Study of Ni adsorption on NKF-6 zeolite

The adsorption of ⁶³Ni from aqueous solutions using NKF-6 zeolite was investigated by a batch technique under ambient conditions. The adsorption was investigated as a function of contact time, pH, ionic strength, foreign ions, humic substances (FA/HA) and temperature. The kinetic adsorption was well described by the pseudo-second-order rate equation. The adsorption of ⁶³Ni on NKF-6 zeolite was strongly dependent on pH and ionic strength, and the adsorption of ⁶³Ni increased with increasing NKF-6 zeolite content. At low pH values, the presence of FA enhanced the adsorption of ⁶³Ni on NKF-6 zeolite, but the presence of HA had no drastic effect. At high pH values, the presence of FA or HA decreased the adsorption of ⁶³Ni on NKF-6 zeolite. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic parameters (i.e., ΔH⁰, ΔS⁰and ΔG⁰) for the adsorption of ⁶³Ni were determined from the temperature dependent isotherms at 293.15, 313.15 and 333.15 °K, respectively, and the results indicate that the adsorption reaction was favored at high temperature. The results suggest that the adsorption process of ⁶³Ni on NKF-6 zeolite is spontaneous and endothermic.     

NO2对二甲苯光氧化生成SOA及其吸光度影响

NO₂是大气中常见污染气体,影响大气二次有机气溶胶（Secondary organic aerosol,SOA）的形成.运用实验室烟雾箱模拟二甲苯大气光氧化反应过程,研究NO₂对二甲苯SOA生成量、光学特性和化学组成的影响.结果显示,NO₂促进二甲苯SOA的形成,NO₂浓度从0增长到900×10^-9,二甲苯SOA的质量浓度增长2倍左右,并且邻二甲苯SOA质量浓度大于对二甲苯SOA.这是因为邻位取代基相比于对位取代基更倾向于形成醛,有利于聚合反应形成低聚物,促进SOA形成.此外,NO₂浓度增加显著提高所生成SOA的单位质量吸光度（Mass absorption coefficients,MAC）,这是由于前体物邻二甲苯和对二甲苯化学结构不同,邻二甲苯所生成的含氮有机物具有更强吸光性,从而导致邻二甲苯SOA的MAC_{λ=365 nm}大于对二甲苯SOA的MAC_{λ=365 nm}.在线气溶胶质谱仪分析结果进一步显示：二者光化...     

不同C/P下AOA-SBR工艺磷形态转化规律及污泥特性

采用5组厌氧/好氧/缺氧(AOA)模式运行的SBR反应器, 考察不同C/P(120, 40, 24, 17, 13)下AOA-SBR系统磷形态转化规律及污泥特性.结果表明, 5组反应器的COD、TN、NH₄⁺-N去除效果均优于一级A标准.随着C/P的降低, 系统TP去除量逐渐提高.C/P小于24时, TP的去除效果开始变差且波动剧烈, 在C/P为40时系统TP去除效果最稳定, 平均去除率为99.22%.磷形态结果表明, 随着C/P的降低, 污泥中各项磷形态含量均有所升高.IP是TP最主要的磷形态, 不同C/P下IP占TP的含量相近(约96%).随着C/P的降低, NAIP、AP占污泥TP的含量与IP都呈先上升后下降的趋势, 而OP占污泥TP的含量保持下降趋势.生物有效磷(NAIP与OP之和)对污水除磷效果影响最大, C/P为40的系统中污泥中生物有效磷占比最高, 污水TP去除效果最好.污泥MLSS与SVI值随着C/P的降低而增大, C/P较低的系统有发生污泥膨胀的风险.高通量测序表明, 随着C/P的降低, 除Dechloromonas外, PAOs与DPB含量均有所下降, 污水TP去除效果较差且波动较大.     

炼化废水中COD与BOD_5相关性的探讨

为了及时掌握炼化废水的BOD5值，因此对COD与BOD5之间的相关性进行了探讨试验；COD与BOD5的测定采用国家标准方法，连续20d，用最小二乘法计算COD与BOD5的相关关系式；通过相关式由COD值可求出当天相应的BOD5值，为及时调整污水处理设施提供依据。     

河北省人为土地灾害及减灾对策

针对河北省人为土地灾害较重的特点，概述了灾害的类型、分布及其危害，分析了致灾原因，提出减轻灾害、谋求可持续发展的对策。     

Mn2+协同PDS对酸性蓝80的电催化降解性能研究

以酸性蓝80（AB80）模拟染料废水,采用E-Mn²⁺-PDS协同体系,对AB80进行电催化降解实验.对比了不同催化体系的降解效率,探讨了Mn²⁺与PDS浓度、pH值和电流密度等单因素对E-Mn²⁺-PDS体系电催化降解效率的影响,对E-Mn²⁺-PDS体系中的氧化性物质、AB80的分解产物及其在体系中的矿化程度进行了研究,并分析了降解机理.结果表明：与其他催化体系比较,E-Mn²⁺-PDS协同体系最优,对AB80的降解率高达99.9%.pH值是最主要的影响因素,pH=3时,E-Mn²⁺-PDS协同体系的降解率为99.6%;协同体系中的氧化性物质包括硫酸根自由基（SO₄^-×）,羟基自由基（HO×）,还有活性Mn³⁺;AB80在协同体系中经过多种化学反应形成11种主要分解产物.协同体系对AB80的矿化率是直接电催化的2.6倍;降解机理为：PDS被Mn²⁺与电流激发出SO₄^-×后,SO₄^-×与水反应生成HO×,然后HO×与电流将Mn²⁺氧化为活性Mn³⁺,三种氧化性物质协同降解污染物.     

铜绿微囊藻生长代谢的密度依赖性特征及分子机制

蓝藻水华是淡水湖库普遍面临的水环境问题,目前水华形成机制研究大多关注外界环境因素而忽略了藻类自身及群体的关键调节作用.因此,本文以初始细胞密度为单一变量,考察了不同初始细胞密度条件下蓝藻生长、营养物质利用、叶绿素、藻毒素、胞外分泌物随时间的变化情况.结果发现,初始细胞密度会影响铜绿微囊藻的环境适应性和生长情况,当接种密度≥1×10⁶ cell·mL^-1,铜绿微囊藻适应期消失,初始细胞密度从1×10⁵ cell·mL^-1增加至1×10⁷ cell·mL^-1,最高细胞密度增加了68%,生长速率提高了21%,并且叶绿素变化趋势与生长情况一致.胞外分泌物随初始细胞密度增加而逐渐增加,有利于蓝藻细胞聚集成膜.当初始细胞密度较低（1×10⁵ cell·mL^-1）时,单细胞藻毒素分泌量反而增加,以提高蓝藻的环境适应能力.在高初始密度（1×10⁷ cell·mL^-1）条件下,铜绿微囊藻主要通过上调丙酮酸代谢和碳代谢,促进细胞生长增殖.因此,细胞密度是影响铜绿微囊藻生长代谢的重要因素,在蓝藻水华形成过程中可能发挥重要作用,水华防治应当在细胞密度较低的阶段进行.     

Emission characteristics of offshore fishing ships in the Yellow Bo Sea, China

Maritime transport has been playing a decisive role in global trade. Its contribution to the air pollution of the sea and coastal areas has been widely recognized. The air pollutant emission inventories of several harbors in China have already been established. However,the emission factors of local ships have not been addressed comprehensively, and thus are lacking from the emission inventories. In this study, on-board emission tests of eight diesel-powered offshore fishing ships were conducted near the coastal region of the northern Yellow Bo Sea fishing ground of Dalian, China. Results show that large amounts of fine particles( 0.5 μm, 90%) were found in maneuvering mode, which were about five times higher than those during cruise mode. Emission rates as well as emission factors based on both distance and fuel were determined during the cruise and maneuvering modes(including departure and arrival). Average emission rates and distance-based emission factors of CO, HC and PM were much higher during the maneuvering mode as compared with the cruise mode. However, the average emission rate of Nitrous Oxide(NOx) was higher during the cruise mode as compared with the maneuvering modes. On the contrary, the average distance-based emission factors of NOxwere lower during the cruise mode relative to the maneuvering mode due to the low sailing speed of the latter.     

Effect of phosphate releasing in activated sludge on phosphorus removal from municipal wastewater

Aluminum and ferric salts are commonly used in municipal wastewater treatment plants(WWPTs) for phosphorus(P) removal. In this study, on-site jar tests were conducted to determine the removal of different P species from the fresh samples in the presence and absence of activated sludge(AS) with different doses of alum, poly-aluminum chloride,and ferric chloride at different p H. The soluble P(SP) concentration in the samples was about 0.63 mg/L. When the mixed liquor containing AS was treated with 8 mg/L of Al, SP could be reduced to 0.13 mg/L, while it was reduced to 0.16 mg/L with only 1 mg/L of Al after sedimentation removal of AS from sample. Chemical analysis determined that AS contained 59.8 mg-P/g-TSS and 43.8 mg-Al/g-TSS and most of the P was associated with the aluminum hydroxide. We discovered that the phosphate in the AS could readily be released from it, which was mainly responsible for ineffective removal of P to low levels in mixed liquor even with very high alum dose. This study provides new insight into the behavior and fate of P in the wastewater treatment plants that use alum to enhance P removal in the final effluent.     

中国南方喀斯特地区石灰土容重传递函数模型及影响因素研究

土壤容重(BD)数据的缺失严重影响了我国南方喀斯特地区土壤碳储量的估算,亟待利用已有数据来构建容重传递函数模型(PTFs)。本文利用南方喀斯特分布省份的石灰土土壤普查数据,首次较为系统地研究了喀斯特地区石灰土的容重传递函数模型及影响因素。研究结果表明:(1)国内外已发表的容重PTFs对中国南方喀斯特地区非地带性石灰土的适用性较差,需要进行优化或重新建立新的容重函数预测模型;(2)优化后的模型Shiri et al(2017)~*、韩光中等(2016)-a~*和韩光中等(2016)-c~*的预测精度得到明显提高;(3)基于石灰土亚类建立的PTFs具有很高的拟合度和预测精度,比优化模型更加适宜于喀斯特石灰土的土壤容重预测;(4)不同石灰土亚类容重预测的影响因素存在差异,其中土壤有机质含量是石灰土容重预测的关键因素,与各亚类土壤的BD都有很高的相关性;(5)土壤容重传递函数模型的适用性不仅与研究区域有关,同时也与研究的土壤类型有关。建议在今后喀斯特地区土壤容重预测模型研究中充分考虑地域差异性和土壤类型因素。