海带的碳酸钠消解过程动力学

以海带为原料,考察了消解反应温度、碳酸钠浓度、搅拌速度及海带块尺寸对消解反应动力学、褐藻胶收率及产品黏度的影响。结果表明,随温度、碳酸钠浓度、搅拌速度的升高,消解反应速度明显加快,褐藻胶提取速率随之增大。海带块大小对反应速率也存在一定的影响,海带块越小,褐藻酸钠提取反应速率越快。确定的较佳消解条件为:Na2CO3浓度为0.5%,消解温度为60℃,搅拌速度200r/min,海带块尺寸为20 mm。在此条件下,产品的产率可超过22%,黏度超过了20 000 mPa.s。研究结果为优化传统海带消解工艺,节约碱耗,缩短反应时间、提高产品收率和品质提供了参考。

新烟碱类杀虫剂呋虫胺的研究进展

新烟碱类农药自20世纪80年代上市以来便受到广泛应用。呋虫胺作为典型的第三代新烟碱类杀虫剂,因其高效、广谱等优点在全球二十多个国家登记使用。近年来,随着呋虫胺的大量使用,其对非靶标生物的潜在危害,以及在农业生产中大量投入导致的环境风险引起了人们的重点关注。因此,阐明呋虫胺的生物活性和生态毒理,揭示其环境行为归趋,这对于呋虫胺的生态风险评价与科学合理使用具有重要意义。笔者旨在综述呋虫胺对靶标害虫的生物活性、对非靶标生物的生态毒理,及其在生态环境中的耗散动力学规律,并对其应用前景进行展望,以期为呋虫胺的合理使用和科学管理提供有效参考。

Biodegradation Kinetics for Pre-treatment of Klebsiella pneumoniae Waste with Autothermal Thermophilic Aerobic Digestion

Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneu-moniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermo-philic aerobic digestion(ATAD) . Based on an Arrhenius-type equation,an empirical model was developed to corre-late the removal of total suspended solid(TSS) with the initial TSS concentration,influent reaction temperature,aeration rate and stirring rate. The reaction temperatures of the ATAD system could be raised from the ambient temperatures of 25 °C to a maximum temperature of 65 °C. The exponentials for the initial TSS concentration,aeration rate and stirring rate were 1.579,-0.8175 and-0.6549,respectively,and the apparent activation energy was 6.8774 kJ·mol-1. The correlation coefficient for the pre-exponential factor was 0.9223. The TSS removal effi-ciency predicted by the model was validated with an actual test,showing a maximum relative deviation of 10.79%. The new model has a good practicability.