Effect Of pH Adjustment Research Articles

Chemical, structural, and catalytic characteristics of Al-MCM-41 prepared by pH-controlled synthesis

Detailed investigations on the effect of pH adjustment at a value of 11 during Al-MCM-41 synthesis with regard to changes in structure, chemical composition, and catalytic activity are described. Long-range order (XRD), surface area (BET), and pore size distribution (BJH) improved remarkably when the pH of the synthesis gel was adjusted intermediately. The Si/Al ratio (AAS) and the yield of Al-MCM-41 nearly doubled in the case of a threefold pH adjustment. The catalytic activity for Friedel–Crafts acylation of 2-methoxynaphthalene was about three times higher for pH-adjusted samples. These effects became less pronounced with increasing number of adjustments. Comparable results were obtained when acetic, sulfuric, nitric, or citric acid was used for the pH adjustment.

Effect of various preheat treatments on the heat stability of unconcentrated milk

Abstract The effect of preheating milk and serum-free casein micelle dispersions (SPFCM) was studied over a range of temperatures. Important differences were recorded after preheating at different temperature–time combinations. The effect of pH adjustment after various preheat treatments was also studied. Removal of lactose before preheat treatment had a significant effect.

Exopolysaccharide production from whey lactose by fermentation with Lactobacillus delbrueckii ssp. bulgaricus

ABSTRACTRopy Lactobacillus delbrueckii ssp. bulgaricus (strain RR) was used for production of exopolysaccharide in sweet whey and simulated whey permeate (SWP) supplemented with combinations of lactose, KH2PO4, NH4Cl, casamino acids, and mineral salts. Media were incubated at 32, 37, and 44°C for 72h. Periodic adjustment of pH to ∼6.2 increased viscosity and lactose utilization, and the free galactose and lactic acid in the media. The effect of pH adjustment was greater than that of supplementation with nutrients or minerals. Fermentation of supplemented SWP generally produced lower viscosities than did fermentation of supplemented sweet whey. After 24h fermentation, viscosity decreased in pH adjusted media. Viscosity of media was highest when incubation was at 32°C and lowest with incubation at 44°C.

Anaerobic degradation of paper mill sludge

The effect of pH adjustment and surfactant addition on the anaerobic degradation of sludge from a pulp and paper mill waste treatment plant was monitored by COD (Chemical Oxygen Demand) and EOX (Extractable Organic Halogen) analysis. COD decreased by 29–64% and EOX by 22–50%, in all treatments (including control, non-adjusted, sludges). Adjusting the initial pH to 7.0 with sodium bicarbonate, but not with potassium hydroxide, accelerated degradation. Maximum decreases in dry weight, COD and EOX, compared to the control, were seen in sludges receiving bicarbonate; after 5 months the reductions were 60% (COD) and 50% (EOX). The results indicate that the use of bicarbonate to adjust pH could be advantageous in anaerobic treatment of organochloride-containing residues.

The effect of pH adjustment of 1% lidocaine on the onset of sensory and motor blockade of epidural anesthesia in nonpregnant gynecological patients

Using a double-blind randominzed study protocol, we examined the distribution of sensory blockade and the quality of motor blockade after epidural anesthesia with 1% lidocaine with or without bicarbonate in nonpregnant gynecological patients.Alkalinization significantly decreased the time to onset of sensory blockade. However, there were no statistically significant differences between the low-pH and high-pH groups with respect to motor blockade or the distribution of sensory blockade.We conclude that pH-adjusted 1% lidocaine offers the advantage of a more rapid onset of sensory blockade, while motor blockade and the distribution of anesthesia are unaffected by pH change in epidural anesthesia.

The effect of pH adjustment of 1% lidocaine on the onset of sensory and motor blockade of epidural anesthesia in nonpregnant gynecological patients

The effect of pH adjustment of 1% lidocaine on the onset of sensory and motor blockade of epidural anesthesia in nonpregnant gynecological patients

TREATMENT OF KRAFT PULP AND PAPER WASTEWATERS BY MEANS OF FOAM SEPARATION

Abstract The pulp and paper industry is the third largest industrial consumer of fresh water in the United States. The current use rate of over two trillion gallons annually is expected to increase as the demand for paper products continues to rise Of the various methods of producing paper from wood, the Kraft process is the most widely used. Color, dissolved and suspended organic matter, and dissolved inorganic solids are major pollutants in Kraft processing wastewater. Current federal regulations limit the amount of solids and organic matter that a Kraft facility may dispose into public waters, so most plants have some form of wastewater treatment In this study, the capacity of a continuous-flow, foam separation system to effect removals of color from a Kraft process wastewater was evaluated. The cationic surfactant, EHDABr, was used to precipitate color bodies in the wastewater and create a foam to carry the precipitates from the wastewater. The effect of pH adjustment was also considered. Color remova...

Aging effect of lime and phosphate addition on phosphorus availability in an acid soil

Abstract The efficiency of applied P fertilizer is usually low and declines with time after P addition. It also may be affected by soil pH. We investigated effects of aging and soil pH on P uptake with a mechanistic nutrient uptake model. The uptake model uses both solution P (Pli) and resin‐exchange P (Psi) in determining soil P supply to the root. Effect of aging of lime and P addition may have separate effects on Pli, Psi and predicted P uptake. A 5x2x4x4 factorial experiment with five levels of soil pH (4.6, 5.8, 6.9, 7.6, and 8.2) with two incubation times of pH adjustment (10 and 40 days before P application) and four different reaction times after P addition (4, 25, 72, and 140 days) of four rates of P (0, 175, 350, and 525 mg P/kg) was conducted with a sample of Rarden (clayed, mixed, mesic Aquic Hapludults) soil to evaluate the aging effect of pH adjustment, soil pH, and P addition on Pu, Psi, and predicted P uptake using the Barber‐Cushman nutrient uptake model. The incubation time of 40 days be...

The Effect of pH Adjustment of 0.5% Bupivacaine on the Latency of Epidural Anesthesia

The Effect of pH Adjustment of 0.5% Bupivacaine on the Latency of Epidural Anesthesia

The Effect of pH Adjustment of Bupivacaine on Onset and Duration of Epidural Anaesthesia for Caesarean Section

The Effect of pH Adjustment of Bupivacaine on Onset and Duration of Epidural Anaesthesia for Caesarean Section

Discussion: The effect of pH adjustment on the internal corrosion rate of residential cast-iron and copper water distribution pipes

Discussion: The effect of pH adjustment on the internal corrosion rate of residential cast-iron and copper water distribution pipes

Improvement of Thiamin Retention in Canned Low-Acid Foods Through pH Adjustment

The effect of pH adjustment, in the range 5.0–6.9, on the thiamine retection after thermal processing of canned pea, corn, pork and beef liver purees was studied. In all foods tested, reduction of pH, in the range studied, dramatically increased the retention of thiamin after processing. Retention of thiamin in processed pea and corn purees adjusted to pH 5.6 increased by 95% and 63%, respectively, as compared to samples having normal pH (6.9 for pea and 6.5 for corn).

Effects of pH, Calcium Chloride, and Chymosin Concentration on Coagulation Properties of Abnormal and Normal Milk

Individual Holstein cow milk samples were selected for good and poor chymosin-coagulation characteristics. The effect of pH adjustment, addition of .02% calcium chloride, and variation in chymosin concentration on coagulation properties of good and poor coagulating samples was evaluated. Pooling 50% good and 50% poor coagulating samples did not improve the average coagulation properties of the poor samples. Reducing milk pH to 6.3 caused a significant decrease in coagulation time but a less marked increase in curd firmness. The greatest increase in curd firmness was obtained by a combination of reducing milk pH, addition of .02% calcium chloride, and reducing chymosin concentration. High-chymosin concentration at reduced pH decreased coagulation time without substantially increasing curd firmness. Curd disintegration was more apparent at high-chymosin concentration in the poor coagulating samples.

The effect of pH adjustment on the microbiology of chicken scald-tank water with particular reference to the death rate of salmonellas.

In laboratory experiments adjustment of the pH of chicken scald‐tank water to 9.0 ± 0.2 lowered the D52°C value of a strain of Salmonella typhimurium from 34.5 to 1.25 min. Factory trials where the scald water was maintained at pH 9.0 ± 0.2 for the after‐lunch period showed that both the total bacterial population and the number of coli‐aerogenes organisms were substantially reduced. Addition of sodium hydroxide also increased the rate of accumulation of total dry matter in the water. Sodium carbonate was as effective as NaOH in increasing the death rate of Salm. typhimurium and would appear to be a suitable alternative.

COPPER SORPTION BY SOILS AT LOW CONCENTRATIONS AND RELATION TO UPTAKE BY PLANTS

SummaryCopper sorption was measured in 14 agricultural soils from England and Wales with a wide range of properties. Sorption from 0.01 M CaCl2 was described by the Freundlich adsorption isotherm when Cu in solution was initially at 200 HM and greater, but at lower initial concentrations (i. e. 100 fiM and less) there was a steep rise in the gradients of the isotherms. At initial concentrations of 100 JIM and less, sorption was linearly correlated to the concentration of Cu remaining in solution; the gradients of these relationships varied considerably amongst the soils and were highly correlated to soil pH. There was no correlation between either the gradients or the extrapolated values of final solution concentration at which there was no sorption of added Cu by the soils (an ‘equilibrium’ concentration), and other determined soil properties.The effect of pH adjustment on sorption varied between the 5 soils examined although, in general, there was increasing sorption with increasing pH. Extrapolated values for ‘equilibrium’ concentrations for an individual soil were higher at pH 6.0 or greater, than at pH 5.5. A large proportion of the Cu in the final solutions was apparently complexed but this varied between soils and was dependent on both pH and total concentration. There was little effect of varying pH of the final solution on these proportions in most soils.Neither extractable Cu in the soils, nor the sorption characteristics were related to availability as measured by uptake by perennial ryegrass.

Letters to the Editor

The effect of pH adjustment plus any other commercial corrosion inhibitor on lead corrosion is discussed. Also discussed is water pricing elasticity.