Acid dosing

The principal reason, however, why sulfuric acid is used as part of many cooling water pretreatment programs (as when dosed to the makeup line) or treatment programs (as when dosed to the tower basin) is to produce salts that are more soluble than calcium carbonate. Thus the point at which calcium salt saturation is reached is extended and the risk of fouling and crystalline scale on heat transfer surfaces is minimized. 

Arguments against the use of sulfuric acid have traditionally centered around the physical handling hazard and the risks of corrosion due to poor control. Today there are also some environmental concerns due to the increase in sulfates that eventually discharge into rivers and streams. 

Environmental concern practices such as zero discharge or limited discharge can help to offset this potential problem. 

There is no doubt that sulfuric acid is extremely dangerous if not handled correctly and carefully, but the vast majority of operators using acid for cooling systems have appropriate equipment permanently installed and are experienced in its handling and application. 

In many cases sulfuric acid is present at the user s site as part of a manufacturing process. The hazard risk is then generally small and under control nevertheless, all operators or company health and safety committees should periodically reexamine their acid handling systems to ensure that all that can be done to prevent dangerous situations occurring is in fact being done. 

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The antiulcer agent rebamipide ((2-(4-chlorobenzoy-lamino)-3-[2(lH)-quinolinon-4-yl]propionic acid) dose-dependently decreased hydroxyl radical signal generated by the Fenton reaction in an e.s.r. study. Rebamipide is active as a hydroxyl radical scavenger and inhibitor of superoxide production by neutrophils (Yoshikawa etal., 1993). 

The kinetics of dissolution of pure CaC03 and soil CaC03, as indicated by the volume of C02 released and Ca dissolved during extraction, are presented in Fig. 4.3. It shows that dissolution of both pure and soil CaC03 by the NaOAc-HOAc solutions at various pHs reached a plateau after two hours. This indicates that a certain acid dose reacts completely with the proper content of soil carbonate within two hours. Tessier et al. (1979) reported that after five hours of leaching sediments, there was no increase in the calcium concentration, thus indicating that it is unnecessary to allow 16 hours for extraction of the CARB fraction, as was originally done in this sequentially selective dissolution procedure. 

Cacodyl ic acid Dosed orally without effect at 100 mg/kg BW daily for 10 days 4... 

Before entering the perraeator for salt removal, the feed is either acidified or modified with proprietary chemicals for scale control. While both approaches have their followers, despite its handicaps, acid dosing today appears predominant in the industry in fact some RO permeator manufacturers will only warranty their product for acid. Studies to be initiated shortly at our laboratory should hopefully quantitatively evaluate the relative merits of these approaches. It is hoped that at least equivalence if not superiority for proprietary scale control chemicals will be unequivocally established so that one can drop acid use and satisfy many who are justifiably reluctant to use acid, for reasons familiar to all. 

Renal function impairment- Upon treatment initiation, the recommended zoledronic acid doses for patients with reduced renal function (mild to moderate renal impairment) are listed in the following table. These doses are calculated to achieve the same AUC as that achieved in patients with Ccr of 75 mL/min. Ccr is calculated using the Cockcroft-Gault formula. 

Recommended Zoledronic Acid Dose for Patients with Mild to Moderate... 

During treatment, measure serum creatinine before each zoledronic acid dose and withhold treatment for renal deterioration. In the clinical studies, renal deterioration was defined as follows ... 

Effervescent granules 325 mg w/2.781 g sodium bicarbonate 2.224 g citric acid/dose measure (ofc) Bromo Se/fzer(Warner-Lambert)... 

Alginic Acid + Aluminum Hydroxide Magnesium Tnsilicate (Gaviscon) [Antacid] [OTC] Uses Heartburn hiatal hernia pain Action Protective layer blocks gastric acid Dose 2—4- tabs or 15-30 mL PO qid followed by H2O Caution [B, -] Avoid in renal impair or Na -restricted diet Disp Tabs, susp SE D, constipation Interactions T Absorption OF tetracyclines EMS None OD May cause constipation, loss of appetite, muscle weakness, and peripheral edema symptomatic and supportive... 

Aluminum Hydroxide + Magnesium Carbonate (Gaviscon Extra Strength/ Liquid) [OTC] [Antacid/Aluminum Magnesium Salts] Uses Relief of heartburn, acid indigestion Action Neutralizes gastric acid Dose Adults. 15-30 mL PO pc hs Peds. 5-15 mL PO qid or PRN avoid in renal impair Caution T Mg (w/ renal insuff) [C, ] Disp Liq, chew tabs SE Constipation, D Interactions In addition to AlOH effects OF histamine blockers, hydantoins, nitrofurantoin, phenothiazines, ticlopidine, T effects OF... 

Calcium Acetate (PhosLo) [Calcium Supplement/ Anti arrhythmic/Mmeral/ Electrolyte] Uses ESRD-associated hyper-phos-phatemia Action Ca " supl w/o aluminum to X P04 absorption Dose 2-4 tabs PO w/ meals Caution [C, ] Contra t Ca Disp Gelcap SE Can t Ca, hypophosphatemia, constipation Interactions t Effects OF quinidine X effects W/ large intake of dietary fiber, spinach, rhubarb X effects OF atenolol, CCB, etidronate, tetracyclines, fluoroquinolones, phenytoin, Fe salts, thyroid hormones EMS Pts have reduced renal Fxn, monitor ECG for signs of electrolyte disturbances OD S/Sxs of hypercalcemia (confusion, weakness, GI upset, constipation, N, V, and cardiac arrhythmias) give IV fluid for diuresis symptomatic and supportive Calcium Carbonate (TumS/ Alka Mints) [Antacid/ Calcium Supplement/Mineral/ Electrolyte] [OTC] Uses Hyperacidity associated w/ peptic ulcer Dz, hiatal hernia, etc Action Neutralizes gastric acid Dose 500 mg—2 g PO PRN -1- in renal impair Caution [C, ] Disp Chew tabs, susp SE t -1- PO constipation Interactions X Effect OF tetracyclines, fluo-... 

Esomeprazole (Nexium) [Gastric Acid Inhibitor/Proton Pump Inhibitor] Uses Short-term (4-8 wk) for erosive esophagitis/GERD H. pylori Infxn in combo w/ antibiotics Action Proton pump inhibitor, gastric acid Dose Adults. GERD/erosive gastritis 20 0 mg/d PO x 4-8 wk 20 0 mg IV 10-30 min inf or >3 min IV push, 10 d max Maint 20 mg/d... 

Uses Hypertriglyceridemia, coronary heart Dz Action Fibric acid Dose 1200 mg/d PO bid 30 min ac am pm Caution [C, ] t Warfarin effect, sulfony-lureas t risk of myopathy w/ HMG-CoA reductase inhibitors X effects w/ cyclosporine Contra Renal/hepatic impair (SCr >2.0 mg/dL), gallbladder Dz, primary biliary cirrhosis, use w/ repaglinide (i glucose) Disp Tabs 600 mg SE Cholelithiasis, GI upset Interactions t Effects OF anticoagulants, sulfonylureas t risk of rhabdomyolysis W/ HMG-CoA reductase inhibitors X effects W/ rifampin X effects OF cyclosporine EMS t Effects of anticoagulants OD May... 

Conversion to monotherapy for patients receiving valproic acid PO Titrate lamotrigine to 200 mg/day, maintaining valproic acid dose. Maintain lamotrigine dose and decrease valproic acid to 500 mg/day, no greater than 500 mg/day/wk, then maintain 500 mg/day for 1 wk. Increase lamotrigine to 300 mg/day and decrease valproic acid to 250 mg/day. Maintain for 1 wk, then discontinue valproic acid and increase lamotrigine by 100 m day each wk until maintenance dose of 500 mg/day reached. 

Birnbaum AK, Hardie NA, Conway IM, et at Valproic acid doses, concentrations, and clearances in elderly nursing home residents. Epilepsy Res 2004 62 157-162. 

Uses Acute chronic gout Action X Renal tubular absorption of uric acid Dose 100-200 mg PO bid for 1 wk, T PRN to maint of 200—400 mg bid max 800 mg/d take w/ food or antacids plenty of fluids avoid salicylates Caution [C (D if near term), /-] Contra Renal impair, avoid salicylates peptic ulcer blood dyscrasias, near term PRG, allergy Disp Tabs, caps SE N/V, stomach pain, urolithiasis, leukopenia Interactions T Effects OF oral anticoagulants, oral hypoglycemics, MTX X effects W/ ASA, cholestyramine, niacin, salicylates, EtOH X effects OF acetaminophen, theophylline, verapamil EMS T Effects of anticoagulants and oral hypoglycemic X effects of verapamil OD May cause N/V, loss of coordination, dyspnea, Szs symptomatic and supportive... 

Armstrong et al. have extensively studied the effect of this radiation on grafting butadiene, styrene, vinyl chloride, vinyl esters, acrylic, and methacrylic esters, acrylonitrile and other less common monomers on Nylon 66 fibers. They observed the influence of oxygen, water, methanol, acetic acid, dose of irradiation as well as temperature (160-163). 

Sulfates in surface waters are usually present at lower levels, typically 20 to 60 ppm, but the level can rise to several hundred ppm in subsurface waters. If high alkalinity makeup waters also contain high sulfates, the use of sulfuric acid dosing as a treatment to reduce the alkalinity can be ruled out because when the cooling water is cycled up, the total sulfate content can easily exceed the solubility limit of calcium sulfate (solubility is dependent on temperature but is in the range 1800 to 2000 ppm), and scaling readily occurs. 

A very large petrochemical facility has many cooling systems and a variable water quality due to seasonal fluctuations. The river water makeup supply water is pumped approximately 100 km across a desert plain. The supply water pH can quickly increase to 8.6, the TDS rises to 1300 ppm, SS to 500 ppm (before clarification), chlorides to 650 ppm, and total hardness to 600 ppm. As a consequence, priority is given to stabilizing the makeup water quality as much as possible using acid dosing, but control is poor and acid incursions take place. 

When the treated water pH exceeds 9.4 to 9.6, the use of carbon dioxide to recarbonate the water is recommended. Alternatives include the use of sulfuric acid dosing, or a suitable chemical additive such as a threshold treatment or a calcium carbonate dispersant. 

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