•Amidoximated chitosan-grafted polyacrylonitrile was used for uranium adsorption.•Doehlert design of RSM was used to study the adsorption process.•Experimental values showed good agreement with predicted values.•CTS-g-PAO had high adsorption capacity (312 mg/g) and removal efficiency (86%).The amidoximated chitosan-grafted polyacrylonitrile (CTS-g-PAO) was prepared for the adsorption of uranium from water. The effects of pH, concentration of uranium and the solid–liquid ratio on the adsorption of uranium by CTS-g-PAO were optimized using Doehlert design of response surface methodology (RSM). The adsorption capacity and removal efficiency achieved 312.06 mg/g and 86.02%, respectively. The adsorption process attained equilibrium only in 120 min. More than 80% of the absorbed uranium could be desorbed by 0.1 mol/l HCl or EDTA-Na, and CTS-g-PAO could be reused at least 3 times. The CTS-g-PAO and U(VI) ions formed a chelate complex due to FTIR spectral analysis. The surface morphology of CTS-g-PAO was also investigated by SEM. The adsorption process was better described by Langmuir isotherm and pseudo second order kinetic model. Results obtained indicated that CTS-g-PAO was very promising in adsorption of uranium from water.

SYP-3343, (E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazole-5-yloxy)methyl)phenyl)-3-methoxyacrylate, is a newly developed strobilurin fungicide. However, the environmental behavior and fate of SYP-3343 in soil have not been well-documented. In this study, 14C-labeled SYP-3343 was employed to investigate the dynamic characteristics in three typical soils under aerobic conditions. Radioactivity analysis after high-performance liquid chromatography (HPLC) showed that SYP-3343 degraded rapidly in the coastal soil with a half-life of 43.8 days. After incubation of 100 days, its extractable residues were greater than 76.0% and bound residues were less than 12.4%, indicating that SYP-3343 was not easy to accumulate in soils. The mineralization to 14CO2 reached 5.4% for acidic soil, 2.8% for neutral soil, and 1.7% for alkaline soil, suggesting that it was difficult to cleave the pyrazole ring completely. In addition, dynamic characteristics of SYP-3343 in sterile and non-sterile loamy soil showed that soil microbes affected SYP-3343 residue in soil and could accelerate the process of degradation and mineralization.

Pyraoxystrobin, ((E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazol-5-yloxy) methyl) phenyl)-3-methoxyacrylate) is a novel strobilurin fungicide with excellent and broad spectrum antifungal efficiency. Environmental behaviors of the new fungicide must be assessed to understand its potential risks to the environment. In this study, the extractable residues, bound residues and mineralization, as well as the dissipation rates of pyraoxystrobin were investigated in three flooded soils using a 14C tracing technique. Results showed that pyraoxystrobin didn't undergo appreciable dissipation during the 100 day incubation period in some tested soils, with 70.01%, 28.58% and 83.85% of the parent compound remaining in the solonchak, cambisol and acrisol soils at the end of the experiment, respectively. Almost no 14C-pyraoxystrobin was mineralized to 14CO2 (<0.5%) over the experimental period. Organic matter had a dominating influence on the bound residues formation and the fractions of bound residues increased as the soil organic matter content increased. Less than 9% of the radioactivity was found in the aqueous phase, while the majority of extractable residues (>65.39%) were recovered in the organic extracts. This study aims to give a deep insight into the environmental behaviors of pyraoxystrobin and may be beneficial for the risk assessment of other analogous fungicides.

Zinc isotope separations were studied by displacement chromatography using the chelating properties of malate, citrate and lactate exchange resin and EDTA as ligands. After each chromatographic operation, the heavier zinc isotopes were found to preferentially fractionated into the carboxylate complex solution phase. The separation coefficients (ε) for zinc isotope separation had the largest value and were obtained for the isotopic pairs 68Zn/64Zn (7.16 × 10−4) and 66Zn/64Zn (3.08 × 10−4), respectively, at 298 ± 1 K. The separation coefficient per unit mass differences (ε/ΔM) for the isotopic pair of 68Zn/64Zn was found to range around 1.55 × 10−4.

Nitrogen isotope enrichment experiments were conducted to obtain highly enriched 15N by ion-exchange process. 15NH4Cl (15N = 80%) as feeding materials were used to perform the chromatographic operation with two different flow rates and column diameters. Both separation coefficient (ɛ) and height equivalent to a theoretical plate (HETP) have same values in two run experiments. The value of HETP was more enlarged when high enrichment of 15N was obtained in comparison with that of low enrichment. 99.756% 15N and 13.63 g 15N whose percentage was over 99.0% were successfully achieved by 25 m chromatographic migration with the flow rate and column diameter at 50 cm3/mL, 3.0 cm, respectively. High flow rate and large column diameter have advantages to the enrichment of 15N by ion exchange process.

Zinc adsorption and isotope effects in ligand exchange system were studied by using macroporous chelating exchange resin. Zinc equilibrium adsorption capacity was calculated as 2.5 mmol/g and it took about 1 h to reach the dynamic sorption balance. Heavier zinc isotopes were found at the front band region, the separation coefficient (ɛ), 7.2 × 10−4 and height equivalent to a theoretical plate (HETP) 1.32 mm for isotopic pair of 68Zn/64Zn were obtained by 5 m chromatographic operation under 298 ± 1 K in the present chelating exchange resin.

Pyraoxystrobin, ((E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazol-5-yloxy) methyl) phenyl)-3-methoxyacrylate) is a novel strobilurin fungicide with excellent and broad spectrum antifungal efficiency. Environmental behaviors of the new fungicide must be assessed to understand its potential risks to the environment. In this study, the extractable residues, bound residues and mineralization, as well as the dissipation rates of pyraoxystrobin were investigated in three flooded soils using a 14C tracing technique. Results showed that pyraoxystrobin didn't undergo appreciable dissipation during the 100 day incubation period in some tested soils, with 70.01%, 28.58% and 83.85% of the parent compound remaining in the solonchak, cambisol and acrisol soils at the end of the experiment, respectively. Almost no 14C-pyraoxystrobin was mineralized to 14CO2 (<0.5%) over the experimental period. Organic matter had a dominating influence on the bound residues formation and the fractions of bound residues increased as the soil organic matter content increased. Less than 9% of the radioactivity was found in the aqueous phase, while the majority of extractable residues (>65.39%) were recovered in the organic extracts. This study aims to give a deep insight into the environmental behaviors of pyraoxystrobin and may be beneficial for the risk assessment of other analogous fungicides.