Characteristics and sources of heavy metal pollution in desert steppe soil related to transportation and industrial activities

Environmental Science and Pollution Research - A study area was selected from the industrial region of Gaoshawo Town, Yanchi County, Ningxia, to explore the level of heavy metal pollution in desert...     

环境样品中多氯联苯分析的新进展

综述了环境中多氯联苯（ＰＣＢｓ）分析方法的新进展，阐述液液，液固萃取，精制富集待测物，色谱，色／质鉴定，对多维气相色谱改进ＰＣＢｓ分离，色谱／富里叶红外，保留指数区分ＰＣＢｓ异构件进行讨论。     

臭椿治理铜污染土壤的实验测定

臭椿（Ailanthus altissima）具有很强的抗逆性，能适应多种不良的环境，在中国广泛分布，是一个很有潜力的修复铜污染土壤的物种。通过种植实验检验臭椿修复铜污染土壤的能力。臭椿实生苗移植于4种不同铜的质量分数（0、29、57和86 mg·kg-1）、3种不同的施肥处理（对照、有机肥、无机肥）的土壤，经过5周种植，测量臭椿根、茎、叶的铜含量及各部分生物量。试验结果表明：1）土壤铜浓度的差异对臭椿生长没有显著影响；2）土壤施肥处理显著影响臭椿生长，施加无机肥生长最佳，对照次之，施有机肥最低；3）随土壤铜浓度增加，臭椿根、茎、叶的铜含量增加，然后趋缓，但似乎根、茎、叶的铜含量变化不同步；4）土壤肥力对臭椿茎、叶的铜含量没有显著影响，但对根的铜含量影响显著，施加无机肥的根中铜含量显著增加。臭椿经过短短5周处理，其体内铜的质量分数就到达120μg·g-1，且铜在各组织中的分布比为根：茎：叶＝2?1?2。相比一些超富集铜的草本植物，臭椿的铜吸收能力尚有距离，但其高生长、高抗逆性、深根系的特点，加之其对其他众多重金属元素的吸收能力使得这个物种在生物修复污染土壤方面的作用不容小觑。本研究丰富了治理土壤重金属污染的物种库，为进一步寻找重金属“超富集植物”，更有效的治理土壤污染提供一定的参考价值。     

浙江农村生活污水处理设施水污染物排放标准修订需求分析与建议

以浙江《农村生活污水处理设施水污染物排放标准》(DB33/973—2015)的修订为研究切入点,对比了现行标准与国家和浙江农村生活污水治理的管理要求,分析了浙江农村生活污水处理现状并梳理其他省(自治区、直辖市)标准情况.研究发现DB33/973—2015已不符合浙江实际情况且不能满足浙江对农村生活污水的管理需求,必须开...     

Research on energy structure and development strategy from 2010 to 2015 in Qingdao,China

With the fast development of Qingdao’s economy, the energy consumption is increasing significantly. In this paper, based on the energy statistic data in Qingdao area from 2010 to 2015, energy consumption structure was analyzed, indicating the existence of single energy structure; that is, coal, petroleum, and natural gas are dominant in the area. Thus, some issues between energy supply and demand have been brought. To solve present problem, we put forward to formulate the development strategy of energy, including energy savings, the exploitation of petroleum and natural gas resources, the development and utilization of renewable energy sources, and energy policy. It is worthy of mentioning that, according to the geological investigation, the shale gas may be abundant in Qingdao area and the gas resource amount estimated is huge. This is our first finding, important for developing unconventional energy and adjusting the energy structure in Qingdao in the future. Therefore, we suggest that Qingdao government should take action to develop local new energy resources for satisfying the energy demand.     

UV/Fenton氧化处理PVA溶液

为了对PVA(聚乙烯醇)溶液中PVA去除进行研究,采用UV/Fenton氧化技术氧化处理PVA溶液。探究了UV/Fenton氧化PVA溶液的影响因素,主要研究了反应时间、初始pH、H2O2/COD和H2O2/Fe2+,获得了各个因素对PVA溶液COD去除率的影响规律以及PVA溶液经处理后的B/C(BOD5/COD)变化规律。实验表明,随着H2O2/COD投加比的增加,COD去除率不断增加,B/C呈现先增加后减少的现象;随初始pH的增加,COD去除率以及B/C均呈现先增加后减少的现象;随着H2O2/Fe2+不断增加,COD去除率以及B/C均呈现先增加后减少的现象;随反应时间的增加,COD去除率以及B/C均增加之后趋于稳定。当H2O2/COD=1.5,pH=4,H2O2/Fe2+物质的量之比为10,T=30 min时COD去除率效果比较好,经过处理之后溶液的 B/C由0.1 增至0.6,可生化性提高,为后续生物处理创造条件。     

硝酸钙缓释颗粒原位修复黑臭底泥的作用机制及其应用

为解决水体中沉积底泥的内源污染释放问题,亟需高效底泥修复技术。硝酸盐为底泥微生物的电子受体,可通过反硝化作用氧化底泥的黑臭物质,是极具潜力的底泥修复剂。为探明硝酸盐在实际工程中的修复效果和潜在问题,结合实验室模拟和实际修复工程,分析了投加硝酸钙颗粒对黑臭底泥原位修复的环境过程。结果表明,投加硝酸钙缓释颗粒产品能显著提高底泥氧化还原势能（以Fe(II)/Fe(III)表征）,促进黑臭物质转化,实际硫化物氧化率达85.2%,使得底泥由黑转黄,最终实现修复目标。同时,硝酸钙修复底泥的过程不受上覆水水质影响,且因修复过程消耗了大量底泥耗氧物质（硫化物和易降解有机质）,使水体整体复氧能力提高。另一方面,钙离子的加入使磷素以较为稳定的钙磷形态转化,能改变水相总磷的归趋（TP_SedCaN < TP_CK,p < 0.01）。然而,由于反硝化产气增加了底泥孔隙,增加了泥水界面表面积和污染物扩散通量,故在修复初期存在底泥污染物和硝酸盐向其浓度较低的水相扩散,产生了一定风险,而实际上这也有利于泥相污染物的加速释放。因此,建议在可控工程段,联合覆盖法阻断污染物扩散或联合曝气加速水相污染物氧化,以确保在控制风险的前提下达到最优的底泥修复效果。     

北京市2014年PM2.5质量浓度变化特征

利用北京市发布的PM2.5质量浓度数据,分析了2014年PM2.5日平均质量浓度变化情况,以及全年平均日变化特征、分季节的日变化特征、分星期的日变化特征。结果表明：北京市2014年PM2.5污染较为严重,但相比往年有所减弱,其中2月和10月污染最为严重,5-6月及8-9月污染较轻。全年平均日变化呈现“W”型,白天在07：00和15：00存在2个谷值,峰值出现在10：00,21：00-03：00 PM2.5污染在一天中最为严重。秋冬季节的日变化趋势相似,其夜间PM2.5质量浓度明显高于白天。春季和夏季的日变化与全年平均日变化差别很大。分星期的日变化曲线变化趋势存在较大差异,但峰值和谷值出现的时间基本一致。     

Thermal and Rheological Properties of Poly(lactic acid)/Low-Density Polyethylene Blends and Their Supercritical CO<Subscript>2</Subscript> Foaming Behavior

Low-density polyethylene (LDPE) was employed to improve the thermal and rheological properties as well as the supercritical CO₂ foaming behavior of poly(lactic acid) (PLA) through melt mixing and batch foaming method, due to its long branched chain structure, moderate crystallization capacity and good foamability. The differential scanning calorimetry and polarized optical microscope results showed that the introduction of LDPE had a slight effect for promoting the crystallization of PLA. An important synergistic effect on the rheological properties of PLA/LDPE blends was found through rotational rheometer. With the content of LDPE, the size of spherical LDPE dispersion phase became bigger gradually, which was observed by scanning electron microscope (SEM). A very interesting cellular morphology evolution from flower-like cellular structure to complex cellular structure and then to mono-porous cell structure was found in the SEM images of the PLA/LDPE blending foams with the foaming temperature at 95 °C. The effect of blending ratio and foaming temperature on the cellular morphology and foaming parameters was investigated.     

The Effect of Composite Nucleating Agent on the Crystallization Behavior of Branched Poly (Lactic Acid)

Composite nucleating agent (CNA) consisting of zinc oxide as a crystallization promoter and phenylphosphonic acid zinc salt (PPZn) as an heterogeneous nucleation agent was employed to improve the crystallization behaviors of branched poly (lactic acid) (B-PLA) which was prepared by use of multi-functional epoxy-based chain extender (CE). The differential scanning calorimeter results showed that the crystallinity and crystallization temperature of prepared B-PLA/CNA were higher than that of linear poly (lactic acid) (L-PLA) and B-PLA at a high cooling rate. The corresponding phenomena of heterogeneous nucleation of B-PLA/CNA were observed by means of polarized optical microscope. The crystalline mechanism research results show that the degradation reaction and chain extending reaction were occurred simultaneously after the addition of CE and CNA into the PLA, PPZn as an effective nucleation points could increase the nucleation density and the degraded short molecular chains with higher chain mobility would improve crystal growth during the crystallization of the branched PLA. Non-isothermal cold crystallization kinetics of various B-PLA with different content of CNA was studied. The corresponding result showed that the crystallinity and crystallization rate increased obviously with the CNA content greater than or equal to 5phr, as well as the crystallization time decreased. The similar experimental results of non-isothermal and isothermal melt crystallization kinetics also showed that CNA had a significant impact on crystallization behavior of B-PLA.