基于APCS-MLR和PMF模型的赤泥堆场周边耕地土壤重金属污染源解析

为探究重庆某赤泥堆场周边耕地土壤重金属污染特征和来源,分析土壤中8种重金属元素（Cd、Cr、Hg、Ni、Pb、As、Cu和Zn）含量和空间分布特征,利用单因子污染指数法和内梅罗综合污染指数法对土壤重金属污染特征进行评价,并在相关性分析的基础上采用APCS-MLR和PMF模型定量解析重金属来源.结果表明,除土壤Cr外,其他7种重金属元素含量均值均高于重庆市土壤背景值.土壤重金属整体处于中度污染水平,其中Cd、Hg和As为中度污染,Pb、Cu、Ni和Zn为轻度污染.土壤Cr、Ni、Pb、Cu和Zn空间分布格局相似,相互间呈极显著正相关（P < 0.01）;Cd、Hg和As空间分布特征有较大差异,且相互间相关性不显著（P > 0.05）.源解析表明,研究区土壤重金属来源较为复杂,APCS-MLR和PMF模型均能解析出4种相同的污染源,分别为赤泥堆场渗滤排放和自然来源、火力发电排放源、农业活动与自然来源和有色金属冶炼排放源.两种模型源解析结果差异较小,APCS-MLR模型中4种污染源贡献率分别为51.8%、18.0%、15.9%和14.3%,而在PMF模型中分别为45.9%、12.8%、21.5%和19.8%.     

赤泥基纳米零价铁对多金属污染土壤修复效果

为实现重金属复合污染（Pb、Zn、Cu和Cd）土壤同步修复,构建土壤-小白菜体系,探究赤泥（RM）、纳米赤泥（RMn）以及纳米赤泥负载纳米零价铁（RMn-nZVI）这3种不同赤泥基钝化剂对Pb、Zn、Cu和Cd复合污染土壤的修复效果与机制,并考察土壤中Pb、Zn、Cu和Cd形态分布对小白菜积累Pb、Zn、Cu和Cd的控制作用.结果显示,3种钝化剂施用可显著提高土壤pH,降低土壤酸可提取态（F1）Pb、Zn、Cu和Cd含量,增加残渣态（F4）含量,最终钝化效果表现为：RMn-nZVI>RMn>RM.此外,3种钝化剂显著降低了小白菜可食用部分Pb、Zn、Cu和Cd的积累,其中RMn-nZVI处理下降低程度最高,Pb、Zn、Cu和Cd含量分别下降35.11%、45.05%、69.52%和59.63%.结果表明,纳米赤泥负载纳米零价铁新型钝化材料在重金属复合污染土壤修复领域具有一定的应用潜力.     

基于FBM法追踪秦皇岛海域赤潮迁移扩散

在Delft3D-FLOW模型模拟水动力的基础上,基于FBM粒子追踪法建立和验证赤潮迁移扩散模型.模拟了秦皇岛海域潮流和风生流,分析了风生流对赤潮迁移扩散的作用,对比分析了FBM法、拉格朗日法和常规布朗运动法在赤潮迁移扩散模拟中的特性,测试了模型Hurst指数的敏感性并得出其在赤潮模拟中的合理取值范围.主要结论为：①秦皇岛海域的赤潮主要随潮流的涨落而往复移动,一个涨落潮周期内赤潮的净迁移距离较小;②秦皇岛海域夏季潮流较弱,但风对赤潮迁移具有一定影响,易产生东北向风生流,导致赤潮更易往东北方向迁移;③Hurst指数较明显地影响粒子云的扩散范围,Hurst指数取0.80±0.03能比较真实地模拟秦皇岛海域赤潮的迁移扩散;④FBM法可模拟赤潮的non-Fickian扩散现象,使其模拟的粒子云扩散范围和分布形状明显优于拉格朗日法和常规布朗运动法.     

Adsorptive removal of Drimarine Red HF-3D dye from aqueous solution using low-cost agricultural waste: batch and column study

This study involves the utilisation of peanut husk for the removal of Drimarine Red HF-3D dye from aqueous solutions. Batch study experiments were conducted with native, HNO₃-treated and Na-alginate-immobilised peanut husk biomass. Maximum dye removal (95.24 mg/g) was obtained with HNO₃-treated biomass. The experimental data were successfully explained with a pseudo-second-order kinetic model for all types of biosorbents. The equilibrium data fitted well to the Freundlich adsorption isotherm model. A thermodynamic study was also carried out to check the nature of the adsorption process. A fixed-bed column study for Drimarine Red HF-3D was carried out to optimise the effect of bed height, flow rate and initial dye concentration using peanut husk biomass. The column study showed that biosorption capacity increased with the increase in initial dye concentration and bed height, but decreased with increased flow rate. Data for Drimarine Red HF-3D were in very good agreement with the bed depth service time model. Fourier transform infrared analysis demonstrated the involvement of different functional groups in dye biosorption. These results showed that peanut husk biomass possessed good potential for the removal of Drimarine Red HF-3D from aqueous solution.     

Roe and red deer as bioindicators of heavy metals contamination in north-western Poland

The present paper examines the degree of environmental contamination in areas covered by the Natura 2000 programme, located in north-western Poland, with selected heavy metals based on their concentration in target organs of roe and red deer. Lead, cadmium, copper, iron, and zinc concentrations were determined by inductively coupled plasma–atomic emission spectrometry. Residues of lead and cadmium were found in most of the analysed samples of roe and red deer organs The concentration of cadmium in the organs of the animals studied was much higher than that of lead. The median for Pb in liver and kidneys was 0.055 and 0.092 μg/g dry weight (d.w.) in roe deer, and 0.067 and 0.081 μg/g d.w. in red deer, respectively. The median for liver and kidney cadmium was 0.770 and 6.139 μg/g d.w. in roe deer, and 0.422 and 6.365 μg/g d.w. in red deer, respectively. Our study has demonstrated that this area is laden with lead and cadmium. This is evidenced by the fact that maximum permissible levels of these elements in the organs of red and roe deer, which were used as bioindicators of environmental contamination, were exceeded.     

离子交换膜应用于光/电/化学协同催化反应器

在光/电/化学协同催化反应器中,以离子交换膜代替盐桥连通阴、阳两室,以30 mg/L的甲基红溶液为目标降解物,考察了不同连通方式、初始pH和阴极电位对反应的影响. 结果表明:甲基红在阳离子膜型反应器中的表观反应速率常数明显高于盐桥型及阴离子交换膜型反应器,这是由于阳离子交换膜可以及时有效地将阳极室中产生的H+转移至阴极室中参与阴极反应. 甲基红在阳离子膜型反应器中的去除率随溶液初始pH的增高而降低,随阴极电位的增加先增大后减小,最佳反应条件为pH=2.0～3.0,阴极电位(-E_c)=0.6 V.      

灵菌红素对有害藻类的除藻活性研究

研究了沙雷氏菌的天然产物灵菌红素对引起海洋赤潮和淡水水华的有害藻类的除藻活性和光解性质.结果表明,5.0μg/mL灵菌红素能够在24h内将新月菱形藻、中肋骨条藻、水华鱼腥藻和微小平列藻培养液中的藻类全部杀死,除藻活性高达100%.5.0μg/mL灵菌红素在30000lx光强下36h完全分解,不会给自然环境带来二次污染.     

加压溶氧光催化反应器降解活性艳红X-3B

探讨了加压溶氧条件对活性艳红X-3B的降解与脱色的作用,考察了加压条件下pH值,TiO2投加量及温度等对活性艳红X-3B降解的影响.结果表明,加压条件与常压条件下变化趋势基本一致.加压充氧有助于活性艳红X-3B的降解与脱色,加压充N2对反应基本没有作用,说明增加活度不是关键因素,加压使溶液中溶解氧增加是导致活性艳红X-3B降解与脱色的主要原因.光催化降解过程,发色基团最易被打碎,60min内降解效果显著,而萘环和苯环降解效果不十分明显.CODCr的降解与色度的褪除成正相关,脱色率越高,COD的降解率也越高.     

高效絮凝剂制备的前期浸取研究

我国油田多采用絮凝剂处理含油污水。为得到高效、廉价的絮凝剂,使用赤泥最优化制备聚合氯化铝铁。通过化学分析法和X射线衍射分析,得出赤泥中铝﹑铁元素含量。正交实验结果表明:影响Fe溶出的因素由强到弱依次为盐酸用量系数﹑反应温度﹑目数和反应时间,最佳浸出条件为目数80～120、液固比5.5、反应温度95℃、反应时间3.5h。     

亚热带土壤氮素反硝化过程中N2O的排放和还原

将采集于江西鹰潭的45个发育于不同成土母质和不同利用方式的土壤样本,在密闭、淹水、充N2的严格厌氧条件下进行了28d的培养试验(30℃),在培育过程中,定期测定NO3--N(加入量为200mg·kg-1)含量和培养瓶上部空间N2O的含量变化.实验结果表明,N2O含量(N)随培养时间t的变化可用方程N=A×(1-exp(-k1 t))-B×exp(k2 t)拟合(A表示培养过程中N2O总排放量;B为常数;k1和k2分别为N2O排放速率常数和还原速率常数,拟合值和实测值之间回归方程的决定系数R2=0.84±0.11).不同土壤之间培养期间N2O总排放量(A)的变异可以用培养7d内被反硝化的NO3--N量和N2O排放率(A值与28d内被反硝化的NO3--N总量的百分比)进行解释(R2=0.829,p＜0.01).被反硝化的NO3--N量则主要受土壤有机碳含量或有机氮矿化量控制,N2O排放率则随k2的增大而呈指数下降(p＜0.01).由此可见,在该实验条件下,还原N2O能力强的土壤,在相同量的NO3--N被反硝化的情形下,排放的N2O可能较少.但影响k2值的主要因素还有待进一步研究.