粉煤灰对硫化钠烟气脱硫的影响研究

通过对烟气带入吸收系统的粉煤灰物理性质及化学组成的分析，研究了粉煤灰对硫化钠法烟气脱硫反应的可能影响，并对粉煤灰的去除工艺进行了探讨。     

(Z)-11-Pentacosene is the major sex pheromone component inDrosophila virilis (Diptera)

Summary A crude cuticular extract from 3450 virgin 9–13 day old female fruit flies(Drosophila virilis), was subjected to chromatography accompanied by bioassay for sex pheromone activity. After three chromatographic steps, fractions containing active monoenes and dienes were obtained. Chemical analysis by infrared absorption, gas liquid chromatography and gas chromatography/mass spectrometry of the active fraction indicated that active monoenes were comprised chiefly of (Z)-11-pentacosene (abbreviated (Z)-11-C_25:1), (Z)-13-C_27:1, (Z)-13- and (Z)-14-C_29:1. Synthetic monoenes were made, and only (Z)-11-C_25:1 elicited good courtship behaviour in maleD. virilis. Therefore it was concluded that (Z)-11-C_25:1 was a major sex pheromone. A total of 16.2±1.32 µg of cuticular hydrocarbons was isolated from 10 day old females, including 5.9±0.56 µg of (Z)-11-C_25:1. An additive effect was suggested from the higher observed courtship response when using a mixture of active dienes with the active monoene.     

生物炭对土壤氮素淋失的抑制作用

淋洗作用是土壤氮肥损失途径之一,也是环境水体氮素污染的重要途径。研发降低土壤氮素淋失的技术途径不仅有助于提高氮肥利用率和降低化肥的施用量,而且有助于防治水体污染和改善生态环境。本文通过淋滤实验研究了生物炭对我国两种重要土壤类型黒钙土和紫色土氮素淋失的影响。由玉米秸秆制成的生物炭按10 t/ha,50 t/ha,100 t/ha的比例施用于土壤,同时模拟田间尿素施用量240 kg.N/ha并用相当于每天10 mm的降水量用去离子水淋洗土壤。对淋滤液氮素组成和含量分析结果显示,在不施用生物炭的条件下,黒钙土和紫色土总氮的淋失量分别占土壤(土壤+尿素)总氮含量的7.5%和9.0%,氮素的淋失主要发生在前130 mm降水过程中,其淋失量占全部淋失量的96%。在淋失的成分中,除硝态氮外,有机氮也是重要的组成物质,二者均占淋失总氮量的48%。生物炭的施用可以大幅度地降低氮素的淋失作用。50 t/ha和100t/ha的生物炭施用量降低黑钙土氮素淋失分别为29%和74%,减少紫色土氮素淋失分别达41%和78%。但10 t/ha的生物炭施用量却增加黒钙土和紫色土氮素淋失量分别达到22%和2%。这表明较低的生物炭施用量会促进氮素的淋失。生物炭对有机氮淋失的抑制作用大于硝态氮。100 t/ha的生物炭施用量对有机氮和硝态氮淋失的降低率分别为88%和62%左右,因土壤类型不同而有所差异。上述研究结果为寻求防治土壤氮素淋失的技术方法提供了理论依据。     

直接红染料在粉煤灰上的吸附行为研究

文章探讨了直接红染料在粉煤灰上的吸附行为及其机理。结果显示,粉煤灰对直接红染料有较好的去除效果;当NaCl浓度≤12.5 g/L,盐分增加对直接大红的去除率影响不明显,NaCl浓度≥15 g/L,盐分增加,直接大红的去除率有所增大;当十二烷基磺酸钠浓度≤0.5 g/L,直接大红在粉煤灰上的吸附量随表面活性剂浓度上升明显下降,继续增加表面活性剂浓度,影响则不明显。     

粉煤灰基质滤料处理含锰废水的研究

通过静态吸附试验研究了粉煤灰基质滤料对废水中Mn2+的吸附性能,主要探讨了滤料投加量、吸附时间、原水浓度、振荡频率等因素对吸附效果的影响。结果表明:随着投加量增加,Mn2+去除率提高,单位吸附量线性下降;随着吸附时间延长,Mn2+去除率提高,超过80 min后提高幅度变缓,吸附过程符合二级动力学模型;振荡频率的增大对吸附有一定的促进作用,但超过200 r/min后提高不明显。     

Kinetics and equilibrium of adsorption of dissolved organic matter fractions from secondary effluent by fly ash

Fly ash was used as a low-cost adsorbent for removing dissolved organic matter (DOM) in secondary effluent. Batch experiments were conducted under various adsorbent dosages, pH, contact time, temperatures and DOM fractional characteristics. Under the optimum conditions of fly ash dosage of 15 g/L, temperature of 303 K and contact time of 180 min, a removal of 22.5% of the dissolved organic carbon (DOC), 23.7% of UV-254, 25.9% of the trihalomethanes precursors in secondary effluent was obtained. The adsorption of DOM fractions onto fly ash all followed the pseudo second-order kinetic model, and the hydrophilic fraction adsorption by fly ash also fitted the intraparticle diffusion model quite well. Freundlich and Langmuir models were applicable to the fly ash adsorption and their constants were evaluated. The maximum adsorption capacities of the adsorptions revealed that fly ash was more effective in adsorbing hydrophilic fraction than the acidic fractions. Structure changes of the DOM fractions after fly ash adsorption were also characterized via spectrum analyzing. Those mechanisms presented critical step toward improved efficiencies of fly ash adsorption via further surface-modification.     

Cu2+和Cd2+在改性纳米黑碳表面上的吸附-解吸

通过Cu2+或Cd2+单体系和Cu2+-Cd2+复合体系中Cu2+或Cd2+的吸附-解吸试验,研究了改性纳米黑碳(MBC)对Cu2+和Cd2+的吸附特性和吸附稳定性.结果表明:Cu2+和Cd2+在MBC上的吸附可以分为快、慢2个阶段,30 min达到饱和吸附量的90%以上.Cu2+和Cd2+在MBC上的吸附等温线均能用Langmuir方程和Freundlich方程拟合.Cu2+和Cd2+在MBC上的最大吸附量分别为417和245 mmol/kg,n值分别为2.56和3.85.MBC对Cu2+和Cd2+是优惠吸附,且对Cu2+的吸附能力大于Cd2+.吸附在MBC上的Cu2+和Cd2+的解吸率均随着吸附量的增加而增大,Cu2+在MBC上的解吸率为1.45%～20.20%,Cd2+为2.67%～31.40%.Cu2+和Cd2+在MBC上存在着竞争吸附,其最大吸附量均随着竞争离子浓度的增加而降低.MBC对Cu2+吸附量和吸附稳定性均大于Cd2+.MBC对重金属有强的吸附作用,可探索其在含重金属废水处理和重金属污染土壤钝化修复中的应用.     

掺粉煤灰水泥砂浆抗稀硫酸侵蚀的试验研究

为研究稀硫酸侵蚀掺粉煤灰水泥砂浆的规律,对砂浆试块进行长期浸泡试验,用滴酸法间接测得腐蚀速率并结合偏相关理论分析了影响砂浆试块腐蚀速率各个因素。分析表明:pH值相同时,粉煤灰掺量0%~30%的砂浆试块的腐蚀过程符合浓度边界层溶解反应模型;试块的流动度与抗腐蚀能力呈负相关;掺粉煤灰并不能明显改善水泥砂浆的抗稀硫酸侵蚀的性能。     

新型颗粒粉煤灰净水剂对六价铬的吸附

采用自制颗粒粉煤灰净水剂,研究其对水溶液中的六价铬离子的吸附性能和影响因素,探讨了该净水剂对六价铬的吸附机理。研究表明:颗粒粉煤灰能有效吸附水溶液中的六价铬离子;影响吸附效果的因素重要性顺序为:pH>净水剂投加量>振荡时间>温度;该净水剂对六价铬吸附与Langmuir吸附等温方程和Freundlich吸附等温方程均很吻合,属于单分子层吸附;液膜扩散起主要作用,吸附过程符合二级动力学方程。     

湖南澧阳平原黑褐色土的稀土元素地球化学特征及其环境意义

通过对澧阳平原大量的野外考察、典型剖面玉成(YC)黑褐色土壤剖面的系统取样和室内粒度、稀土元素地球化学分析,以及OSL和AMS14C年代测定,探讨了黑褐色土的稀土地球化学特征,揭示了黑褐色土的形成年代、形成过程与形成环境.研究结果表明,黑褐色土层XREE变化范围分布在184.63-264.261μg·g-1,其平均值为207.93μg·g-1;低于剖面的∑REE总平均值219.87Pμg·g-1,与洞庭盆地的红土∑REE平均值(211.6μg·g-1)大体相当,但明显高于镇江下蜀黄土(207.7μg·g-1)和黄土高原黄土(159.2μg·g-1),表明YC剖面黑褐色土上经过了相对较强的风化成壤作用.YC剖面黑褐色土的稀土分布模式与该剖面黄土层、黄土高原黄土、镇江下蜀黄土和洞庭盆地风成红土等典型风成沉积物的分布模式具有一致性,而与河流沉积物、湖泊沉积物和基岩风化红土在稀土的分布模式上具有明显差别.而且,YC剖面沉积物粒度频率曲线呈明显的单峰分布,与典型河流相的双峰粒度频率分布存在显著差异;YC剖面位于澧阳平原中部台地上,比周边高5-10m,不可能是洪水作用沉积物;野外调查进一步表明,沉积物无水流作用痕迹;OSL和AMS14C年代测定表明,黑褐色土层形成的年代对应于23.8-10.6 ka BP,此年代对应于末次冰期的晚期,其形成于相对冷湿的气候环境.因此,黑褐色土层及其上、下部的黄土层均为风成堆积物.