Effect of particle size on CO adsorption and thermodynamic analysis

The liquid nitrogen adsorption method was used to characterize the pore structure of non-cohesive coal in the 061,404 working face of the Lingxin coal mine. The amount of specific surface area of micropores in the sample continuously rose as particle sizes reduced. The volumetric method was used to measure the CO isothermal adsorption curves of three samples (sample I, 0.425–0.25 mm, sample II, 0.18–0.25 mm, and sample III, 0.15–0.18 mm). The experimental results were fitted by the Langmuir model. According to the experimental results, it was conducive to CO adsorption with the conditions of high pressure and low-temperature. The decrease in grain diameter increased the number and volume of micropores in the sample, which improved the adsorption capacity of the sample. In addition, according to the adsorption data, the CO adsorption thermodynamics of three samples were analyzed, including surface potential (Ω), Gibbs free energy change (ΔG) and entropy change (ΔS). The results demonstrated that CO adsorption by coal was a spontaneous process. Sample III has the most substantial adsorption capacity, whereas the sample I has the weakest adsorption capacity.     

Assessing the impact of leather industries on the quality of water discharged into the East China Sea from Wenzhou Watersheds

Ammonium nitrogen and total germanium are among the main pollutants in the wastewater discharged from the leather industry. The intake of high concentrations of ammonium nitrogen and/or total germanium harms human health and biological species, as is well documented in literature. This paper focuses on assessing the trends of ammonium nitrogen and total germanium concentrations through time in two watersheds (Aojiang and Oujiang) in the Wenzhou metropolitan area of Zhejiang Province and their relationships with the released wastewater using regression and correlation statistics. The paper also utilizes the integrated pollution index to evaluate water quality in the two watersheds. Preliminary results show that, from 1992 to 1998 in the Aojing watershed, the concentrations of ammonium nitrogen and total germanium increased 13 and 14 times, respectively, decreasing somewhat after 1998, while between 1992 and 1997 in the Oujiang watershed, the concentrations increased, then decreased after 1997. The concentrations of ammonium nitrogen and total germanium are positively related to the amount of released wastewater. The concentrations of ammonium nitrogen and total germanium exceeded water standards 12 and 3 times, respectively, in Pingyang county of the Aojiang watershed, 14 and 3.3 times in Lucheng District of the Oujiang watershed, and 14 and 3.8 times in the Ouhai Oujiang watershed, respectively. In Pingyang county of the Aojiang watershed, the water quality degraded from Type III in 1992 to over Type V in 2003, and in the Oujiang watershed, the water quality degraded from Type II to over Type IV in 1999, when they were compared with the water quality standards. The water quality slightly improved in 2003 for the Oujiang watershed. It appears that pollution did have a direct positive correlation with leather industry production in the Pingyang Aojing watershed, while there was a negative correlation between the two in the Oujiang watershed. In these two watersheds, the integrated pollution index did not appear to relate to population dynamics and agricultural production. This paper also discusses the current new methodologies and approaches adopted nationally and internationally to reduce the contaminants and purify the environment for maintaining a sustainable and healthier environment in Wenzhou.     

Assessment of the Effectiveness of Environmental Dredging in South Lake,China

Environmental dredging is a primary remedial option for removal of the contaminated material from aquatic environment. Of primary concern in environmental dredging is the effectiveness of the intended sediment removal. A 5-year field monitoring study was conducted to assess the effectiveness of the environmental dredging in South Lake, China. The concentrations of total nitrogen (TN), total phosphors, and heavy metals (Zn, Pb, Cd, Cu, Cr, Ni, Hg, and As) before and after dredging in sediment were determined and compared. Multiple ecological risk indices were employed to assess the contamination of heavy metals before and after dredging. Our results showed that the total phosphorus levels reduced 42% after dredging. Similar changes for Hg, Zn, As Pb, Cd, Cu, Cr, and Ni were observed, with reduction percentages of 97.0, 93.1, 82.6, 63.9, 52.7, 50.1, 32.0, and 23.6, respectively, and the quality of sediment improved based on the criterion of Sediment Quality Guidelines by USEPA and contamination degree values (C_d) decreased significantly (paired t-test, p < 0.05). Unexpectedly, the TN increased 49% after dredging compared to before dredging. Findings from the study demonstrated that the environmental dredging was an effective mechanism for removal of total phosphorus and heavy metals from South Lake. Nevertheless, the dredging was ineffective to remove total nitrogen from sediment. We conclude that the reason for the observed increase in TN after dredging was likely ammonia release from the sediment impairing the dredging effectiveness.     

农业土地利用转变对土壤团聚体组成及碳、氮含量的影响

为探究农业土地利用转变对土壤团聚体组成、稳定性及有机碳（SOC）、全氮（TN）含量变化的影响,选取玉米地、玉米地转变为姜地、稻田和稻田转变为姜地4种农业土地利用类型为研究对象,对土壤水稳性团聚体的组成、稳定性及SOC、TN含量进行测定与分析.结果表明： ①玉米地转变为姜地后,>0.25 mm粒级的大团聚体减少21.48%（p<0.01）,>0.25 mm稳定性团聚体的含量（DR_0.25）显著降低53.39%;稻田转变为姜地后,大团聚体差异不显著,<0.053 mm粒级的粉黏团聚体增加8.93%（p<0.01）;冗余分析和相关分析表明,土壤含水量是团聚体组成和 稳定性的重要影响因素;②玉米地转变为姜地后,0.25~1 mm粒级团聚体中SOC、TN含量分别减少52.68%、50.98%,粉黏团聚体（<0.053 mm）中SOC和TN含量增加约2倍（p<0.01）;稻田转变为姜地后,>0.25 mm的大团聚体和0.053~0.25 mm的微团聚体中的SOC、TN含量均减少（p<0.05）,其中,大团聚体碳氮比与团聚体组成和稳定性存在相关关系（p<0.05）;③所有处理均为大团聚体SOC、TN贡献率最高,转变后的姜地较玉米地、稻田的土壤粉黏团聚体的SOC、TN贡献率显著增加,尤其是较玉米地的粉黏团聚体SOC、TN贡献率增加3倍（p<0.01）;④平均质量 直径（MWD）和几何平均直径（GMD）与大团聚体的SOC、TN含量呈显著正相关（p<0.05）,分形维数（D）与MWD及1~2 mm粒级大团聚体的SOC、TN含量呈显著负相关（p<0.01）,DR_0.25与大团聚体的SOC、TN含量呈显著正相关（p<0.01）.总体上,玉米地和稻田两种用地转变为姜地后,土壤团聚体的组成发生较大变化,团聚体稳定性变化虽不显著,但大团聚体中SOC、TN含量降低,粉黏团聚体中SOC、TN含量增加.本研究的开展对农田科学管理和可持续生产具有重要的指导意义.     

鄱阳湖河湖交错区软体动物重金属富集与迁移特征分析

河湖交错区是鄱阳湖流域重金属污染物进入湖泊的主要通道,也是重金属富集的场所.本文通过在鄱阳湖河湖交错区采集软体动物样品,分析样品的肌肉和内脏中铁（Fe）、锰（Mn）、铜（Cu）、锌（Zn）、铬（Cr）、镍（Ni）、砷（As）、镉（Cd）、铅（Pb）和锑（Sb）的含量,利用生物-沉积物累积因子和碳氮稳定同位素对鄱阳湖软体动物重金属的富集特征及营养结构和食源关系进行研究,并利用综合目标危险系数进行健康风险评估.结果表明：①鄱阳湖软体动物重金属含量存在显著的种间和组织间的差异,且受体长体重的稀释作用,与所在栖息地的关系不大,但与区域背景环境存在明显的对应关系,均低于水产限量标准值.软体动物对重金属Cu、Zn和Cd具有明显的富集能力,蚌（圆顶珠蚌、三角帆蚌、背瘤丽蚌和褶纹冠蚌）易从环境中富集更多的Mn和Cd,而螺（铜锈环棱螺和大沼螺）则易富集Cu和Zn;②软体动物δ¹³C值为-29.84‰~-21.13‰,δ¹⁵N值为4.09‰~11.51‰,螺和蚌存在明显不同的食物来源.软体动物中的重金属并不随δ¹⁵N值的变化表现出显著的改变,但与δ¹³C值存在显著的线性关系;其中Cu和Zn与δ¹³C值表现为显著的正相关关系,而Mn、Cr、As、Cd、Pb和Sb表现为显著的负相关关系;③健康风险评估结果表明,不论是成人还是儿童,综合目标危险系数（TTHQ） 均大于1,表明鄱阳湖河湖交错区软体动物重金属的富集会对人群食用产生较为显著的健康风险,其中Mn和As是主要的贡献者,且食用蚌的风险略高于螺.研究结果可为鄱阳湖水生态安全、水生生物多样性保护及食品安全评估提供科学依据和理论支撑.     

低温下废铁屑对厌氧氨氧化系统的影响

考察了在低温条件下(<20℃)废铁屑及其投加方式对厌氧氨氧化反应器脱氮性能和微生物群落的影响.结果表明,当废铁屑投加量为10g/L时,直接(R2)和间接(R3)投加方式均会对厌氧氨氧化反应造成短期抑制,总氮去除率分别降低4.7%和3.4%;30d连续运行后,2组反应器总氮去除率均提升至70%左右;反应器稳定运行阶段,R2的R_s(NO₂^--N与NH₄⁺-N去除量之比)和R_p(NO₃^--N生成量与NH₄⁺-N去除量之比)为1.57和0.22, R3的R_s和R_p为1.49和0.23,比R2更接近厌氧氨氧化反应理论值.废铁屑在水中发生腐蚀,降低DO并提高pH值,且R2,R3污泥中铁含量分别为对照组的1.64倍和1.93倍,废铁屑不仅改善了厌氧氨氧菌的生境,还满足了其对铁元素的需求.高通量测序结果显示,在20~50d的运行过程中, R1,R2,R3中优势厌氧氨氧化菌属Candidatus_Kuenenia的相对丰度分别增加-1.05%,0.14%和0.96%,废铁屑的投加促进了厌氧氨氧化菌在低温下的生长,且间接投加促进效果更为显著.     

长江河口潮区界溶解态无机氮磷的通量

利用长江河口潮区界大通站的水质资料探讨了溶解态无机氮、磷浓度和通量的变化。结果表明：NO3^-,NH4^ ,DIN的浓度随季节变化不明显，而NO2^-,PO4^3-的浓度是枯季较高、洪季较低：1963－1984年间，NO3^-,NO2^-,NH4^ 、DIN和PO4^3-的年平均浓度分别为17．1、0．43、7．1、24．7、0．19μmol/L，平均通量分别为33．1、0．51、3．67、10．5和0．54kg/s，平均年通量分别为104.44,1.61,11.56,33.1和1.70万t；溶解态无机氮、磷的通量由于受到流量的影响而在年内分配不均匀，其中NO3^-,NO^-,NH4^ DIN和PO4^3-在洪季的通量分别为全年的72．9％，58．1％、69．2％、71％和68．3％；NO3^-,NO2^-，DIN年通量的总变化趋势是稳步上升，且与氮肥使用量成高度显著的正线性相关。1998年，NO3^-,NO2^-,NH4^ 和PO4^3-的年通量分别为477．3，1．356、3．097和2．296万t。     

氮添加对不同坡度退化高寒草甸土壤真菌多样性的影响

为明确不同坡度退化高寒草甸土壤真菌多样性对外源氮添加的响应规律,选取三江源区果洛州不同坡度退化程度相近的高寒草甸,进行外源氮添加试验,探讨不同氮添加水平：低等量氮添加（LN,2 g ·m^-2）、中等量氮添加（MN,5 g ·m^-2）和高等量氮添加（HN,10 g ·m^-2）对不同坡度退化草地土壤真菌多样性的影响.结果表明：①土壤中真菌分布类群集中于子囊菌门（Ascomycota）、担子菌门（Basidiomycota）、被孢霉门（Mortierellomycota）和球囊菌门（Glomeromycota）,其中优势菌门为子囊菌门和担子菌门.子囊菌门、根肿黑粉门和油壶菌门等相对丰度在不同坡度间差异显著（P<0.05）.而同一坡度不同氮添加处理下真菌各门丰度变化差异均不显著.②优势属为被孢霉属和Archaeorhizomyces,它们对不同坡度和不同氮添加水平的响应无差异性.③已鉴定95个菌属在不同坡度间存在显著差异（P<0.05）.④一些相对丰度<1%的属在同一坡度不同水平氮添加间存在显著差异（P<0.05）.5 α和β多样性分析整体表现为在不同坡度和不同氮添加水平下土壤真菌群落无差异性.表明退化高寒草甸土壤真菌对外源氮添加的响应不敏感.     

浅析珠三角地区有机废气治理技术的开发应用

珠江三角洲地区大气污染最明显的特点就是臭氧浓度的升高导致大气氧化性增强,而挥发性有机化合物(VOCs)和氮氧化物是大气臭氧生成的重要前体物。珠三角地区工业体系发达,VOCs的生产及使用企业众多,由于VOCs的种类繁多,性质各异,排放条件多样,目前已经形成了一系列的VOCs废气实用治理技术。     

脱硝工艺的技术比较

对包括SCR和SNCR在内的各种脱硝技术进行了比较,分析了各种脱硝方法的使用条件和特点,同时对未来脱硝技术的发展进行了预估,得出了优先选择SCR和SNCR,并发展各种脱硝技术的结论,为脱硝技术的选择与使用提供了技术参考。