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191.
192.
采用两种阳离子表面活性剂,四丁基溴化铵(TBA)及聚乙烯亚胺(PEI)对碳纳米管进行改性,并研究了全氟辛酸(PFOA)、全氟辛烷磺酸盐(PFOS)、全氟己烷磺酸盐(PFHxS)在改性碳纳米管上的吸附行为.研究结果显示,除PFOS在TBA修饰的碳纳米管(TBA-MWCNTs)上的吸附等温线呈线性外,全氟化合物在原碳纳米管(Pri-MWCNTs)、TBA-MWCNTs及PEI修饰的碳纳米管(PEI-MWCNTs)上的吸附均为非线性.吸附等温线可以用Freundlich及Langmuir模型拟合.与Pri-MWCNTs相比,PEI-MWCNTs的零电荷点(pHzpc)增加了6.2个单位,全氟化合物的吸附系数Kd值增加2—3倍;而TBA-MWCNTs的pHzpc增加了1.0个单位,PFOS在高平衡浓度下的Kd值增加了两倍.随着溶液pH值的降低,全氟化合物在Pri-MWCNTs和PEI-MWCNTs上的吸附量有所增加,而在TBA-MWCNTs上的吸附受pH值的影响不大.这说明疏水作用及静电作用是全氟化合物在Pri-MWCNTs和PEI-MWCNTs上吸附的主要机制,而疏水作用则为TBA-MWCNTs上吸附的主要机制.与单溶质体系相比,PFOS与PFOA同时存在时二者在PEI-MWCNTs上吸附的Kd值均有所减小,且PFOA的减小程度大于PFOS.PFOS在TBA-MWCNTs上吸附的Kd值在高浓度下几乎不受PFOA的影响. 相似文献
193.
逐级分离法提取河流表层沉积物中的粘土矿物 总被引:2,自引:0,他引:2
采用选择性化学萃取剂对河流表层沉积物中的有机质、铁/锰氧化物进行逐级分离,并依据斯托克斯(Stokes)法则提取其中的粘土矿物,以达到逐级分离的效果.利用TOC测定法和火焰原子吸收法(FAAS)定最分析并验证沉积物中碳酸盐、有机质和铁、锰氧化物的去除效果;利用X-射线衍射(XRD)和扫描电镜(SEM)考察粘土矿物的主要成分和提取效果.结果表明,有机质的去除率可达到90%以上,铁、锰氧化物的去除率分别达到98.90%和77.92%,占可萃取态铁、锰的绝大部分;沉积物中粘土矿物的主要成分为伊利石、伊利石/蒙脱石混层和高岭石,非粘土矿物的主要成分是石英和正长石,沉积物提取粘土矿物前后的XRD以及ESEM谱图的变化进一步验证了粘土矿物的提取效果. 相似文献
194.
Fen LI Tao LEI Yanping ZHANG Jinzhi WEI Ying YANG 《Frontiers of Environmental Science & Engineering》2015,9(2):190
To recycle the sludge resource from sewage treatment plants and solve the problem of odor pollution, the sludge was converted into an adsorbent by carbonized pyrolysis and the process was optimized by orthogonal experiments. The capability for odor removal as well as the structure of the adsorbent was studied with H2S as a target pollutant. The results indicate that the main factor affecting the deodorization performance of the adsorbent is the activating time. The sludge adsorbent sample SAC1 prepared under optimum conditions exhibits the best deodorization performance with a H2S breakthrough time of 58 min and an iodine value nearly that of the coal activated carbon. The breakthrough time of H2S is much longer than that on the coal activated carbon. On the other hand, characterization results from X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS) and scanning electron microscope (SEM) techniques show that SAC1 is composed of mainly graphite carbon with lower oxygen content on the surface. The bulk of SAC1 exhibits a honeycomb structure with well developed porosity and a high specific surface area of 120.47 m2·g-1, with the average pore diameter being about 5 nm. Such a structure is in favor of H2S adsorption. Moreover, SAC1 is detected to contain various metal elements such as Zn, Fe, Mg, etc., leading to a superior deodorization property to that of coal activated carbon. 相似文献
195.
Yanping HOU Haiping LUO Guangli LIU Renduo ZHANG Yong LUO Bangyu QIN Shanshan CHEN 《Frontiers of Environmental Science & Engineering》2013,7(4):526-530
In this study, DOW CORNING 1-2577 Conformal Coating was proposed for the cathode diffusion layer of the microbial fuel cell (MFC). In MFCs, stainless steel mesh cathodes using DOW CORNING 1-2577 Conformal Coating/carbon as the diffusion layer and two poly (dimethylsiloxane) (PDMS)/carbon diffusion layers and carbon cloth cathode with four poly (tetrafluoroethylene) (PTFE) diffusion layers were constructed for comparison. Under the same operational condition, the MFCs with the DOW CORNING 1-2577 Conformal Coating/carbon diffusion layer produced the maximum power density of 1585±52 mW·m-2, compared with those using poly (tetrafluoroethylene) (PTFE) diffusion layers (1421±45 mW·m-2) and poly (dimethylsiloxane) (PDMS)/carbon diffusion layers (1353±49 mW·m-2). The DOW CORNING 1-2577 Conformal Coating could be an alternative for the diffusion layer construction in the MFC due to its remarkable performance and much simple construction procedure. 相似文献
197.
198.
SWOT分析模型在巴彦淖尔市战略环境评价中应用研究 总被引:1,自引:0,他引:1
SWOT分析模型是战略规划研究的一种分析技术,近年来在区域规划研究中得到广泛利用。本文在进行巴彦淖尔市发展规划环评中,从环境保护角度出发,采用SWOT分析方法对区域经济发展的优势、劣势、机遇和压力进行了分析,提出巴市经济发展策略应突出增长型战略,同时兼顾其他三类发展战略,构建经济快速发展、优势资源保护性开发、环境压力显著降低的生态型工业集群的建议,有助于促使区域经济实现友好又快发展,且对今后偏重政策层面的战略环评编制具有一定的参考价值。 相似文献
199.
根据消弧线圈容量及所在系统电容电流现状、系统中电气设备绝缘类型,依据相关技术标准,对宁夏电网消弧线圈配置现状进行了分析,提出了消弧线圈应根据配网结构采取分区配置,固体绝缘为主的系统不宜采用消弧线圈的建议。分析结果表明:采取消弧线圈的分区配置方式不仅能够避免消弧线圈配置不合理造成的浪费,而且能够有效消除弧光单相接地对配电网安全运行的威胁。 相似文献
200.
Yueqin Yu Lingxiu Liu Yanyan Kong Erchi Zhang Yanping Liu 《Journal of Polymers and the Environment》2011,19(4):926-934
A high-swelling superabsorbent was synthesized with biodegradable N-maleyl chitosan as cross-linker, acrylic acid (AA) and acrylamide (AM) as the monomers, ammonium peroxodisulfate–sodium bisulfite
(NaHSO3) as redox initiation system, by means of aqueous solution polymerization. The best reaction condition was based on the orthogonal
experiment design. The optimal conditions on distilled water absorbency and on 0.9 wt% NaCl solution absorbency were monomer
concentration 20 wt%, mole ratio of AA to (AA + AM) 60%, the neutralization degree of AA 40%, cross-linker concentration 2%
and monomer concentration 25 wt%, mole ratio of AA to (AA + AM) 60%, neutralization degree of AA 50% and cross-linker concentration
1%, respectively. Factors influencing the water absorbency of superabsorbent also were investigated, by single factor experiment
method. The absorbency of superabsorbents in distilled water and 0.9 wt% NaCl solution increased and then decreased with the
increasing of monomer concentration, mole ratio of AA to (AA + AM) and degree of neutralization of AA. With the increasing
of cross-linker concentration, the absorbency in distilled water increased and then decreased, but it decreased all the time
in 0.9 wt% NaCl solution. In enzymatic degradation tests, the weight loss of superabsorbent was related to the content of
cross-linker. 相似文献