分光光度法测定总氮的准确度研究

采用碱性过硫酸钾消解紫外分光光度法测定水中总氮时常出现空白值偏高、样品平行性较差、实验准确度不高等现象.为此,从总氮的测定过程出发,探讨了影响总氮测定的主要因素,有利于提高水质总氮测定的准确度.结果表明,分析试剂纯度、实验用水水质、器皿的清洗程度等对总氮的测定均有一定影响,适当延长消解时间与提高消解温度也有利于降低总氮的空白值.因此可通过优化各实验条件来提高实验的准确性,以保证实验室的设备仪器、检测人员和环境等条件满足分析要求.     

大兴安岭地区生态产品优势分析研究

大兴安岭地区生态优良、环境优美、地域广阔、森林浩瀚,是特有的寒温带生态系统.近年来,省委省政府落实"绿水青山就是金山银山"发展理念,结合我省大小兴安岭地区生态优势,制定保护规划、实施天保工程,有效提高了森林生态系统的服务功能.大兴安岭地区何以能生产出优质的生态产品?以蓝莓产业和产品为案例进行分析,认为:大兴安岭地区整体生态优势明显,主要体现在具有"冬季寒冷自然休眠、夏季昼长温差大"的气候条件;具有"纬度高、山坡缓、河流繁、水量大"的地理特征;具有"气洁、水清、土沃、排放少"的环境优势;具有"林广、树密、生物多样、生境完整"的生态优势;具有"质优、安全、营养、环保"的产品品质.     

海水生物滤器氨氮沿程转化规律模型

生物滤器是海水循环水养殖系统中的核心水处理单元,其主要用于去除对养殖生物有害的氨氮、有机物等.本研究基于吸附原理和一级反应生物膜理论构建了氨氮在生物滤器中沿程转化规律的数学模型,并通过实验加以验证.实验所用生物滤器采用竹制空心生化球填料,装填高度为70 cm,在pH为7.1～7.6,DO为5～7 mg.L-1,气水比20∶1左右,有机负荷约为4g.(m3.h)-1,水力停留时间(HRT)为1 h条件下,生物滤器中氨氮的去除主要发生在填料高度0～10 cm处,10～70 cm处氨氮去除量很少.进水氨氮质量浓度的增大和水力停留时间的降低都会导致出水氨氮质量浓度增大.此外,模型对进水氨氮质量浓度较低时的沿程出水氨氮质量浓度具有很好的预测效果;当进水氨氮质量浓度较高时,预测值略低于实际结果.     

高岭土负载纳米Fe/Ni同时去除水中Cu2+和NO3-

工业废水常含有不同污染物如重金属离子和无机阴离子,而如何有效去除复合污染物就成为环境科学前沿研究的挑战性课题.这些污染物因化学性质不同而导致去除机理和途径也不同.本文采用合成高岭土负载纳米双金属Fe/Ni(K-Fe/Ni)同步去除水中Cu2+和NO-3.结果表明K-Fe/Ni能有效去除水中Cu2+和NO-3,但它们的去除效果却会相互受到影响.在Cu2+浓度为200mg·L-1时,NO-3的去除率达到42.5%;而未加入Cu2+时,NO-3的去除率仅有26.9%,说明Cu2+的存在提高了NO-3降解效率.同样,水中NO-3的存在也影响Cu2+的去除(Cu2+去除率从99.7%降到96.5%).但NO-3浓度对去除Cu2+的影响小于Cu2+浓度对NO-3的影响.通过BET比表面积、X射线衍射(XRD)、扫描电镜(SEM)、X射线能量散射(EDS)和X射线光电分析(XPS)对K-Fe/Ni表征的结果显示,反应后K-Fe/Ni的表面存在铁的氧化物、Ni0和被还原的Cu0.基于以上结果,我们发现K-Fe/Ni同步去除水中Cu2+和NO-3的机理是:高岭土负载下的纳米Fe0作为还原剂,在Ni0的催化产氢作用下将Cu2+还原成Cu0并沉积在K-Fe/Ni上而形成纳米Fe/Ni/Cu三金属催化剂,从而加速催化水中NO-3降解.     

密云水库底泥和库滨区土壤中氨氧化细菌的多样性和丰度

采用分子生物学方法（T-RFLP、定量PCR）研究了密云水库底泥沉积物和库滨带土壤中氨氧化细菌（AOB）的多样性和丰度特征,并使用Canoco for Windows 4.5软件和皮尔森相关系数法,探究了环境因子对AOB群落的影响.结果表明,沉积物和库滨区土壤中AOB的多样性和数量都存在较大的差异.其中,AOB群落被聚成两大类：沉积物与土壤.沉积物样品中AOB群落结构与其它样品差异较大.沉积物中AOB的多样指数最低,而在农田土壤中AOB多样性指数最高.农田土壤中的amoA基因拷贝数最大,是底泥沉积物中的48倍.此外,RDA（Redundancy Analysis）分析表明,在沉积物和水陆交错带土壤中,AOB的优势种与NH₄⁺-N、NO₃^--N、TOC、pH成正相关关系,而在陆相土壤和农田土壤中,AOB的优势种与这些环境因子成负相关关系.其中,TOC是影响AOB的群落结构的关键理化因子.     

滇池水葫芦规模化控养生态环境效应分析

水葫芦规模化控养是"十二五"期间滇池治理的重要措施之一。首先介绍了滇池水葫芦规模化控养现状,比较了滇池草海和外海在水葫芦控养前后水质的变化情况,指出滇池水葫芦规模化控养对草海水体生态恢复效果显著,可以在滇池选择适宜水葫芦生长的水域继续扩大水葫芦控养面积,使水葫芦在滇池生态治理中发挥更大的作用。     

以废气为热源生产二水氯化钙的新工艺

针对在氯化法生产钛白粉的过程中产生的大量高热值废气和氯化钙废水,提出以废气为热源生产二水氯化钙的新工艺。以焚烧的方式处理氯化尾气,将产生的热量用于浓缩蒸发氯化钙废水,生产工业级二水氯化钙产品,达到以废治废的目的。不仅处理了工业废气和废水,在节约能源的同时创造了一定的经济效益。     

Interface-mediated synthesis of monodisperse ZnS nanoparticles with sulfate-reducing bacterium culture

We have created a new method of ZnS nanospheres synthesis. By interface-mediated precipitation method (IMPM), monodisperse ZnS nanoparticles was synthesized on the particle surface of sulfate-reducing bacterium nutritious agar culture. Sulfate-reducing bacterium (SRB) was used as a sulfide producer because of its dissimilatory sulfate reduction capability, meanwhile produced a variety of amino acids acting as templates for nanomaterials synthesis. Then zinc acetate was dispersed into nutritious agar plate. Subsequently agar plate was broken into particles bearing much external surface, which successfully mediated the synthesis of monodisperse ZnS nanoparticles. The morphology of monodisperse ZnS nanospheres and SRB were examined by scanning electron microscopy (SEM), and the microstructure was investigated by X-ray diffraction (XRD). The thermostability of ZnS nanoparticles was determined by thermo gravimetric-differential thermo gravimetric (TG-DTG). The maximum absorption wavelengh was analysed with an ultraviolet-visible spectrophotometer within a range of 199–700 nm. As a result, monodisperse ZnS nanoparticles were successfully synthesized, with an average diameter of 80 nm. Maximum absorption wavelengh was 228 nm, and heat decomposed temperature of monodisperse ZnS nanoparticles was 596°C.     

Numerical simulation of alga growth and control in Dalian Bay

WAHMO model was used to simulate the distribution of pollutants in Dalian Bay, China as to predict well as the growth and control of alga. The observed and predicted values of main pollutants showed a good trend at all study locations and the different between them can be ignored. Simulation results illustrated that phosphate was one of limited factors to control algal growth at the location near the sewage outfall, meanwhile, away from the sewage outfall, the synergy of ammonium nitrogen and phosphate was the limited factor.     

Interface-mediated synthesis of monodisperse ZnS nanoparticles with sulfate-reducing bacterium culture

We have created a new method of ZnS nanospheres synthesis. By interface-mediated precipitation method (IMPM), monodisperse ZnS nanoparticles was synthesized on the particle surface of sulfate-reducing bacterium nutritious agar culture. Sulfate-reducing bacterium (SRB) was used as a sulfide producer because of its dissimilatory sulfate reduction capability, meanwhile produced a variety of amino acids acting as templates for nanomaterials synthesis. Then zinc acetate was dispersed into nutritious agar plate. Subsequently agar plate was broken into particles bearing much external surface, which successfully mediated the synthesis of monodisperse ZnS nanoparticles. The morphology of monodisperse ZnS nanospheres and SRB were examined by scanning electron microscopy (SEM), and the microstructure was investigated by X-ray diffraction (XRD). The thermostability of ZnS nanoparticles was determined by thermo gravimetric-differential thermo gravimetric (TG-DTG). The maximum absorption wavelengh was analysed with an ultravioletvisible spectrophotometer within a range of 199-700 nm. As a result, monodisperse ZnS nanoparticles were successfully synthesized, with an average diameter of 80 nm. Maximum absorption wavelengh was 228 nm, and heat decomposed temperature of monodisperse ZnS nanoparticles was 596℃.