesis ◽

High Nutrient ◽

Proteomic Responses

Various studies have observed that increased nutrient supply promotes the growth of bloom-forming cyanobacteria, but only a limited number of studies have investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. We investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nutrients significantly promoted the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under high nutrient levels. Overexpressed proteins related to photosynthesis, and amino acid synthesis, were responsible for the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth by inducing the overexpression of the cell division regulatory protein FtsZ. NtcA, that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis, was overexpressed under the high nitrogen condition, which consequently induced overexpression of 2 microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provides a comprehensive description of changes in the proteome of M. aeruginosa in response to an increased supply of 2 key nutrients.

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PENDEKATAN EKSPLORASI RESERVOIR ONSHORE MELALUI PEMETAAN REMBESAN MIKRO HIDROKARBON DENGAN CITRA HIPERSPEKTRAL

Seminar Nasional Geomatika ◽

10.24895/sng.2018.3-0.1042 ◽

2019 ◽

Vol 3 ◽

pp. 1181

Author(s):

Muhamad Iqbal Januadi Putra

Keyword(s):

Ferrous Iron

Kapabilitas citra satelit hiperspektral yang memiliki keunggulan spektral sangat berpotensi untuk dimanfaatkan dalam eksplorasi keberadaan reservoir onshore. Kemampuan ini dilakukan melalui perekaman spektral fenomena rembesan mikro hidrokarbon yang menimbulkan ekspresi anomali spektral tanah dan menjadi kunci keberadaan sumber hidrokarbon. Dalam penelitian ini, Sub-Cekungan Jatibarang dipilih sebagai wilayah penelitian. Berdasarkan teori spektral rembesan mikro hidrokarbon, citra Hyperion dapat digunakan sebagai alat untuk mendeteksi keberadaan fenomena rembesan mikro hidrokarbon sebagai penduga keberadaan reservoir onshore karena memiliki spektrum panjang gelombang yang peka terhadap objek anomali hidrokarbon. Sehingga, penelitian ini bertujuan untuk mendeteksi area rembesan mikro hidrokarbon dengan citra Hyperion di Cekungan Jatibarang. Hydrocarbon Index (HI) yang memanfaatkan saluran 155 (1.699 nm), 158 (1.729 nm), dan 160 (1.749 nm) digunakan sebagai algoritma untuk medeteksi area rembesan mikro hidrokarbon di Sub-Cekungan Jatibarang. Gejala anomali alterasi kaolinite, ferrous iron dan gejala anomali vegetasi dengan indeks NDVI digunakan sebagai pembanding akurasi HI. Hasil penelitian ini menunjukkan adanya sebaran rembesan mikro hidrokarbon di wilayah Kecamatan Tukdana (Indramayu), Kecamatan Pasekan (Indramayu), dan Kecamatan Ligung (Majalengka). Area sebaran rembesan mikro hidrokarbon teraglomerasi pada wilayah pesisir utara Kecamatan Pasekan. Secara umum, keberadaan rembesan mikro hidrokarbon berkorelasi dengan tingkat anomali alterasi kaolinite, ferrous iron, dan anomali vegetasi.

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Synthesis and Breakdown of the Universal Precursors to Biological Metabolism Promoted by Ferrous Iron

10.26434/chemrxiv.7178930.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Kamila B. Muchowska ◽

Sreejith Jayasree VARMA ◽

Joseph Moran

Keyword(s):

Amino Acids ◽

Chemical Reaction ◽

Metabolic Pathways ◽

Ferrous Iron ◽

Reaction Network ◽

Tca Cycle ◽

Chemical Reaction Network ◽

Metabolic Precursors ◽

Tca Cycle Intermediates

How core biological metabolism initiated and why it uses the intermediates, reactions and pathways that it does remains unclear. Life builds its molecules from CO2 and breaks them down to CO2 again through the intermediacy of just five metabolites that act as the hubs of biochemistry. Here, we describe a purely chemical reaction network promoted by Fe2+ in which aqueous pyruvate and glyoxylate, two products of abiotic CO2 reduction, build up nine of the eleven TCA cycle intermediates, including all five universal metabolic precursors. The intermediates simultaneously break down to CO2 in a life-like regime resembling biological anabolism and catabolism. Introduction of hydroxylamine and Fe0 produces four biological amino acids. The network significantly overlaps the TCA/rTCA and glyoxylate cycles and may represent a prebiotic precursor to these core metabolic pathways.

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