Sorption and desorption behavior of benzidine in different solvent-sediment systems

The sorption and desorption behavior of benzidine in eight solvent-sediment systems were studied using a batch method. The solvents tested included deionized water (DI), calcium chloride solution (CaCl2), sodium hydroxide solution (NaOH), acetonitrile (ACN), a mixture of acetonitrile and ammonium acetate solution (ACN-NH4OAc), methanol (MeOH), ammonium acetate solution (NH4OAc) and hydrochloric acid solution (HCl). Three sets of sorption isotherm experiments were conducted separately in these eight solvents with seven days, three weeks, and two months of contact times, respectively. The results demonstrated nonlinear benzidine sorption phenomena in all eight solvents with higher sorption affinities for sediment sites in the aqueous solvents than in the organic solvents. The results from the desorption experiments revealed that the benzidine desorption efficiencies in the solvents decreased in an order, which was approximately the reverse order of its sorption affinity. Results also suggested that hydrophobic partitioning and covalent binding processes dominated in the desorption experiments, while cation exchange process had little effect on desorption of benzidine. A three-stage model was subsequently applied to simulate the desorption data in the selected solvents of ACN, ACN-NH4OAc and NaOH, respectively. The rapidly desorbing initial fractions were about 0.13-0.20, 0.15-0.26, and 0.18-0.25 for ACN, ACN-NH4OAc and NaOH, respectively. Finally, the sorbed concentrations of benzidine in slowly and very slowly desorbing domains in the selected solvents were correlated with the maximum sorption capacities obtained from the Langmuir sorption isotherm model. The maximum sorption capacities of benzidine were found to be comparable to the amount of benzidine residing in the slowly and very slowly desorbing domains.     

负载型固体超强酸催化剂上的烷基化反应

本文利用Ｐｔ／ＳＯ＾２－４／ＺｒＯ２,Ｐｔ／ＷＯ３／ＺｒＯ２负载于大比表面Ａｌ２Ｏ３固体强酸催化剂,进行异丁烷和丁烯的烷基化反应。     

DNA同源性分析最终确定新疆中华根瘤菌（Sinorhizobium xinjiangensis）为一独立种

针对S.xinjiangensis分类地位的争议,从新疆再次分离获得34株快生大豆根瘤菌,在16SrDNAPCR-RFLP分析和SDS全细胞蛋白电泳分群的基础上,进行了16SrDNA全序列相似性和DNA同源性分析.所测4个菌株和S.fredii模式菌株USDA205的16SrDNA全序列有很高的相似性.而DNA同源性分析说明新分离的菌株代表与原定的S.xinjiangensis为一个DNA同源群.其模式菌株CCBAU110与S.fredii的2株参比菌株USDA194、2048之间的DNA同源性分别为31.5%和28.7%.S.fredii的模式菌株USDA205与新分离的菌株代表及原定的S.xinjiangensis的模式菌株和2个参比菌株之间的DNA同源性为20.8%～39%,远低于70%.属于种水平上的差异.按照国际细菌分类委员会以DNA同源性≥70%且△Tm≤5℃作为定种的标准,S.xinjiangensis是Sinorhizobium属中不同于S.fredii的一个独立的种.表3参20     

利用下水管网系统净化城市污水的中试研究

采用充纯氧及固定化细胞技术在２７５．５ｍ市政下水管网系统中进行了日处理１５００ｍ＾３污水的中试。对单纯充氧、充氧加固定化细胞二种工艺及不同 氧量刊物了比较研究。结果表明,在加固定化细胞条件下,充纯氧（Ｖ（Ｏ２）：Ｖ（Ｈ２Ｏ）＝０．０７８：１）可使流过此段管道的污水的污染物去除６５％以上,基本达到国家污水综合排放二级标准。     

论可持续发展视野中的农村社会支持

本文阐述了如何可持续发展观来指导农村社会支持,并提出在农村社会支持活动中,引进社会保险、社会服务、生态保护和心理培育等新的机制,运用综合性评价指标体系对各种农村社会支持项目及其结果进行经济效益、社会效益和心理效益三个方面的分析。     

山东省主要河流中抗生素污染组成及空间分布特征

采用固相萃取-液相色谱/串联质谱法研究了山东省境内四大流域主要河流中抗生素污染组成及空间分布特征,涉及我国用量最大的6类共20种抗生素。结果表明:20种抗生素均有检出,且大环内酯类、喹诺酮类和四环素类抗生素整体检出浓度较高。就流域而言,半岛诸河流域抗生素污染较小,平均总质量浓度61.4 ng/L;海河流域、小清河流域和淮河流域相对较为严重,平均总质量浓度分别为232、175、118 ng/L。抗生素空间分布呈现一定的规律,检出浓度较高的点位主要集中在人口密集区下游,抗生素污染与周边生活污水、养殖企业废水和城市污水处理厂排水密切相关,而且抗生素组成可从一定程度上反映出污染来源。     

Carbon emission reduction and cost–benefit of methane digester systems on hog farms in China

Three different sizes of hog farms were selected to analyze the carbon emissions reduction and the cost–benefit of three methane digester systems. The sizes of the digesters are 2,200, 2,200 and 800 m³, respectively. The sales of slaughter hogs from them are 50,000, 35,000 and 10,000 head, respectively. The carbon emissions reductions were 5,237, 4,017, and 1,334 tons, respectively. The results show that while the methane digester systems have a significant effect on carbon emissions reduction, it is difficult to operate the systems sustainably. If the carbon emissions reduction can be traded at high enough prices in the carbon offset markets, then the systems will be profitable and sustainable. Newly established China's domestic carbon offset market could provide this possibility, but more government support is needed. In addition, this study shows that scale economies make the digester adoption relatively more profitable for larger farms than smaller ones.     

油气勘探开发建设项目环境影响评价管理探讨

油气勘探开发建设项目存在滚动开发的特点,在近年来的环境影响评价管理实践中引发较多矛盾。文章分析了目前油气勘探开发建设项目环评管理中存在的环评要求不清晰、分类管理需细化、审查尺度不统一等问题,并从界定建设项目类型、明确环评开展时间和要求、明确环评文件编制类型、界定项目重大变更四个方面提出了改进油气项目环评管理的建议。     

羟胺强化Fenton反应降解水中氯酚

针对传统Fenton体系Fe（Ⅲ）累积和pH适用范围过窄等缺点,采用羟胺（HA）强化的HA-Fenton体系,以对氯苯酚（4-CP）为目标污染物进行降解实验,考察了Fe（Ⅱ）投加量、H2O2投加量、HA投加量和溶液pH等工艺条件对4-CP去除率的影响。实验结果表明：HA-Fenton体系适用于酸性和弱酸性条件,最佳pH范围为3.0~4.0;在溶液pH为3.0、Fe（Ⅱ）投加量为5.0 μmol/L、H2O2投加量为0.4 mmol/L、HA投加量为0.20 mmol/L的最适条件下,反应10 min, 4-CP去除率达64.25 %。     

高含盐废水脱盐处理技术研究进展

综述了几种常见的高含盐废水脱盐处理技术的发展历程、工艺原理、优缺点及目前的研究进展,分析了热分离、膜分离、电渗析、离子交换、电吸附、微生物脱盐等方法的优缺点,展望了未来废水脱盐工艺的发展方向。指出：脱盐方法将根据各类水体的水质特点更加精细化;多种脱盐技术联合应用也是今后废水脱盐的发展方向。