Rapid, selective heavy metal removal from water by a metal-organic framework/polydopamine composite

Drinking water contamination with heavy metals, particularly lead, is a persistent problem worldwide with grave public health consequences. Existing purification methods often cannot address this problem quickly and economically. Here we report a cheap, water stable metal–organic framework/polymer composite, Fe-BTC/PDA, that exhibits rapid, selective removal of large quantities of heavy metals, such as Pb2+ and Hg2+, from real world water samples. In this work, Fe-BTC is treated with dopamine, which undergoes a spontaneous polymerization to polydopamine (PDA) within its pores via the Fe3+ open metal sites. The PDA, pinned on the internal MOF surface, gains extrinsic porosity, resulting in a composite that binds up to 1634 mg of Hg2+ and 394 mg of Pb2+ per gram of composite and removes more than 99.8% of these ions from a 1 ppm solution, yielding drinkable levels in seconds. Further, the composite properties are well-maintained in river and seawater samples spiked with only trace amounts of lead, illustrating unprecedented selectivity. Remarkably, no significant uptake of competing metal ions is observed even when interferents, such as Na+, are present at concentrations up to 14 000 times that of Pb2+. The material is further shown to be resistant to fouling when tested in high concentrations of common organic interferents, like humic acid, and is fully regenerable over many cycles

People from Brač, emigrant press in Chile and newspaper Domovina - from the late 19th century to the beginning of World War I

Cilj je rada postaviti ishodišta za proučavanje povijesti hrvatskog iseljeničkog novinstva u Čileu od najranijeg razdoblja doseljenja Hrvata do kraja 1914. godine, među kojima je brojčano dominantnu grupaciju činilo stanovništvo s Brača. Radilo se prvenstveno o ekonomskoj migraciji uzrokovanoj ekonomskim promjenama u društvu općenito, ali i ekonomskim promjenama kao posljedicama političkih kretanja. U novu domovinu donose tradicionalnu potrebu organiziranja u razna društva, ali i svijest o vlastitoj nacionalnoj pripadnosti s vlastitim jezikom. Neobično brza asimilacija (već u prvoj generaciji) dovodi u pitanje opstojnost te potrebu očuvanja baštine. Iseljeničke novine u kojima surađuju, uređuju ih i pokreću Bračani – novinari, među kojima se ističu Ivan Krstulović i Luka Bonačić s novinama „Domovina“ iz Punta Arenasa, u dosadašnjoj literaturi sagledavane su gotovo isključivo s aspekta političke orijentacije i borbe. Cilj je rada kroz primjer rubrike „Iz mjesta i okolice“, koja je održala kontinuitet tijekom cijelog razdoblja izlaženja lista „Domovina“ i čijim je sastavnim dijelom bila, prikazati, s aspekta socijalne povijesti, da su lokalne novine odražavale i bilježile pojave i događanja značajna za svakodnevni život zajednice sa svrhom očuvanja njezina identiteta.The topic of this paper is to set the starting point for studying the history of Croatian emigrant journalism in Chile from the earliest period of the settlement of Croats until the end of 1914, including the dominant population group from Brač. It was primarily the economic migration, which was caused by economic changes in the society in general, and economic changes as a consequence of political movements. The immigrants had the need for organizing themselves in various societies in the new country, and they also had the awareness of their own nationality and language. The unusually rapid assimilation (already in the first generation) calls into question the viability and the need to preserve heritage. Immigrant newspapers edited and run by Brač emigrant journalists, most notably Ivan Krstulović and Luka Bonačić, with the newspaper Domovina from Punta Arenas, were in the current literature perceived almost exclusively in terms of political orientation and struggle. The aim of this paper is to show that the local newspaper Domovina reflected and recorded phenomena and events significant for the daily life of the community with the intention of preservation its identity from the perspective of social history, especially in the section From the town and surrounding areas

Recent Advances in Carbon Capture with Metal-Organic Frameworks

The escalating level of CO2 in the atmosphere is one of the most critical environmental issues of our age. The carbon capture and storage from pilot test plants represents an option for reducing CO2 emissions, however, the energy cost associated with post-combustion carbon capture process alone is similar to 30% of the total energy generated by the power plant. Thus, the generation of carbon capture adsorbents with high uptake capacities, great separation performance and low cost is of paramount importance. Metal-organic frameworks are infinite networks of metal-containing nodes bridged by organic ligands through coordination bonds into porous extended structures and several reports have revealed that they are ideal candidates for the selective capture of CO2. In this review we summarize recent advances related to the synthesis of porous MOFs and the latest strategies to enhance the CO2 adsorption enthalpies and capacities at low-pressures, increase hydrolytic and mechanical stabilities, and improve the ease of regeneration. Although they show great promise for post-combustion carbon capture, there are still major challenges that must be overcome before they can be used for such a large-scale application

Catalyst-Free Synthesis of Aryl Diamines via a Three-Step Reaction Process

The formation of C–N bonds with aryl amines is one of the most widely studied reactions in organic chemistry. Despite this, it is still highly challenging, often requiring expensive, precious metal-based catalysts. Here we report an easy catalyst-free methodology for constructing C–N bonds. The method, which proceeds via the in situ formation of closed ring amidinium ions, allows the preparation of a series of symmetrical and/or unsymmetrical aryl diamines in notably high yields (82–98%) and purity and with a variety of different substituents. The methodology is shown successful for the preparation of aryl diamines having <i>para</i>- and/or <i>meta</i>-substituted carboxyl, nitro, bromo, methoxy, or methyl groups. This green synthetic pathway, which is catalyst free, requires only three steps, and proceeds without the need for purification. Further, it is a new sustainable, economically viable method to achieve an otherwise challenging bond formation

Applications of neutron scattering to understanding structure and gas storage properties of metal-organic frameworks and related materials

The development of nanostructured materials with predictable and controllable connectivity and functionalities has sparked a multitude of research directions. We have been studying emerging metal-org. framework (MOFs) systems and their adsorption properties for methane storage, carbon capture, gas sepns. and hydrogen storage. Neutron methods including powder diffraction, vibrational and rotational spectroscopy, and quasi-elastic scattering, are invaluable to advancing our understanding the performance (or lack of performance) of novel storage and adsorption systems. This will be illustrated by discussing several examples taken from our recent research involving both MOFs other microporous materials

Catalyst-Free Synthesis of Aryl Diamines via a Three-Step Reaction Process

The formation of C–N bonds with aryl amines is one of the most widely studied reactions in organic chemistry. Despite this, it is still highly challenging, often requiring expensive, precious metal-based catalysts. Here we report an easy catalyst-free methodology for constructing C–N bonds. The method, which proceeds via the in situ formation of closed ring amidinium ions, allows the preparation of a series of symmetrical and/or unsymmetrical aryl diamines in notably high yields (82–98%) and purity and with a variety of different substituents. The methodology is shown successful for the preparation of aryl diamines having <i>para</i>- and/or <i>meta</i>-substituted carboxyl, nitro, bromo, methoxy, or methyl groups. This green synthetic pathway, which is catalyst free, requires only three steps, and proceeds without the need for purification. Further, it is a new sustainable, economically viable method to achieve an otherwise challenging bond formation

Na3CsCo7(PO4)6: A New Magnetic Cobalt(II) Phosphate Compound Containing an Interesting Cobalt Network Structure Made of Triangular Lattices

A new cobalt(II) phosphate compd. has been synthesized using high-temp. flux methods in the CsCl/NaCl media at 650°C. The title compd., Na3CsCo7(PO4)6, forms vibrant purple plate crystals. It crystallizes in a monoclinic space group C2/c (no. 15) with the cell dimensions a = 12.844(3)Å, b = 10.764(2)Å, c = 15.630(3)Å, β = 113.54(3)°, and V = 1980.96(3)Å3. The X-ray single crystal structure reveals that the Co2+ cations adopt CoOn coordination, including square-planner (n = 4), square pyramidal (n = 5) and octahedral (n = 6) geometries. These polyhedra share corner oxygen atoms to form an extended three-dimensional network structure. The Co2 cations are magnetic ions, and the possible magnetic lattice can be viewed as being constructed by triangular lattices, see the structure below. In this presentation, we will discuss the results of solid state synthesis, crystal growth, structure anal., UV-Vis spectroscopy, and magnetic characterization of the title compd

Hydrogen storage properties of copper and silver exchanged zeolite SSZ-13

Copper and silver cation-exchanged zeolite SSZ-13 present an interesting opportunity to study the mechanism of interaction of adsorbate gases, primarily hydrogen (H2), with the ion-exchange sites in zeolites as there is only one type of cation site, in contrast to many zeolites. Cation-exchange in zeolites has been shown to result in more H2 specific binding sites and higher adsorption capacity. Detg. the relationship between the H2-cation interaction and the type of cation is crit. to designing new types of H2 storage materials, including MOFs and porous carbons. The interaction of H2 with cation-exchanged zeolites can provide crit. information on the relative binding strengths to the zeolite host, as well as how the host framework changes as a function of the quantity of gas adsorbed. We present a multifaceted approach to the study of H2 adsorption in both copper- and silver-exchanged SSZ-13 and for comparison the host framework SSZ-13. Powder neutron diffraction was employed to locate each of the site specific binding sites for H2 from in situ adsorption allowing for the accurate detn. of the location of the adsorbed gas relative to the zeolite framework. Possible cation-migration as a function of adsorbed H2 is considered relative to that of gas adsorbed in cation-exchanged zeolites X and Y (FAU). Addnl., inelastic neutron scattering spectroscopy was used to probe the relative rotational energies of the adsorbed H2 as a function of the quantity of gas loaded. Low-pressure gas adsorption measurements reveal an increased H2 uptake in the cation-exchanged zeolites over that of the host framework without exchange