Heterogeneous reaction of SO2 on CaCO3 particles: Different impacts of NO2 and acetic acid on the sulfite and sulfate formation

Despite the heterogeneous reaction of sulfur dioxide (SO₂) on mineral dust particles significantly affects the atmospheric environment, the effect of acidic gases on the formation of sulfite and sulfate from this reaction is not particularly clear. In this work, using the in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique, we employed a mineral dust particle model (CaCO₃) combined with NO₂ and acetic acid to investigate their effects on the heterogeneous reaction of SO₂ on CaCO₃ particles. It was found that water vapor can promote the formation of sulfite and simulated radiation can facilitate the oxidation of sulfite to sulfate. The addition of NO₂ or acetic acid to the reaction system altered the production of sulfate and sulfite accordingly. There was a synergistic effect between NO₂ and SO₂ that promoted the oxidation of sulfite to sulfate, and a competitive effect between acetic acid and SO₂ that inhibited the formation of sulfite. Moreover, light and water vapor can also affect the heterogeneous reaction of SO₂ with the coexistence of multiple gases. These findings improve our understanding of the effects of organic and inorganic gases and environmental factors on the formation of sulfite and sulfate in heterogeneous reactions.     

Mechanisms of allicin exposure for the sludge fermentation enhancement: Focusing on the fermentation processes and microbial metabolic traits

As a frequently used product with antimicrobial activity, consumed allicin might be discharged and concentrated in waste-activated sludge (WAS). However, the influence of allicin (as an exogenous pollutant) on WAS fermentation has not been clearly revealed. This study aimed to disclose the impacts of allicin on volatile fatty acid (VFA) generation during WAS fermentation. The results showed that the appropriate presence of allicin (10 mg/g TSS) significantly enhanced the VFA yield (1894 versus 575 mg COD/L in the control) with increased acetate proportion (24.3%). Further exploration found that allicin promoted WAS solubilization, hydrolysis and acidification simultaneously. Metagenomic analysis revealed that the key genes involved in extracellular hydrolysis metabolism (i.e., CAZymes), membrane transport (i.e., gtsA and ytfT), substrate metabolism (i.e., yhdR and pfkC) and fatty acid synthesis (i.e., accA and accD) were all highly expressed. Allicin also induced the bacteria to produce more signalling molecules and regulate cellular functions, thereby enhancing the microbial adaptive and regulatory capacity to the unfavourable environment. Moreover, the variations in fermentative microbes and their contributions to the upregulation of functional genes (i.e., ytfR, gltL, INV, iolD and pflD) for VFA generation were disclosed. Overall, the simultaneous stimulation of functional microbial abundances and metabolic activities contributed to VFA production in allicin-conditioned reactors.     

Environmental surveillance of SARS-CoV-2 RNA in wastewater systems and related environments in Wuhan: April to May of 2020

Wastewater-based epidemiology(WBE) has emerged as an effective environmental surveillance tool in monitoring fecal-oral pathogen infections within a community. Congruently, SARS-Co V-2, the etiologic agent of COVID-19, has been demonstrated to infect the gastrointestinal tissues, and be shed in feces. In the present study, SARS-Co V-2 RNA was concentrated from wastewater, sludge, surface water, ground water, sediment, and soil samples of municipal and hospital wastewater systems and related envi...     

Assessing the influence of environmental conditions on secondary organic aerosol formation from a typical biomass burning compound

The atmospheric chemistry in complex air pollution remains poorly understood. In order to probe how environmental conditions can impact the secondary organic aerosol (SOA) formation from biomass burning emissions, we investigated the photooxidation of 2,5-dimethylfuran (DMF) under different environmental conditions in a smog chamber. It was found that SO₂ could promote the formation of SOA and increase the amounts of inorganic salts produced during the photooxidation. The formation rate of SOA and the corresponding SOA mass concentration increased gradually with the increasing DMF/OH ratio. The addition of (NH₄)₂SO₄ seed aerosol accelerated the SOA formation rate and significantly shortened the time for the reaction to reach equilibrium. Additionally, a relatively high illumination intensity promoted the formation of OH radicals and, correspondingly, enhanced the photooxidation of DMF. However, the enhancement of light intensity accelerated the aging of SOA, which led to a gradual decrease of the SOA mass concentration. This work shows that by having varying influence on atmospheric chemical reactions, the same environmental factor can affect SOA formation in different ways. The present study is helpful for us to better understand atmospheric complex pollution.     

The black rock series supported SCR catalyst for NO x removal

Environmental Science and Pollution Research - Black rock series (BRS) is of great potential for their plenty of valued oxides which include vanadium, iron, alumina and silica oxides, etc. BRS was...     

道路车辆电工电子设备高加速寿命试验

成熟的汽车企业已经将高加速环境应力试验引入装车电工电子设备的研发、试产和批量供货的管理中,其需求已进入国内检测市场。本文以已发布的车企文件为基础,介绍并讨论高加速寿命试验（HALT）的各项要素和实验室要求。高加速应力筛选（HASS）和稽核（HASA）另行拟文讨论。     

Biomass of Speckled Alder on an Air-Polluted Mountain Site and its Response to Fertilization

The article summarizes outcomes of a biomass study conducted in a young speckled alder plantation on a cold mountain site. At this location, the previously existing old forest was clear felled because of damage from air pollution, and present-day surface humus is in need of restoration. The intention of this study was to quantify the biomass and nutrients accumulated by alders and their components and assess whether the initial fertilization resulted in increased biomass production and nutrient accumulation in the biomass. Besides the control, two fertilized treatments were installed. In the surface treatment (SUT), the amendment was applied as a base dressing in small circles around trees. In the planting-hole treatment (PHT), the amendment was incorporated into soil inside the planting holes. Five growth seasons after planting and fertilization, six alders from each treatment were harvested including roots. Their biomass was quantified and analyzed for macroelements. The greatest pool of dry mass (DM) was branches in the control and stem wood in the fertilized treatments. The greatest pools of macroelements were leaves and branches. The most pronounced effects of fertilization were recorded in the DM and consequently in the absolute quantities of nutrients. The DM of an average tree in the control, SUT, and PHT was 85, 226, and 231 g, respectively. The absolute contents of nutrients per tree in the fertilized treatments showed the following increases, as compared with the control: (N) 2.5–2.6 times; (P) 1.6–2.4 times; (K) 1.8–2.1 times; and (Mg) 1.8–2.0 times, respectively. Speckled alder responded positively to fertilization.     

南水北调中线工程与汉江中下游地区农业的持续发展

南水北调中线工程是指从汉江的丹江口水库引水供给华北地区,同时考虑鄂,豫两省汉江唐白河流域和淮河流域的需水要求的战略性工程,是调整水资源的空白布局,解决我国北方缺水问题的紧迫任务。汉江中下游地区是湖北省的粮仓和重要的产业基地,是汉江流域经济发展的中心。由于调水的影响,汉江丹江口以下的流量及季节性分配将发生变化,航运,水质,农业灌溉,工业生产以及城市发展等将受到不同程度的影响,直接关系到汉江中下游地区     

北洛河流域植物多样性地理格局与环境关系

通过野外调查和历史文献及标本统计分析,确定并分析北洛河流域种子植物信息数据.结果表明：该区共有种子植物123科581属1671种,占黄土高原种子植物的83.67%、67.24%、51.83%,集中分布于大型科（>50种）、较大科（21~50种）和单种属（1种）、小型属（2~5种）内.11个干流流经的地理单元植物相似性聚类分为5组,较早分离的是黄龙县,最大类因子午岭山脉连接而包含4个地理单元（富县、合水县、宜君县、黄陵县）.富县、合水县和黄龙县植物丰富度SD值最高,洛川县、华池县和甘泉县SD值最低.该区地理成分在属级水平上有15个分布区类型16个变型,以温带分布及其变型为主（287属,占49.40%）,并与热带分布及其变型联系紧密（115属,占19.79%）,植物丰富度SD值与温带成分显著正相关;黄陵县、洛川县、黄龙县R/T值最高,热带性质最强,华池县、定边县R/T值最低,热带性质最弱.R/T值受海拔影响,随温度和降水从东南向西北递减.该区植物起源古老,分化程度高,物种多样性丰富,地理成分复杂,是重要的植物种质资源库.植物物种多样性地带性格局过渡性明显,体现出这些类群的生态位需求.需加强保护该区原生环境和植物,合理开发利用,可选择6大优势科（菊科、禾本科、蔷薇科、豆科、唇形科和毛茛科）中适地适树适草的物种（温带性质）,进行植被恢复和水土流失治理.