环境保护督察巡视:党政同责的顶层制度

环境保护督察巡视是党政同责的核心制度安排。本文从环保督察巡视与党政同责的关系与实践出发,认为该制度是从决策源头监督,既有法律依据,也有政策要求,其他部门的督察以及环保考核、约谈等实践为环保督察巡视积累了经验。从环保督察巡视制度的内涵与特征来看,该制度有明确的行动指南、统一的党政同责督察体系、较高的督察组权威、明确的巡视重点与突破方向等特点。最后,本文从理顺环境目标责任制度、制定督察实施细则、提升督察巡视权威性、开展第三方评估与社会监督等方面提出了政策建议。     

Watering techniques and zero-valent iron biochar pH effects on As and Cd concentrations in rice rhizosphere soils, tissues and yield

Zero-valent iron amended biochar (ZVIB) has been proposed as a promising material in immobilizing heavy metals in paddy fields. In this study, the impacts of pH of ZVIB (pH 6.3 and pH 9.7) and watering management techniques (watering amount in the order of CON (control, 5/72)>3/72>1–3/72>3/100>1/72, with 5/72, for example, representing irrigation given to 5 cm above soil surface in 72 hr regular interval) on As and Cd bioavailability for rice and its grain yield (Yield_BR) were investigated in a pot experiment. Brown rice As (As_BR) content was irrelative to the watering treatments, while significantly decreased (>50%) with the addition of both ZVIB materials. The diminutions of brown rice Cd (Cd_BR) content as well as the Yield_BR were highly dependent on both the soil amendment materials’ pH and watering amount. Among all the watering treatments, 3/72 treatment (15% less irrigation water than the CON) with ZVIB 6.3 amendment was the optimum fit for simultaneous reduction of As_BR (50%) and Cd_BR contents (19%) as well as for significant increment (12%) of the Yield_BR. Although high pH (9.7) ZVIB application could also efficiently decrease As and Cd contents in brown rice, it might risk grain yield lost if appropriate (e.g. 3/72 in our study) watering management technique was not chosen. Therefore, ZVIB would be an environmentally friendly option as an amendment material with proper selection of watering management technique to utilize As and Cd co-contaminated arable soils safely for paddy cultivation.     

Deactivation of Cu-SAPO-34 by urea-related deposits at low temperatures and the regeneration

Selective catalytic reduction(SCR) with urea catalyzed by Cu-SAPO-34 is an effective method to eliminate NO_x from diesel exhaust. However, urea-related deposits may form during cold-start and urban driving due to low exhaust temperatures. The activity of CuSAPO-34 at 175°C is significantly degraded by urea exposure, and 300°C is required for regeneration. Through in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) and temperature-programmed hydrolysis studies, the dominant stable deposit at 175°C is identified as biuret, which can be eliminated at 300°C. The urea-derived deactivation and regeneration mechanisms of Cu-SAPO-34 were compared with those of anatase-supported catalysts.     

Improved activity and durability of Rh-based three-way catalyst under diverse aging atmospheres by ZrO2 support

The catalytic activity and durability of Rh/ZrO_2 catalyst were investigated compared with Rh/Al_2O_3 catalyst under diverse aging atmospheres, including lean, rich and lean–rich cyclic aging atmospheres, to simulate the real working conditions of three-way catalyst.Oxidation states and microstructures of rhodium species were investigated to correlate with the catalytic performance of the catalysts. The catalytic performance and durability of the Rh catalyst under diverse aging atmospheres were drastically enhanced by ZrO_2 support. ZrO_2 support was confirmed to be able to effectively inhibit rhodium sintering even under diverse aging conditions. It can also successfully keep Rh species in an active low-valence state on the surface of the catalyst. The superiority of ZrO_2 support compared to Al_2O_3 was verified by the Rh-based monolith catalyst.     

Minimizing Bias in Virally Seeded Water Treatment Studies: Evaluation of Optimal Bacteriophage and Mammalian Virus Preparation Methodologies

One key assumption impacting data quality in viral inactivation studies is that reduction estimates are not altered by the virus seeding process. However, seeding viruses often involves the inadvertent addition of co-constituents such as cell culture components or additives used during preparation steps which can impact viral reduction estimates by inducing non-representative oxidant demand in disinfection studies and fouling in membrane assessments. The objective of this study was therefore to characterize a mammalian norovirus surrogate, murine norovirus (MNV), and bacteriophage MS2 at sequential stages of viral purification and to quantify their potential contribution to artificial oxidant demand and non-representative membrane fouling. Our results demonstrate that seeding solvent extracted and 0.1 micron filtered MNV to ~10⁵ PFU/mL in an experimental water matrix will result in additional total organic carbon (TOC) and 30 min chlorine demand of 39.2 mg/L and 53.5 mg/L as Cl₂, respectively. Performing sucrose cushion purification on the MNV stock prior to seeding reduces the impacts of TOC and chlorine demand to 1.6 and 0.15 mg/L as Cl₂, respectively. The findings for MNV are likely relevant for other mammalian viruses propagated in serum-based media. Thus, advanced purification of mammalian virus stocks by sucrose cushion purification (or equivalent density-based separation approach) is warranted prior to seeding in water treatment assessments. Studies employing bacteriophage MS2 as a surrogate virus may not need virus purification, since seeding MS2 at a concentration of ~10⁶ PFU/mL will introduce only ~1 mg/L of TOC and ~1 mg/L as Cl₂ of chlorine demand to experimental water matrices.     

Modification of CeO2-ZrO2 catalyst by potassium for NOx-assisted soot oxidation

Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method.The ageing treatment was performed in static air at 800°C for 20 hr to evaluate the thermal stability of the catalyst.The catalysts were characterized by X-ray diffraction,BET surface area,oxygen storage capacity,NOx-temperature programmed desorption and soot-temperature programmed oxidation measurements.By introduction of potassium,the maximum soot oxidation rate temperature(Tm) of the ceria-zirconia based catalyst de...     

环境空气功能区划分方案调整的技术思路

国内大部分地区现行的环境空气功能区划方案都是在1997年制定划分的,随着城市化进程的扩大及区域相关规划的调整变化,原环境空气功能区划分方案与现行的土地利用规划、风景区旅游规划、区域总体发展规划等存在一定的不协调,导致环境空气保护的一系列措施实际操作性不强。近年来不少地方已经为了和谐各规划的矛盾、促进区域可持续发展,提出对原环境空气功能区划局部地区的调整,本文结合相关案例,就编制环境空气功能区划调整可行性方案的技术思路进行梳理。     

Effects of tungsten oxide on the activity and thermal stability of a sulfate-derived titania supported platinum catalyst for propane oxidation

A Pt/WO₃/TiO₂ catalyst for propane oxidation was prepared by a stepwise wet impregnation method, and was aged at 800℃ for 5 hr. Compared to the sulfate-derived titania supported catalyst, the introduction of tungsten oxide as stable Bronsted acid sites led to the formation of more metallic platinum active sites at the Pt/WO₃ interface. The dissociation of surface intermediates for propane oxidation was promoted on the WO₃-modified catalyst. This, as well as the inhibition effects of tungsten oxide on the sintering of anatase and the phase transformation to rutile, resulting in a high activity and thermal stability for the Pt/WO₃/TiO₂ catalyst.     

Quantifying the adsorption and uptake of CuO nanoparticles by wheat root based on chemical extractions

This study screened out eluants for efficiently desorbing metal nanoparticles from plant root surface, and distinguished the proportions of CuO-nanoparticles uptake and adsorption.     

冶炼厂废水泵的汽蚀

常用离心泵排送冶炼厂废水时,废水泵易发生汽蚀。分析了形成废水泵汽蚀的各种因素,特别分析了废水生成“汽蚀核子”的特点,找出了防治废水泵汽蚀的有效措施。