Pharmaceutical adsorption from the primary and secondary effluents of a wastewater treatment plant by powdered activated carbon

<p>This study investigated the powdered activated carbon (PAC) adsorption of 13 pharmaceuticals from the primary (and secondary) effluents of a wastewater treatment plant. In addition to fresh PAC, PAC that was previously used for pharmaceutical elimination from the secondary effluent was also examined for its reuse potential in the primary effluent. The results showed a comparably negligible pharmaceutical uptake by fresh and used PACs in the primary effluent, in contrast to a substantial uptake by both PACs in the secondary effluent. This result indicated a severe adsorption competition induced from the primary effluent organic matter, i.e. the considerably higher constituents of low molecular and hydrophobic components. Furthermore, the competition effect even resulted in a desorption of the negatively charged pharmaceuticals from the used PAC into the primary effluent. It was concluded that adding fresh PAC to the secondary effluent is preferred and that recycling the used PAC into the activated sludge tank could not offer an additional pharmaceutical adsorption.</p

[(C₂H₅)₄N][U₂O₄(HCOO)₅], an Ammonium Uranyl Formate Framework Showing Para- to Ferro-Electric Transition: Synthesis, Structures, and Properties

We report an ammonium uranyl formate framework of formula [(C2H5)4N]­[U2O4(HCOO)5], prepared by using components of tetraethylammonium, uranyl, and formate. The compound possesses a layered structure of anionic uranyl–formate wavy sheets and intercalated (C2H5)4N+ cations. The sheet consists of pentagonal bipyramidal uranyl cations connected by equatorial anti–anti and anti–syn HCOO– bridges, and it has a topology of 33·43·54 made of edge-sharing square and triangle grids. The high-temperature (HT) phase belongs to the chiral but nonpolar tetragonal space group P4̅21m. In the structure, one HCOO– is 2-fold disordered, showing a flip motion between the two anti–syn orientations. On cooling, this flip motion slowed and finally froze, leading to a phase transition at ∼200 K. The low-temperature (LT) structure is monoclinic and polar in space group P21; the cations shift, and the layers slide. Especially, the concerted and net shifts of the ammonium cations toward the −b direction, with respect to the anionic sheets, result in an estimated spontaneous polarization of 0.86 μC cm–2 in LT. The phase transition is thus para- to ferro-electric, in Aizu notation 4̅2mF2, accompanied by significant, anisotropic dielectric anomalies, with a quite significant thermal hysteresis. Variable-temperature luminescent spectroscopy and differential scanning calorimetry confirmed the transition and provided further information. The structure–property relationship is established

A New Series of Chiral Metal Formate Frameworks of [HONH₃][M^II(HCOO)₃] (M = Mn, Co, Ni, Zn, and Mg): Synthesis, Structures, and Properties

We report the synthesis, crystal structures, IR, and thermal, dielectric, and magnetic properties of a new series of ammonium metal formate frameworks of [HONH₃]­[M^II(HCOO)₃] for M = Mn, Co, Ni, Zn, and Mg. They are isostructural and crystallize in the nonpolar chiral orthorhombic space group <i>P</i>2₁2₁2₁, <i>a</i> = 7.8121(2)–7.6225(2) Å, <i>b</i> = 7.9612(3)–7.7385(2) Å, <i>c</i> = 13.1728(7)–12.7280(4) Å, and <i>V</i> = 819.27(6)–754.95(4) ų. The structures possess anionic metal formate frameworks of 4⁹·6⁶ topology, in which the octahedral metal centers are connected by the anti–anti formate ligands and the hydroxylammonium is located orderly in the channels, forming strong O/N–H···O_formate hydrogen bonds with the framework. HONH₃⁺ with only two non-H atoms favors the formation of the dense chiral 4⁹·6⁶ frameworks, instead of the less dense 4¹²·6³ perovskite frameworks for other monoammoniums of two to four non-H atoms because of its small size and its ability to form strong hydrogen bonding. However, the larger size of HONH₃⁺ compared to NH₄⁺ resulted in simple dielectric properties and no phase transitions. The three magnetic members (Mn, Co, and Ni) display antiferromagnetic long-range ordering of spin canting, at Néel temperatures of 8.8 K (Mn), 10.9 K (Co), and 30.5 K (Ni), respectively, and small spontaneous magnetizations for the Mn and Ni members but large magnetization for the Co member. Thermal and IR spectroscopic properties are also reported

A New Series of Chiral Metal Formate Frameworks of [HONH₃][M^II(HCOO)₃] (M = Mn, Co, Ni, Zn, and Mg): Synthesis, Structures, and Properties

We report the synthesis, crystal structures, IR, and thermal, dielectric, and magnetic properties of a new series of ammonium metal formate frameworks of [HONH₃]­[M^II(HCOO)₃] for M = Mn, Co, Ni, Zn, and Mg. They are isostructural and crystallize in the nonpolar chiral orthorhombic space group <i>P</i>2₁2₁2₁, <i>a</i> = 7.8121(2)–7.6225(2) Å, <i>b</i> = 7.9612(3)–7.7385(2) Å, <i>c</i> = 13.1728(7)–12.7280(4) Å, and <i>V</i> = 819.27(6)–754.95(4) ų. The structures possess anionic metal formate frameworks of 4⁹·6⁶ topology, in which the octahedral metal centers are connected by the anti–anti formate ligands and the hydroxylammonium is located orderly in the channels, forming strong O/N–H···O_formate hydrogen bonds with the framework. HONH₃⁺ with only two non-H atoms favors the formation of the dense chiral 4⁹·6⁶ frameworks, instead of the less dense 4¹²·6³ perovskite frameworks for other monoammoniums of two to four non-H atoms because of its small size and its ability to form strong hydrogen bonding. However, the larger size of HONH₃⁺ compared to NH₄⁺ resulted in simple dielectric properties and no phase transitions. The three magnetic members (Mn, Co, and Ni) display antiferromagnetic long-range ordering of spin canting, at Néel temperatures of 8.8 K (Mn), 10.9 K (Co), and 30.5 K (Ni), respectively, and small spontaneous magnetizations for the Mn and Ni members but large magnetization for the Co member. Thermal and IR spectroscopic properties are also reported

Two Systems of [DabcoH₂]²⁺/[PipH₂]²⁺–Uranyl–Oxalate Showing Reversible Crystal-to-Crystal Transformations Controlled by the Diammonium/Uranyl/Oxalate Ratios in Aqueous Solutions ([DabcoH₂]²⁺ = 1,4-Diazabicyclo-[2.2.2]-octaneH₂ and [PipH₂]²⁺ = PiperazineH₂)

We present here two systems of [dabco­H2]2+–uranyl–oxalate and [pip­H2]2+–uranyl–oxalate in which [dabco­H2]2+ and [pip­H2]2+ are cations of doubly protonated 1,4-diaza­bicyclo-[2.2.2]-octane (dabco) and piperazine (pip), respectively. Each system yielded two different crystals and showed the reversible crystal-to-crystal transformations between them in aqueous solutions, controlled by the ratio of reactants or building blocks in the reaction systems. The four compounds in pairs are [dabco­H2]­[UO2­(C2O4)2­(H2O)]·2H2O (dabco1) and [dabco­H2]­[(UO2)2­(C2O4)3­(H2O)2]·2H2O (dabco2), and [pip­H2]­[UO2­(C2O4)2­(H2O)]·4H2O (pip1) and [pip­H2]­[(UO2)2­(C2O4)3­(H2O)2]·2H2O (pip2). Besides the cations and lattice water, dabco1 and pip1 contain mononuclear anions of [UO2­(C2O4)2­(H2O)]2–, whereas dabco2 and pip2 possess dinuclear anions of [(UO2)2­(C2O4)3­(H2O)2]2–, and in all structures, the uranium ion shows a pentagonal bipyramid environment made up of equatorial oxalate, water, and apical oxygen. The needle crystals of dabco1 belong to the chiral space group P6522. In the structure, the [UO2­(C2O4)2­(H2O)]2– anions form anionic helixes along the 65 axis and they are further linked by N–H···O hydrogen bonds between the interhelix [dabco­H2]2+ cation and oxalates of the anion. Disorder of lattice water and the [dabco­H2]2+ cation is observed in dabco1. The thin plate crystals of pip1 in space group P1̅ possess a lamellar structure, with dense layers of [pipH2]2+·2­[UO2­(C2O4)2­(H2O)]2– pillared by other crystallographically unique [pip­H2]2+ cations, and the structure contains lattice water forming branched zigzag water chains. Block crystals of dabco2 and pip2, in monoclinic space groups C2/c and P21/c, respectively, are of similar layer-like structures, possessing the dinuclear [(UO2)2­(C2O4)3­(H2O)2]2– anion with one tetradentate oxalate bridge. The anions and ammonium cations form chains by N–H···O hydrogen bonds between them and then further form stacked layers via O–H···O hydrogen bonds among the coordinated and lattice water and the oxalate ligands. The ratio of diammonium/uranyl/oxalate in the reaction systems controlled the final outcomes and the occurrence of transformation, no transformation, and reverse transformation. The thermal stability; UV–vis, IR, and Raman spectra; and luminescence were also investigated

[(C₂H₅)₄N][U₂O₄(HCOO)₅], an Ammonium Uranyl Formate Framework Showing Para- to Ferro-Electric Transition: Synthesis, Structures, and Properties

We report an ammonium uranyl formate framework of formula [(C₂H₅)₄N]­[U₂O₄(HCOO)₅], prepared by using components of tetraethylammonium, uranyl, and formate. The compound possesses a layered structure of anionic uranyl–formate wavy sheets and intercalated (C₂H₅)₄N⁺ cations. The sheet consists of pentagonal bipyramidal uranyl cations connected by equatorial <i>anti</i>–<i>anti</i> and <i>anti</i>–<i>syn</i> HCOO^– bridges, and it has a topology of 3³·4³·5⁴ made of edge-sharing square and triangle grids. The high-temperature (HT) phase belongs to the chiral but nonpolar tetragonal space group <i>P</i>4̅2₁<i>m</i>. In the structure, one HCOO^– is 2-fold disordered, showing a flip motion between the two <i>anti</i>–<i>syn</i> orientations. On cooling, this flip motion slowed and finally froze, leading to a phase transition at ∼200 K. The low-temperature (LT) structure is monoclinic and polar in space group <i>P</i>2₁; the cations shift, and the layers slide. Especially, the concerted and net shifts of the ammonium cations toward the −<i>b</i> direction, with respect to the anionic sheets, result in an estimated spontaneous polarization of 0.86 μC cm^–2 in LT. The phase transition is thus para- to ferro-electric, in Aizu notation 4̅2<i>mF</i>2, accompanied by significant, anisotropic dielectric anomalies, with a quite significant thermal hysteresis. Variable-temperature luminescent spectroscopy and differential scanning calorimetry confirmed the transition and provided further information. The structure–property relationship is established

Two Systems of [DabcoH₂]²⁺/[PipH₂]²⁺–Uranyl–Oxalate Showing Reversible Crystal-to-Crystal Transformations Controlled by the Diammonium/Uranyl/Oxalate Ratios in Aqueous Solutions ([DabcoH₂]²⁺ = 1,4-Diazabicyclo-[2.2.2]-octaneH₂ and [PipH₂]²⁺ = PiperazineH₂)

We present here two systems of [dabco­H₂]²⁺–uranyl–oxalate and [pip­H₂]²⁺–uranyl–oxalate in which [dabco­H₂]²⁺ and [pip­H₂]²⁺ are cations of doubly protonated 1,4-diaza­bicyclo-[2.2.2]-octane (dabco) and piperazine (pip), respectively. Each system yielded two different crystals and showed the reversible crystal-to-crystal transformations between them in aqueous solutions, controlled by the ratio of reactants or building blocks in the reaction systems. The four compounds in pairs are [dabco­H₂]­[UO₂­(C₂O₄)₂­(H₂O)]·2H₂O (<b>dabco1</b>) and [dabco­H₂]­[(UO₂)₂­(C₂O₄)₃­(H₂O)₂]·2H₂O (<b>dabco2</b>), and [pip­H₂]­[UO₂­(C₂O₄)₂­(H₂O)]·4H₂O (<b>pip1</b>) and [pip­H₂]­[(UO₂)₂­(C₂O₄)₃­(H₂O)₂]·2H₂O (<b>pip2</b>). Besides the cations and lattice water, <b>dabco1</b> and <b>pip1</b> contain mononuclear anions of [UO₂­(C₂O₄)₂­(H₂O)]^2–, whereas <b>dabco2</b> and <b>pip2</b> possess dinuclear anions of [(UO₂)₂­(C₂O₄)₃­(H₂O)₂]^2–, and in all structures, the uranium ion shows a pentagonal bipyramid environment made up of equatorial oxalate, water, and apical oxygen. The needle crystals of <b>dabco1</b> belong to the chiral space group <i>P</i>6₅22. In the structure, the [UO₂­(C₂O₄)₂­(H₂O)]^2– anions form anionic helixes along the 6₅ axis and they are further linked by N–H···O hydrogen bonds between the interhelix [dabco­H₂]²⁺ cation and oxalates of the anion. Disorder of lattice water and the [dabco­H₂]²⁺ cation is observed in <b>dabco1</b>. The thin plate crystals of <b>pip1</b> in space group <i>P</i>1̅ possess a lamellar structure, with dense layers of [pipH₂]²⁺·2­[UO₂­(C₂O₄)₂­(H₂O)]^2– pillared by other crystallographically unique [pip­H₂]²⁺ cations, and the structure contains lattice water forming branched zigzag water chains. Block crystals of <b>dabco2</b> and <b>pip2</b>, in monoclinic space groups <i>C</i>2/<i>c</i> and <i>P</i>2₁/<i>c</i>, respectively, are of similar layer-like structures, possessing the dinuclear [(UO₂)₂­(C₂O₄)₃­(H₂O)₂]^2– anion with one tetradentate oxalate bridge. The anions and ammonium cations form chains by N–H···O hydrogen bonds between them and then further form stacked layers via O–H···O hydrogen bonds among the coordinated and lattice water and the oxalate ligands. The ratio of diammonium/uranyl/oxalate in the reaction systems controlled the final outcomes and the occurrence of transformation, no transformation, and reverse transformation. The thermal stability; UV–vis, IR, and Raman spectra; and luminescence were also investigated

Perovskite-Like Polar Lanthanide Formate Frameworks of [NH₂NH₃][Ln(HCOO)₄] (Ln = Tb–Lu and Y): Synthesis, Structures, Magnetism, and Anisotropic Thermal Expansion

A series of isostructural hydrazinium lanthanide (Ln) formate framework compounds of [NH₂NH₃]­[Ln­(HCOO)₄] for Ln³⁺ ions from Tb³⁺ to Lu³⁺ and Y³⁺ have been successfully prepared by utilizing NH₂NH₃⁺. The compounds crystallize in orthorhombic polar space group <i>Pca</i>2₁, with cell parameters at 180 K of <i>a</i> = 18.2526(7)–18.1048(5) Å, <i>b</i> = 6.5815(2)–6.5261(2) Å, <i>c</i> = 7.6362(3)–7.5044(2) Å, and <i>V</i> = 917.33(6)–886.67(4) ų, showing the effect of lanthanide contraction. The compounds possess polar perovskite-like structures incorporating the hydrazinium cations in the cavities of the NaCl-like framework, in which the Ln³⁺ ions in a bicapped trigonal prism are connected by anti–anti and syn–anti formate groups. The N–H···O_formate hydrogen-bonding interactions are between the hydrazinium cations and the anionic framework. One anti–anti formate group is frustrated by the competitive N–H···O_formate hydrogen-bonding interactions. It thus twists or flips upon warming, resulting in large anisotropic thermal expansion and negative thermal expansion below 180 K. A comparison with the transition metal and magnesium analogues revealed that the structural compactness, tighter binding of the hydrazinium cation by the framework, and symmetrically better match between the framework and ammonium cation for Ln compounds could inhibit the occurrence of phase transition in the series. The IR spectroscopic, thermal, and magnetic properties are investigated

Perovskite-Like Polar Lanthanide Formate Frameworks of [NH₂NH₃][Ln(HCOO)₄] (Ln = Tb–Lu and Y): Synthesis, Structures, Magnetism, and Anisotropic Thermal Expansion

A series of isostructural hydrazinium lanthanide (Ln) formate framework compounds of [NH₂NH₃]­[Ln­(HCOO)₄] for Ln³⁺ ions from Tb³⁺ to Lu³⁺ and Y³⁺ have been successfully prepared by utilizing NH₂NH₃⁺. The compounds crystallize in orthorhombic polar space group <i>Pca</i>2₁, with cell parameters at 180 K of <i>a</i> = 18.2526(7)–18.1048(5) Å, <i>b</i> = 6.5815(2)–6.5261(2) Å, <i>c</i> = 7.6362(3)–7.5044(2) Å, and <i>V</i> = 917.33(6)–886.67(4) ų, showing the effect of lanthanide contraction. The compounds possess polar perovskite-like structures incorporating the hydrazinium cations in the cavities of the NaCl-like framework, in which the Ln³⁺ ions in a bicapped trigonal prism are connected by anti–anti and syn–anti formate groups. The N–H···O_formate hydrogen-bonding interactions are between the hydrazinium cations and the anionic framework. One anti–anti formate group is frustrated by the competitive N–H···O_formate hydrogen-bonding interactions. It thus twists or flips upon warming, resulting in large anisotropic thermal expansion and negative thermal expansion below 180 K. A comparison with the transition metal and magnesium analogues revealed that the structural compactness, tighter binding of the hydrazinium cation by the framework, and symmetrically better match between the framework and ammonium cation for Ln compounds could inhibit the occurrence of phase transition in the series. The IR spectroscopic, thermal, and magnetic properties are investigated

Kinetics of Cell Inactivation, Toxin Release, and Degradation during Permanganation of Microcystis aeruginosa

Potassium permanganate (KMnO4) preoxidation is capable of enhancing cyanobacteria cell removal. However, the impacts of KMnO4 on cell viability and potential toxin release have not been comprehensively characterized. In this study, the impacts of KMnO4 on Microcystis aeruginosa inactivation and on the release and degradation of intracellular microcystin-LR (MC-LR) and other featured organic matter were investigated. KMnO4 oxidation of M. aeruginosa exhibited some kinetic patterns that were different from standard chemical reactions. Results indicated that cell viability loss and MC-LR release both followed two-segment second-order kinetics with turning points of KMnO4 exposure (ct) at cty and ctr, respectively. KMnO4 primarily reacted with dissolved and cell-bound extracellular organic matter (mucilage) and resulted in a minor loss of cell viability and MC-LR release before the ct value reached cty. Thereafter, KMnO4 approached the inner layer of the cell wall and resulted in a rapid decrease of cell viability. Further increase of ct to ctr led to cell lysis and massive release of intracellular MC-LR. The MC-LR release rate was generally much slower than its degradation rate during permanganation. However, MC-LR continued to be released even after total depletion of KMnO4, which led to a great increase in MC-LR concentration in the treated water