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J.D. Hem

Publications and source records attributed to J.D. Hem.

At least 19 recordsLinked to original sources
USGS2014

Fluctuations in concentration of dissolved solids of some southwestern streams

The concentration of dissolved solids in waters of streams of the Southwestern United Stated fluctuates widely as the stream discharge changes. These fluctuations may be extensive in a period of a few days or even a few hours. Data in this paper show the extent of the day‐to‐day changes in specific conductance and discharge of the Rio Grande at San Acacia, New Mexico, during the spring run‐off period of 1945. Data also are presented to show rapid fluctuations in concentration for the Pecos River near Artesia, New Mexico, the Gila River near Bylas, Arizona, and the Rio Grande at San Acacia during typical summer months. Hourly changes in chloride and discharge are shown for a day of approximately normal flow for the Pecos River near Malaga, New Mexico, and for a 36‐hour period of extremely low flow for the Gila River near Fort Thomas, Arizona.

Arizona, New Mexico↗
USGS2006

Some aspects of chemical equilibrium in ground water

The influence of individual factors such as geologic and hydrologic characteristics of environment, biologic activity in soil, and pollutants on ground ‐ water composition is discussed. Aspects of chemical equilibria in ground water , sorption reactions, carbonate equilibria, chemistry of iron, and factors altering equilibria are presented.

Groundwater↗
USGS1991

Coprecipitation mechanisms and products in manganese oxidation in the presence of cadmium

Manganese oxidation products were precipitated in an aerated open-aqueous system where a continuous influx of mixed Mn 2+ and Cd 2+ solution was supplied and pH was maintained with an automated pH-stat adding dilute NaOH. X-ray diffraction and electron diffraction identified the solids produced as mixtures of Cd 2 Mn 3 4+ O 8 , Mn 2+ 2 Mn 4+ 3 O 8 , MnO 2 (ramsdellite), and CdCO 3 . Mean oxidation numbers of the total precipitated Mn as great as 3.6 were reached during titrations. During subsequent aging in solution, oxidation numbers between 3.8 and 3.9 were reached in some precipitates in less than 40 days. Conditional oxidation rate constants calculated from a crystal-growth equation applied to titration data showed the overall precipitation rate, without considering manganese oxidation state in the precipitate, was increased by a factor of ~4 to ~7 when the mole ratio (Cd/Mn + Cd) of cadmium in the feed solution was 0.40 compared with rate constants for hausmannite (Mn 2+ Mn 2 3+ O 4 precipitation under similar conditions but without accessory metals. Kinetic experiments were made to test effects of various Cd/Mn + Cd mole ratios and rates of addition of the feed solution, different temperatures from 5.0 to 35°C, and pH from 8.0 to 9.0. Oxidation rates were slower when the Cd mole ratio was less than 0.40. The rate increased by a factor of ~10 when pH was raised one-half unit. The effect of temperature on the rate constants was also substantial, but the meaning of this is uncertain because the rate of formation of Mn 4+ oxide in the absence of Cd or other accessory metals was too slow to be measurable in titration experiments. The increased rate of Mn 4+ oxide formation in the presence of Cd 2+ can be ascribed to the formation of a labile adsorbed intermediate, CdMn 2 O 4 Int , an analog of hausmannite, formed on precipitate surfaces at the beginning of the oxidation process. The increased lability of this structure, resulting from coordination-chemical behavior of Cd 2+ during the titration, causes a rapid second-stage rearrangement and facilitates disproportionation of the Mn 3+ ions. The Mn 2+ ions thus released provide a positive feedback mechanism that couples the two steps of the conversion of Mn 2+ to Mn 4+ more closely than is possible when other metal ions besides manganese are not present. During aging of precipitates in contact with solutions, proportions of Cd 2 Mn 3 O 8 and MnO 2 increased at the expense of other precipitate components.

Geochimica et Cosmochimica Acta↗
USGS1989

Coprecipitation and redox reactions of manganese oxides with copper and nickel

Open-system, continuous-titration experiments have been done in which a slow flux of ∼0.02 molar solution of Mn 2+ chloride, nitrate, or perchlorate with Cu 2+ or Ni 2+ in lesser concentrations was introduced into an aerated reactor solution held at constant temperature and at constant pH by a pH-stat titrator that added dilute NaOH. The resulting mixtures of metal oxyhydroxides and their native solutions were aged for periods as long as 2 1/2 years. Fresh and aged precipitates were characterized by chemical analysis, oxidation state determinations, X-ray and electron diffraction, and electron microscopy. The precipitates can be described as mixtures of oxide and oxyhydroxide species, using concepts of equilibrium and nonequilibrium chemical thermodynamics. The metal-ion content of the aged precipitates in systems that contained copper is distributed among three principal components. One of these is a mixed oxide Cu 2 Mn 3 O 8 in which all Mn is in the 4+ oxidation state. A major component in all precipitates is feitknechtite, βMnOOH. These forms are supplemented by CuO or by birnessite or ramsdellite forms of MnO 2 where stoichiometry and thermodynamic calculations predict them. In systems that contained nickel and manganese, identifiable components included βMnOOH, Ni(OH) 2 , and the same two forms of MnO 2 . The oxidation number of the precipitated manganese increased during aging, and the pH of the supernatant solution decreased. The maximum Mn oxidation number observed was 3.55 in an Mn + Cu precipitate aged for 18 months. Concentrations of Cu 2+ and Ni 2+ generally decreased to values substantially below those predicted by oxide or hydroxide equilibrium. Scavenging effects of this type are common in natural aqueous systems.

Geochimica et Cosmochimica Acta↗
USGS1987

Synthesis and stability of hetaerolite, ZnMn2O4, at 25°C

A precipitate of nearly pure hetaerolite, ZnMn 2 O 4 , a spinel-structured analog of hausmannite, Mn 3 O 4 , was prepared by an irreversible wprecipitation of zinc with manganese at 25°C. The synthesis technique entailed constant slow addition of a dilute solution of Mn 2+ and Zn 2+ chlorides having a Mn/Zn ratio of 2:1 to a reaction vessel that initially contained distilled deionized water, maintained at a pH of 8.50 by addition of dilute NaOH by an automated pH stat, with continuous bubbling of CO 2 -free air. The solid was identified by means of X-ray diffraction and transmission electron microscopy and consisted of bipyramidal crystals generally less than 0.10 μm in diameter. Zn 2+ ions are able to substitute extensively for Mn 2+ ions that occupy tetrahedral sites in the hausmannite structure. Hetaerolite appears to be more stable than hausmannite with respect to spontaneous conversion to γMnOOH. The value of the standard free energy of formation of hetaerolite was estimated from the experimental data to be −289.4 ± 0.8 kcal per mole. Solids intermediate in composition between hetaerolite and hausmannite can be prepared by altering the Mn/Zn ratio in the feed solution.

Geochimica et Cosmochimica Acta↗
USGS1985

Thermodynamic stability of CoOOH and its coprecipitation with manganese

A precipitate of cobalt oxyhydroxides formed by bubbling oxygen through a dilute solution of Co(NO 3 ) 2 held at pH 9.0 and 25°C was aged for 23 months in contact with the original solution, with access to atmospheric oxygen. Co 3 O 4 and CoOOH were identified in the precipitate by X-ray diffraction. Chemical equilibria involving these solids were evaluated by measurements of solution pH and Co 2+ activities and by redox potential measurements and gave a ΔG coOOH 0 "> ΔGcoOOH0 of −92.3 ± 0.5 kcal/mole "> −92.3 ± 0.5 kcal/mole . This value and other thermodynamic data show relative feasibility of hypothetical reaction steps and changes in reaction paths during automated coprecipitation titrations and subsequent aging of a precipitate that finally contained βMnOOH, MnO 2 (birnessite) and CoOOH.

Geochimica et Cosmochimica Acta↗
USGS1981

Rates of manganese oxidation in aqueous systems

The rate of crystal growth of Mn 3 O 4 (hausmannite) and βMnOOH (feitknechtite) in aerated aqueous manganous perchlorate systems, near 0.01 M in total manganese, was determined at pH levels ranging from 7.00 to 9.00 and at temperatures from 0.5 to 37.4°C. The process is autocatalytic, but becomes psuedo first-order in dissolved Mn 2+ activity when the amount of precipitate surface is large compared to the amount of unreacted manganese. Reaction rates determined by titrations using an automated pH-stat were fitted to an equation for precipitate growth. The rates are proportional to surface area of oxide and degree of supersaturation with respect to Mn 2+ . The oxide obtained at the higher temperature was Mn 3 O 4 , but at 0.5° C only βMnOOH was formed. At intermediate temperatures, mixtures of these solids were formed. The rate of precipitation of hausmannite is strongly influenced by temperature, and that of feitknechtite much less so. The difference in activation energy may be related to differences in crystal structure of the oxides and the geometry of polymeric hydroxy ion precursors.

Geochimica et Cosmochimica Acta↗
USGS1978

Redox processes at surfaces of manganese oxide and their effects on aqueous metal ions

Mn oxides precipitated from aerated solutions of Mn2+ by raising the pH are reported in various publications to have the approximate composition Mn3O4 or MnOOH. These oxyhydroxides in turn can disproportionate to Mn2+ and MnO2 resulting in a substantial decrease in equilibrium Mn solubility. The disproportionation can catalyze the oxidation of Mn2+ and other metals by facilitating electron-transfer processes. Diversion of some electron transfers from Mn species to other metal ions can greatly decrease the equilibrium solubility of Co, Pb, Ni and some other elements in the presence of mixed-valence Mn oxides. Some scavenging and coprecipitation effects involving Mn oxides may be attributable to redox processes. Equilibrium solubilities for Mn, Co and Pb are summarized in four graphs. ?? 1978.

Chemical Geology↗
USGS1977

Reactions of metal ions at surfaces of hydrous iron oxide

Cu, Ag and Cr concentrations in natural water may be lowered by mild chemical reduction involving ferric hydroxide-ferrous ion redox processes. V and Mo solubilities may be controlled by precipitation of ferrous vanadate or molybdate. Concentrations as low as 10 −8.00 or 10 −9.00 M are readily attainable for all these metals in oxygen-depleted systems that are relatively rich in Fe. Deposition of manganese oxides such as Mn 3 O 4 can be catalyzed in oxygenated water by coupling to ferrous-ferric redox reactions. Once formed, these oxides may disproportionate, giving Mn 4+ oxides. This reaction produces strongly oxidizing conditions at manganese oxide surfaces. The solubility of As is significantly influenced by ferric iron only at low pH. Spinel structures such as chromite or ferrites of Cu, Ni, and Zn, are very stable and if locally developed on ferric hydroxide surfaces could bring about solubilities much below 10 −9.00 M for divalent metals near neutral pH. Solubilities calculated from thermodynamic data are shown graphically and compared with observed concentrations in some natural systems.

Geochimica et Cosmochimica Acta↗
USGS1976

Geochemical controls on lead concentrations in stream water and sediments

The equilibrium distribution of lead in solution and adsorbed on cation exchange sites in sediment theoretically may be calculated from equations representing selectivities of substrate for lead over H + , Ca 2+ and Na + , and the stabilities of lead solute species. Such calculations include consideration of total concentrations of major ions, cation exchange capacity (CEC) of substrate, and pH, at values expected in various natural systems. Measurements of CEC and selectivity coefficients were made for synthetic halloysite, a finely divided amorphous 1:1 clay prepared by precipitation from a mixture of solutions of aluminum and silica. Where suspended sediment having the same properties is present in concentrations of 10-1,000 mg/1 at pH 6–8, more than 90% of the lead present can be adsorbed on sediment surfaces. The cation exchange behavior of lead and other minor cationic species in natural systems could be predicted by this type of model if enough other supporting information were available. Information of the type needed describing natural stream sediments, however, is presently inadequate for accurate predictions.

Geochimica et Cosmochimica Acta↗
USGS1974

Kaolinite synthesis at 25°C

The addition of quercetin, an organic flavone (C 15 H 10 O 7 ), to aqueous solutions containing silica and aluminum and adjusted to final p H's from 6.5 to 8.5 produced a 1 : 1 alumninosilicate precipitate which, after 6 to 16 months of aging in solution at 25°C, contained as much as 5 percent well-formed kaolinite plates. Similar solutions containing no organic material produced relatively amorphous precipitates with the same composition and stability (standard free energy of formation = -897±1 kilocalories per mole) but with substantially smaller amounts of crystaline material even after 2 years of aging.

Science↗
USGS1973

Solubility of cryolite at 25° C and 1 atmosphere pressure

For natural cryolite from Greenland the activity product for the reaction (in water), Na 3 Al F 6 c --> 3Na + + Al 3+ + 6F - , was found to be 10 -34.3 +/- 0.1 . This is in good agreement with earlier work in which equilibrium was approached from supersaturation.

Journal of Research of the U.S. Geological Survey↗
USGS1968

Activity product constant of cryolite at 25°C and one atmosphere using selective-ion electrodes to estimate sodium and fluoride activities

The activity product constant of cryolite (Na 3 AlF 6 ) at 25°C and 1 atm total pressure was calculated from data for solutions from which synthetic cryolite or mixtures of cryolite and a solid apparently related to ralstonite had precipitated. The activities of fluoride and of sodium were estimated using specific ion electrodes. The activity of Al 3+ was calculated from aluminum concentrations using equations which involve aluminum species existing in water solutions containing fluoride and hydroxide ions. For the reaction Na 3 AlF 6 ( c ) = 3 Na ( aq ) + + Al 3+ ( aq ) + 6 E - ( aq ) the activity product constant K so is 10 −33.84 , and the standard free energy of formation at 25°C is -745.4±1.0 kcal mole −1 . This latter is identical to a value from the literature which is based on calorimetric data. Although cryolite and related minerals are easily precipitated in the laboratory, their relative scarcity in nature suggests that the effect of influences, perhaps solutes other than those occurring in the structure, may inhibit or prevent the formation of cryolite.

Geochimica et Cosmochimica Acta↗
USGS1960

Chemical equilibrium diagrams for ground-water systems/les graphiques de l'équilibre chimique pour les systèmes des eaux souterrainnes

Chemical equilibrium in water in contact with calcite is expressed by means of a pH grid overlay on a log-log plot of activities of bicarbonate vs. calcium ions. Solubility of ferrous iron and the solid-phase minerals that would be stable in a solution containing activities of 10 ppm of sulfate and 100 ppm of bicarbonate or related species is expressed by means of a stability-field diagram with pH as abscissa and redox potential as ordinate.The diagrams can be used to tell whether water injected in recharge wells may form precipitates that may plug the aquifer and have other uses in studies of natural water chemistry.

International Association of Scientific Hydrology ↗
USGS1952

The industrial utility of public water supplies in the Mountain States, 1952

The location of industrial plants is dependent on an ample water supply of suitable quality. Information relating to the chemical characteristics of the water supplies is not only essential to the location of many plants but also is an aid in the manufacture and distribution of many commodities. Public water supplies are utilized extensively as a source of supply for many industrial plants, used either as delivered for domestic consumption or with further treatment if necessary to meet specific needs of the plant, such as water· for processing, cooling, and steam generation. The industrial use of water in the United States in 1950 was estimated to be more than 75 billion gallons per day from private sources. In addition, about 6 billion gallons per day was estimated to be taken from public water supplies. U.S. Geological Survey Water-Supply Paper 658, "The industrial utility of public water supplies in the United States, 1932" contains information pertaining to the public water supplies of 670 of the larger cities throughout the United States. This report, which is still in print and being distributed, has filled an important need in the field of water-supply engineering. The demand for more up-to-date information and more extended coverage has led to studies by the Geological Survey for revision of the information contained in the 1932 report. The revised report, which will include data pertaining to public water supplies of more than 1, 200 cities in the United States, will eventually be published as a Geological Survey Water-Supply Paper. However, in order that the information might be available at the earliest possible time, nine preliminary reports are being issued which give data on the ·larger cities in each state. These nine reports are being released as Geological Survey Circulars, each covering a group of states as delineated by the Bureau of Census in taking the census of the population of the country. (See fig. 1). The reports give descriptive information and analytical data for approximately three-fourths of the cities that will be included in the final report for each of the states. This circular is the second of the series and includes data for the States of Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming. The report gives the population (1950) of the city, population supplied, ownership, sources and treatment of supplies, capacity of treatment plants, storage facilities for both raw and finished waters, and chemical analyses of the water for 11 cities in Arizona, 8 in Colorado, 12 in Idaho, 9 in Montana, 8 in Nevada, 9 in New Mexico, 9 in Utah, and 8 in Wyoming. The data for each city are essentially the same as will appear in the complete report for the whole country.

Arizona, Colorado, Idaho, Montana, Nevada, New Mex↗