Preferential binding between intracellular organic matters and Al13 polymer to enhance coagulation performance

Coagulation is the best available method for removing intracellular organic matter (IOM), which is released from algae cells and is an important precursor to disinfection by-products in drinking water treatment. To gain insight into the best strategy to optimize IOM removal, the coagulation performance of two Al salts, i.e., aluminum chloride (AlCl₃) and polyaluminum chloride (PACl, containing 81.2% Al₁₃), was investigated to illuminate the effect of Al species distribution on IOM removal. PACl showed better removal efficiency than AlCl₃ with regard to the removal of turbidity and dissolved organic carbon (DOC), owing to the higher charge neutralization effect and greater stability of pre-formed Al₁₃ species. High pressure size exclusion chromatography analysis indicated that the superiority of PACl in DOC removal could be ascribed to the higher binding affinity between Al₁₃ polymer and the low and medium molecular weight (MW) fractions of IOM. The results of differential log-transformed absorbance at 254 and 350?nm indicated more significant formation of complexes between AlCl₃ and IOM, which benefits the removal of tryptophan-like proteins thereafter. Additionally, PACl showed more significant superiority compared to AlCl₃ in the removal of < 5?kDa and hydrophilic fractions, which are widely viewed as the most difficult to remove by coagulation. This study provides insight into the interactions between Al species and IOM, and advances the optimization of coagulation for the removal of IOM in eutrophic water.     

Effects of protein properties on ultrafiltration membrane fouling performance in water treatment

Protein-like substances always induce severe ultrafiltration (UF) membrane fouling. To systematically understand the effect of proteins, regenerated cellulose UF membrane (commonly used for protein separation) performance was investigated in the presence of bovine serum albumin (BSA) under various water conditions. Results showed that although trypsin enhanced the membrane flux via proteolysis, catalysis took a long time. Membrane fouling was alleviated at high solution pH and low water temperature owing to the strong electrostatic repulsion force among BSA molecules. Both Na⁺ and Ca²⁺ could increase membrane flux. However, Ca²⁺ played a bridging role between adjacent BSA molecules, whereas membrane fouling was alleviated via a hydration repulsion force with Na⁺. The order of influence on membrane fouling was as follows: Ca²⁺ concentration > Na⁺ concentration > pH > temperature > trypsin concentration. Furthermore, a polyvinylidene fluoride UF membrane experiment showed that Ca²⁺ could reduce the fouling induced by BSA. Thus, the differences in UF membrane performance will have application potential for alleviating UF membrane fouling induced by proteins during water treatment.     

石灰、羟基磷灰石、秸秆生物炭对烟草吸收镉的影响

烟草是我国重要经济作物且极易吸收镉(Cd),如何降低烟草Cd含量已引起广泛关注。通过盆栽实验,在Cd(0.83 mg·kg^(-1)和12 mg·kg(-1)和12 mg·kg^(-1))污染土壤中添加2 g·kg(-1))污染土壤中添加2 g·kg^(-1)或16 g·kg(-1)或16 g·kg^(-1)石灰(Ca(OH)_2)、羟基磷灰石(HAP)或秸秆生物炭,分析3种钝化材料对土壤Cd的钝化效率及烟草Cd吸收的降低效率。结果表明：(1)种植60 d后,施用16 g·kg(-1)石灰(Ca(OH)_2)、羟基磷灰石(HAP)或秸秆生物炭,分析3种钝化材料对土壤Cd的钝化效率及烟草Cd吸收的降低效率。结果表明：(1)种植60 d后,施用16 g·kg^(-1)石灰或HAP均显著(P<0.05)提高土壤pH值,轻微(0.83 mg·kg(-1)石灰或HAP均显著(P<0.05)提高土壤pH值,轻微(0.83 mg·kg^(-1)Cd)、中度(12 mg·kg(-1)Cd)、中度(12 mg·kg^(-1)Cd)Cd污染土壤pH值分别提高1.98～2.84和1.99～3.06;(2)3种钝化材料均使土壤Cd有效态含量降低,其中,16 g·kg(-1)Cd)Cd污染土壤pH值分别提高1.98～2.84和1.99～3.06;(2)3种钝化材料均使土壤Cd有效态含量降低,其中,16 g·kg^(-1)石灰使土壤Cd有效态含量降低69.7%～71.5%;(3)生物炭(2 g·kg(-1)石灰使土壤Cd有效态含量降低69.7%～71.5%;(3)生物炭(2 g·kg^(-1)和16 g·kg(-1)和16 g·kg^(-1))显著(P<0.05)提高烟草生物量且降低烟草Cd含量,轻微、中度Cd污染土壤烟草生物量分别提高5.07倍～18.5倍和5.00倍～29.7倍,烟草根、茎、叶Cd含量分别降低68.7%～74.6%、32.1%～50.7%、70.2%～82.5%(轻微)和68.7%～74.6%、51.4%～59.3%、33.2%～46.5%(中度),根、茎、叶Cd富集系数亦显著降低,根(Cd_(0.83):122降至31～38.1,Cd_(12):24.7降至12.2～16.8),茎(Cd_(0.83):203降至35.6～60.6,Cd_(12):41.7降至17.6～23.1),叶(Cd_(0.83):247降至100～120,Cd_(12):48.6降至26.0～32.5);(4)溶液吸附实验发现,HAP和生物炭均通过表面吸附Cd(-1))显著(P<0.05)提高烟草生物量且降低烟草Cd含量,轻微、中度Cd污染土壤烟草生物量分别提高5.07倍～18.5倍和5.00倍～29.7倍,烟草根、茎、叶Cd含量分别降低68.7%～74.6%、32.1%～50.7%、70.2%～82.5%(轻微)和68.7%～74.6%、51.4%～59.3%、33.2%～46.5%(中度),根、茎、叶Cd富集系数亦显著降低,根(Cd_(0.83):122降至31～38.1,Cd_(12):24.7降至12.2～16.8),茎(Cd_(0.83):203降至35.6～60.6,Cd_(12):41.7降至17.6～23.1),叶(Cd_(0.83):247降至100～120,Cd_(12):48.6降至26.0～32.5);(4)溶液吸附实验发现,HAP和生物炭均通过表面吸附Cd⁽²⁺⁾,且该吸附过程符合准二级动力学模型,表明在钝化过程中这2种钝化剂与Cd(2+),且该吸附过程符合准二级动力学模型,表明在钝化过程中这2种钝化剂与Cd⁽²⁺⁾发生键能结合的化学吸附。研究表明,3种钝化剂在同等剂量水平下,生物炭提高烟草生物量且降低Cd吸收最显著,可优先选作降低烟草Cd吸收的钝化剂。     

Probabilistic health risk assessment for residents exposed to potentially toxic elements near typical mining areas in China

Environmental Science and Pollution Research - Public health problems caused by toxic elements in mining areas have always been an important topic worldwide. However, existing studies have focused...     

资源禀赋对区域可持续发展的影响研究

资源禀赋是一个国家或地区社会-经济-环境系统稳态存在与发展的物质基础,在现今中国乃至世界得到了广泛关注。由于长期以来,资源禀赋受到人类经济活动的极大影响和干扰,资源禀赋的流动和利用受到市场运行机制的控制,这一现象已经成为影响和制约各个区域可持续发展的关键。首先基于对资源禀赋有关定义的理解,列举分析了资源禀赋消耗的时空差异,并且指出传统市场经济体制对资源禀赋的作用与影响以及其与区域可持续发展的核心关系。考虑到资源禀赋对于区域可持续发展的重要作用,针对区域间经济活动影响资源分配、利用效率等问题,文章提出:1)运用系统生态学视角重新考虑与评估经济活动所造成的严峻生态环境形势;2)兼顾经济效益、社会效益与生态效益多重发展目标,建立合理的资源开发与分配政策目标;3)实施循环经济促进可持续发展,提高资源禀赋合理利用效率;4)通过多角度、系统化评价方法,开展资源禀赋形成、组成及价值核算等相关研究;5)在国民经济发展过程中建立资源禀赋消耗的约束性指标。从以上5个方面出发,提出了在生态文明的起点下有效促进资源禀赋合理开发利用与区域协调发展的对策建议。     

长江流域鲤鱼和鲟鱼的模型建立与剂量率估算研究

针对长江流域两种典型淡水鱼类-鲤鱼和鲟鱼,通过实验对两种鱼类各部分的浓集性质进行了研究,并建立了相关的的简化解剖学模型(区分了不同组织和器官部分)和外照射环境模型;用蒙特卡罗方法模拟源器官和环境水体对靶器官的能量沉积,采用某厂址水体数据以及实验得到的鱼类不同部位的浓集系数,估算了上述两种鱼类在该环境中所受到的内外照射剂量率,并与ERICA方法进行了比较分析.     

Nitrobenzene biodegradation ability of microbial communities in water and sediments along the Songhua River after a nitrobenzene pollution event

More than 100 t of nitrobenzene (NB) and related compounds were discharged into the Songhua River,the fourth longest river in China,because of the world-shaking explosion of an aniline production factory located in Jilin City on November 13,2005.As one of the efforts to predict the fate of residual NB in the river,NB biodegradation abilities by microbes in the water and sediments from different river sections were evaluated systematically.The results indicated that microbial communities from any section ...     

Nitrobenzene biodegradation ability of microbial communities in water and sediments along Songhua River after a nitrobenzene pollution event

More than 100 t of nitrobenzene (NB) and related compounds were discharged into the Songhua River, the fourth longest river in China, because of the world-shaking explosion of an aniline production factory located in Jilin City on November 13, 2005. As one of the efforts to predict the fate of residual NB in the river, NB biodegradation abilities of the microbes in the water and sediments from different river sections were evaluated systematically. The results indicated that microbial communities from any section of the river, including one section at the upper stream of the NB discharging point, had the ability to biodegrade NB under aerobic (for river water samples) conditions at 22±1℃ or anaerobic (for sediment samples) conditions at 10±1℃. NB degradation rates of microbial communities in the downstream sites were markedly higher than those in the upstream site, indicating that the NB degradation abilities were enhanced because of the pollution of NB. Aerobic degradation got neglected at a temperature of 10℃ or lower. The production of nitrosobenzene and aniline during the aerobic biodegradation suggested the existence of at least two different NB degradation pathways, and the occurrence of the catechol-2,3-dioxygenase (C23O) gene and the significant decrease of dissolved organic carbon (DOC) indicated that NB could be mineralized under aerobic conditions. Although it was a fact that the river have frozen-up during the NB accident, it was speculated that biodegradation was not the major process responsible for the decrease of NB flux in the river.     

Development and application of innovative technologies for drinking water quality assurance in China

The continuously deteriorating quality of source water is threatening the safety of drinking water in China. Various efforts have been made to update water treatment processes to decrease the pollution problems of drinking water, such as protection of drinking water sources, enhancement of conventional treatment processes, and development of new or advanced treatment technologies. This paper reviews a variety of protection and remediation methods for drinking water sources, development and application of drinking water treatment technologies, new technologies for special pollutants removal from groundwater, and the latest research progress on water distribution systems in China.     

工业化高速发展时期广州市的碳收支变化初步研究

为了了解我国发达城市在工业化高速发展进程中CO2的收支状况,以广州市为研究对象,首次估算了其从1990年到2003年每年的净固碳量和释碳量,并分析了其变化趋势。研究结果表明,这13年间广州市的净固碳量与总释碳量年均增长率分别为0.93%与7.16%;到2003年,其净固碳量为2.57Mt,而其总释碳量已达到22.79Mt,其中约70%的释碳量源于化石燃料的燃烧。工业化高速发展时期也是释碳量日益高于净固碳量的时期,两者之间差距的逐步加大,已经使得广州市目前的碳收支状况发展到了极不平衡的程度。而逐年递增的人口和以化石燃料为主的能源消费是造成广州市碳收支严重失衡的主要原因。