Activated Carbons Impregnated with Na2S and H2SO4: Texture, Surface Chemistry and Application to Mercury Removal from Aqueous Solutions

The effects of treatment of an activated carbon with Sulphur precursors on its textural properties and on the ability of the complex synthesized for mercury removal in aqueous solutions are studied. To this end, a commercial activated carbon has been modified by treatments with aqueous solutions of Na2S and H2SO4 at two temperatures (25 and 140 °C) to introduce sulphur species on its surface. The prepared adsorbents have been characterized by N2 (-196 °C) and CO2 (0 °C) adsorption, thermogravimetric analysis, temperature-programmed decomposition and X-ray photoelectron spectroscopy, and their adsorption capacities to remove Hg(II) ions in aqueous solutions have been determined. It has been shown that the impregnation treatments slightly modified the textural properties of the samples, with a small increase in the textural parameters (BET surface area and mesopore volumes). By contrast, surface oxygen content was increased when impregnation was carried out with Na2S, but it decreased when H2SO4 was used. However, the main effect of the impregnation treatments was the formation of surface sulphur complexes of thiol type, which was only achieved when the impregnation treatments were carried out at low temperature (25 °C). The presence of surface sulphur enhances the adsorption behaviour of these samples in the removal of Hg(II) cations in aqueous solutions at pH 2. In fact, complete Hg(II) removal is only obtained with the sulphur-containing activated carbons.

Removal of 8-quinolinecarboxylic acid pesticide from aqueous solution by adsorption on activated montmorillonites

Sodium montmorillonite (Na-M), acidic montmorillonite (H-M), and organo-acidic montmorillonite (Org-H-M) were applied to remove the herbicide 8-quinolinecarboxylic acid (8-QCA). The montmorillonites containing adsorbed 8-QCA were investigated by transmission electron microscopy, FT-IR spectroscopy, X-ray diffraction analysis, X-ray fluorescence thermogravimetric analysis, and physical adsorption of gases. Experiments showed that the amount of adsorbed 8-QCA increased at lower pH, reaching a maximum at pH 2. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The Langmuir model provided the best correlation of experimental data for adsorption equilibria. The adsorption of 8-QCA decreased in the order Org-H-M > H-M > Na-M. Isotherms were also used to obtain the thermodynamic parameters. The negative values of ΔG indicated the spontaneous nature of the adsorption process.

Reductive Removal of the Pivaloyl Protecting Group from Tetrazoles by a Naphthalene-Catalyzed Lithiation Process

The reaction of various 1-pivaloyl-1H-tetrazoles with excess lithium and a catalytic amount of naphthalene (20 mol%) led, after treatment with methanol, to the corresponding free tetrazoles through reductive C–N bond cleavage. This methodology represents a reasonable alternative to other nonreductive protocols.

Algerian natural montmorillonites for arsenic(III) removal in aqueous solution

The adsorption of As(III) from aqueous solutions using naturally occurring and modified Algerian montmorillonites has been investigated as a function of contact time, pH, and temperature. Kinetic studies reveal that uptake of As(III) ions is rapid within the first 3 h, and it slows down thereafter. Equilibrium studies show that As(III) shows the highest affinity toward acidic montmorillonite even at very low concentration of arsenic. The kinetics of As(III) adsorption on all montmorillonites used is well described by a pseudo-second-order chemical reaction model, which indicates that the adsorption process of these species is likely to be chemisorption. Adsorption isotherms of As(III) fitted the Langmuir and Freundlich isotherm models well. The adsorption of As(III) is pH-dependent obtaining an optimal adsorption at pH 5. From the thermodynamic parameters, it is concluded that the process is exothermic, spontaneous, and favorable. The results suggest that M1, M2, and acidic-M2 could be used as low-cost and effective filtering materials for removal of arsenic from water.

Enhanced removal of 8-quinolinecarboxylic acid in an activated carbon cloth by electroadsorption in aqueous solution

The effect of the electrochemical treatment (potentiostatic treatment in a filter-press electrochemical cell) on the adsorption capacity of an activated carbon cloth (ACC) was analyzed in relation with the removal of 8-quinolinecarboxylic acid pollutant from water. The adsorption capacity of an ACC is quantitatively improved in the presence of an electric field (electroadsorption process) reaching values of 96% in comparison to 55% in absence of applied potential. In addition, the cathodic treatment results in higher removal efficiencies than the anodic treatment. The enhanced adsorption capacity has been proved to be irreversible, since the removed compound remains adsorbed after switching the applied potential. The kinetics of the adsorption processes is also improved by the presence of an applied potential.

The flora of Jamaica; a description of the plants of that island, arranged according to the natural orders.

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Company orders, 1810 May 2

A printed request for Croswell to appear for military duty.

Rules and orders respecting the Steward, Cook & Butler of Harvard College, [1686]

These regulations are a revision of the original 1650 rules that laid out the duties of the Steward, Butler, and Cook. In these updated regulations, the Rector and Tutor are now responsible for signing off on the Steward's accounts rather than the President and Fellows.

The Lawes and Orders of Harvard Colledge, 1655-1708

The 21-page handwritten copy of the College laws is laid out in two columns, and lacks a cover. In the left-hand column, in an unidentified hand, are the Laws of 1655 in English with additions dated April 9, 1660, August 24, 1663, and December 5, 1667, and an order of the General Court dated Sept. 4, 1656. In the right-hand column, in the hand of President John Leverett, are the Latin Laws of 1642-1646, with an occasional reference to the Latin Laws of 1686 and 1692, and two extracts from the Corporation records about the reading of the Scriptures dated January 26 and May 27, 1708.

The Lawes and Orders of Harvard Colledge, 1655

Handwritten copy of the College laws used by Harvard presidents Charles Chauncy and Leonard Hoar, in a modern hardcover binding. The last six pages of the volume contain additional entries through 1672, some in the hand of President Chauncy. One entry details the 1666 expulsion of Harvard students Mason, Hubbard, and Wintrop for the hanging of "Goodma Sells doge upon the signe post."

Orders for expenditures for University Hall, 15 May 1813-13 May 1814

Contains one sewn volume of work orders for the construction of University Hall in the hand of Loammi Baldwin between May 1813 and May 1814. The volume contains 46 completed work orders for supplies and services for "building the new Dining Halls and Chapel in Cambridge" payable to Hon. John Davis, Harvard treasurer. Completed work orders are noted with the name of the payee, amount paid, and the supplies or services fulfilled. Work orders 47 through 60 in the volume are unused.

A general system of nature, through the three grand kingdoms of animals, vegetables, and minerals, systematically divided into their several classes, orders, genera, species, and varieties, with their habitations, manners, economy, structure and peculiarities. /

v. 7 (1806)

Elements of the science of botany, as established by Linnaeus; with examples to illustrate the classes and orders of his system.

1-2

Elements of the science of botany, as established by Linnaeus; with examples to illustrate the classes and orders of his system.

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Rules and orders relating to a Professor of the Mathematicks, of Natural and Experimental Philosophy, in Harvard College, 18 January 1726

This folder contains a single document describing the "rules and orders" of the Hollis Professor of Mathematics and Natural Philosophy. The document begins by defining the subjects to be taught by the Hollis Professor including natural and experimental philosophy, elements of geometry, and the principles of astronomy and geography. It then outlines the number of public and private lectures to be given to students, how much extra time the professor should spend with students reviewing any difficulties they may encounter understanding class subject matter discussed, and stipulates that the professor's duties shall be restricted solely to his teaching activities and not involve him in any religious activities at the College or oblige him to teach any additional studies other than those specified for the Hollis Professor of Mathematics and Natural Philosophy. Furthermore, the rules establish the professor's salary at £80 per year and allow the professor to receive from students, except those students studying theology under the Hollis Professor of Divinity, an additional fee as determined by the Corporation and Board of Overseers, to supplement his income. Moreover, the rules assert that all professorship candidates selected by the Harvard Corporation must be approved by Thomas Hollis during his lifetime or by his executor after his death. Finally, the rules state that the Hollis professor take an oath to the civil government and declare himself a member of the Protestant reformed religion. This document is signed by Thomas Hollis and four witnesses, John Hollis, Joshua Hollis, Richard Solly, and John Williams.