Effect Of Inorganic Additives Research Articles

Real-time monitoring of zinc phosphating process by quartz crystal impedance system

The zinc phosphating process in manganese-modified low-zinc phosphating baths has been monitored firstly by an in situ quartz crystal impedance system (QCIS) which allows rapid and simultaneous measurements of admittance spectra of the zinc-coated piezoelectric quartz crystal (PQC) resonator. The electrical equivalent circuit parameters are obtained by non-linear least square regression analysis of synchronously acquired conductance and susceptance data. The experimental results show that the kinetic growth process of zinc phosphate coating can be monitored on-line by measuring the equivalent circuit parameters and frequency shifts of the zinc-coated PQC resonator. According to the motional inductance ( L m ) change of zinc-coated PQC during zinc phosphating treatment, the whole process can be divided into four regions: pickling reaction, exponential growth, linear growth and exponential decay growth, respectively. And effects of inorganic additives (Ni 2+ and/or Mn 2+) on the properties and performance of zinc phosphating coatings as well as the variations of equivalent circuit parameters of zinc-coated PQC during the phosphating treatment are also investigated.

The effect of exchangeable cations on low-temperature oxidation and self-heating of a Victorian brown coal

The effect of inorganic additives, when applied into a coal by ion-exchange, on low-temperature oxidation and self-heating of a Victorian brown coal is studied in this article. Acid-washed coal, and acid-washed coal ion-exchanged separately with seven additives, were prepared. Each of the samples was then tested in a wire-mesh reactor to obtain its critical ambient temperature, above which thermal runaway occurs. The relative effectiveness of the additives is determined by comparing their critical ambient temperatures with that of the acid-washed coal. Magnesium acetate (Mg(Ac) 2), calcium chloride (CaCl 2), and sodium chloride (NaCl) were found to inhibit low-temperature oxidation, while copper acetate (Cu(Ac) 2), potassium acetate (KAc), and sodium acetate(NaAc), promote the reaction. The effect of additive loading was also investigated for NaAc and Ca(Ac) 2. The effectiveness of NaAc to promote low-temperature oxidation is enhanced with an increase in its loading, while that of Ca(Ac) 2 remains unchanged with varying additive loading. Low-temperature oxidation kinetics were estimated by a transient energy balance and compared with the low-temperature oxidation and self-heating behaviour of the samples.

Effect of Inorganic Additives on Solutions of Nonionic Surfactants

The salt effects of 10 transition metal cations on nonionic surfactants were investigated by the action of their salts (nine nitrates, two sulfates) on the cloud point (CP) of octoxynol 9. All cations investigated raised the CP of octoxynol 9 by complexation with its ether groups, which represents salting in. However, aside from Ag+, these CP increases were no larger than those caused by Li+and by di- and trivalent cations not belonging to the transition metal group, even though the transition metal cations have a greater capacity for forming complexes. This unremarkable, average salting-in capacity of most transition metal cations is attributed to competition for their coordination sites between the ether groups of the surfactant and water. With the exception of silver, the solid nitrates of all transition metals examined form stable solid hydrates containing three to nine molecules of water of crystallization, which indicates a high affinity of the cations for water. Only AgNO3forms no stable solid hydrates. The low affinity of Ag+for water results in a commensurately higher capacity for binding the ether groups of the surfactant. This was shown by the facts that AgNO3produced the largest CP increases and that it was the only salt to reversibly precipitate an insoluble adduct with octoxynol 9 from concentrated solutions. The only salt that oxidized the surfactant when its solution was heated in a nitrogen atmosphere and illuminated during CP measurements was Fe(NO3)3. Oxidative degradation produced small but progressive CP reductions.

Effect of Inorganic Additives on Solutions of Nonionic Surfactants

The effect of salts on the nonionic surfactant octoxynol 9 was studied by the changes they produced in its cloud point (CP): CP increases indicate salting in. The temperatures by which the sodium salts of water structure-breaking (chaotropic) anions increased the CP of 2.0% octoxynol solutions were measured as a function of salt concentration. The curves representing changes in CP versus salt molality rose to a maximum in a parabolic fashion, followed by steep decreases. Their ascending branches, corresponding to salting in, were caused by a disruption of the water structure due to the chaotropic effect of the anions combined with the effect of elevated CP temperatures. The descending branches were due to salting out by Na+. The net CP increases due to the chaotropic effect of the anions were calculated at each concentration by subtracting the CP decrease due to Na+from the observed CP increase of the respective Na+salts. With the exception of ClO4−, the plots of CP changes produced by the chaotropic anions rose in a nearly linear fashion to a maximum and then levelled off. The levelling off occurred at the salt concentration and CP temperature leading to the maximum disruption of the water structure of which each anion was capable. The chaotropic anions were ranked in the following order according to their capacity for increasing the CP: SCN−> I−> [Fe(CN)5NO]2−> ClO4−> BF4−. Even though the thiosulfate anion is a very soft Lewis base, it lowered the CP in direct proportion to its molality; i.e., it enhanced the structure of water and promoted salting out at all concentrations.

Effect of Inorganic Additives on Solutions of Nonionic Surfactants: X. Micellar Properties

The study of the interaction between electrolytes and nonionic surfactants was extended to the micellar properties of octoxynol 9 at 25°C. Density, surface tension, viscosity, and static and dynamic light scattering were measured in water (where dilute octoxynol solutions had a cloud point of 64°C), in a salting-out electrolyte, 0.40 m Na 2SO 4 (cloud point lowering = 28°C), and in the salting-in electrolytes 1.80 m NaSCN (cloud point increase = 27°C) and 2.00 m Mg(NO 3) 2 (cloud point increase = 14°C). The intrinsic viscosity of octoxynol in Na 2SO 4 was twice as large as in water and NaSCN, the diffusion coefficient was 2.5 times smaller, the micellar molecular weight was 5 and 14 times larger than in water and NaSCN, respectively, and the micellar hydration was at least twice as large. The micellar properties in Mg(NO 3) 2 differed from those in the other three media: The partial specific volumes in the latter were independent of surfactant concentration and had comparable values, while decreasing significantly with increasing surfactant concentration in the former. The micellar molecular weights and aggregation numbers were nearly the same in Mg(NO 3) 2 and NaSCN and amounted to ≈ 1 3 of the corresponding values in water; the intrinsic viscosities were 98 and 83% of that in water, respectively, while the micellar diffusion coefficients at infinite dilution were 59 and 120%. The apparent diffusion coefficients in Mg(NO 3) 2 increased slightly with increasing surfactant concentration while decreasing in the other three media. Only in Mg(NO 3) 2 did the micellar hydration increase with increasing surfactant concentration. These observations point to micellar binding of Mg(NO 3) 2, presumably via complexation of Mg 2+ ions by the ether oxygens of the micellar polyoxyethylene moieties, which rendered the surfactant somewhat cationic.

Effects of Inorganic Additives on the Isotropic Grain Growth Law of High Purity Alumina.

Effects of Inorganic Additives on the Isotropic Grain Growth Law of High Purity Alumina.

The effect of inorganic additives on the decomposition of poly (beta-hydroxybutyrate) into volatile products

Inorganic oxides such as CaO, MgO, PbO, PbO 2, Al 2O 3, ZnO and calcium hydride destabilize PHB to an extent dependent on the basicity of the additive which leads to much easier formation of volatile products compared with PHB itself. Of the additives examined, attention has been focused on the reaction of MgO, which leads to significant formation of a considerably more stable product whose maximum rate of decomposition into volatiles is at 670 K (PHB itself decomposes with a maximum rate at 572 K). An interpretation based on the interaction of MgO with PHB end groups has been proposed.

Coal thermoplasticity and coke structure as related to gasification: Effect of inorganic additives on high pressure dilatometric properties and reactivity towards hydrogen

The effects of potassium carbonate and ferric oxide on the thermoplastic properties of a weakly caking coal have been investigated using a high-pressure dilatometer. The inorganic additives decrease the swelling of the coal, the effect being most pronounced in the pressure range 1–2 MPa. The effects of the additives on dilatometric properties are strongly influenced by heating rate and pressure. The residual chars from the dilatometry experiments were heat-treated further and their reactivity towards hydrogen was examined. Potassium carbonate did not increase the reactivity substantially except when the char was initially carbonized at atmospheric pressure. All the chars prepared with ferric oxide as additive showed higher reactivity than that from coal carbonized alone under identical conditions. The greater reactivity observed for the chars carbonized initially at atmospheric pressure was due to their surface areas being higher than those of chars prepared at higher pressures.

Effect of inorganic additives on solutions of nonionic surfactants VII. Suspension stability

Many electrolytes salt in polyoxyethylated nonionic surfactants by complexation between the cations and the ether oxygens [e.g., Mg(NO 3) 2 and Al(NO 3) 3], or because the anions break the structure of water (NaSCN, NaI). Other electrolytes salt out the surfactants by enhancing the structure of water or by dehydration (NaCl, Na 2SO 4). Primidone suspensions stabilized with octoxynol 9 (Triton X-100) were deflocculated and their sediments caked. In contrast to salting-out electrolytes, salting-in electrolytes flocculated these suspensions strongly and practically eliminated caking. Flocculation was demonstrated by increases in the permeability coefficient of the filter cakes (determined from filtration rates of suspensions and from percolation rates of their filtrates through the cakes), in relative viscosity (ratio of apparent suspension viscosity to viscosity of the suspending medium) and in sedimentation volume of the suspensions, and by decreases in reduced turbidity. Prednisone suspensions stabilized with octoxynol were more flocculated, and their sediments did not cake. A salting-out electrolyte, Na 2SO 4, and a salting-in electrolyte, Mg(NO 3) 2, produced only minor changes in degree of flocculation and in suspension properties.

Effect of inorganic additives on solutions of nonionic surfactants VII. Suspension stability

Many electrolytes salt in polyoxyethylated nonionic surfactants by complexation between the cations and the ether oxygens [e.g., Mg(NO 3) 2 and A

Effect of Inorganic Additives on Solutions of Nonionic Surfactants VI: Further Cloud Point Relations

Disperse dosage forms stabilized with nonionic surfactants frequently contain electrolytes as active ingredients or adjuvants. Salting out of the surfactants by these electrolytes may cause breakdown of the dosage forms. The cloud point of an aqueous solution of octoxynol 9 was used to measure the salt effects. Electrolytes which salt octoxynol 9 out lower its cloud point, while salting-in electrolytes raise it. The observed cloud point effects are discussed according to the mechanisms involved. Salting out by dehydration in competition with octoxynol 9 for the available water was observed with sulfate and phosphate anions, sodium, potassium, and ammonium tribasie cations, and the nonelectrolyte sorbitol. The extensive self-association of water by hydrogen bonds at and below room temperature weakens its solvent power. Ions which reduce this self-association, breaking the structure of water, increased the cloud point of octoxynol 9. Among them were the iodide, thiocyanate, and nitroprusside anions. Ions which tighten the structure of water and enhance its self-association salted the surfactant out, lowering its cloud point. Among these were the fluoride and hydroxide anions. Complex formation between the ether linkages of octoxynol 9 and the following cations increased its cloud point: hydrogen (from strong acids), silver, magnesium, and zinc. Including published data, the only cations which do not form complexes with polyoxyethylated surfactants (and are, therefore, unable to salt them in) were the alkali metal ions sodium, potassium, and cesium and the ammonium ion. The cloud point increases produced by a weak organic base and acids are ascribed to the formation of mixed solvents with water. The hydrotropes sodium salicylate, phenobarbital sodium, and sodium benzoate raised the cloud point appreciably even at low concentrations. The most efficient cloud point boosters were the three surfactants studied, namely, two ionic and a nonionic surfactant with an elevated cloud point. They formed mixed micelles with octoxynol 9. The changes in cloud point caused by electrolytes having a common ion were compared at equal values of a concentration parameter chosen to produce cloud point additivity. By using the nitrate ion as a reference and arbitrarily equating its change in cloud point to zero, cloud point shift values could be assigned to other individual ions. For the anions, these cloud point shift values were related by a smooth function to the lyotropic numbers in the Hofmeister series. There was no correlation between the cloud point shift values and the lyotropic numbers of cations, presumably because of complexation between the ether groups of octoxynol 9 and many of the cations.

The effect of inorganic additives on the formation, composition, and combustion of cellulosic char

At temperature above 300°C the glycosyl units of cellulose are simultaneously depolymerized to a tar and decomposed to a char by evolution of H2O, CO, and CO2. When the glycosyl units are depleted, a stable char is formed containing about 30% aliphatic and 70% aromatic components. The aliphatic component is formed first, but on further heating is converted to polycyclic aromatic structures. The chars formed at lower temperatures are more combustible because the aliphatic component of the char is highly pyrophoric and is oxidized almost at the same temperature at which it is formed (∼360°C). The aromatic component, however, is less reactive and is oxidized at ∼520°C. Consequently, the chars formed at higher temperatures are less combustible. It has been shown that (NH4)2HPO4, which is a well-known flame retardant and smoldering inhibitor, lowers the pyrolysis temperature and increases the char yield by accelerating the decomposition reactions. This affects the composition of the intermediate chars but the final products have about the same composition irrespective of additives. (NH4)2HPO4 also lowers the rate of oxidation of the aromatic component and the corresponding heat release. NaCl, which is an enhancer of smoldering combustion, has a slight stabilizing effect on pyrolysis of cellulose. It lowers the oxidation temperature of the aromatic component and dramatically increases its rate. The corresponding heat release is also increased due to complete oxidation to CO2. The rate of oxidation calculated from the dynamic thermal analysis data is more than tripled by NaCl and significantly reduced by (NH4)2HPO4.

Effect of Inorganic Additives on Solutions of Nonionic Surfactants V: Emulsion Stability

□ Electrolytes often break emulsions to which they were added as active ingredients, adjuvants, or impurities. The stability of oil-in-water emulsions containing octoxynol 9 NF as the emulsifier and various added electrolytes was investigated by measuring droplet size, turbidity, and oil separation on storage at various temperatures and in a centrifugal field at 25°. Electrolytes were added to hexadecane emulsions after emulsification (direct addition); alternatively, hexadecane was emulsified in octoxynol 9–electrolyte mixtures (reverse addition). Xylene emulsions were prepared by direct addition only. Hexadecane emulsions containing 0.10% octoxynol 9 were considerably more stable than xylene emulsions containing 0.60% because the surfactant is practically insoluble in hexadecane, but miscible in all proportions with xylene. An emulsifier soluble in the disperse phase as well as the continuous phase evidently forms less stable interfacial films. The electrolytes investigated were sulfuric and hydrochloric acids, magnesium nitrate, and aluminum nitrate, which salt octoxynol 9 in by complexation between its ether groups and their cations; sodium thiocyanate, which salts the surfactant in by destructuring water; and sodium chloride and sodium sulfate, which salt octoxynol 9 out. The addition of these electrolytes at concentrations up to 2 or 3m to hexadecane emulsions produced fast and extensive creaming, little or no flocculation, no coalescence, and only minor changes in droplet size or turbidity on storage at room temperature. The extent of coalescence during centrifugation was actually reduced by the additives. Such stability is unusual. Droplet size and turbidity depended mainly on octoxynol 9 concentration. The greatest decrease in the former and increase in the latter occurred when the concentration was increased from 0.10 to ~0.4%. All emulsions became slightly coarser on storage at 25°. Stability at 50° was impaired by aluminum nitrate and magnesium nitrate and to a lesser extent by sodium sulfate and sodium chloride. Reverse-addition emulsions differentiated better between the electrolytes than direct-addition emulsions. Electrolytes salting octoxynol 9 in, especially by complexation, generally produced the finest and most stable emulsions. Similarly, xylene emulsions were destabilized more by the electrolytes which salted the emulsifier out than by those salting it in. Centrifugation of hexadecane emulsions at 7800×g compressed the creamed emulsion layer into a plug of clear, transparent, isotropic gel from which coalesced hexadecane separated slowly on further centrifugation. These semisolid gels contained the hexadecane as discrete, uncoalesced droplets because, on immersion in water or octoxynol 9 solutions with or without electrolytes, they turned opaque, liquefied, and redispersed spontaneously into emulsions of nearly the same average droplet size as the original emulsions.

Effect of Inorganic Additives on the Reactions of Isomeric Transition-Activated 80Br and 82Br in the Gaseous HBr–CH4 System

Abstract The effects of various inorganic additives with and without dipole moments on the product yield distributions have been examined in the CH4–H80mBr and CH4-H82mBr systems. Indications were that the ion-clusters formed in the reactions of IT-activated 80Br and 82Br play an important role in determining individual product yield distributions.

Effect of Inorganic Additives on Solutions of Nonionic Surfactants III: CMC's and Surface Properties

Continuing work on the interaction of inorganic additives with nonionic surfactants in aqueous solution dealt with their effect on the CMC and surface tension. The surfactants were octoxynol and polyoxyethylated oleyl alcohol, containing an average of 9.5 and 10 ethylene oxide units, respectively. Their CMC values were lowered by most electrolytes studied, representing salting out of the surfactants. The steepest reductions in the CMC were produced by the nitrates of sodium and potassium, which had been found to lower the cloud points of nonionic surfactants, salting them out because of the inability of their cations to form complexes with the ether oxygen linkages of the polyoxyethylene moieties. However, even electrolytes with cations such as hydrogen, lithium, calcium, nickel, lead, and aluminum capable of forming complexes with the ether oxygens, thereby increasing the cloud points of the surfactants, lowered their CMC values. In the presence of increasing concentrations of the latter electrolytes, the CMC values frequently went through minima and approached the CMC of the surfactant in the absence of additives. Increases in the CMC over the entire range of additive concentrations investigated were produced by cadmium nitrate for octoxynol, urea for polyoxyethylated oleyl alcohol, and magnesium nitrate for both. Net increases in the plateau or micellar surface tension of polyoxyethylated oleyl alcohol, i.e., in the constant surface tension of surfactant solutions above the CMC, were brought about by the nitrates of cadmium, aluminum, and magnesium at low concentrations only and by urea at all concentrations. This increase is interpreted as salting in. The area per surfactant molecule adsorbed at the air-water interface was reduced by all added electrolytes. Urea caused no such reduction.

Effect of inorganic additives on solutions of nonionic surfactants IV: Krafft points.

Two polydisperse polyoxyethylated nonionic surfactants were found to possess Krafft points as well as cloud points. The significance of the Krafft point and the reason why it is rarely observed in nonionic surfactants are discussed. The values of the Krafft and cloud points of the two surfactants underwent only small changes as a function of surfactant concentration in the range of 0.5-7.5% (w/w). All electrolytes investigated, as well as urea, raised the Krafft points by between 1 and 4 degrees in the concentration range of 0.5-4 molal. Included were salting-in electrolytes, which raised the cloud points, as well as salting-out electrolytes, which lowered them. Electrolytes that salt out nonionic surfactants strongly may depress the cloud point to the Krafft point temperature, rendering a water-soluble surfactant insoluble in salt solutions at all temperatures.

Effect of Inorganic Additives on Solutions of Nonionic Surfactants II

The effect of electrolytes and urea on the cloud points of the following three nonionic polyoxyethylated surfactants was studied: cetyl, stearyl, and oleyl alcohol adducts containing 10 ethylene oxide units. The results were similar to those obtained previously with polyethylene oxide and with a polyoxyethylated alkylphenol. Nitrates of cations capable of forming stable solid complexes with model ethers like dioxane raised the cloud points in proportion to their concentrations by up to 35°. They salted the surfactants in through complexation with the ether oxygens. The order of effectiveness in raising the cloud points was lead nitrate > hydrochloric acid > cadmium nitrate > sulfuric acid > magnesium nitrate > aluminum nitrate > nickel nitrate > lithium nitrate > calcium nitrate. Only the nitrates of sodium, potassium, ammonium, and cesium lowered the cloud points, salting the surfactants out. These cations do not form complexes with ether oxygens. Urea, sodium perchlorate, and sodium iodide, which break the structure of water, raised the cloud points. This salting‐in process is ascribed to increased hydration of the ether groups of the polyoxyethylated surfactants due to depolymerization of water by urea and the perchlorate and iodide anions. The bromide, chloride, and sulfate of sodium lowered the cloud points. The surfactant with the alkylaryl moiety was salted in more extensively but salted out only slightly more than the three surfactants with the linear hydrocarbon chain. The data indicate the need for revising the theories of the effects of salts on the solubility of nonelectrolytes in water. None of the theories takes into account the interaction between electrolytes and nonelectrolytes, even though many nonelectrolytes compete with water as ligands for the cations.