Characterization of interaction between different adsorbents and copper by simulation experiments using sediment-extracted organic matter from Taihu Lake,China

The complex capacity of different types of organic matters （OMs） for Cu was quantitatively studied by simulation experiments using different adsorbents prepared from the sediment in Taihu Lake. The free Cu was measured with ion selective electrode （ISE） and complex capacity was calculated using a conditional formation constant model. The result indicated that the complex capacity was 0.048 mmol·g-1, 0.009 and 0.005 mmol.g-1for raw sediment, sediment without DOM, sediment without insoluble organic matters but with DOM and sediment without OM. Insoluble organic matter played a major role in the sorption of Cu in sediment and it can adsorb most Cu from water column. In the solution, Cu mainly existed as a complex with DOM and the DOM-Cu complexation capacity was 327.87 mg. g-1. The change of TOC and pH indicated ion-exchange in the interaction between free Cu and DOM. When the Cu concentration in the experiment reached the complex capacity of DOM, precipitation was the major mechanism to remove Cu from water phase, which was observed from UV absorbance change of DOM, that is, its aromaticity increased while molecular weight decreased. The desorption result indi- cated that DOM was more capable of desorbing Cu from adsorbents without OM than adsorbent with OM. The desorbed quantity with DOM was 1.65, 1.78 and 2.25 times higher than that with water for adsorbents without OM, raw adsorbents （sediment） and adsorbents without DOM.     

船舶柴油机选择性催化还原积碳臭氧直接氧化再生

为解决船舶柴油机SCR催化剂积碳再生问题,提出了臭氧直接氧化再生的方法。实验用玻璃纤维无胶滤筒采集PM,然后在管式炉中用臭氧氧化滤筒中的PM,研究了温度和臭氧浓度对PM氧化的影响。实验表明,臭氧的最佳氧化温度窗口为200~240℃,PM氧化速度随臭氧浓度提高明显加快,PM氧化率可以达到92%以上。根据实验结果,提出了船舶柴油机SCR积碳O3低温再生技术方案。     

印制板蚀刻液再生及铜回收技术与设备

由深圳市拓鑫环保设备有限公司开发的印制板蚀刻液再生及铜回收技术与设备,适用于印制板三废的治理。主要技术内容 一、基本原理利用含重金属溶液的选择性分离技术,对含铜废水中的铜进行选择性分离,使蚀刻废液得以再生循环利用的同时,获得高纯度的金属铜板。针对线路板生产蚀刻过程的特点,高效利用蚀刻废液中残留的有用成分,去除废液中影响蚀刻效果的成分,形成了分离铜、蚀刻液再生、电解铜、蚀刻液循环利用的技术方案,使因铜离子浓度过高而失去蚀刻功能的废液得以再生,同时获得高纯度铜板。对低含铜废水则是把其中的铜选择性分离,电解制成铜板,从而达到减少污染、回收资源的目的。     

阴离子洗涤剂离子选择性电极的研制

阴离子洗涤剂污染水体,破坏水生态平衡。目前应用亚甲蓝分光光度法进行监测,操作繁琐,抗干扰能力差,且使用大量的有毒溶剂氯仿,因此需对该方法进行改进。本文着重介绍一种新型的电活性基团与功能高分子支撑体相键合的离子选择性液态膜电极。以聚苯乙烯进行氯甲基化、季铵化,制成聚苯乙烯敏感膜离子选择性电极。液膜离子选择性电极是近年来发展起来的一种基于电化学原理的离子测试最新工具。它优越于玻璃电极和固态膜电极,具有较高选择性,活性材料广泛。曾报道在聚氯乙烯的端基上引入季铵基活性基团,制成选择性电极。但存在着活性物…     

中小型燃煤烟气脱硫脱硝实验研究

介绍了选用熟石灰Ca(OH)2作脱硫剂的半干法烟气脱硫工艺来脱除SO2;选用NH3作还原剂,活性炭作催化剂,在低温(＜200℃)和氧气存在的条件下选择性催化还原(SCR法,属干法)NOx的技术来脱除NOx.实验表明:脱硫率＞92.5%,脱硝率＞74.6%,半干法烟气脱硫工艺和干法(SCR法)烟气脱硝技术适宜于中小型燃煤烟气的脱硫脱硝.     

立体抽采条件下高瓦斯采空区煤自燃危险性预测

为准确预测高瓦斯采空区煤自燃的状况,通过分析发现高抽巷是监测采空区遗煤自然发火的最有效地点。推算出采空区气体在高抽巷中所占的体积分数,进而确定采空区遗煤不同的燃烧阶段所对应的CO体积分数和CO指数。结果表明:当高抽巷中的CO体积分数Chdr CO<30×10-6或CO指数ICO<0.5%时,采空区的遗煤处于低温氧化阶段;当高抽巷中的CO体积分数Chdr CO≥30×10-6或CO指数ICO≥0.5%时,采空区遗煤进入自然发火危险阶段,此时必须采取措施控制采空区自燃氧化的进一步发展。对80501工作面的采空区煤自燃成功地进行预测预报,实现了安全生产。     

Fe2O3 particles as superior catalysts for low temperature selective catalytic reduction of NO with NH3

Fe203 particle catalysts were experimentally studied in the low temperature selective catalytic reduction （SCR） of NO with NH3. The effects of reaction temperature, oxygen concentration, [NH3]/[NO] molar ratio and residence time on SCR activity were studied. It was found that Fe203 catalysts had high activity for the SCR of NO with NH3 in a broad temperature range of 150-270℃, and more than 95% NO conversion was obtained at 180℃ when the molar ratio [NH3]/[NO] = 1, the residence time was 0.48 seconds and 02 volume fraction was 3%. In addition, the effect of SO2 on SCR catalytic activity was also investigated at the temperature of 180℃. The results showed that deactivation of the Fe2O3 particles occurred due to the presence of SO2 and the NO conversion decreased from 99.2% to 58% in 240 min, since SO2 gradually decreased the catalytic activity of the catalysts. In addition, X-ray diffraction, Thermogravimetric analysis and Fourier transform infrared spectroscopy were used to characterize the fresh and deactivated Fe2O3 catalysts. The results showed that the deactivation caused by SO2 was due to the formation of metal sulfates and ammonium sulfates on the catalyst surface during the de-NO reaction, which could cause pore plugging and result in suppression of the catalytic activity.     

汽车尾气净化催化剂Ag/SAPO-34选择性催化还原NO

评价了Ag/SAPO-34分子筛催化剂选择性还原NO的活性,并运用漫反射红外光谱原位研究NO在Ag/SAPO-34催化剂上的选择性催化还原机理.结果表明Ag/SAPO-34有良好的低温活性,在氧气浓度为3.6%和温度为573K～673K时NO还原成N2的转化率达70%;催化剂活性随C3H6浓度的增加而升高,随空速的增加而稍有下降.基于漫反射红外光谱,认为反应机理为:NO、丙烯和氧反应,在Ag/SAPO-34催化剂上生成吸附的有机-氮氧化物,再由这些吸附物种分解成N₂,催化还原的关键是形成有机-氮氧化物中间体.氧的作用是充分促进丙烯活化以及增加NO_x吸附态含量,并且氧的存在是有效产生一系列中间物不可缺少的条件.     

Effect of manufacturing methods of AgCl/Al2O3 catalyst on selective catalytic reduction of NOx

The AgCl/Al2O3 catalyst has potential for use in the selective catalytic reduction (SCR) of NOx. A compound hydrocarbon, following oxygenation is used as a type of reducing agent. In this experiment, the AgCl/Al2O3 catalyst was produced by four different methods, and the differences among their reduction catalysis of NOx were compared. Ethanol was used as a type of reducing agent. X-ray diffraction analysis was performed to study the crystalline structure and scanning electron microscope and transmission electron microscope (TEM) were applied to determine the microindentation. The results indicated that, in the range of 350–400°C, there was no significant difference on the NOx reduction rate; however, there was dispersion at high and low temperature ranges. The size of the AgCl particles was about 20–100 nm.     

焙烧温度对CeO_2(ZrO_2)/TiO_2选择性催化脱硝性能的影响

采用溶胶-凝胶法并以不同温度焙烧制备一系列CeO_2(ZrO_2)/TiO_2(CZT)催化剂,考察了CZT催化剂固相结构、酸量、比表面积等性能与催化活性的关系。采用XRD、BET、NH3-TPD、H2-TPR以及XPS等表征技术对催化剂进行表征。结果表明:焙烧温度为450℃时CZT催化剂具有最高的催化活性,其在240~400℃的温度窗口内活性均高于90%,且具有较好的抗水和抗硫中毒能力。随着焙烧温度的提高,催化剂表面的Ce和Zr原子进入体相晶格且Ce0.5Zr0.5O2向Ce0.75Zr0.25O2转变,导致催化剂的储释氧能力和氧化还原性能降低。另外,锐钛矿和金红石型TiO_2晶粒尺寸的增加,催化剂的有效比表面积和总酸量降低,因此CZT催化活性随着焙烧温度的提高而有所降低。换言之,大的比表面积、良好的氧化还原性能、表面Ce4+的富集以及酸性位的增多均有利于NH3-SCR活性的提高。