Authors:Yanhong Shi, Yongde Yue, Haiqun Cao, Feng Tang, Rimao Hua, Xiangwei Wu and Jun Tang
Octachlorodipropyl ether (OCDPE) is a chloroalkyl ether widely used as an insecticide synergist, which was considered as a widespread persistent pollutant. Photodegradation kinetics of OCDPE in selected organic solvents was studied using the high-performance thin-layer chromatography (HPTLC) method in this paper. The results showed that photochemical reaction of OCDPE in organic solvents such as n-hexane, methanol, acetonitrile, and acetone under the irradiation of ultraviolet light could well be described by the first-order kinetic equation. The photodegradation rate constants of OCDPE in methanol, acetone, acetonitrile, and n-hexane were 0.3310, 0.2382, 0.0287, and 0.0276 h−1, and the corresponding half-lives were 2.09, 2.91, 24.1, and 25.1 h, respectively. Photodegradation kinetics of OCDPE under sunlight was slower than UV light, the half-lives of which were 8.87 and 2.09 h, respectively. The main photodegradation products of OCDPE in acetone and methanol under UV light were detected by HPTLC, which included product 01 (RF = 0.19) and product 02 (RF = 0.82). Identification of the main photodegradation products of OCDPE requires further studies.
Authors:Bao Borong, Shen Chaohong, Bao Yizhi, Wang Gaodong, Qian Jun and Cao Zhengbai
In this work, ten disubstituted amides have been synthesized and the extracting ability for U and Th fission products (mainly Zr, Nb and Ru) and the tendency of third phase formation have been studied. From the preliminary studies, two disubstituted amides, N-octylcaprolactam (OCLA) and N-(2-ethyl) hexylcaprolactam (EHCLA) were chosen for further studies. All studies were compared with those obtained by using TBP under exactly the same conditions. The dependence of aqueous nitric acid concentration, extractant concentration, temperature, -ray irradiation on extraction of Th, U and some fission products were studied. Back extraction of Th and U from organic phases and third phase formation were also studied. The studies of the reaction mechanism indicate that Th and U are extracted as disolvates, whereas HNO3 is extracted as monosolvate. Extraction distribution of Th and U decrease with increase of temperature, indicating the extraction reaction to be exothermic. Preliminary studies show that OCLA and EHCLA have better -irradiation stabilities compared with TBP.
Authors:Jing-Guo Cao, Ping Gu, Jun Zhao, Dong Zhang and Yue Deng
This study characterized the removal of strontium from an aqueous solution via co-precipitation followed by microfiltration
(CPMF) on a lab-scale. Sodium carbonate was used as the precipitating agent. Ferric chloride was added to a settler at a dosage
of 20 mg/L to improve strontium removal, and it was added to a membrane separator at a dosage of 10 mg/L to reduce membrane
fouling. The concentration of strontium in the raw water used in this study was about 5 mg/L. In two intermittent tests, where
dosages of sodium carbonate were 2000 mg/L and 1000 mg/L, the mean decontamination factors (DFs) were 237 and 158 and the
mean concentration factors (CFs) were 288 and 462, respectively. Although the mean DF value was lower when the sodium carbonate
dosage was 1000 mg/L instead of 2000 mg/L, the rate at which the specific flux (SF) of the membrane declined decreased as
the amount of the effluent treated increased. The problem of strontium release at the beginning of the operation was controlled
by a continuous test in which the dosage of sodium carbonate still was 1000 mg/L and the other parameters were the same as
in the other tests. The results showed that the mean DF and CF were 157 and 480, respectively.
Authors:Yunfeng Hu, Jinpeng Cao, Jun Deng, Baoyu Cui, Mingwei Tan, Junfei Li and Hongsheng Zhang
We investigated the reductive amination of ethanol to acetonitrile on Cu/γ-Al2O3. The different catalysts were characterized by XRF, XRD, H2-TPR and CO adsorption, and products were identified by FTIR and GC–MS. Our results show that dehydrogenation of ethanol takes place over Cu sites, γ-Al2O3 not only plays the role of the carrier and has catalytic dehydration function. Cu sites with high metal area and good stability are necessary to get high yield of acetonitrile. Among the impregnation, coprecipitation and physical mixing methods, impregnation is the most suitable to form Cu sites for meeting the requirements. The phase of copper species and the stability of Cu/γ-Al2O3 catalysts are closely related to Cu loading. With the increase of copper loading up to 15%, Cu/γ-Al2O3 shows good stability, which is more important for long period reaction. The effect of different reaction conditions such as reaction temperature, ethanol WHSV and ammonia/ethanol molar ratio were also investigated.
Authors:Shen Chao-Hong, Bao Bo-Rong, Wang Gao-Dong, Qian Jun, Bao Ya-Zhi and Cao Zheng-Bai
Extraction of uranium(VI), thorium(IV) from nitric acid has been studied with N-octylcaprolactam and N-(2-ethyl)hexylcaprolactam. Distribution coefficients of U(VI), Th(IV) and HNO3 as a function of aqueous NHO3 concentration, extractant concentration and temperature have been studied. The compositions of extracted species, thermodynamic parameters of extraction have been evaluated. Third phase formation in extraction of U(VI) has been studied. Back extraction behavior of U(VI) and Th(IV) from the organic phase has also been tested. The results obtained are compared with those obtained by using TBP under the same experimental conditions.
Authors:Bao Bo-Rong, Bao Ya-Zhi, Shen Chao-Hong, Wang Gao-Dong, Qian Jun and Cao Zheng-Bai
A study on solvent extraction of U(VI), Th(IV) and HNO3 from nitric acid media by DEHSO is described. Extraction coefficients of U(VI), Th(IV) and HNO3 as a function of aqueous HNO3 concentration, extractant concentration and temperature have been studied. From the data the compositions of extracted species, equilibrium constants and enthalpies of extraction reaction have been evaluated. Back-extraction of U(VI) and Th(IV) from the organic phase by dilute nitric acid has also been tested. All studies on DEHSO are compared with TBP.
Authors:Wenbin Cao, Xingfa Gao, Li Qu, Zhenlin Chen, Genmei Xing, Jun Tang, Huan Meng, Zhen Chen and Yuliang Zhao
It was found that Sc2@C84 or Sc2O3 could be “kicked” into the cavities of single wall carbon nanotubes (SWNTs) by reactor neutrons. Neutron irradiation also
efficiently induces coalescing reactions between two fullerene cages with an atom-spacer, forming a C2m=C=C2n type of carbon nanomaterials. This process provides a new subject of studying interactions (and their consequences) of neutrons
with nanoparticles, which may put new insights for neutron sciences.
Authors:Kit-leong Cheong, Ding-tao Wu, De-jun Hu, Jing Zhao, Kai-yue Cao, Chun-feng Qiao, Bang-xing Han and Shao-ping Li
Multiple species of ginseng are well-known Chinese medicinal herbs. The glycome of Panax species has various beneficial effects; however, studies related to their systematic profiling are very limited. Therefore, the systematic profiling of the glycome of Panax species was investigated in this study. The sugars from different locations and different species of Panax (Panax ginseng, Panax quinquefolium, and Panax notoginseng) were prepared by microwave-assisted extraction. Free mono- and oligo-saccharides were identified by high-performance thin-layer chromatography (HPTLC). Furthermore, polysaccharides were compared and characterized by using saccharide mapping based on HPTLC analysis. The results showed that the mono- and oligo-saccharide in Panax species were similar, including the glucan and pectin type of polysaccharides in different locations and different species of Panax, respectively. The data are helpful to better understand the glycome of different species of Panax and may contribute to rational usage of polysaccharides from Panax species.
Authors:Li Kuang, Wo Wang, Yan Huang, Xiaorong Chen, Zhen Lv, Jun Cao, Ming Ai and Jianmei Chen
Background and aims
Internet addiction (IA) is common among young students. This study aimed to examine the influence and mechanisms of IA and susceptible personality traits on the impact of suicidal ideation in adolescent students in China.
This cross-sectional study (09/2012–09/2015) used stratified cluster sampling with “school type” for stratification; 136,266 students from 63 schools completed the questionnaire. Logistic regression analysis was performed to estimate the effect of IA (Young's Internet Addiction Test) and susceptible personality (Barratt impulsiveness scale, Buss & Perry Aggression Questionnaire; and Eysenck Personality Questionnaire-R Short Scale) on suicidal ideation (Scale of Suicidal Ideation).
Suicidal ideation was observed in 20,218 (14.77%) of the students, and IA was detected in 28,836 (21.16%) subjects. Compared with those without IA, students with IA had a higher prevalence of suicidal ideation (P < 0.0001). No planning impulsiveness had a predictive effect on suicidal ideation in the impulsive personality trait, while in the aggressive personality trait, hostility and self-aggression had a predictive effect on suicidal ideation (all P < 0.0001). High psychoticism and neuroticism were impact factors for suicidal ideation, but extroversion was a protective factor (all P < 0.0001).
These results highlight the importance of assessing personality traits and reducing IA as a possible means of lessening suicidal ideation. Susceptible personality (such as high psychoticism, high neuroticism, and low extroversion) play a prominent role in influencing the probability of having suicidal behavior among those recently exposed to IA.
IA and susceptible personality traits were significantly correlated with suicidal and self-harm ideation among adolescent students.