Comparision of China’s volatile organic compound pollution management: a computable general equilibrium approach

The public health and ecological impacts of volatile organic compound (VOCs) pollution have become a serious problem in China, arousing increasing attention to emissions control. In this context, this paper analyses the effectiveness of VOC reduction policies, namely pollution charges and environmental taxes at the national and industrial sector levels. It uses a computable general equilibrium model, which connects macroeconomic variables with VOC emissions inventory, to simulate the effects of policy scenarios (with 2007 as the reference year). This paper shows that VOC emissions are reduced by 2.2% when a pollution charge equal to the average cost of engineering reduction methods – the traditional approach to regulation in China – is applied. In order to achieve a similar reduction, an 8.9% indirect tax would have to be imposed. It concludes that an environmental tax should be the preferred method of VOC regulation due to its smaller footprint on the macroeconomy. Other policies, such as subsidies, should be used as supplements.     

纳米二氧化钛可见光催化的研究进展

TiO2纳米材料是目前研究最为广泛的光催化纳米材料之一。但TiO2通常只在紫外光下具有光催化活性,严重影响了它的实际应用范围。光敏化作用以及配合物-金属电子转移等途径可将TiO2的光响应范围拓展到可见光区域,成为TiO2光催化领域的研究热点。综述了近年来光敏化作用和配合物-金属电子转移等方法在TiO2可见光催化领域的研究进展,旨在为今后进一步扩大TiO2的实际应用提出新的研究方向。     

二氧化碳驱油工艺中油酸咪唑啉对碳钢的缓蚀行为研究

目的 研究CO2驱油工艺中咪唑啉缓蚀剂对油套管P110钢腐蚀的缓蚀机制与规律。方法 模拟长庆油田CO2驱工艺环境为实验条件,采用失重挂片、电化学测试、微观表征等手段,研究油酸咪唑啉缓蚀剂对P110碳钢的腐蚀抑制行为。结果 P110钢的腐蚀速度随着CO2分压的升高而增大,但是增大幅度不明显。当CO2分压为2、6 MPa时,油酸咪唑啉对P110钢腐蚀具有显著的抑制效果,缓蚀效率均超过98%,试片表面基本完整;当CO2分压升高到8 MPa时,油酸咪唑啉的缓蚀性能明显下降,缓蚀效率仅为64.33%,试片表面存在明显的腐蚀特征。结论 CO2分压升高到8 MPa时,P110钢表面携带过剩的正电荷,不利于油酸咪唑啉缓蚀剂的吸附。     

Ca2+在饮用水铜绿微囊藻控制中的应用

为改善饮用水藻类的混凝去除效果,以铜绿微囊藻为研究对象,考察了单独投加Ca²⁺、Ca²⁺与PAC联用、Ca²⁺与CO₃^2-原位结晶三种方法的除藻效果,并对Ca²⁺和结晶产物CaCO₃的除藻机制进行探讨.结果表明,单独采用Ca²⁺时,Ca²⁺在低浓度下对藻细胞具有吸附电中和作用,高浓度时同时还有架桥作用,但两者均无法实现对铜绿微囊藻的去除.Ca²⁺与PAC联用,Ca²⁺可以通过吸附电中和显著提高PAC的除藻效果,最大去除率可达98.0%,同时Ca²⁺与溶解性藻源有机物（dAOM）的络合可将残余铝降低50%以上.含藻水中原位CaCO₃结晶对铜绿微囊藻的去除率最高可达83.5%,其产物为带正电荷、粒径2~4 μm左右的球型球霰石.球霰石对藻细胞的去除机制包括球霰石与藻细胞的互絮凝,以及球霰石团聚物对藻细胞的卷扫絮凝,同时球霰石还可以作为加重剂促进藻晶产物沉降分离.自来水厂采用CaCO₃原位结晶与PAC联用除藻,可望降低PAC投加量和残余铝风险,并解决CaCO₃原位结晶导致的浊度和pH偏高问题.研究成果为饮用水除藻提供了新思路.     

自供电式同步翻转电荷提取电路的优化设计

目的 解决现有接口电路俘能效率低、开关控制电路模块结构复杂等问题。方法 基于电压翻转及电荷提取技术,提出一种自供电式同步翻转电荷提取的压电能量俘获电路(Self-Powered Optimized Synchronous Inversion and Charge Extraction Circuit,SP-OSICE)。该电路设计了2个电压峰值检测电路,检测压电换能器两端电压峰值,并在正峰值处进行一次电压翻转,然后在负峰值处采用同步电荷提取方法,提取压电换能器寄生电容上储存的电荷,提高能量的收集效率。结果 在低负载区,SP-OSICE电路的输出功率略低于SICE电路的输出功率,随着负载电压的增大,SP-OSICE电路的输出功率略高于SICE电路,且可达到全桥整流电路最大输出功率的6倍以上。结论 SP-OSICE电路优化了SICE电路中的开关控制策略,无需整流桥结构,提高了接口电路的输出功率。整体电路采用自供电设计,无需外部辅助电路控制晶体管通断,降低了电路结构的复杂性。仿真和实验结果均验证了SP-OSICE电路的优势。     

纳滤膜去除内分泌干扰物/医药化合物研究进展

如何有效去除水中内分泌干扰物、医药活性化合物等有机微污染物的研究逐渐增加,其中,纳滤膜由于其较高的去除率得到了广泛关注。但由于纳滤膜去除这些物质的分离机理较为复杂,有时并不明确,给实验带来较大困难。文章总结了纳滤膜去除水中内分泌干扰物/医药活性化合物的典型应用及其三种分离机理——筛分作用、电荷作用、吸附作用,并对去除过程中所产生的问题和解决方案加以总结。为今后纳滤膜去除内分泌干扰物/医药活性化合物的研究提供参考依据。     

可变电荷与恒电荷土壤胶体对DNA吸附与解吸特征

采用平衡法研究了红壤胶体、砖红壤胶体、潮土胶体和褐土胶体在不同pH值条件下DNA吸附与解吸特征.结果表明,在NaCl和KCl电解质体系中,4种土壤胶体在吸附过DNA后,溶液pH值均有不同程度的增加,pH增加的幅度为红壤胶体>砖红壤胶体>潮土胶体>褐土胶体;NaCl电解质体系>KCl电解质体系.土壤胶体对DNA的吸附量均随着pH值的升高而降低,在pH为2~4,不同胶体对DNA的吸附量保持最大值,约为13.1~14.8μg.mg-1.当平衡溶液pH值从4.2开始上升至8.6,在NaCl体系中,砖红壤胶体和红壤胶体上DNA的吸附量下降幅度约5.5μg.mg-1,而在KCl体系中,DNA的吸附量下降幅度约2.1μg.mg-1.2种电解质体系,潮土胶体与褐土胶体上DNA的吸附量下降幅度约为8.3~12.2μg.mg-1.DNA吸附量下降幅度为恒电荷土壤(潮土和褐土)胶体>可变电荷土壤(红壤和砖红壤)胶体.用NaOAc和NaH2PO4对土壤胶体吸附DNA的解吸时,可变电荷土壤胶体与恒电荷土壤胶体解吸规律有明显差异.在3种溶液pH值为3、5和7时,可变电荷土壤(红壤和砖红壤)胶体上NaOAc解吸率约10%~24.5%,Na...     

A simple formula for calculating the ionization potential of two-electron ions

The ionization potential of one-electron ions can be calculated from a well-known simple equation, but no such equation has been available for calculating the ionization potential of multi-electron ions. I report here an equation that accurately gives the ionization potential of helium-like (i.e., two-electron) ions as a function of the atomic number, the relative difference from experimental values being below 1% for all ions for which reliable experimental data were found (Z = 3–29). The equation also predicts the stability of the negative hydrogen ion (the hydride ion), H⁻, although with twice too large a value for the ionization potential.     

胶态水合二氧化锰絮凝粒子的结构形貌及其混凝机理

采用透射电镜技术观察了胶态水合二氧化锰絮凝粒子的结构形貌并采用Zeta电位测定仪对粒子的荷电特征进行了研究;利用红外光谱、XRD等技术对粒子的界面性质进行了表征;通过混凝试验考察了KMnO₄ 还原法制备的水合二氧化锰胶体对原水的混凝性能并探讨了混凝机理.结果表明,胶态水合二氧化锰粒子在去离子水和原水中荷负电,在去离子水中,粒子直径为10　nm并形成网状结构,有利于发挥吸附架桥作用;粒子具有丰富的表面羟基,比表面积为151.422　m²/g,为δ-MnO₂,表现出优良的吸附污染物的界面特性;较低投量的胶态水合二氧化锰表现出对原水的优良混凝效能和去除有机微污染的效能.     

Adsorption behavior of condensed phosphate on aluminum hydroxide

Sodium pyrophosphate （pyro-P, Na4P2OT）, sodium tripolyphosphate （tripoly-P, Na3P3O10）, and sodium hexametaphosphate （meta-P, （NaPO3）6） were selected as the model compounds of condensed phosphate to investigate the adsorption behavior of condensed phosphate on aluminum hydroxide. The adsorption was found to be endothermic and divisible into two stages： （1） fast adsorption within 1 h; and （2） slow adsorption between 1 and 24 h. The modified Freundlich model simulated the fast adsorption stage well; the slow adsorption stage was described well by the first-order kinetics. The activation energies of pyro-P, tripoly-P, and meta-P adsorption on aluminum hydroxide were determined to be 20.2, 22.8 and 10.9 kJ/mol P adsorbed, respectively, in the fast adsorption stage and to be 66.3, 53.5 and 72.5 kJ/mol P adsorbed, respectively, in the slow adsorption stage. The adsorption increased the negative charge of the aluminum hydroxide surface. Transmission electron microscopy and energy dispersive X-ray analysis analyses provided evidence that the adsorption was not uniform on the surface and that the small crystals contributed more to the fast adsorption than the normal sites did. The results from X-ray fluorescence spectrometry and X-ray photoelectron spectroscopy tests also revealed the uneven adsorption of condensed phosphate as a function of the penetration depth. More condensed phosphates were adsorbed on the outer surface of aluminum hydroxide than in its inner parts.