Desorption of CO2, SO2, and NH3 in the vacuum evaporation of desulfurization wastewater

Environmental Science and Pollution Research - Mechanical vapor compression and multi-effect evaporation have been widely used in achieving zero discharge of desulfurization wastewater as they are...     

Environmental knowledge,behaviors, and attitudes regarding caffeine consumption among Chinese university students from the perspective of ecopharmacovigilance

Environmental Science and Pollution Research - Caffeine is considered the most representative pharmaceutical emerging contaminant (PEC) because of its ubiquity, high environmental abundance,...     

Sugarcane monoculture drives microbial community composition,activity and abundance of agricultural-related microorganisms

Environmental Science and Pollution Research - Sugarcane monoculture (SM) often leads to soil problems, like soil acidification, degradation, and soil-borne diseases, which ultimately pose a...     

Knowledge map and global trends in extreme weather research from 1980 to 2019: a bibliometric analysis

Environmental Science and Pollution Research - There is an increasing number of studies focusing on extreme weather all over the world, but global trends and research topics related to extreme...     

不同湿地模型中根系微生物的多样性

为了研究不同植物和滤料组合的小型湿地模型在处理养殖池塘水体过程中根系微生物群落的特征,并分析植物对根系微生物富集的影响,本研究对两种植物(茭白和慈菇)和两种滤料(石榴石和磁铁矿)进行组合构建了6种不同的湿地模型,并利用高通量测序技术分析湿地植物根系微生物的结构特点和多样性.结果表明:不同湿地模型根系微生物的种类和数量各不相同;所有收集的微生物总体上属于52个门,118个纲,455科,905个属和1 426个种;根据Shannon指数,茭白(平均为5.77)比慈菇(平均为5.29)在微生物富集方面具有更强的能力;但是,慈菇和茭白根系微生物中变形菌门的比例分别平均为61.97%和51.78%,说明慈菇能够更好地富集变形菌.β-变形菌纲为实验期间不同植物根际富集的主要细菌类群.本研究结果为人工湿地植物优化选择提供了理论基础和湿地组合最佳构建提供了基础资料.     

Simultaneous removal of Cu(II) and Cr(VI) by Mg–Al–Cl layered double hydroxide and mechanism insight

Mg–Al–Cl layered double hydroxide (Cl-LDH) was prepared to simultaneously remove Cu(II) and Cr(VI) from aqueous solution. The coexisting Cu(II) (20 mg/L) and Cr(VI) (40 mg/L) were completely removed within 30 min by Cl-LDH in a dosage of 2.0 g/L; the removal rate of Cu(II) was accelerated in the presence of Cr(VI). Moreover, compared with the adsorption of single Cu(II) or Cr(VI), the adsorption capacities of Cl-LDH for Cu(II) and Cr(VI) can be improved by 81.05% and 49.56%, respectively, in the case of coexisting Cu(II) (200 mg/L) and Cr(VI) (400 mg/L). The affecting factors (such as solution initial pH, adsorbent dosage, and contact time) have been systematically investigated. Besides, the changes of pH values and the concentrations of Mg²⁺ and Al³⁺ in relevant solutions were monitored. To get the underlying mechanism, the Cl-LDH samples before and after adsorption were thoroughly characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. On the basis of these analyses, a possible mechanism was proposed. The coadsorption process involves anion exchange of Cr(VI) with Cl⁻ in Cl-LDH interlayer, isomorphic substitution of Mg²⁺ with Cu²⁺, formation of Cu₂Cl(OH)₃ precipitation, and the adsorption of Cr(VI) by Cu₂Cl(OH)₃. This work provides a new insight into simultaneous removal of heavy metal cations and anions from wastewater by Cl-LDH.     

Capability of cation exchange technology to remove proven N-nitrosodimethylamine precursors

N-nitrosodimethylamine(NDMA) precursors consist of a positively charged dimethylamine group and a non-polar moiety, which inspired us to develop a targeted cation exchange technology to remove NDMA precursors. In this study, we tested the removal of two representative NDMA precursors, dimethylamine(DMA) and ranitidine(RNTD), by strong acidic cation exchange resin. The results showed that pH greatly affected the exchange efficiency, with high removal(DMA 78% and RNTD 94%) observed at pH pk_a-1 when the molar ratio of exchange capacity to precursor was 4. The exchange order was obtained as follows: Ca~(2+) Mg~(2+) RNTD~+ K~+ DMA~+ NH_4~+ Na~+. The partition coefficient of DMA~+to Na~+was 1.41 ± 0.26, while that of RNTD~+to Na~+was 12.1 ± 1.9. The pseudo second-order equation fitted the cation exchange kinetics well. Bivalent inorganic cations such as Ca~(2+)were found to have a notable effect on NA precursor removal in softening column test. Besides DMA and RNTD, cation exchange process also worked well for removing other 7 model NDMA precursors. Overall, NDMA precursor removal can be an added benefit of making use of cation exchange water softening processes.     

1025t/h四角切圆煤粉炉内空气过量系数对NO生成的影响

文章采用计算流体力学软件Fluent数值模拟了1 025 t/h四角切圆煤粉炉内的湍流扩散燃烧,分析了空气过量系数对炉内烟气速度、烟气温度和氮氧化物组分的影响。结果表明:空气过量系数会对炉内流场的空气动力学特性和温度场分布均匀性产生显著影响。煤粉炉膛最佳空气过量系数为1.07,此时炉内温度场、速度场和浓度场的分布可使燃烧中间产物HCN和NH_3较好的将燃料型NO还原为N_2,来充分发挥空气分级燃烧降低NO排放的功效。     

某钢铁企业颗粒物无组织排放核算与监测对比分析

以济南东部老工业区一家大型钢铁企业为例,通过前期调研和排放系数核算出颗粒物(TSP)排放总量,再运用公式计算出厂区周边不同距离颗粒物(TSP)的落地浓度。将该落地浓度与厂区周边颗粒物(TSP)的监测值进行对比分析,充分印证了连续点源扩散的高斯模式的准确性和可行性。随着气流经过该厂区,对比上下风向监测点位颗粒物(TSP)浓度迅速升高(增大1.04倍),下风向颗粒物(TSP)浓度超出二级标准1.32倍;颗粒物(TSP)的落地浓度在厂区不同距离上的浓度变化明显,从0.1到10 km其落地浓度稀释了约3 500倍,距离>4 km时,无组织排放的颗粒物(TSP)对周围空气质量直接影响有限。     

基于LiDAR、SRTM DEM的祁连山黑河流域十一冰川2000-2012年物质平衡估算

以祁连山黑河流域十一冰川为例,利用机载三维激光扫描数据（Light Detection And Ranging, LiDAR）和SRTM DEM数据,在LiDAR点云数据预处理、高程数据配准、校正、误差评估的基础上,建立基于大地测量法的冰川物质平衡计算流程。表明：2000-2012年十一冰川冰面高程变化为-7.47±0.92βm,变化率为-0.62±0.08 m·a^-1,估算十一冰川的年均物质平衡为 -0.53±0.07βm w.e.,累积物质平衡为-6.35±0.78βm w.e.,折合水当量约为（330.4±40.8）×10^4βm³;与其他典型监测冰川物质平衡进行对比和分析,论证了估算结果的可靠性;LiDAR数据具有非常高的精度和空间分辨率,目前关于其在冰川物质平衡研究中的应用很少,论文尝试将其应用于冰川物质平衡变化研究中,具有广阔的发展前景。