Degradation of acephate using combined ultrasonic and ozonation method

The degradation of acephate in aqueous solutions was investigated with the ultrasonic and ozonation methods, as well as a combination of both. An experimental facility was designed and operation parameters such as the ultrasonic power, temperature, and gas flow rate were strictly controlled at constant levels. The frequency of the ultrasonic wave was 160 kHz. The ultraviolet-visible （UV-Vis） spectroscopic and Raman spectroscopic techniques were used in the experiment. The UV-Vis spectroscopic results show that ultrasonication and ozonation have a syn- ergistic effect in the combined system. The degradation efficiency of acephate increases from 60.6% to 87.6% after the solution is irradiated by a 160 kHz ultrasonic wave for 60 min in the ozonation process, and it is higher with the combined method than the sum of the separated ultrasonic and ozonation methods. Raman spectra studies show that degradation via the combined ultrasonic/ozonation method is more thorough than photocatalysis. The oxidability of nitrogen atoms is promoted under ultrasonic waves. Changes of the inorganic ions and degradation pathway during the degradation process were investigated in this study. Most final products are innocuous to the environment.

Bio-remediation of acephate–Pb(Ⅱ) compound contaminants by Bacillus subtilis FZUL-33

Removal of Pb^（2＋）and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb^（2＋）and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb^（2＋）and biodegradation of acephate. In the present study, both Pb^（2＋）and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions.Batch experiments were conducted to study the influence of p H, interaction time and Pb^（2＋）concentration on the process of removal of Pb2＋. At the temperature of 25°C, the maximum removal of Pb^（2＋）by B. subtilis FZUL-33 was 381.31 ± 11.46 mg/g under the conditions of p H 5.5, initial Pb^（2＋）concentration of 1300 mg/L, and contact time of 10 min. Batch experiments were conducted to study the influence of acephate on removal of Pb^（2＋）and the influence of Pb2＋on biodegradation of acephate by B. subtilis FZUL-33. In the mixed system of acephate–Pb2＋, the results show that biodegradation of acephate by B. subtilis FZUL-33 released PO43＋, which promotes mineralization of Pb2＋. The process of biodegradation of acephate was affected slightly when the concentration of Pb2＋was below 100 mg/L. Based on the results, it can be inferred that the B. subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.

Acute Toxicity of Four Organophosphorus Pesticide Products

Acute toxicity of phoxim,acephate,isofenphos-methyl and isocarbophos on male SD rats of clean grade was carried out by gastric lavage method at room temperature of 18℃. These rats are 4 to 5 months old with body weight of 180 to 220 kg. The results indicate that the orders of the toxicity of these four pesticides on SD rats are isofenphos-methyl,isocarbophos,acephate,phoxim. We found that the median lethal concentration of phoxim in 24 h,48 h,72 h and 96 h is 3. 892 g /kg,3. 051 g /kg,2. 618 g /kg and 2. 458 g /kg respectively; the median lethal concentration of isofenphos-methyl in 24 h,48 h,72 h and 96 h is 0. 015 g /kg,0. 013g /kg,0. 012g /kg and 0. 011 g /kg respectively; the median lethal concentration of isocarbophos in 24 h,48 h,72 h and 96 h is 0. 049 g /kg,0. 046 g /kg,0. 043 g /kg,0. 041 g /kg respectively; and the median lethal concentration of acephate in 24 h,48 h,72 h and 96 h is 0. 137 g /kg,0. 113 g /kg,0. 100 g /kg,0. 085 g /kg respectively. Finally,we evaluated the characteristics of toxicity effect and safe concentration of these pesticides to SD rats.

Hydrothermal synthesis of hierarchical SnO_(2)nanomaterials for high-efficiency detection of pesticide residue

Acephate pesticide contamination in agricultural production has caused serious human health problems.Metal oxide semiconductor(MOS)gas sensor can be used as a portable and promising alternative tool for efficiently detection of acephate.In this study,hierarchical assembled SnO_(2)nanosphere,SnO_(2)hollow nanosphere and SnO_2 nanoflower were synthesized respectively as high efficiency sensing materials to build rapid and selective acephate pesticide residues sensors.The morphologies of different SnO_(2)3 D nanostructures were characterized by various material characterization technology.The sensitive performance test results of the 3 D SnO_(2)nanomaterials towards acephate show that hollow nanosphere SnO_(2)based sensor displayed preferable sensitivity,selectivity,and rapid response(9 s)properties toward acephate at the optimal working temperature(300℃).This SnO_(2)hollow nanosphere based gas sensor represents a useful tool for simple and highly effective monitoring of acephate pesticide residues in food and environment.According to the characterization results,particularly Brunauer-Emmett-Teller(BET)and Ultraviolet-Visible Spectroscopy(UV-vis),the obvious and fast response can be attributed to the mesoporous hollow nanosphere structure and appropriate band gap of SnO_2 hollow nanosphere.