防污漆中活性物质海洋环境风险评估关键技术探讨

防污漆中的活性物质对海洋生态环境和人类健康造成的潜在风险受到日益广泛的关注,一些发达国家已建立了针对活性物质海洋环境风险评估的技术体系,但我国相关研究目前尚属空白。综述了防污漆活性物质海洋环境风险评估的研究背景、相关法规、技术标准和发展现状,针对环境风险评估的2个重要组成部分(危害性评估和暴露评估)中的关键技术进行了探讨。在危害性评估中,重点分析和比较了受试生物物种的选择原则、生态毒理数据的要求以及预测无效应浓度的推导方法和应用范围;在暴露评估中,系统阐述了活性物质在水环境中释放速率的计算及修正方法、环境浓度的预测模型、现有的暴露场景及其局限性等。本文以期为我国开展防污漆活性物质海洋环境风险评估提供研究基础和科学依据,并提出了今后的研究重点和方向。     

Montmorillonite-Cu(II)/Fe(III) oxides magnetic material as adsorbent for removal of humic acid and its thermal regeneration

In this work, the adsorption features of montmorillonite and the magnetic properties of Cu(II)/Fe(III) oxides were combined in a material to produce magnetic adsorbent, which can be separated from the medium by a simple magnetic process after adsorption. The magnetic material is effective for the removal of humic acid. At pH 6.1, 96% removal was observed from 4.4 mg l(-1) humic acid solution containing 0.02 M NaCl. The adsorption is pH and ionic strength dependent. Adsorption is favored at lower pH values and dissolved NaCl can enhance the adsorption. The adsorption mechanism of humic acid to the magnetic material was suggested to be the ligand exchange reaction between carboxylic groups of humic acid molecules and the magnetic material surface. The magnetic material can be thermally regenerated. The temperature and time required to achieve good regeneration efficiency were determined to be 300 degrees C and 3 h, respectively. The regenerated adsorbent is still magnetic and approximately has as high specific saturation magnetization and good adsorption capacities as the as-prepared adsorbent.     

腐植酸对土壤改良作用探讨

土壤污染导致土壤的物理、化学和生物学性质发生改变,降低农作物的产量和质量,并最终危害人体健康。腐植酸具有良好的生理活性和吸收、络合、交换等功能,能较好的改良土壤。本文介绍了腐植酸的特性,腐植酸对重金属的污染的防治、对农药的增效及污染防治、对酸性土壤性能的影响及节水抗旱作用几方面内容,并对腐植酸的应用前景进行了展望。     

两级序批式生物膜法对厌氧消化液的处理研究

采用两级序批式生物膜法(SBBR)处理猪场废水厌氧消化液,考察了不同类型的填料以及填料的不同组合方式对污染物的去除效果。试验结果表明:组合3(1级反应器中投加碳素纤维填料,2级反应器中投加组合填料)COD去除能力较好,可达93.7%,组合1(1级,2级反应器中均投加碳素纤维填料)NH4+-N和TN去除率最高,分别为69.2%、70.4%;此外对运行过程中的DO浓度和pH值的变化情况进行监测,DO浓度受有机物降解和硝化反应的共同影响,pH值受曝气量的影响较多。因此,可以通过DO浓度和pH值来判断反应系统中污染物的变化情况和反应所处阶段。     

铝合金管缩为长锥管金属沿轴向延伸和壁厚变化规律的研究

对铝合金管在无芯棒情况下,缩为内锥为2.5°左右长锥管的金属沿轴向延伸率和壁厚变化规律进行研究,提出了相应的计算公式,可做为确定管坯长度和模具型腔尺寸的依据.     

Anaerobic oxidation of arsenite by bioreduced nontronite

The redox state of arsenic controls its toxicity and mobility in the subsurface environment. Understanding the redox reactions of arsenic is particularly important for addressing its environmental behavior. Clay minerals are commonly found in soils and sediments, which are an important host for arsenic. However, limited information is known about the redox reactions between arsenic and structural Fe in clay minerals. In this study, the redox reactions between As(III)/As(V) and structural Fe in nontronite NAu-2 were investigated in anaerobic batch experiments. No oxidation of As(III) was observed by the native Fe(III)-NAu-2. Interestingly, anaerobic oxidation of As(III) to As(V) occurred after Fe(III)-NAu-2 was bioreduced. Furthermore, anaerobic oxidization of As(III) by bioreduced NAu-2 was significantly promoted by increasing Fe(III)-NAu-2 reduction extent and initial As(III) concentrations. Bioreduction of Fe(III)-NAu-2 generated reactive Fe(III)-O-Fe(II) moieties at clay mineral edge sites. Anaerobic oxidation of As(III) was attributed to the strong oxidation activity of the structural Fe(III) within the Fe(III)-O-Fe(II) moieties. Our results provide a potential explanation for the presence of As(V) in the anaerobic subsurface environment. Our findings also highlight that clay minerals can play an important role in controlling the redox state of arsenic in the natural environment.     

深床过滤颗粒截留机理研究

对深床过滤过程中颗粒物与滤料之间的相互作用进行了理论分析,讨论了两者间的相互作用及影响因素对微絮凝深床过滤进行了中试研究,考察了1～l0μm粒径颗粒在500cm滤床中的截留情况,并连续65h监测滤柱水头损失的变化;在滤速为24m/h情况下,计算了1～10μm粒径颗粒所受的水流剪切力;利用理论分析,分别讨论了表面电位为-25mV及-125mV、粒径为1～10μm的颗粒与滤料之间的物理化学作用力.理论计算值对实验结果进行了很好的解释,说明可以通过颗粒与滤料间的作用力分析来研究均质滤料深床过滤运行规律.     

改性TiO2电极光电催化降解甲基橙

采用热分解法制备了掺杂Sn、Ru的改性TiO2光电极,研究了不同催化方式、溶液pH和外加偏压条件下改性TiO2光电极对甲基橙降解效果的影响。实验结果表明,当溶液pH为1.0、外加偏压0.7 V、反应时间120 min时,甲基橙降解率可达到92.5%。结合XRD、SEM和电化学阻抗等分析手段对TiO2光电极表面形貌及其催化机理进行了探讨。     

超滤膜系统污染物的形貌及组成分析

通过SEM、能谱、FTIR以及电感耦合等离子体质谱的分析方法对被污染超滤膜面的无机污染物、有机污染物和微生物进行了识别和分析。研究结果表明:超滤膜面无机污染物主要为Fe(OH)3、Cu(OH)2、Al(OH)3和Si等胶体物和少量CaSO4;有机污染物主要为多菌霉素类化合物;微生物可能富含铁类化合物。同时污染膜的清洗液分析结果说明该超滤膜污染物主要为无机胶体和有机物。     

恶臭气体生物处理技术研究进展

介绍了恶臭气体的种类、危害、特征、处理方法及原理；概述了恶臭气体的3种主要生物处理方法：生物滤池、生物滴滤池和生物洗涤器，介绍3种方法的工艺流程、技术特点及最新研究进展；提出了生物法处理恶臭气体亟需解决的问题及研究方向。