Competitive removal of DOM and bromide in raw waters by MIEX and iron coagulation

2013 ◽  
Vol 13 (1) ◽  
pp. 123-129
Author(s):  
Zhizhen Xu ◽  
Ruyuan Jiao ◽  
Xiaomin Yan ◽  
Dongsheng Wang ◽  
Mary Drikas ◽  
...  
Keyword(s):  
High Performance ◽  
Fluorescence Spectra ◽  
Ion Exchange Resin ◽  
Disinfection Byproducts ◽  
Size Exclusion ◽  
Low Molecular Weight ◽  
Raw Water ◽  
Potential Risks ◽  
Safety Of Drinking Water ◽  
Magnetic Ion

Dissolved organic matter (DOM) and bromide as principal precursors to halogenated disinfection byproducts (DBPs) have potential risks on the safety of drinking water after disinfection. Removal of DOM and bromide in raw water from two different waterworks using magnetic ion exchange resin (MIEX), ferric coagulation and their combination was investigated. Results showed that as MIEX dose increased, DOM and bromide coexisting in raw water could be removed effectively. DOM tended to be mainly removed by MIEX at low dose (<4 mL/L), regardless of the bromide concentration. Bromide could compete for exchange sites with DOM at high MIEX dosage (>4 mL/L). The fluorescence spectra and high performance size-exclusion chromatogram analysis indicated that at low MIEX dosage, bromide decreased the removal of low molecular weight (MW), soluble microbial byproduct-like and aromatic protein-like organic matters, which had lower affinity with MIEX in raw water. The removal of high MW humic acid, which presented greater affinity with MIEX, was not influenced at low MIEX dose but decreased at high MIEX dose with the addition of bromide. The combination of MIEX and ferric coagulation significantly enhanced the removal of DOM and reduced the requisite ferric dose by at least 67% compared to coagulation alone.

Characterisation of natural organic matter (NOM) removed by magnetic ion exchange resin (MIEX® Resin)

2009 ◽  
Vol 9 (2) ◽  
pp. 199-205 ◽  
Author(s):  
M. R. D. Mergen ◽  
B. J. Adams ◽  
G. M. Vero ◽  
T. A. Price ◽  
S. A. Parsons ◽  
...  
Keyword(s):  
Charge Density ◽  
Natural Organic Matter ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Low Molecular Weight ◽  
Raw Water ◽  
Density Measurements ◽  
Organic Species ◽  
Magnetic Ion ◽  
Insight Into

The aim of the research presented in this paper was to gain greater insight into the characteristics of NOM removed by MIEX® Resin. Previous studies have shown that MIEX® Resin increases the level of removable DOC when used in combination with coagulation, suggesting that these two processes target a different type of organics. Initially the characteristics of DOC in regenerant solutions from four different MIEX® Resin treatment plants were analysed and compared to DOC in the respective raw water. Following this the raw water and the regenerant solutions were coagulated and the characteristics of the residual DOC analysed and compared to the regenerant solutions prior to coagulation. From the regenerant solutions it was seen that MIEX® Resin targets DOC of increased UV254 absorbance, increased charge density and of mid to low molecular weight (5 to 2 kDa). In terms of hydrophobicity no preference of MIEX® Resin for a specific NOM type was seen. The presence of hydrophilic neutral acids in the regenerant solution was unexpected since the removal of only highly charged organic species was expected. Charge density measurements however revealed the presence of functional groups, allowing hydrophilic neutrals to be removed by anion exchange. Comparative coagulation of the raw water and regenerant solution showed that both a residual DOC of similar hydrophobicity in the sub 3 kDa area. Considering that this DOC fraction was present in the regenerant it was concluded that MIEX® Resin removes organics recalcitrant to coagulation from raw water and therefore increases DOC removal when both methods are combined.

Comparison of exopolysaccharides from mucoid and nonmucoid strains of Clavibacter michiganensis subspecies sepedonicus

1993 ◽  
Vol 39 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Paul J. Henningson ◽  
Neil C. Gudmestad
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Size Exclusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Molecular Weight ◽  
Neutral Sugar ◽  
Clavibacter Michiganensis ◽  
Serological Reaction ◽  
Molecular Weights ◽  
Exclusion Chromatography

The exopolysaccharides produced by six strains of Clavibacter michiganensis ssp. sepedonicus were isolated and purified by liquid chromatography. Neutral sugar composition and molecular weights were determined for each polysaccharide fraction, using gas chromatography and high-performance size-exclusion chromatography. The serological reaction of each fraction was tested using enzyme-linked immunosorbent assay. Exopolysaccharide from nonmucoid strains contained only low molecular weight polysaccharides (1.5 × 103 to 1.1 × 104). Exopolysaccharide from mucoid and intermediate strains could be separated into low (4.0 × 103 to 1.1 × 104) molecular weight and high (5.0 × 105 to 1.6 × 106) molecular weight fractions. High molecular weight polysaccharides were composed almost exclusively of galactose, glucose, and fucose. The ratios of these sugars were highly variable among strains. Low molecular weight polysaccharides were primarily composed of galactose with significant and varying amounts of glucose, rhamnose, mannose, and ribose. All polysaccharide fractions except one, produced by a nonmucoid strain, reacted in the immunoassay test.Key words: exopolysaccharide, polysaccharide, Clavibacter, michiganensis, sepedonicus.

Application of a Magnetic Resin (MIEX) in Raw Water

2013 ◽  
Vol 361-363 ◽  
pp. 801-804
Author(s):  
Jian Wei Ma ◽  
Ya Rui Song
Keyword(s):  
Ion Exchange ◽  
Natural Organic Matter ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Raw Water ◽  
Nitrogen And Phosphorus ◽  
Dissolved Organic Matters ◽  
Primary Focus ◽  
Magnetic Ion ◽  
Magnetic Resin

The objective of this research was to compare enhanced coagulation with anion exchange for removal of natural organic matter (NOM) and bromide. Treatment with a magnetic ion exchange resin (MIEX) was the primary focus of this study. The performance of the magnetic ion exchange resin,MIEX, in the treatment of raw water was investigated. MIEX can effectively remove UV-absorbing substances DOC. The removal of organic substances is accompanied by the elimination of other undesirable components, such as nitrogen and phosphorus. The optimal process parameters are at resin doses of 5-10 mL L1and contact time of 10-15 min, as determined via jartests. Based on this study, MIEX treatment is a suitable and efficient pretreatment method for the removal of extra dissolved organic matters and nitrates in raw water .

scholarly journals Changes in Hydrophobic Interactions among Gluten Proteins during Dough Formation

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1244
Author(s):  
Sonoo Iwaki ◽  
Katsuyuki Hayakawa ◽  
Bin-Xiao Fu ◽  
Chikako Otobe
Keyword(s):  
High Performance ◽  
Hydrophobic Interactions ◽  
Fluorescence Analysis ◽  
Size Exclusion ◽  
Front Face ◽  
Low Molecular Weight ◽  
Gluten Proteins ◽  
Dough Mixing ◽  
Difference Gel Electrophoresis ◽  
Monomeric Proteins

In this study, changes in hydrophobic interactions among gluten proteins were analyzed during dough mixing. Size-exclusion high-performance chromatography and two-dimensional fluorescence difference gel electrophoresis were performed on proteins extracted with 1-propanol by weakening the hydrophobic interaction. The amount of proteins extracted with 30% 1-propanol increased from the start of mixing to peak consistency, suggesting that the hydrophobic interactions among the strongly aggregated proteins weakened and resulted in disaggregation. The amount of proteins extracted with 10% 1-propanol decreased during hydration, indicating that these proteins aggregated through relatively weak hydrophobic interactions. The proteins that extractability decreased were mainly low molecular weight glutenin, α-gliadin, and γ-gliadin. The amount of monomeric proteins extracted with 30% 1-propanol decreased after peak consistency. The decreased protein was mainly ω-gliadin, indicating that ω-gliadin aggregated with other proteins through hydrophobic interactions. A front-face fluorescence analysis was performed on the dough with the addition of 8-anilino-1-naphthalenesulfonic acid or thioflavin T. The fluorescence intensity increased as a result of exposure to the hydrophobic groups of the gluten proteins and the formation of protein aggregates during dough mixing. These results indicate the importance of hydrophobic interactions in dough formation.

Anion exchange pretreatment for the removal of natural organic matter from humic rich water

2011 ◽  
Vol 11 (6) ◽  
pp. 699-710 ◽  
Author(s):  
M. Molczan ◽  
M. Szlachta
Keyword(s):  
Anion Exchange ◽  
Complete Removal ◽  
Ion Exchange Resin ◽  
Positive Influence ◽  
Operating Conditions ◽  
Main Process ◽  
Raw Water ◽  
Treatment Techniques ◽  
Commercial Aluminium ◽  
Magnetic Ion

The treatment of humic rich water using anion exchange, coagulation and PAC-adsorption was studied, both independently and in sequence in that order. The commercial aluminium-based coagulant PAX-16, powdered activated carbon W35 and the magnetic ion exchange resin (MIEX®) were used in the study. The source of humic substances was natural water (25.0 g C/m3 as DOC) flowing out from the Great Batorow Peat-Bog (Lower Silesia, Poland). In addition to DOC, color, UV254 absorbance, specific UV absorbance (SUVA254), turbidity, pH and alkalinity were also analyzed. Regardless of the applied technology, in the phase of raw water treatment extraordinary solutions were necessary to treat the humic rich water – a high coagulant (13.1 g Al/m3) or PAC (>200 mg/dm3) dose or a low bed volume (200 BVs) in the case of anion exchange. MIEX®DOC pretreatment had a very positive influence on the course and effects of coagulation resulting in a higher coagulant efficiency for removing organic compounds. In this respect, MIEX®DOC pretreatment allowed the application of a required coagulant dose four times lower compared to the coagulation of raw water. In testing the sequence of processes (MIEX®DOC – coagulation – PAC-adsorption), coagulation was the main process responsible for reducing the SUVA254 value. The improvement in water quality after PAC-adsorption was not significant, although the process removed DOC fractions that could not be removed by coagulation. Each of the applied methods played a role in the treatment of humic rich water and the nearly complete removal of NOM was achieved (in the sequence of processes) under relatively rational operating conditions for the treatment techniques.

Purification Raw Water by Magnetic Resin (MIEX)

2013 ◽  
Vol 726-731 ◽  
pp. 3185-3188
Author(s):  
Jian Wei Ma ◽  
Ya Rui Song
Keyword(s):  
Ion Exchange ◽  
Natural Organic Matter ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Raw Water ◽  
Nitrogen And Phosphorus ◽  
Dissolved Organic Matters ◽  
Primary Focus ◽  
Magnetic Ion ◽  
Magnetic Resin

The objective of this research was to compare enhanced coagulation with anion exchange for removal of natural organic matter (NOM) and bromide. Treatment with a magnetic ion exchange resin (MIEX) was the primary focus of this study. The performance of the magnetic ion exchange resin,MIEX, in the treatment of raw water was investigated. MIEX can effectively remove UV-absorbing substances DOC. The removal of organic substances is accompanied by the elimination of other undesirable components, such as nitrogen and phosphorus. The optimal process parameters are at resin doses of 5-10 mL L1and contact time of 10-15 min, as determined via jartests. Based on this study, MIEX treatment is a suitable and efficient pretreatment method for the removal of extra dissolved organic matters and nitrates in raw water .

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

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