黑龙江省土地沙漠化控制作用重要性评价

根据黑龙江省沙漠化现状和评价方法与指标对黑龙江省的生态系统进行沙漠化控制作用重要性评价,评价结果将黑龙江省沙漠化控制重要地区分为4级,即极重要、中等重要、比较重要和一般重要四个级别,确定了它们的分布区域.这一成果为黑龙江省生态功能区划和区域可持续发展奠定了基础,提供了科学依据.     

氨基淀粉絮凝剂合成工艺

以玉米淀粉为原料，以环氧氯丙烷(ECH)作交联剂，合成高交联淀粉(CS)；以HC1O4作引发剂，以ECH作醚化剂，合成中间产物3-氯-2-羟基丙烯基交联淀粉(CHCS)，在碱性条件下再与乙二胺反应，得到对重金属离子具有螯合能力的氨基淀粉(CAS)。最佳醚化条件：CS含水质量分数为7．0％，ECH与CS的摩尔比为2．5：1，HC104与CS的摩尔比为0．03：1，反应时间为8h，反应温度为95℃。以该法制得的CAS对废水中铜离子的去除能力为78．5mg／g。     

红枫湖水库水体富营养化及浮游植物群落结构特征

2008-2009年通过对红枫湖水库浮游植物及环境因子进行采样调查,并运用综合营养状态指数对红枫湖水库营养状态进行评价.研究结果显示,红枫湖水库浮游植物全年以蓝藻、绿藻为主的优势种群落,且在2008-2009年经常性局部发生蓝藻水华:冬、春季节主要是水华束丝藻(Aphanizomenon flos-aquae)的蓝藻水华;夏季主要是微囊藻属(Microcystis)蓝藻水华;秋季浮游植物主要是颗粒直链藻(Melosira)和小环藻属(Cyclotella)为主的硅藻类群,未出现水华现象.通过综合营养状态指数计算得红枫湖水库水体水质处于富营养化状态.     

印染污泥连续过滤压榨过程

研究了连续进料情况下,过滤压力、压榨起始点和压榨压力对印染污泥过滤效果的影响。研究发现,提高过滤压力可以改善过滤效率,缩短过滤时间,但滤饼含水率并无明显影响。过滤压力0.6 MPa下过滤2.3 h后滤液量达到2 900 g,此时过滤进入压密阶段。结果表明,若适当提前压榨,可在滤饼含水率变化不大的情况下显著缩短过滤时间,且该污泥在滤液量为2 750 g时开始压榨,滤饼含水率仅提高约1%,而过滤时间缩短为原来的87%(2 h)。进一步研究压榨压力对污泥脱水的影响,发现提高压榨压力也可以提高滤液流速,降低滤饼含水率,但因为在高压下更容易发生絮体破裂成细微粒子等现象,使过滤介质堵塞或滤饼中的一些孔变成盲孔,所以过高的压力不仅不能起到提高压榨效率的作用,反而会使滤饼含水率有所上升,且该污泥的最佳压榨压力为2.5 MPa。     

pH对铜在黄土中吸持及其形态的影响

用黄土为吸持剂,以石英砂作对照,研究了pH对铜的吸持及形态的影响,并用MINTEQA2模型对铜离子的沉淀形态进行了理论计算.结果表明:无论吸持剂是石英砂还是黄土,随着pH的升高,吸持曲线都分为3区:低pH微吸持区、中pH吸持增长区和高pH强吸持区.含沙量一定,随着铜液初始浓度的增加,吸持量、可交换态含量和碳酸盐结合态含量均增加;铜液初始浓度一定,随着含沙量的增加,吸持量、可交换态含量和碳酸盐结合态含量均减少.MINTEQA2模型计算结果表明,对于不同的吸持剂,铜离子发生沉淀的比例及沉淀的物质组成是不同的;以黄土为吸持剂时,中pH范围内随着含沙量的增加铜离子沉淀的比例减少.     

Factors influencing the contents of metals and As in soils around the watershed of Guanting Reservoir, China

Topsoil samples from 61 sites around the Guanting Reservoir,China,were measured for Cu,Zn,Cr,Ni,Cd,Pb and As concentrations.The mean concentrations of Cu,Zn,Cr,Ni,Cd,Pb and As were 16.8,59.4,37.8,18.3,0.32,20.1 and 8.67 mg/kg dry weight,respectively.Factors that influence the dynamics of these metals in soils around the watersheds of Beijing reservoirs were examined.The influence of atmospheric deposition,land use,soil texture,soil type and soil chemical parameters on metal contents in soils was investigated.Atmospheric deposition,land use and soil texture were the important factors affecting heavy metal residues.Soil type and soil chemical parameters were also involved in heavy metal retention in soils.The data provided in this study are considered crucial for reservoir remediation,especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.     

矸石基X型分子筛对水中Co2+、Cu2+、Cd2+和Cr3+的去除

以煤矸石为原料,采用碱熔后水热合成法制备X型分子筛并进行XRD、SEM、BET和Zeta电位分析。研究其对水中Co2+、Cu2+、Cd2+和Cr3+4种离子的吸附性能,包括吸附等温线、吸附动力学以及初始金属离子浓度、pH值对吸附性能的影响。所合成的矸石基X型分子筛的BET比表面积为676.02 m2/g,微孔孔容为0.263 cm3/g。吸附实验表明,矸石基X型分子筛能有效去除上述4种离子,同时实现煤矸石的资源化和金属离子的去除。4种离子的平衡吸附量均随初始浓度的增大而增大,相同条件下平衡吸附量的大小顺序为Cd2+>Cr3+>Cu2+>Co2+。准二级动力学模型能很好地描述4种离子的吸附动力行为。Langmuir模型对Co2+、Cu2+和Cd2+吸附的拟合较Freundlich模型高,说明其主要表现为物理吸附过程。4种离子的吸附速率均由液膜扩散和颗粒内扩散共同控制。     

Evaluation of soil washing process with carboxymethyl-β-cyclodextrin and carboxymethyl chitosan for recovery of PAHs/heavy metals/fluorine from metallurgic plant site

Polycyclic aromatic hydrocarbons(PAHs)/heavy metals/fluorine(F) mixed-contaminated sites caused by abandoned metallurgic plants are receiving wide attention. To address the associated environmental problems,this study was initiated to investigate the feasibility of using carboxymethyl-β-cyclodextrin(CMCD) and carboxymethyl chitosan(CMC) solution to enhance ex situ soil washing for extracting mixed contaminants. Further,Tenax extraction method was combined with a first-three-compartment model to evaluate the environmental risk of residual PAHs in washed soil. In addition,the redistribution of heavy metals/F after decontamination was also estimated using a sequential extraction procedure. Three successive washing cycles using50 g/L CMCD and 5 g/L CMC solution were effective to remove 94.3% of total PAHs,93.2% of Pb,85.8% of Cd,93.4% of Cr,83.2% of Ni and 97.3% of F simultaneously. After the 3rd washing,the residual PAHs mainly existed as very slowly desorbing fractions,which were in the form of well-aged,well-sequestered compounds; while the remaining Pb,Cd,Cr,Ni and F mainly existed as Fe–Mn oxide and residual fractions,which were always present in stable mineral forms or bound to non-labile soil fractions. Therefore,this combined cleanup strategy proved to be effective and environmentally friendly.     

Crystallization and Mechanical Properties of Recycled Poly(ethylene terephthalate) Toughened by Styrene–Ethylene/Butylenes–Styrene Elastomer

Recycled poly(ethylene terephthalate) (R-PET) was blended with 15–30 wt% of styrene–ethylene/butylenes–styrene (SEBS) block copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Effects of nucleation and toughening of the elastomers were evaluated systematically by study of morphology, crystallization, thermal and mechanical properties of the blend. The addition of 30 wt% SEBS promoted the formation of co-continuous structure of the blend and caused the fracture mechanism to change from strain softening to strain hardening. Addition of SEBS-g-MA resulted in significant modification of phase morphology and obviously improved the impact strength. The compatibilization reaction of PET with SEBS-g-MA accelerated the crystallization of PET and increased the crystallinity. The shifts in glass transition temperature of PET towards that of SEBS-g-MA and the higher modulus for R-PET/SEBS-g-MA (70/30) blend found by DMA are also indications of better interactions under the conditions of compatibilization and interpenetrating structure.     

Preparation and microwave absorbing properties of the core-nanoshell composite absorbers with the magnetic fly-ash hollow cenosphere as core

Electromagnetic (EM) wave pollution has become the chief physical pollution for environment. The core-nanoshell composite absorbers with magnetic fly-ash hollow cenosphere as core and nanocrystalline magnetic material as shell were prepared by high-energy ball milling. The results of X-ray diffraction analysis (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and vector network analyzer (VNA) analysis indicated that perfect-crystalline nanomagnetic material coating was gotten with a particle size of 12 nm, being dried at 60°C for 2 hr and calcined at 400°C for 1 hr after ball milling. The exchange-coupling interaction happened between ferrite of cenosphere and soft magnet γ-Fe₂03 coating, it enhances magnetic loss of composite absorbers. In the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the core-nanoshell composite absorbers can achieve ?30 dB, it is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption.