腐殖酸与镉离子在水合二氧化锰表面的分配系数研究

水体中腐殖酸(HA)和金属离子广泛存在,二者的相互作用对其在水中天然矿物颗粒表面的吸附、降解等环境行为具有重要影响.本文采用离子交换平衡法测定了HA和镉离子(Cd(Ⅱ))的配位数(co-ordination number,x)和络合稳定常数(complex stability constant,K),系统考察了pH值和离子强度对x和K的影响,并研究了HA和Cd(Ⅱ)在水合二氧化锰(HMO)表面的分配关系.结果表明:pH值对HA和Cd(Ⅱ)的配位数影响较小(x=1.651~1.752),而对络合稳定常数影响显著(log K=1.652~3.548);在不同pH值条件下,离子强度对HA和Cd(Ⅱ)的络合稳定常数影响均较小,而其配位数均随溶液离子强度的增加而提高;不同温度条件下,HA-Cd(Ⅱ)络合物在HMO表面的分配系数(Kd)均低于HA和Cd(Ⅱ)在HMO表面的分配系数,表明HA-Cd(Ⅱ)络合体系的存在抑制了HMO对Cd(Ⅱ)和HA的去除作用.     

Power to gas: an option for 2060 high penetration rate of renewable energy scenario of China

Replacing conventional fossil fuel power plants with large-scale renewable energy sources (RES) is a crucial aspect of the decarbonization of the power sector and represents a key part of the carbon-neutral strategy of China. The high penetration rate of renewable energy in the electricity system, however, implies the challenges of dealing with the intermittency and fluctuation of RES. Power to gas (P2G), which can convert surplus renewable power into a chemical form of energy (i.e., synthetic gas), can help handle this challenge and supply new energy carriers for various energy sectors. By modeling three potential 2060 energy mix scenarios in China, this paper aims to describe the possible contribution of the high penetration rate of renewable energy combined with P2G in the future sustainable energy system. Different schemes are listed and compared, and the results are used in a basic economic evaluation of the synthetic gas production cost for the P2G plants. Ideally, nearly 18 million tons of carbon dioxide would be recycled and transformed into methane (around 9.37 km³) annually in China. Considering a zero price for the excess renewable power and future costs of the components, the levelized cost of energy (LCOE) of the final production of methane is estimated at 0.86 $/m³_SNG.

     

一种基于蚯蚓学习行为的神经毒性实验方法研究

土壤生物的学习行为是一种综合性的神经高级活动,对土壤中的神经毒性污染物生态风险监测具有重要价值.本研究设计了一套试验装置,基于蚯蚓对白光刺激的厌恶本性,通过振动-白光配对刺激,对蚯蚓进行学习训练,使蚯蚓领会借助加速移动阻止白光刺激的策略,通过蚯蚓到达移动位移阈值的时间测定,对蚯蚓的学习行为进行测试,建立了蚯蚓的学习行为...     

营口市大气污染物来源解析数值模拟研究

该研究基于WRF-CMAQ搭建本地化模型对营口市2018年1、4、7和10月的大气污染状况进行模拟,并采用零置法定量解析SO2、NO2、PM10和PM2.5的来源.研究发现:营口市大气污染总体呈现出"西北部沿海地区污染重、东南山区污染轻"的态势,污染高值区主要集中在西南沿海人口较为稠密地区.4个季节中,钢铁源对PM10...     

蚯蚓顶体效应及其在土壤健康质量诊断中的应用研究

蚯蚓在评价土壤生态环境污染方面起着重要作用,但目前与生殖毒性相关的蚯蚓生物标志物中缺乏可以灵敏和快速对污染物生殖毒性进行诊断的生物标志物.本研究采用考马斯亮蓝法对蚯蚓精子顶体反应进行检测;采用响应面分析法优化苯甲酰精氨酸乙酯/乙醇脱氢酶(BAEE/ADH)联合测定法,以建立蚯蚓精子顶体酶活性测定法.结果表明,蚯蚓精子顶体率为(47.67±3.87)% ,最优测定条件为洗涤2次,抽提时间24 h,ADH浓度1.8 mg·mL-1 ,氧化型辅酶Ⅰ(NAD)浓度12 mg·mL-1 .为考察方法的可靠性,采用醋酸棉酚污染土壤暴露实验进行方法学考察.数据表明,醋酸棉酚污染土壤暴露3d后,检测出顶体酶活性变化,且与精子密度具有一定的相关性(r=0.9908).建立的蚯蚓顶体酶活性测定方法可以快速和有效的检测醋酸棉酚的生殖毒性变化,蚯蚓顶体酶活性有望作为生物标志物应用于土壤污染的生态毒理学快速诊断中.     

不同污染方式进入土壤的氯氰菊酯在蚯蚓体内的蓄积特征及其生长毒性

农药污染严重威胁我国的土壤生态系统安全.选择我国应用较广的氯氰菊酯为代表性农药污染物,采用一次和叠加的污染方式模拟氯氰菊酯进入土壤并逐渐累积的过程,以云南耕地常见的蚯蚓优势种——皮质远盲蚓(Amynthascorticis)为实验生物,研究了氯氰菊酯在土壤中的降解变化,以及蚯蚓对不同污染方式进入土壤的氯氰菊酯吸收蓄积的累积特征和生长毒性响应.结果显示,不同污染方式进入土壤的氯氰菊酯,在土壤中的降解均符合一级动力学特征c=c0e-kt,以一次污染方式进入土壤的氯氰菊酯降解半衰期为27.7～28.9 d;以叠加污染方式进入土壤的氯氰菊酯降解半衰期为25.7～26.6 d.氯氰菊酯浓度为4～6 mg·kg-1 ,暴露55 d时,蚯蚓对以一次污染方式进入土壤的氯氰菊酯蓄积量为0.34～0.73 mg·kg-1 ,生物-土壤蓄积因子(FBSA)为0.85～1.05;蚯蚓对以叠加污染方式进入土壤的氯氰菊酯蓄积量为0.86～1.51 mg·kg-1 ,FBSA 为1.16～1.42.与一次污染方式比较,以叠加污染方式进入土壤的氯氰菊酯,更有利于蚯蚓对其进行生物富集,从而表现出较强的生长毒性.研究结果可为土壤农药叠加污染累积的生态风险防治提供基础数据和理论依据.     

基于Fluent的整体式催化反应系统降解甲苯的数值模拟

为得到甲苯在整体式催化系统中的燃烧规律,利用Fluent 18.1对整体式催化反应系统中甲苯-空气在铂(Pt)上的燃烧特性进行了数值模拟。通过假设多孔介质内气固间局部能够达到热平衡,建立了三维的多孔介质催化燃烧模型。经验证,该模型能够很好地反映甲苯在整个系统中的燃烧特性。通过对整个反应系统中温度场、浓度场和速度场的工况探究和通过分段控制燃烧反应发现:贫燃条件有利于催化燃烧,富燃条件有利于引发热力燃烧;当量比小于1,入口流速小于2 m·s~(-1)时,有利于催化燃烧,催化转化率在96%以上;当量比较高,入口流速较大时,有利于引发热力燃烧。以上研究结果为该技术的实际应用提供了参考。     

Extraction,chemical compositions,and cytotoxic activities of essential oils of Thevetia peruviana

Abstract

In this study, The essential oil of flowers, fruits, and leaves of Thevetia peruviana, which were collected in Vietnam, were being reported for the first time. The essential oil of flowers was extracted by different methods: n-hexane extraction, distillation water, and supercritical CO₂ extraction. The compositions of essential oil of different parts of Thevetia peruviana were analyzed by GC-FID and GC/MS systems. Major chemical compositions of essential oil were identified as monoterpenes, sesquiterpenes, terpenoids, and sterol. The activities of total essential oil extracts of the Thevetia peruviana exhibit inhibitory activities against five cancer cell lines.