Studies on catalytic reduction of nitrate in groundwater

Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated. Pd-Cu/γ-Al₂O₃ catalyst was prepared by impregnation and characterized by brunauer-emmett-teller (BET), inductive coupled plasma (ICP), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). It was found that total nitrogen was effectively removed from the nitrate solution (100 mg/L) and the removal efficiency was 87%. The catalytic activity was affected by pH, catalyst amount used, concentration of sodium formate, and initial concentration of nitrate. As sodium formate was used as reductant, precise control in the initial pH was needed. Excessively high or low initial pH (7.0 or 3.0) reduced catalytic activity. At initial pH of 4.5, catalytic activity was enhanced by reducing the amount of catalyst, while concentrations of sodium formate increased with a considerable decrease in N₂ selectivity. In which case, catalytic reduction followed the first order kinetics. Translated from Acta Scientiae Circumstantiae, 2006, 26(4): 567–571 [译自: 环境科学学报]     

可伸缩接地装置在浮顶罐中的应用

介绍了浮顶罐浮盘与罐壁之间的电气连接--可伸缩接地装置,它易于安装、检测和维护,能快速对地泄放雷电电荷和静电电荷,同时降低雷电流频率下的趋肤效应,尽可能地消除二次电弧,防止油罐密封处产生火花放电引起的火灾.     

燃煤电厂烟气脱硫技术发展现状

综述近年来国内外应用及正在研究开发的脱硫工艺，包括国内应用的石灰石－石膏，海水，磷铵复肥，喷雾干燥，炉内喷钙，电子束烟气脱硫及国外的尿素，改进的石灰石－石膏，再生法脱除ＳＯ２和ＮＯＸ等新方法，并对其中发生的化学反应，特点及存在的问题进行了较详细的分析。     

Isolation and characterization of a bacterial strain that efficiently degrades sex steroid hormones

A bacterial strain, ZY3, growing on sex steroid hormones as the sole source of carbon and energy was isolated from the sewage treatment plant of a prophylactic steroids factory. ZY3 degrades the 3-methoxy-17β-hydroxy-1,3,5(10),8(9)-δ-4-estren (MHE). This strain was preliminarily identified as Raoultella sp. ZY3 according to its morphology and its 16S rRNA gene sequence. During the experimental period (72 h), the optimum temperature, pH and 3-MHE concentration for the degradation of hydride by the strain ZY3 were 35°C, 10 and 10 mg/L, respectively. The degradation rate of the sex steroid hormones increased to 87% and 85% after the addition of maltose and peptone, respectively.     

Photocatalysis enhancement by electric field: TiO2 thin film for degradation of dye X-3B

According to the theory of photocatalysis, the efficiency of photocatalysis decreases mostly due to the recombination of photo-generated electron-hole pairs. An electric field across a photocatalyst can promote the separation of photo-generated electrons and holes and prevent them from recombination so as to enhance the efficiency of photocatalysis. And the synergetic decomposition efficiency of photocatalysis and an electric field is greater than that of the simple combine of their single efficiency. The performance of photocatalysis enhanced by electric field (PEEF) and operating conditions such as the direction of the electric field, the voltages between the two electrodes, the material of the electrodes, which may affect the efficiency of PEEF, were investigated in this paper. The results indicate that the system of PEEF abides the established theory of photocatalysis.     

春蚕期桑叶氟化物含量变化规律分析与研究

春蚕桑叶氟化物中毒引起政府部门的高度重视。通过对历年来桑叶含氟量监测数据统计分析，找出春蚕期桑叶含氟量日均值变化规律，并对规律成因进行探讨研究，为春蚕防氟工作提供科学依据。     

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

Adding iron salt or iron hydroxide to sludgemixed liquor in an aeration tank of a conventional activated sludge processes (bioferric process) can simultaneously improve the sludge’s filterability and enhance the system’s treatment capacity. In view of this, Fe(OH)₃ was added to a submerged membrane bioreactor (SMBR) to enhance the removal efficiency and to mitigate membrane fouling. Bioferric process and SMBR were combined to create a novel process called Bioferric-SMBR. A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out. Bioferric-SMBR showed potential superiority, which could enhance removal efficiency, reduce membrane fouling and improve sludge characteristic. When volumetric loading rate was 25% higher than that of common SMBR, the removal efficiencies of Bioferric-SMBR on COD, dye, and NH₄ ⁺-N were 1.0%, 9.5%, and 5.2% higher than that of common SMBR, respectively. The trans-membrane pressure of Bioferric-SMBR was only 36% of that in common SMBR while its membrane flux was 25% higher than that of common SMBR. The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged. The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans. The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR, respectively.     

Zn2+ loading as a critical contributor to the circ_0008553-mediated oxidative stress and inflammation in response to PM2.5 exposures

Inflammation is a major adverse outcome induced by inhaled particulate matter with a diameter of ≤ 2.5 µm (PM_2.5), and a critical trigger of most PM_2.5 exposure-associated diseases. However, the key molecular events regulating the PM_2.5-induced airway inflammation are yet to be elucidated. Considering the critical role of circular RNAs (circRNAs) in regulating inflammation, we predicted 11 circRNAs that may be involved in the PM_2.5-induced airway inflammation using three previously reported miRNAs through the starBase website. A novel circRNA circ_0008553 was identified to be responsible for the PM_2.5-activated inflammatory response in human bronchial epithelial cells (16HBE) via inducing oxidative stress. Using a combinatorial model PM_2.5 library, we found that the synergistic effect of the insoluble core and loaded Zn²⁺ ions at environmentally relevant concentrations was the major contributor to the upregulation of circ_0008553 and subsequent induction of oxidative stress and inflammation in response to PM_2.5 exposures. Our findings provided new insight into the intervention of PM_2.5-induced adverse outcomes.     

北方农村清洁取暖区域性典型案例实施方案及经验总结

目前,我国已有43个县、市入选北方清洁取暖试点城市。随着农村清洁取暖工作的深入开展,及时总结不同试点地区在技术路径、实施方案、推进模式等方面的先进经验,对其后续工作的顺利完成及其他地区未来清洁取暖工作的有效开展都具有重要意义。本文对2020年3月26日召开的北方农村清洁取暖经验交流会上所介绍的8个专题报告,从清洁取暖整体进展、典型案例经验分享、企业市场化运作机制和服务模式等方面进行了总结和归纳。文中所提到的5个典型区域性案例都能依据本地资源状况和经济水平等因地制宜地提出切实可行的农村清洁取暖模式,在有序推进过程中不断优化调整实施路径,并结合企业的力量积极探索绿色金融方案和运营模式,为清洁取暖注入新的资金动力,充分调动了社会各方对清洁取暖的参与度,也有效改善了农户的室内热舒适性、空气质量和居住水平,提升了农户满意度和接受度。     

基于VIKOR法的潍坊市水资源承载力综合评价

水资源承载力综合评价通常涉及到社会、经济、资源和环境等多种因素的影响.多准则妥协解排序法（VIKOR）可协调处理多种因素间的相互关系,是评价城市水资源承载力的有效手段之一.本文利用VIKOR法对潍坊市水资源承载力进行综合评价,通过构建水资源承载力综合评价指标体系,利用CRITIC法计算权重,标准化数据并进行分析计算和排序,以利益比率Q_i作为综合评价值,Q_i值越小,表明水资源承载力越高.结果发现,在2008-2017年,潍坊市水资源承载力综合评价值呈下降趋势,从2008年的0.7378下降至2017年的0.0000,表明潍坊市水资源承载力稳步提高.通过分析潍坊市水资源承载力各子系统的变化趋势发现,潍坊市水资源承载能力依然有较大的提升空间.通过对2017年潍坊市各市、区、县水资源承载力进行对比可知,诸城市、青州市、安丘市和临朐县综合评价值较低,分别为0、0.1645、0.2267和0.2503,说明水资源承载力较高;潍城区、坊子区、寒亭区和奎文区综合评价值较高,分别为0.3475、0.4739、0.5938和0.9131,说明水资源承载力较低.表明潍坊市部分地区产业结构和布局与水资源条件不相匹配,水资源开发利用水平超出当地水资源承载力.