催化湿式氧化处理H-酸溶液的反应动力学

两阶段一级反应动力学模型和广义动力学模型被用来描述湿式氧化 ( WAO)及催化湿式氧化 ( CWAO)反应过程 ,并确定了动力学参数 .2个模型的计算值均与实验值相符 ,而广义动力学模型相对更准确些 .2个模型均表明反应分 2个步骤 :首先是H-酸被迅速氧化成小分子有机酸 ,后者再缓慢氧化 .这 2个步骤由模型参数加以表征 ,因而模型可被用来对 CWAO催化剂进行评价 .     

产品环境试验顺序的优化选择

首先介绍了产品进行环境试验的目的及其重要性,对环境试验项目之间的相互影响及合理顺序进行了分析,并阐述了选择环境试验项目顺序所遵循的一般原则,说明在进行环境试验时,必须针对具体试验项目,注意合理的试验顺序,才能确保试验结果的真实性、代表性和可比性。     

一级动力学反应方程参数估计中若干问题的讨论

在农药的环境行为研究中,常用一级动力学反应方程来模拟农药的降解或残留。本文论述了用线性回归分析法估计一级化学动力学方程参数时存在的初始浓度飘移和非本义最优化问题,讨论了与此相关联的试验设置、安全间隔期、分段模拟和试验数据处理等问题,提出了解决问题的初步设想。     

对环境监测与环境监理运作秩序的思考

阐述了环境监测与环境管理监理之间的关系,指出建立科学合理的环境监测与环境监理运作秩序,对充分发挥各自作用,推动整个环境保护工作向科学化,规范化,法制化是具有积极意义,结合实践,提出了建立环境监测与环境监理运作秩序的思路。     

Sorption of dissolved lead from shooting range soils using hydroxyapatite amendments synthesized from industrial byproducts as affected by varying pH conditions

For immobilization technologies to be successful, the use of readily available and cost advantageous amendment is important when the remediation targets vast amounts of contaminated soils. The objectives of this study were to investigate whether the byproduct-synthesized hydroxyapatite can be used as an immobilizing amendment for dissolved Pb from a shooting range soil, and to model the kinetic data collected from dissolution experiments. A soil–solution kinetic experiment was conducted under fixed pH conditions as a function of time. A Pb-contaminated soil was reacted with various hydroxyapatite amendments to determine the dissolution rate and mineral products of soil Pb. Three types of amendments used were pure hydroxyapatite (HA), and poorly crystalline hydroxyapatites synthesized from gypsum waste (CHA), and synthesized from incinerated poultry litter (PHA). The dissolved Pb concentration decreased with the addition of amendments at pH 3–7. Both CHA and PHA were more effective than HA for attenuating Pb dissolution at pH 6 and above. According to the thermodynamic calculation at pH 6, the dissolved Pb concentration for CHA and PHA treatments was predicted to be 66% and 50% lower than that of HA treatment, respectively. A better Pb immobilization effect demonstrated by CHA and PHA resulted in their greater solubility at higher pH, which may promote the formation of chloropyromorphite precipitates. Dissolution kinetics of soil Pb was adequately explained by pseudo-first order and pseudo-second order equations in acid pH ranges. According to the ion exchange model, an adequate agreement between the experimental data and regression curves was shown in the initial 40 min of the reaction process, but the accuracy of model predictability decreased thereafter. According to kinetic models and dissolution phenomena, CHA and PHA amendments had better Pb sorption capacity with rapid kinetics than pure hydroxyapatite at weak acid to neutral pH.     

交通行为意识的行为控制作用

引用心理学中意识对行为的控制作用,简单描述了人的行为过程,得出行为意识对行为控制起到"总开关"的作用;指出增强交通行为意识是实现交通行为控制的有效手段;将交通行为意识分为3种,即交通安全意识、交通守法意识和交通秩序意识,依据心理学中意识建立和强化的一般方法提出了建立与增强3种交通行为意识的基本方法,包括教育、宣传、刺激、处罚、回报(包括自然回报和人为回报)及激励等6种方法。笔者提出的交通行为意识增强及激励的方法,为确保交通参与者的交通安全和进一步提高道路交通管理水平提供新的理论和方法依据。     

Cesium and strontium sorption by selected tropical and subtropical soils around nuclear facilities

The dynamics of Cs and Sr sorption by soils, especially in the subtropics and tropics, as influenced by soil components are not fully understood. The rates and capacities of Cs and Sr sorption by selected subtropical and tropical soils in Taiwan were investigated to facilitate our understanding of the transformation and dynamics of Cs and Sr in soils developed under highly weathering intensity. The Langmuir isotherms and kinetic rates of Cs and Sr sorption on the Ap1 and Bt1 horizons of the Long-Tan (Lt) and the A and Bt1 horizons of the Kuan-Shan (Kt), Mao-Lin (Tml) and Chi-Lo (Cl) soils were selected for this study. Air-dried soil (<2 mm) samples were reacted with of 7.5 × 10⁻⁵ to 1.88 × 10⁻³ M of CsCl (pH 4.0) or 1.14 × 10⁻⁴ to 2.85 × 10⁻³ M of SrCl₂ (pH 4.0) solutions at 25 °C. The sorption maximum capacity (q_m) of Cs by the Ap1 and Bt1 horizons of the Lt soil (62.24 and 70.70 mmol Cs kg⁻¹ soil) were significantly (p < 0.05) higher than those by the A and Bt1 horizons of the Kt and Cl soils (26.46 and 27.49 mmol Cs kg⁻¹ soil in Kt soil and 34.83 and 29.96 mmol Cs kg⁻¹ soil in Cl soil, respectively), however, the sorption maximum capacity values of the Lt and Tml soils did not show significant differences. The amounts of pyrophosphate extractable Fe (Fe_p) were correlated significantly with the Cs and Sr sorption capacities (for Cs sorption, r² = 0.97, p < 1.0 × 10⁻⁴; for Sr sorption, r² = 0.82, p < 2.0 × 10⁻³). The partition coefficient of radiocesium sorbed on soil showed the following order: Cl soil ? Kt soil > Tml soil > Lt soil. It was due to clay minerals. The second-order kinetic model was applied to the Cs and Sr sorption data. The rate constant of Cs or Sr sorption on the four soils was substantiality increased with increasing temperature. This is attributable to the availability of more energy for bond breaking and bond formation brought about by the higher temperatures. The rate constant of Cs sorption at 308 K was 1.39-2.09 times higher than that at 278 K in the four soils. The activation energy of Cs and Sr sorbed by the four soils ranged from 7.2 to 16.7 kJ mol⁻¹ and from 15.2 to 22.4 kJ mol⁻¹, respectively. Therefore, the limiting step of the Cs⁺ or Sr²⁺ sorption on the soils was diffusion-controlled processes. The reactive components, which are significantly correlated with the Langmuir sorption maxima of Cs and Sr by these soils, substantially influenced their kinetic rates of Cs and Sr sorption. The data indicate that among components of the subtropical and tropical soils studied, short-range ordered sesquioxides especially Al- and Fe-oxides complexed with organics play important roles in influencing their capacity and dynamics of Cs and Sr sorption.     

环境测试舱自吸附甲醛重释放规律与影响因素研究

广泛用于板材污染物释放量测试、空气净化产品净化效果测试等实验中的环境测试舱,往往由于其内壁黏附性杂质而对目标测试物产生不可忽视的自吸附作用,自吸附污染物将作为二次释放源出现重释放,研究目标测试物的自吸附消耗量及重释放规律,探索有效控制措施,有利于对环境测试舱实验应用及室内污染控制提出指导性实际意义。分别选取0.2%甲醛溶液、大芯板作为同一自制玻璃环境测试舱2期实验(I期、Ⅱ期)的不同甲醛释放源,通过近90 d追踪测试,经不同释放源、不同控制条件下舱内壁自吸附甲醛的多次重释放实验,结合非线性拟合分析方法,总结出舱内壁自吸附甲醛重释放甲醛浓度变化符合一阶递增指数函数:y=A1×exp(-x/t1)+y0,(A1<0、t1>0)。曲线参数y0值可用于评价实验条件下测试舱内自吸附甲醛残余量;y0值与环境舱舱体材质、环境温湿度、舱外甲醛浓度及空气交换手段有关,而与释放源及其释放平衡浓度高低无明显关系。大开舱门短时间抽气式空气交换对舱内自吸附甲醛残余有适度清除效果,使y0值降低,同时有利于再次平衡状态的快速建立;而长时间的无动力空气交换,或者自来水洗及去离子水洗等处理手段对舱内壁自吸附甲醛残余无明显清除作用。     

Modelling the biphasic sorption of simazine,imidacloprid, and boscalid in water/soil systems

The sorption kinetics of simazine (6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine), imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine), and boscalid (2-chloro-N-(4′-chlorobiphenyl-2-yl)nicotinamide), three pesticides of wide use in agriculture, was determined in five different water/soil systems over a time interval from the initial few seconds to about 1 month. In all the experiments, sorption kinetics showed a biphasic pattern characterized by an initial, relatively short phase with a high sorption rate and a later phase with much a lower sorption rate. Initial sorption capacity increased with soil organic carbon content and with sorbate hydrophobicity. We postulate that the first phase of the process involves a fast second-order sorption reaction on superficial sites of soil particles, whereas the second phase depends on diffusion-controlled migration to internal binding sites. A kinetic equation based on this hybrid model accurately fitted all data sets. Less satisfactory results were obtained employing the pseudo-first order, pseudo-second order, Elovich, two site non-equilibrium, or Weber-Morris equation. The superior performance of the hybrid model for describing boscalid sorption probably reflects the high hydrophobic character and consequent low diffusion rates of this compound. The accuracy of modelling was in any case strongly dependent on the time interval considered.     

Persistence and Dissipation Kinetics of Spiromesifen in Chili and Cotton

In a field study carried out at three different locations, the dissipation of spiromesifen on cotton and chili was studied and its DT₅₀, and DT₉₉ were estimated at each location. Spiromesifen was sprayed on chili at 96 and 192 g a.i. ha⁻¹ and cotton at 120 and 240 g a.i. ha⁻¹. Samples of chili fruits were drawn at 0, 1, 3, 5, 7, 10, 15, 21, 30 days after treatment and that of cotton seed and lint at first picking and harvest. Soil samples were drawn 30 days after treatment from 0 to 15 and 15 to 30 cm layer. Quantification of residues was done on GC–MS in Selected Ion Monitoring (SIM) mode in mass range 271–274 m/z. The LOQ of this method was found 0.033 μg g⁻¹, LOD being 0.01 μg g⁻¹. The DT₅₀ of spiromesifen when applied at recommended doses in chili fruits was found to be 2.18–2.40 days. Ninety-nine percent degradation was found to occur within 14.5–16.3 days after application. Residues of spiromesifen were not detected in cotton seed and lint samples at the first picking. In soil, no residues of spiromesifen were detectable 15 days after treatment.