Rheology of aqueous BeO suspension with NH4PAA as a dispersant

AbstractThe effects of dispersant amount and solids loading on rheological behaviors of aqueous BeO suspensions were investigated. The relationship of viscosity and solids loading determined experimentally was compared with five various existing models. BeO aqueous suspensions exhibited a shear dependent behavior from shear thinning to shear thickening with the increasing of shear rate. The rheological behaviors of the suspensions are in reasonable accord with the model proposed by Liu, and are basically consistent with the Dabak model and Chong model, but are discrepant to other two models proposed by Krieger–Dougherty and Kitano. The maximum solids loading is estimated to be 0.577

The Response of Thiols to Cadmium Stress in Spinach (Spinacia Oleracea L.)

The aim of this study is to examine the thiol species for the high cadmium (Cd) tolerance of spinach and provide information for the improvement of soil utilization. The spinach was cultured in aqueous solution with concentrations of Cd ranging from 1 to 9 mg/L. The time responses of glutathione (GSH) and phytochelatins (PCs, PC2-PC4) in the tissues of spinach were monitored via HPLC–MS/MS, and the concentrations of Cd in the roots, shoots and leaves were detected by ICP–OES. Data were analyzed via one-way ANOVA and Spearman correlation to assess the relationships among the types of thiols and the changes between types of thiols and Cd. As Cd stress increased, Cd concentrations in tissues also increased. The total thiol contents responded to Cd stresses with correlations r ranging from 0.394 (root), 0.520 (shoot) to 0.771 (leaf) (p < 0.01). GSH and PC3 were dominant on most of the days under Cd stress. The correlation r between improvements in GSH and increments of Cd concentration in roots was −0.808 (p < 0.01), and r between changes in PC3 and changes in Cd concentrations in leaves was −0.503 (p < 0.01). No correlation can be found between GSH and the subtypes of PCs in shoots, but strong positive correlations within the subtypes of PCs. Thiols can be produced in different tissues of spinach, while the shoots are only a transport tissue for GSH

Determination of olaquindox, carbadox and cyadox in animal feeds by ultra-performance liquid chromatography tandem mass spectrometry

<p>Olaquindox, carbadox, and cyadox are chemically synthesised antibacterial and growth-promoting agents for animals. At high doses they may exert mutagenicity and hepatic and adrenal toxicities in animals. Regrettably, these substances are frequently abused or misused when added into animal feeds. Thus, developing a sensitive and reliable method for simultaneous determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds is crucially important for food safety monitoring. In this paper we optimised instrumental conditions, extraction solvents, solid phase extraction cartridges, and pH of the loading solvents on the Oasis HLB cartridge. Under the optimal conditions, mean recoveries ranged from 74.1 to 111%, and intra-day and inter-day variations were lower than 14.6% and 10.8%, respectively. The limits of quantification for olaquindox, carbadox, and cyadox were 0.05 mg kg⁻¹, 0.10 mg kg⁻¹, and 0.025 mg kg⁻¹, respectively. The proposed method uses ultra-performance liquid chromatography tandem mass spectrometry and is sensitive and reliable for the simultaneous determination of olaquindox, carbadox, and cyadox in three kinds of animal feeds (specifically, mixed feed, concentrated feed, and additive premixed feed). This method has good precision, high sensitivity, and good reproducibility, and thus it can be used for convenient and accurate determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds.</p

Studies of the Ligand Effect on the Synthesis of Dialuminoxanes by Various β-Diketiminato Ligands

Reactions of LH (L = HC­[C­(Me)­N­(2,6-Me₂C₆H₃)]₂) with Me_<i>n</i>AlCl_3–<i>n</i> in diethyl ether afforded the adducts LH·AlMe_<i>n</i>(Cl)_3–<i>n</i> (<i>n</i> = 2, <b>3</b>; 1, <b>4</b>; 0, <b>5</b>) in good yields. Treatment of <b>3</b> at elevated temperatures in toluene resulted in LAlMeCl (<b>2</b>) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (<b>2</b>) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl­(Me)]₂(μ-O) (<b>7</b>) and dimeric [LAlMe­(μ-OH)]₂ (<b>8</b>). A convenient route for the preparation of [LAlMe­(μ-OH)]₂ (<b>8</b>) was the NHC-assisted controlled hydrolysis of LAlMeI (<b>9</b>). Stepwise hydrolysis of LAlH₂ (<b>11</b>) gave dialuminoxane hydride [LAl­(H)]₂(μ-O) (<b>12</b>) and dialuminoxane hydroxide [LAl­(OH)]₂(μ-O) (<b>13</b>), respectively. Anhydrous treatment of LAlCl₂ (<b>1</b>) or LAlMeCl (<b>2</b>) with Ag₂O afforded chlorinated dialuminoxane [LAl­(Cl)]₂(μ-O) (<b>14</b>) and [LAl­(Me)]₂(μ-O) (<b>7</b>), respectively

Studies of the Ligand Effect on the Synthesis of Dialuminoxanes by Various β-Diketiminato Ligands

Reactions of LH (L = HC­[C­(Me)­N­(2,6-Me₂C₆H₃)]₂) with Me_<i>n</i>AlCl_3–<i>n</i> in diethyl ether afforded the adducts LH·AlMe_<i>n</i>(Cl)_3–<i>n</i> (<i>n</i> = 2, <b>3</b>; 1, <b>4</b>; 0, <b>5</b>) in good yields. Treatment of <b>3</b> at elevated temperatures in toluene resulted in LAlMeCl (<b>2</b>) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (<b>2</b>) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl­(Me)]₂(μ-O) (<b>7</b>) and dimeric [LAlMe­(μ-OH)]₂ (<b>8</b>). A convenient route for the preparation of [LAlMe­(μ-OH)]₂ (<b>8</b>) was the NHC-assisted controlled hydrolysis of LAlMeI (<b>9</b>). Stepwise hydrolysis of LAlH₂ (<b>11</b>) gave dialuminoxane hydride [LAl­(H)]₂(μ-O) (<b>12</b>) and dialuminoxane hydroxide [LAl­(OH)]₂(μ-O) (<b>13</b>), respectively. Anhydrous treatment of LAlCl₂ (<b>1</b>) or LAlMeCl (<b>2</b>) with Ag₂O afforded chlorinated dialuminoxane [LAl­(Cl)]₂(μ-O) (<b>14</b>) and [LAl­(Me)]₂(μ-O) (<b>7</b>), respectively

Grafting amino groups to enhance the adsorption of antimonate by MIL-100(Fe) for from natural water: Performance and mechanism

MIL-100(Fe) was modified by amino groups (MIL-100(Fe)-NH2) to enhance the removal of antimonate (Sb(V)) with low concentration (50−200 μg/L) from natural water through batch adsorption experiments. With the initial Sb(V) concentration up to 200 μg/L, the residual Sb(V) concentration after treated by MIL-100(Fe)-NH2 was only 3.52 ± 0.131 μg/L, lower than the drinking water standards (5 μg/L) in China, while that was much higher (94.2 ± 3.52 μg/L) after pristine MIL-100(Fe) treatment. Based on results of XPS analysis, and adsorption kinetics and isotherms, we concluded that Sb(V) substituted the terminal −OH groups of MIL-100(Fe) to form inner-sphere complexes by coordination reactions with Fe nodes and be adsorbed by hydrogen bonding as well. The grafted amino groups (−NH2) adsorbed Sb(V) by hydrogen bonding and facilitated the coordination reactions between Sb(V) and Fe nodes. The higher KL value (0.0116 ± 0.00,118 L/μg) obtained by fitting with the Langmuir isotherm model, while that of unmodified MIL-100(Fe) was 4.74 × 10−4 ± 5.85 × 10−5 L/μg, also confirmed that the −NH2 groups greatly enhanced the affinity between MIL-100(Fe) and Sb(V). Furthermore, MIL-100(Fe)-NH2 still worked nicely in a wide pH range (2 − 12), with varied ionic strength (0.05 µmol/L−1.5 mol/L), coexisting ions (CO32−, NO3−, SO42−, Cl−, H2PO4−), and even in the real water bodies. Additionally, MIL-100(Fe)-NH2 exhibited good reusability and low Fe leaching (99.92 μg/L). We hope MIL-100(Fe)-NH2 become a candidate for effective removal of Sb(V), even other heavy metals from natural waterbodies