Effect of pH on flux during ultrafiltration of sweet whey and buttermilk

1995 ◽  
Vol 62 (3) ◽  
pp. 441-449 ◽  
Author(s):  
Harohally G. Ramachandra Rao ◽  
Michael J. Lewis ◽  
Alistair S. Grandison
Keyword(s):  
Concentration Polarization ◽  
Combined Effects ◽  
Ph Change ◽  
Deposit Formation ◽  
Effect Of Ph ◽  
Flux Decline ◽  
Sweet Whey ◽  
Effects Of Ph

SummaryThe flux patterns for sweet whey and buttermilk were strongly influenced by pH. Increasing the pH of buttermilk from 6·6 to 8·0 tended to reduce initial flux values and reduce deposit formation on the membrane as indicated by lower values for the fouling coefficient. Flux was mostly controlled by concentration polarization. Reducing the pH below 6·6 increased the flux but caused more deposit on the membrane as indicated by high fouling coefficient values. Almost the opposite was found for sweet whey. The initial flux increased as pH increased, followed by considerable flux decline, which was linked to greater fouling of the membrane. Reducing the pH reduced the initial flux considerably but also reduced further fouling. These changes are thought to be brought about by the combined effects of pH change on the proteins and minerals, and in particular on calcium.

Effect of pH and NH4NO3 as a Spray Additive on Penetration of NAA Through Isolated Tomato Fruit Cuticle

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 550a-550 ◽  
Author(s):  
Royal G. Fader ◽  
Martin J. Bukovac
Keyword(s):  
Direct Measurement ◽  
Sodium Citrate ◽  
Tomato Fruit ◽  
Initial Slope ◽  
Control Effect ◽  
Solution Ph ◽  
Ph Change ◽  
Effect Of Ph ◽  
Spray Droplets ◽  
Partition Behavior

We have reported that NH4NO3 (AN, 8 mM, pH 4.2), applied as simulated spray droplets, enhanced penetration of 14C-NAA through isolated leaf and fruit cuticles. One explanation for this response is that AN depresses NAA (pKa= 4.2) dissociation, increasing the nondissociated moiety, which penetrates more readily than the anion (NAA'). Direct measurement of AN (concn. 0-800 mM) effect on NAA (215 μM) dissociation as indexed by change in solution pH revealed no significant effect, with a pH change from 4.19 to 4.05. This change is not sufficient to account for the observed enhancement. When 14C-NAA, buffered (20 mM sodium citrate) at pH 3.2, 4.2, 5.2, 6.2, was partitioned against chloroform, there was a marked increase in NAA partitioning into chloroform as pH was decreased. AN (8 mM) did not alter this partition behavior, also indicating no effect on NAA dissociation. However, in cuticle penetration studies, using a finite dose system with 14C-NAA buffered at pH 3.2, 4.2, 5.2, 6.2, and in the presence and absence of 8 mM AN, there was no marked or consistent pH or AN (-70 to + 232 % of no AN control) effect on penetration as indexed by initial slope (4-12 h) or penetration after 120 h. The possible effects of AN and buffer on penetration of 14C-NAA from the droplet deposit will be discussed.

scholarly journals Pyrite (FeS2)-supported ultrafiltration system for removal of mercury (II) from water

2021 ◽  
Author(s):  
Dong Suk Han ◽  
Kawsher M. D. Solayman ◽  
Ho Kyong Shon ◽  
Ahmed Abdel-Wahab
Keyword(s):  
Membrane Filter ◽  
Pyrite Surface ◽  
Ph Change ◽  
Filtration Process ◽  
Sem Images ◽  
Flux Decline ◽  
Cake Layer ◽  
Water Effects ◽  
Almost All ◽  
Over Time

AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.

Combined effects of dissolved organic matter, pH, ionic strength and halides on photodegradation of oxytetracycline in simulated estuarine waters

2019 ◽  
Vol 21 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Ya-nan Zhang ◽  
Jianchen Zhao ◽  
Yangjian Zhou ◽  
Jiao Qu ◽  
Jingwen Chen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Ionic Strength ◽  
Dissolved Organic Matter ◽  
Combined Effects ◽  
Estuarine Waters ◽  
Effects Of Ph

Combined effects of pH, DOM, ionic strength, and specific halides on the photodegradation of representative antibiotics in estuarine waters were revealed.

Preparation of TiO2 nano-particle photocatalysts by a multi-gelation method: the effect of pH change

2008 ◽  
Vol 34 (1) ◽  
pp. 103-111 ◽  
Author(s):  
B. Neppolian ◽  
D. R. Eddy ◽  
S. Sakai ◽  
Y. Okada ◽  
H. Nishijima ◽  
...  
Keyword(s):  
Nano Particle ◽  
Ph Change ◽  
Effect Of Ph

The Synthesis of Kanamycin Analogs I. α-D-Glucopyranosyl Derivatives of Deoxystreptamine

1973 ◽  
Vol 51 (1) ◽  
pp. 53-66 ◽  
Author(s):  
R. U. Lemieux ◽  
T. L. Nagabhushan ◽  
K. J. Clemetson ◽  
L. C. N. Tucker
Keyword(s):  
Conformational Change ◽  
Ph Change ◽  
Synthetic Compounds ◽  
Effects Of Ph ◽  
Derivatives Of

The procedure developed in this laboratory for the synthesis of α-D-glucopyranosides based on the reaction of dimeric tri-O-acetyl-2-deoxy-2-nitroso-α-D-glucopyranosyl chloride with alcohols was employed to synthesize the three α-D-glucopyranosyl deoxystreptamines and 4,6-di-O-α-D-glucopyranosyl deoxystreptamine. Effects of pH change on the n.m.r. spectra of kanamycins A and B and of the above synthetic compounds are interpreted in terms of a conformational change.

scholarly journals Effect of pH, ionic strength and univalent inorganic ions on the reconstitution of aspartate aminotransferase

1974 ◽  
Vol 137 (2) ◽  
pp. 199-203 ◽  
Author(s):  
Liliana Gianfreda ◽  
Gennaro Marino ◽  
Rosaria Palescandolo ◽  
Vincenzo Scardi
Keyword(s):  
Ionic Strength ◽  
Aspartate Aminotransferase ◽  
Pyridoxal Phosphate ◽  
Water Structure ◽  
Inorganic Ions ◽  
Halide Ions ◽  
Ph Change ◽  
Effect Of Ph ◽  
Ph Range ◽  
Ph Curve

1. The effect of pH change on the reconstitution of aspartate aminotransferase (EC 2.6.1.1), i.e. the reactivation of the apoenzyme with coenzyme (pyridoxal phosphate and pyridoxamine phosphate), was studied in the pH range 4.2–8.9 by using three buffer systems at concentrations ranging from 0.025 to 0.1m. 2. Although the profile of the reconstitution rate–pH curve in the range pH5.2–6.8 (covered by sodium cacodylate–HCl buffer) reflects the influence of the H+ concentration on the reconstitution process, the profile of the curve in the pH ranges 4.2–5.6 and 7.2–8.25 (covered respectively by sodium acetate–acetic acid and Tris–HCl buffers) appears to be influenced by the ionic strength of the buffer. 3. The reconstitution is also influenced by univalent inorganic ions such as halide ions and, to a lesser extent, alkali metal ions, which are known to alter the water structure.

Effect of pH on Advanced Treatment of Mid-Stage Pulping Effluent with Potassium Ferrate

2013 ◽  
Vol 781-784 ◽  
pp. 2146-2149
Author(s):  
Shan Hong Lan ◽  
Rui Chen ◽  
Ping Ma ◽  
Hui Xia Lan ◽  
Yong Dong Wang
Keyword(s):  
Removal Efficiency ◽  
Cod Removal ◽  
Effluent Treatment ◽  
Advanced Treatment ◽  
Potassium Ferrate ◽  
Effect Of Ph ◽  
Cod Removal Efficiency ◽  
Effects Of Ph ◽  
Alkaline Conditions ◽  
The Stability

The effects of pH on the advanced treatment of mid-stage pulping effluent with potassium ferrate were studied. Firstly, the effect of pH on the stability of the potassium ferrate solution was studied, which indicated that potassium ferrate was more stable in alkaline conditions than in acidic and neutral conditions, and the most stability was achieved at pH of 9-10. Then the effect of pH on the mid-stage pulping effluent treatment with potassium ferrate showed that the oxidation increased firstly and then decreased with the increase of the pH. The best treatment efficiency was at pH=4, under which COD removal efficiency reached 40%. The flocculation experiment was conducted using Fe3+ produced by the oxidation reaction as flocculant and PAC as extra flocculant and PAM as coagulant aid. Effect of pH on the flocculation process was studied, which showed that the flocculation effect first increased and then decreased with pH increasing. When pH was 9, COD removal efficiency reached 60%. The final effluent of COD concentration was less than 60mg/L, which met the requirements from the national first-order discharge standard.

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