固相萃取-高效液相色谱法测定水中丙烯酰胺研究

采用固相萃取-高效液相色谱法对水中的丙烯酰胺定性、定量分析。结果显示:丙烯酰胺含量在20μg/L~400μg/L之间呈良好线性关系,回归方程Y=0.476 8X+0.845 4,相关系数R为0.997 72,检出限0.1μg/L,样品回收率在71.85%~92.28%之间,相对标准偏差为3.4%~10.9%。该方法减少了有机溶剂用量,缩短了有机溶剂暴露时间,降低污染,且能满足地表水环境质量标准(GB 3838-2002)限值要求,是水中丙烯酰胺含量准确稳定的检测方法。用该方法测定了呼和浩特市引黄入呼左岸、右岸、中浅和中深4个断面水样,均未检出丙烯酰胺。     

柠檬酸对砷污染土壤的萃取优化条件实验研究

论文以新邱矿矸石山排土场土壤为研究对象,以去离子水做空白试验,选取尿素、十二烷基磺酸钠、碳酸氢钠、醋酸、柠檬酸等12种化学试剂做了萃取剂初选试验;并以柠檬酸为萃取剂进行了三因素三水平L9(33)正交实验。实验结果表明:柠檬酸和氢氧化钠可作为砷污染土壤的萃取剂,具有良好的萃取效果。柠檬酸作为砷污染土壤萃取剂的最优化条件是液土比为10mL/g,萃取时间为12h,萃取剂浓度为0.1mol/L。实验结果可为砷污染土壤的治理提供参考。     

低强度超声波强化SMBR处理中的超声波参数优化研究

研究了利用低强度超声波强化低温一体式膜生物反应器（SMBR）污水生物处理中最优超声波参数的选择。结果表明,功率密度为0.27 W/L、辐照时间为20 min时,超声波对低温SMBR中COD去除的强化效果最佳。SMBR对NH3-N去除效果达到最佳时,超声波功率密度和辐照时间分别为0.27 W/L和15 min。综合考虑,选择更有利于低温时NH3-N去除的超声波参数：功率密度0.27 W/L、辐照时间15 min。经此超声波处理后COD、NH3-N的强化效果在24 h均能保持,故可设置超声波处理的时间间隔为24 h。     

复合催化膜生物反应器处理一氧化氮废气研究

采用溶胶-凝胶法以聚砜(PSF)中空纤维膜为载体制备了Fe-Ti O_2/PSF复合催化膜,以此构建新型复合催化膜生物反应器(HCMBR),实现膜催化与硝化反硝化耦合烟气脱硝,进一步提高NO去除能力.采用Fe-Ti O_2/PSF复合催化膜生物反应器(HCMBR)处理一氧化氮废气,实现了180 d长时间高效稳定运行,NO去除效率可达93.2%,去除能力可达167.1g·(m~3·h)~(-1).适宜运行条件为:气体停留时间9 s、自然光光照强度670 lx,p H为6.8~7.2,n C/n N=3.7.Fe-Ti O_2/PSF复合催化膜加入,复合催化膜生物反应器去除NO的效率比膜生物反应器提高了1.4%~13%,在Fe-Ti O_2/PSF复合催化膜附着稳定的生物膜后,复合催化膜生物反应器去除NO的效率比湿式膜催化反应器提高了59.5%~66%.     

膜污染层微生物与聚丙烯微滤膜间的界面作用及其吸附特征

采用热力学方法及界面吸附理论,对2株膜污染层微生物(Aeromonas veronii M4、Aeromonas caviae N25)与聚丙烯(PP)微滤膜间的界面作用及吸附特征进行研究.结果表明,Aeromonas veronii M4与PP膜表面均表现出明显的疏水性特征,而Aeromonas caviae N25则呈现亲水性特征,并且A.veronii M4的运动性能也要高于A.caviae N25;另外,2株细菌及PP膜的表面均带有负电荷,表现出明显的电子供体特征,而Lewis酸碱分量U_(mlb)~(AB)则在2株细菌与PP膜的界面作用能中占据着主导地位;依据XDLVO理论,A.caviae N25及A.veronii M4与PP膜之间的总界面作用能均为负值,表明二者在膜上的吸附是一个主动吸附过程,而A.veronii M4-PP膜之间的界面作用能负值最大,说明A.veronii M4具有较高的吸附能力;静态吸附结果则表明,A.veronii M4在PP膜上的吸附量要明显高于A.caviae N25,而2株菌在膜上的吸附行为可由准二级动力学模型进行描述.     

反渗透膜面细菌胞外多聚物提取方法研究

城市污水脱盐系统的反渗透(RO)膜面生物污堵问题严重影响了该技术的稳定运行,解析生物污堵机理的关键因素是微生物胞外多聚物(EPS)特征分析,然而目前细菌EPS提取方法多样,无统一标准,制约了EPS分析的可靠性和可对比性.基于此,本文以再生水厂RO膜面污堵物中分离的细菌为对象,采用水浴、超声、离子树脂、碱液4种方法提取EPS,以DOC和DNA含量表征提取的EPS总量和提取过程细胞破裂程度.结果表明,45℃水浴法不造成细胞破裂,提取总量多,是一种有效的提取方法.进一步对比不同提取时间条件下EPS溶液中多糖和蛋白含量变化,以及分子量、荧光特征等,综合认为提取1 h时,提取的EPS中多糖与蛋白相对含量稳定,不同分子量化合物均溶于水中,能客观地反映EPS特征.研究表明,45℃水浴1 h可以作为细菌EPS提取的适用方法应用.     

土壤和沉积物中的聚合有机质对多环芳烃分布和提取的影响

为了研究土壤和沉积物中凝聚型有机碳(碳黑、干酪根)的含量及其对多环芳烃(PAHs)分布和提取的影响,分别用三氟醋酸(TFA)和在375℃下通氧燃烧的方法从珠江三角洲2个污染土壤和5个河口沉积物样品中提取酸非水解有机碳(NHC)和碳黑(BC);用索氏抽提法和不同溶剂的加速溶剂萃取法(包括连续加速萃取法ASESum和标准溶剂萃取法ASESTD)抽提土壤和沉积物中的多环芳烃,并在不同温度梯度(25℃到150℃)下用水为溶剂加速溶剂萃取其水溶态.结果表明,1)NHC是珠江三角洲土壤和沉积物中总有机碳的重要组成部分,NHC碳明显高于BC碳,NHC和BC分别占土壤和沉积物中有机碳的25.6%￣73.8%和4.64%￣17.3%.2)3种有机溶剂(丙酮、甲苯1、甲苯2)连续抽提的PAHs含量是索氏抽提的2.11倍;5种ASE方法(丙酮、甲苯1、甲苯2、ASESum、ASESTD)提取的PAHs含量与NHC含量存在明显的相关性,而且比PAHs含量与BC或无定型有机碳(AOC)含量的相关性更明显.3)在不同温度梯度下水溶态PAHs浓度符合Van’tHoff方程.研究说明除了BC外,非水解有机碳对土壤和沉积物中PAHs的分布和提取具有重要影响.     

土壤生态系统微量元素的生物有效性研究现状

土壤中植物必需的微量营养元素的供给以及有害元素的毒性大小并不仅仅与元素的总量有关,而取决于元素的有效性。文章论述了元素生物有效性的含义,介绍了元素有效性的研究方法,即连续偏提取法和单提取法,并对一些相关问题进行了深入的分析讨论。     

Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coating samples and surficial sediments in the Songhua River, China

Natural surface coating samples （NSCSs） from the surface of shingles and surficial sediments （SSs） in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals （Fe, Mn, Zn, Cu, Pb, and Cd） using the modified sequential extraction procedure （MSEP）. The results show that the differences between NSCSs and SSs in Fe fi＇actions were insignificant and Fe was dominantly present as residual phase （76.22% for NSCSs and 80.88% for SSs） and Fe-oxides phase （20.33% for NSCSs and 16.15% for SSs）. Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase （48.27%） and that in SSs present as residual phase （45.44%）. Zn, Cu, Pb and Cd were found dominantly in residual fractions （〉48%）, and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter （OM）, and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.     

Selective extraction and separation of Fe, Mn oxides and organic materials in river surficial sediments

In order to investigate the adsorption mechanism of trace metals to surficial sediments （SSs）, a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to selectively remove and separate Fe, Mn oxides and organic materials （OMs） in the non-residual fraction from the SSs collected in Songhua River, China. After screening different kinds of conventional extractants of Fe and Mn oxides and OMs used for separation of heavy metals in the soils and sediments, NH2OH .HCl （0.1 mol/L） ＋ HNO3 （0.1 mol/L）, （NH4）2C2O4 （0.2 mol/L） ＋ H2C2O4 （pH 3.0）, and 30% of H2O2 were respectively applied to selectively extract Mn oxides, Fe/Mn oxides and OMs. After the extraction treatments, the target components were removed with extraction efficiencies between 86.09%--3.36% for the hydroxylamine hydrochloride treatment, 80.63%- 101.09% for the oxalate solution extraction, and 94.76%-102.83% for the hydrogen peroxide digestion, respectively. The results indicate that this selective extraction technology was effective for the extraction and separation ofFe, Mn oxides and OMs in the SSs, and important for further mechanism study of trace metal adsorption onto SSs.