Synthesis and characterization of chitosan Schiff base grafted with formaldehyde and aminoethanol: As an effective adsorbent for removal of Pb(II), Hg(II), and Cu(II) ions from aqueous media.

Grafted chitosan materials show the characteristics of high stability, easy separation and recovery, and good heavy metal adsorption capacity, and have received much attention in the adsorption process. Therefore, in this work, novel grafted chitosan-based adsorbent CS-EHBSB@F-AE was prepared by a one-pot reaction of chitosan (CS), 3-ethoxy-4-hydroxybenzaldehyde (EHB), formaldehyde (F) and aminoethanol (F). The microstructure and morphology of the as-prepared composite CS-EHBSB@F-AE were characterized by FT-IR, TGA, DSC, FE-SEM, and BET analyses. The adsorption performance of the as-prepared CS-EHBSB@F-AE composite on Pb(II), Hg(II), and Cu(II) ions from aqueous was investigated using batch experiment and the effects of the initial pH of the solution, contact time, and initial metal ions concentration and temperature on the adsorption efficiency were investigated and discussed. At the best conditions, CS-EHBSB@F-AE exhibited remarkable adsorption capacity of 246.7 mg/g, 203.9 mg/g, and 234.4 mg/g in absorbing Pb(II), Hg(II), and Cu(II), respectively. The adsorption equilibrium and the kinetic studies confirmed that the ions adsorption process fits well with the Langmuir isotherm and pseudo-second-order (PSO) models. Additionally, the adsorption efficiency of Pb(II), Hg(II), and Cu(II) metal ions by the composite CS-EHBSB@F-AE was reduced by increasing the temperature from 298 K to 318 K. In addition, after the sixth ads/des cycles, the as-prepared adsorbent still exhibited high removal efficiency with a decrease in adsorption efficiency of Pb(II) (5.53 %), Hg(II) (15.43 %) and Cu(II) (8.27 %). Finally, we proposed that the ions adsorption by CS-EHBSB@F-AE has happened using the coordination of active groups containing nitrogen and oxygen atoms on the surface of the adsorbent with the Pb(II), Hg(II), and Cu(II) metal ions.

Determination of the Metabolites and Metabolic Pathways for Three ß-Receptor Agonists in Rats Based on LC-MS/MS.

This paper developed a universal detection method by high-performance liquid chromatography-tandem mass spectrometry to detect three typical clenbuterols, CLB, SAL, and RAC, and to investigate the metabolism of ß-agonists in vivo. The parent ions and daughter ions of the three ß-receptor agonist standards and the residues in the muscle, liver, and blood samples of rats were obtained by Total Ions Scan mode. The metabolites produced in different tissues at a specific time were qualitatively and quantitatively analyzed, and the corresponding metabolic pathways were inferred. The results showed that the three ß-receptor agonists mainly existed in the form of prototype drugs in rats, with a small amount of clenbuterol methyl compound and albuterol methyl compound. There were significant differences in residual metabolism between different tissues of the same species. In addition, different ß-receptor agonists have different absorption and utilization rates in rats.

Using pretreated chestnut endothelium to adsorb lead and cadmium ions from water.

The nature chestnut endothelium, as waster source from chestnut (Castaneamollissima) has pigment effecting the process of adsorbing heavy metalions, and the decolorized endothelium has low adsorption capacity. In order to raise the adsorption capacity of heavy metal ions, the discolor endothelium was pretreated by acidic formaldehyde, cis-butenedioic acid and irradiation. Thermodynamic and kinetics model was fitted to the adsorption of Pb (II) and Cd(II) ions onto modified chestnut endothelium by cis-butenedioic acid. Three independent variables including pH, adsorption time and contact temperature were selected as affecting factors to Response Surface. The modified experiment results showed adsorption rate of Pb(II) and Cd(II) ions on the chestnut endothelium modified by 0.5 mol/L cis-butenedioic acid was higher than other modified methods. Thermodynamic and kinetics model was fitted with Langmuir and Pseudo-second-order kinetic model, respectively. 59.23 °C of the adsorption temperature, the 5.72 h of adsorption time and the 6.16 of pH are the optimized conditions of the adsorption rate of Pb2+ on modified chestnut endothelium. 55.93 °C of the adsorption temperature, the 4.43 h of adsorption time and the 6.06 of pH are the optimized adsorption conditions of Cd2+. Under the optimized condition, the experiment value of the adsorption of Pb2+ and Cd2+ was 99.76% and 98.90%, respectively, which are close to the predicted value. The FTIR indicated that C-O, O-H and C-H involved in the adsorption process of Pb2+ and Cd2+.

The mechanisms and process of acephate degradation by hydroxyl radical and hydrated electron.

The degradation process of acephate in aqueous solution with •OH and [Formula: see text] produced by 60Co-γ irradiation and electron pulse radiolysis was studied in the present paper. In the aqueous solution, acephate reacted with [Formula: see text] and transformed to transient species which can absorb weakly in the wavelength range of 300-400 nm and decay very fast. According to the decay of hydrated electron, the reaction rate constant of [Formula: see text] and acephate is (3.51 ±â€¯0.076) × 109 dm3·mol-1·s-1. The transient species produced in the reaction of •OH and acephate do not distinctly absorb the light in the wavelength range of 300-700 nm, so the decay and kinetics of the transient species cannot determinedirectly. The competing reaction of KSCN oracephate with •OH were studied to obtain the reaction rate constant of •OH and acephate, which is (9.1 ±â€¯0.11) × 108 dm3·mol-1·s-1. Although acetylamide and inorganic ions were determined in the products of the reaction of acephate with •OH or [Formula: see text], the concentration of inorganic ions in the products of the reaction of acephate with •OH is higher than that in the product of the reaction of acephate with [Formula: see text]. Moreover, there were sulfide in the products of the reaction of acephatewith [Formula: see text]. The degradation pathways of acephate by •OH and [Formula: see text] were also proposed based on the products from GC-MS.