粉末活性炭对水中农药的吸附性能研究

研究了粉末活性炭对2,4-滴、呋喃丹、甲萘威和莠去津的吸附过程和吸附规律以及投炭量和水质对粉末活性炭吸附性能的影响。结果表明,粉末活性炭能有效去除4种农药;吸附规律符合Freundlich吸附等温线和Langmuir吸附等温线;吸附时间为30 min时,去离子水中的去除率已达到80%以上;随着投炭量的增加,去除率提高,粉末活性炭的吸附容量降低;在不同水质条件下,粉末活性炭的吸附等温线可能不同,因此在应急处理中,首先应该确定该水质下的吸附等温线,然后求出投炭量。     

应用改进分光光度法测定多组分水样的COD

提出改进分光光度法测定多组分水样的化学需氧量(COD)。以多种物质的吸光曲线回归方程,将实时测得的水样吸光度分解成多种物质的吸光度,利用多元一次方程进行求解并计算出COD的方法。新方法对含邻苯二甲酸氢钾和丙烯酰胺水样测量的COD,误差平均值为+5.0%,对更多组分的水样测量紫外吸光度误差较大,通过引入修正系数修正后误差大幅下降,10次测量的变异系数约0.5%,精密度较好。通过分析新方法实际运用时存在的优劣之处,提出综合高锰酸盐指数(CODMn)来弥补其测量上不足的新型废水监测模式,以实现监测的快速测量、低耗能、低污染和实时性。     

改性TiO2光催化降解三苯甲烷类污染物

以硫酸钛为原料采用水热法制备了掺Fe3+TiO2晶体粉末,采用X射线衍射仪(XRD)对样品的结构进行了表征。在可见光条件下,用溴酚蓝、甲基绿、甲基蓝、孔雀石绿、甲基紫和碱性品红等6种典型三苯甲烷类化合物为目标降解物,研究了以自制的掺Fe3+TiO2晶体粉末对它们的催化降解作用。实验结果表明,制备的掺Fe3+TiO2晶体属于锐钛矿型。6种化合物的光催化降解反应遵循拟一级动力学规律,且可用Langmuir-Hinshelwood(L-H)动力学模型描述,其表观反应速度常数(k)的大小顺序为:溴酚蓝<甲基绿<甲基蓝<孔雀石绿<甲基紫<碱性品红,大小变化次序与其半衰期t1/2成反比,并从分子结构上对它们的降解规律进行定性解释。     

零价纳米铁去除ReO4-的研究

采用NaBH4与FeSO4液相还原法制备零价纳米铁,用制得的零价纳米铁去除ReO4-,然后用分光光度法在610 nm处测定ReO4-的吸光度,从而计算零价纳米铁对ReO4-的去除率.结果表明:(1)ReO4-初始浓度越低,反应速率越快,对最终ReO4-去除率影响不大.(2)pH对反应产生很大影响,将溶液pH调至中性或微...     

水丝蚓生物扰动对沉积物磷释放的影响

研究了不同投放密度和不同环境条件下水丝蚓的生物扰动对沉积物磷释放的影响.研究表明,水丝蚓的生物扰动作用对沉积物磷释放有明显的促进作用,与未投放水丝蚓的空白组相比,当水丝蚓密度为1 ind./cm2和2 ind./cm2时,上覆水中总磷的平均浓度分别提高了190%和230%.温度的提高,会加大水丝蚓生物扰动对磷释放的影响...     

Cu~(2+)改性活性炭的制备及其去除废水中CN~-的研究

以活性炭为载体负载溶液中的 Cu~(2+),Cu~(2+)改性活性炭对溶液中 CN~-的去除效果较好。Cu~(2+)改性活性炭的最佳制备条件:活性炭加入量为1 g,质量浓度为5 g/L 的 CuSO_4溶液加入量为50 mL,溶液 pH 为4,负载时间为5.0 h。在此最佳条件下活性炭的最大 Cu~(2+)负载量为25.90 mg(以每克活性炭计)。Cu~(2+)改性后活性炭的 CN~-去除率明显提高,由22.10%提高至94.07%。Cu~(2+)改性活性炭吸附CN~-的最佳实验条件:溶液 pH 为12～13,吸附时间为9 h。Cu~(2+)改性活性炭对 CN~-的饱和吸附量为22 mg/g。Mg~(2+),K~+,Ca~(2+),Cl~-,SO_4~(2-),CO_3~(2-),AsO_3~-对 Cu~(2+)改性活性炭的 CN~-去除率基本没有影响。Cu~(2+)改性活性炭的动态吸附实验表明,开始一段时间流出液中 CN~-含量几乎为零,远低于国家排放标准(0.5 mg/L)。     

A Novel Hyperbranched Polymeric Flocculant for Waste-Water Treatment

Cationic hyperbranched oligomer poly(N-acryloyl-1,2-diaminoethane hydrochloride) (HADE) was firstly synthesized by Michael addition reaction. And then, a series of cationic flocculants poly(acrylamide/N-acryloyl-1,2-diaminoethane hydrochlorides) (PAM-HADEs) with hyperbranched structure was prepared from HADE as macro-monomer and acrylamide (AM). The structures of PAM-HADEs were characterized by Fourier transform infrared spectrometry, ¹H and ¹³C nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). And the properties were systematically evaluated by intrinsic viscosity, zeta potential and hydrodynamic radius. The mechanism of the cationic hyperbranched copolymer used in water treatment was extensively studied via a jar test in which the transmittance of the supernatant, settling time, and average floc size were used to evaluate the flocculability. Compared with the linear flocculant poly (acrylamide/liner-N-acryloyl-1,2-diaminoethane hydrochloride) (PAM-LADE), the novel hyperbranched polymeric flocculants exhibited outstanding flocculability which were reflected by shorter settlement time, high transmittance and large floc size. The primary cause that PAM-HADEs owned excellent flocculability is the more stretching configuration and less chains entanglement of PAM-HADEs in waste-water due to their hyperbranched structure compared with that of the linear PAM-LADE which exhibited curly coil configuration. On the other hand, abundant and exposed cationic terminal groups of PAM-HADEs originated from their hyperbranched structure also hint higher flocculation capacity. At optimum dosages of the polymer, the transmittance of the supernatant is less at low and high pH values, indicating that the natural pH (pH 7.29) of the suspension is the most appropriate pH for the flocculation.     

Long-term recovery narratives following major disasters in Southeast Asia

Regional Environmental Change - Most studies of major disasters focus on the impacts of the event and the short-term responses. Some evaluate the underlying causes of vulnerability, but few...     

Developing a framework for integrating local and scientific knowledge in internationally funded environment management projects: case studies from Kien Giang Province,Vietnam

Local and scientific knowledge, when adequately and properly integrated, produces enormous benefits for natural resource management in comparison to a single knowledge system being used. Adequate and proper integration has major constraints that include ineffective use of the integrated knowledge, thoroughly inclusive processes, and true public participation. A six-stage framework is developed using the results and conclusions of two case studies regarding sustainable management of eroding mangrove-dominated muddy coasts in Vam Ray, Hon Dat district, Kien Giang Province, Vietnam. The framework does not stop with the creation of integrated knowledge, but should undergo a longer process. The new knowledge developed in this framework is the understanding gained and lessons learnt during the testing of products of multiple knowledge systems in a local context rather than products of integrated knowledge systems themselves. The Vam Ray framework promotes a high level of participation, effective use of products of multiple knowledge systems, maximum integration of local and scientific knowledge, local ownership, and sustainability. Therefore, the Vam Ray framework adds a new dimension to the literature in relation to integration of local and scientific knowledge in natural resource management.     

Macroinvertebrate community in relation to water quality and riparian land use in a substropical mountain stream,China

Exploring how water quality and land use shape the benthic macroinvertebrate community composition is of widespread interest in biodiversity conservation and environmental management. In this study, we investigated the structures of benthic macroinvertebrate assemblages and their environmental controls in terms of water quality and riparian land use in the Jinshui River, China. We carried out three campaigns including wet season (August 2009), dry season (November 2009), and normal season (April 2010) based on the hydrological regime in Jinshui basin. The result showed that macroinvertebrate assemblage variations were better explained by water quality factors than land use based on variance partitioning procedure. The land use of 2 km upstream from the sampling sites had explained more variation than that of the whole riparian zone in upstream catchment on macroinvertebrate community, and land use of 2 km upstream also had more interactions with water quality. Canonical correspondence analysis (CCA) indicated that the elements or nutrient of magnesium (Mn), selenium (Se), strontium (Sr), silicon (Si), dissolved inorganic nitrogen (DN), sulfur (S), total organic carbon (TOC), and total nitrogen (TN) in water exhibited a strong relationship with macroinvertebrate assemblages. However, the variance in water quality explained by land use was lower than that explained by water quality in rivers using redundancy analysis. Our study suggested that proximate factors (i.e., water quality) were more important to interpret the macroinvertebrate community compared to ultimate factors (i.e., land use) for macroinvertebrate assemblages in river system.