酸碱改性对氧化铁脱硫剂脱硫性能影响的研究

通过酸碱改性制备了酸式和碱式2种不同表面性质的常温氧化铁脱硫剂,并采用FT-IR技术对其表面酸碱性质和净化硫化氢废气活性进行了研究.结果表明,表面酸碱件质不同的脱硫剂其脱硫反应行为也不同,在脱硫过程中硫化氢氧化生成的硫酸及亚硫酸会影响脱硫剂的表面酸碱性质,造成酸式脱硫剂的表面酸性更强,从而抑制了硫化氢分子在酸式脱硫剂表...     

用于地表水反硝化的纤维素碳源选择研究

为了选取合适的天然有机物作为反硝化细菌碳源用于解决地表水中NO3--N污染问题,以江南大学校内湖水为接种物,选取8种天然纤维素碳源在缺氧状态不同的处理方式下对60 mg/L NO3--N的降解特性进行研究。结果表明,以碱处理作为预处理可明显提高反硝化速率,碳源脱氮率均在96%以上（树皮除外）。2种处理方式中均有NO2--N累积,部分碳源释放NH4＋-N并发生DNRA反应,树叶在2种处理中脱氮效果均较好。结合各碳源脱氮率、耗碳源量以及处理成本,选取基本处理的香樟叶作为最佳纤维素碳源。     

畜禽养殖污水中高效氨氮降解菌的筛选、鉴定及生长条件研究

从养殖污水中分离纯化得到1株高效氨氮降解菌,对其进行形态特征、生理生化、16S rDNA序列分析以及最佳生长条件研究,并将菌株投入养殖污水降解污水中的氨氮。结果表明：AN4菌株在NH4＋-N初始质量浓度为50 mg/L的条件下,24 h内的氨氮降解率为92.5%;初步鉴定该菌株为苍白杆菌属（Ochrobactrum sp.）,菌株的16S rDNA序列在Gen-Bank的登录号为GU345782;AN4菌株在装液量为60.64 mL,pH为7.06,葡萄糖为6.0 g/L的条件下培养,菌株的降解率可以达到94.28%;菌株对养殖污水中氨氮的降解率为12.3%。苍白杆菌菌属能够降畜禽养殖污水中的氨氮还未见报道,AN4菌株的筛选获得为生物降解养殖污水中的氨氮又提供了一种新型菌株。     

Determination of 226Ra and 228Ra in slightly mineralised natural waters

A radiochemical method for simultaneous separation of ²²⁶Ra and ²²⁸Ra from natural waters by precipitating the radionuclides in the form of chromates that have low solubility in weak acetic acid has been described. For analytical purposes the change into soluble state was achieved through high-temperature melting the radium chromates precipitate with sodium and potassium carbonates at certain ratios. The chemical yield for radium-226 amounted to 87.1 ± 1.4% at the efficiency of counting 92.8 ± 0.7%. Calculated in series of 20 parallel determinations, reproducibility of the method was 7%. The chemical yield in separating radium-228 made up 63.8 ± 1.1%.     

废陶瓷的表面改性及其吸附性能

以十八烷基三甲氧基硅烷为改性剂,对废陶瓷进行表面改性,使改性后的废陶瓷粒具有疏水性表而.考察了改性废陶瓷粒对工业废水的有机物去除作用以及对染料废水的脱色作用.实验结果表明,在改性废陶瓷粒径为1 -4 mm、改性废陶瓷加入量为500 g/L、吸附时间为30 min的条件下,造纸废水的COD去除率可达42％,亚甲基蓝溶液的...     

抑制城市内涝的有效措施:雨水资源化

频繁发生的城市内涝灾害,成为城市建设管理工作中讫待解决的的重大问题。地面明流超量、城市大量蓄水场地被侵占、城市路面下渗能力降低是引发内涝的主要原因。城市雨水资源化是从雨水源头做起,增加雨水收集利用量,优化排蓄组合,增大渗透量。既有效地实现雨水资源化,又达到减排与缓排洪水流量,抑制城市内涝的目的。     

Inconsistency and comprehensiveness of risk assessments for heavy metals in urban surface sediments

Numerous indices have been developed to assess environmental risk of heavy metals in surface sediments, including the total content based geoaccumulation index (I_geo), exchangeable fraction based risk assessment code (RAC), and biological toxicity test based sediment quality guidelines (SQGs). In this study, the three indices were applied to freshwater surface sediments from 10 sections along an urbanization gradient of the Grand Canal, China to assess the environmental risks of heavy metals (Cu, Pb, Zn, Cd, and Cr) and to understand discrepancies of risk assessment indices and urbanization effects regarding heavy metal contamination. Results showed that Cd, Zn, and Pb were the most enriched metals in urban sections assessed by I_geo and over 95% of the samples exceeded the Zn and Pb thresholds of the effect range low (ERL) of SQGs. According to RAC, Cu, Zn, Cd, and Cr had high risks of adversely affecting the water quality of the Grand Canal due to their remarkable portions of exchangeable fraction in surface sediment. However, Pb showed a relative low risk, and was largely bounded to Fe/Mn oxides in the urban surface sediments. Obviously, the three assessment indices were not consistent with each other in terms of predicting environmental risks attributed to heavy metals in the freshwater surface sediments of this study. It is recommended that risk assessment by SQGs should be revised according to availability and site specificity. However, the combination of the three indices gave us a comprehensive understanding of heavy metal risks in the urban surface sediments of the Grand Canal.     

The adsorption of short single-stranded DNA oligomers to mineral surfaces

We studied the adsorption of short single-stranded deoxyribonucleic acid (ssDNA) oligomers, of approximately 30 nucleotides (nt) in length, of varying sequence, adenine + guanine + cytosine (AGC) content, and propensity to form secondary structure, to equal surface area samples of olivine, pyrite, calcite, hematite, and rutile in 0.1 M NaCl, 0.05 M pH 8.1 KHCO₃ buffer. Although the mineral surfaces have widely varying points of zero charge, under these conditions they show remarkably similar adsorption of ssDNA regardless of oligomer characteristics. Mineral surfaces appear to accommodate ssDNA comparably, or ssDNA oligomers of this length are able to find binding sites of comparable strength and density due to their flexibility, despite the disparate surface properties of the different minerals. This may partially be due charge shielding by the ionic strength of the solutions tested, which are typical of many natural environments. These results may have some bearing on the adsorption and accumulation of biologically derived nucleic acids in sediments as well as the abiotic synthesis of nucleic acids before the origin of life.     

利用响应曲面法研究蓖齿眼子菜克藻效应的环境因子

水生植物的克藻效应受到多种环境因子的影响.利用响应曲面法,对影响沉水植物蓖齿眼子菜对铜绿微囊藻克藻效应的3个环境因子进行实验研究.通过对曲面模型分析,得出蓖齿眼子菜对铜绿微囊藻的藻细胞个数的相对抑制率在温度、光照强度、全盐莒3个环境因子分别为24℃、2 891 lx、4 407 mg/L时达到最大值.曲面模型经过方差分...     

响应面法优化西兰花总黄酮提取工艺的研究

利用响应面法优化西兰花总黄酮的提取工艺条件。在预试验的基础上,以乙醇为溶剂,提取西兰花总黄酮。选取提取温度、提取时间及液固比、乙醇浓度4个因素进行Box-Benhnken中心组合设计,利用响应面分析法对提取工艺参数进行优化。结果表明,西兰花总黄酮的提取工艺为:乙醇浓度90%,液固比30∶1,提取温度85.28℃,提取时间1.82h;预测值为0.887%,实际得率为0.853%,两者较接近,说明Box-Behnken设计结合响应面分析法可很好地对西兰花总黄酮提取工艺进行优化。