共查询到18条相似文献,搜索用时 78 毫秒
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总结了燃煤烟气中汞污染的现状及蛭石吸附剂研究的进展情况,对烟气中单质汞的脱除进行了研究,提出了蛭石在单质汞的吸附脱除方面存在的潜力,为今后燃煤烟气中单质汞的脱除提出了一定的研究思路. 相似文献
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以活性炭为载体负载溶液中的Cu^2+,Cu^2+改性活性炭对溶液中CN^-的去除效果较好。cu。’改性活性炭的最佳制备条件:活性炭加入量为1g,质量浓度为5∥L的CuSO。溶液加入量为50mL,溶液pH为4,负载时间为5.0h.在此最佳条件下活性炭的最大Cu^2+负载量为25.90mg(以每克活性炭计)。Cu^2+改性后活性炭的CN^-去除率明显提高,由22.10%提高至94.07%。Cu^2+改性活性炭吸附CN^-的最佳实验条件:溶液pH为12~13,吸附时间为9h。Cu^2+改性活性炭对CN^-的饱和吸附量为22mg/g。Mg^2+,K^+,Ca^2+,Cl^-,SO4^2-,CO3^2-,AsO3^-对Cu^2+改性活性炭的CN^-去除率基本没有影响。Cu^2+改性活性炭的动态吸附实验表明,开始一段时间流出液中CN^-含量几乎为零,远低于国家排放标准(0.5mg/L)。 相似文献
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采用异丙醇溶液改性橙皮,考察了模拟废水中初始Pb2+质量浓度、废水pH、改性橙皮加入量和吸附时间等因素对改性橙皮对模拟废水中的Pb2+吸附效果的影响。实验结果表明,在初始Pb2+质量浓度为20 mg/L、废水pH为4、改性橙皮加入量为8 g/L、吸附时间为80 min的条件下,改性橙皮对废水中Pb2+的去除率可达88.41%。经浓度为0.1 mol/L的HCl溶液再生后,改性橙皮再生循环使用4次时效果仍较好。改性橙皮对Pb2+的吸附动力学可用准二级动力学方程很好地描述。改性橙皮对Pb2+的吸附符合Langmuir等温吸附方程,表明改性橙皮对Pb2+的吸附以单分子层吸附为主。 相似文献
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用HNO3、KOH、H2O2和H2O2/UV对粘胶基活性碳纤维(ACF)进行改性,并用扫描电子显微镜和BET的方法对未改性和改性后的ACF进行表征。以ACF为电极,直流稳压电源提供电压,在静态吸附装置中进行NaCI溶液的电吸附脱盐实验。实验结果表明:对同种ACF,随NaCl质量浓度的增加,吸附速率加快,ACF吸附量增大;在相同NaCl质量浓度条件下,电压越高,ACF吸附量越大。对各种ACF电吸附脱盐效果进行比较发现,KOH改性ACF效果最好,HNO3改性ACF效果最差。 相似文献
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将小麦秸秆改性后制备改性秸秆固定化微生物,用于处理钻井泥浆。考察了改性时间、改性剂浓度、改性剂配比对秸秆吸附微生物效果的影响,以及改性秸秆固定化微生物对钻井泥浆的处理效果。实验结果表明:在改性时间为60 min、氢氧化钠溶液浓度为0.1 mol/L、过氧化氢溶液浓度为1.0 mol/L、氢氧化钠溶液与过氧化氢溶液体积比为3∶1的最佳改性条件下,改性秸秆的BET比表面积增大了36.27%,Langmuir比表面积增加了37.63%,微生物吸附量增加了200.77%;在钻井泥浆处理量为1 000 g、改性秸秆固定化微生物加入量为2 g、土壤加入量为1 000 g、处理时间为15 d的条件下,钻井泥浆COD、可溶性盐、石油烃的去除率分别为84.9%,71.6%,90.1%。 相似文献
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采用固定床吸附系统,对自制褐煤活性焦的脱汞性能进行了试验研究,研究发现自制活性焦对烟气中Hg0有一定的吸附能力,随着Hg0的入口浓度的增加,活性焦质量的增加,活性焦的吸附量也在增加。40mg时3号活性焦由10ng/min汞入1:2浓度时26.68%的最大吸附效率提高到40ng/min汞入口浓度时的53.12%。10ng/min汞入口浓度时3号活性焦在40mg时的最大吸附效率为26.68%,而在80mg时吸附效率提高到43.2%。烟气中的SO2、NO气体对活性焦吸附汞有一定的促进作用。在试验的基础上建立了固定床吸附系统的数学模型,基于Lan—mguir吸附系数,考虑吸附过程中颗粒内、外的传质控制过程,建立质量平衡方程。通过Matlab模型计算,计算结果与试验结果基本吻合,计算的活性焦脱汞效率要优于试验数值,计算的是理想情况下活性焦对汞的吸附效率,实际情况会有所降低。 相似文献
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采用HCl溶液对沸石(F0)、蛭石(ZH0)、秸秆(J0)和棕榈生物炭(Z0)进行活化预处理,以环氧氯丙烷为交联剂,将β-环糊精(β-CD)负载到原始材料上,制备了4种新型吸附材料F2、ZH2、J2和Z2。采用FTIR、元素分析、SEM和TG等技术对吸附材料进行了表征,探讨了其对甲基橙的吸附性能。表征结果显示,β-CD被成功地负载到沸石、蛭石、秸秆生物炭和棕榈生物炭上。吸附实验结果表明:负载β-CD后的4种材料对甲基橙的平衡吸附量大小顺序为J2> F2> ZH2> Z2;溶液pH和吸附温度的提高可有效提升4种材料对甲基橙的吸附能力。吸附动力学和热力学研究表明,4种材料对甲基橙的吸附过程中物理吸附起着主导作用,且更趋向于单分子层吸附。4种材料均具有良好的重复使用性能。 相似文献
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Huan Liu Bei Yuan Bi Zhang Hongyun Hu Aijun Li Guangqian Luo Hong Yao 《Journal of Material Cycles and Waste Management》2014,16(1):101-107
Mercury from coal-fired utility boilers, as the largest atmospheric mercury emission source, imposes serious environmental risks and health concerns. In order to explore the possibility of reducing costs of activated carbon injection, we investigated the most promising mercury control technology, Hg0 removal using ZnCl2-impregnated adsorbents derived from sewage sludge. The results demonstrated that sludge-based adsorbents (SBAs) had fairly high mercury adsorption capacity over a wide range of temperatures (80–170 °C). Oxidizing atmosphere could improve the adsorption of Hg0 and weaken the inhibition of SO2 on mercury adsorption to some extent. NO exhibited no obvious impact on mercury removal performance. In addition, to clarify whether oxygen- or chlorine-containing functional groups attributed to good mercury adsorption capacity of SBAs, the oxygen-containing functional groups were removed using Boehm’s method, and a temperature-programmed decomposition desorption experiment was conducted. The results suggest that chlorine-containing functional groups played a significant role in the removal process of mercury from flue gas using SBAs. 相似文献
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A series of laboratory batch leaching tests was conducted to evaluate the performance of different activated carbons in stabilizing mercury in soils. Based on the results of these experiments, an amendment application rate of 5 percent powdered activated carbon (PAC) was selected for in situ field application at a former industrial facility. A geochemical model was also developed to simulate the interactions between mercury and activated carbon in vadose‐zone soils. Modeling was used to (1) better understand possible mercury sequestration mechanisms and (2) predict the in situ performance of PAC. Model results indicate dissolved mercury concentrations observed in batch tests are consistent with equilibrium partitioning of mercury between dissolved organic matter, soil organic matter, and PAC. Activated carbon is predicted to reduce dissolved mercury concentrations via two mechanisms: (1) the formation of stable mercury complexes on PAC surfaces and (2) the direct adsorption of dissolved organic matter that would otherwise be available for mercury dissolution. Study results demonstrate PAC effectiveness for site soils with mercury concentrations below 200 mg/kg. © 2010 Wiley Periodicals, Inc. 相似文献
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Modeling of mercury sorption by activated carbon in a confined,a semi-fluidized,and a fluidized bed 总被引:5,自引:0,他引:5
A process model was developed to simulate elemental mercury sorption by activated carbon in three distinct beds, namely a confined, a semi-fluidized, and a fluidized bed. The model involved the coupling of a kinetic model based on the mechanisms of surface equilibrium and external mass transfer, and a material balance model based on the tank-in-series approach. For surface equilibrium, three different equilibrium laws were used in the model, namely the Henry's Law, the Langmuir isotherm and the Freundlich isotherm. Literature mercury sorption data were used to determine the best-fit values of parameters for these equilibrium expressions. The parameter-fitted model was then used to simulate mercury sorption processes in the three distinct beds. The simulation parameters were mercury concentration, gas flow rate, adsorption temperature and the degree of semi-fluidization. The simulation results have indicated that the model is capable of describing the literature available mercury sorption data. All the three surface equilibrium laws appear to simulate the adsorption profiles equally well mainly because the sorption process occurs in an extremely low concentration range. The simulation results for the three distinct beds have suggested that the confined bed has the best mercury control performance; however, it generates the highest pressure-drop across the bed. A fluidized bed creates the least pressure drop; however, its sorption performance is poor. A semi-fluidized bed offers acceptable performance with affordable pressure-drops and can be a practical candidate for the process. 相似文献
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《Waste management (New York, N.Y.)》1999,19(4):263-268
Cesium removal from de-ionized water, seawater, and limewater using copper ferrocyanide (CFC) and porous media including silica gel, bentonite, vermiculite, and zeolite as adsorbents were investigated; CFC was incorporated with vermiculite to prepare a compound adsorbent for improving the Cs-leaching resistance of solidified borate radwastes. It was shown that the Cs-removal efficiency by CFC, defined as the percentage of cesium removed or adsorpted from solution, was largely affected by pHs of the solutions. Good removal efficiency occurred at pHs ranging from 3 to 12 with the best from 7 to 10. Vermiculite and zeolite were shown to have better removal power than silica gel and bentonite, and vermiculite was chosen to incorporate with CFC to make compound adsorbents because of its good compatibility with CFC floc. Compound adsorbents with different CFC contents were used as additives in the solidification of radioactive borate wastes for improving the cesium leaching resistance of the solidified products. Experimental results showed that the cesium leachability index measured following the method described in ANSI/ANS 16.1 increased from 7.96 to 9.76 by adding 0.25% of a compound adsorbent containing 20% CFC and 80% vermiculite. It indicated that the compound adsorbent is very useful for improving cesium-leaching resistance of the solidified borate wastes. 相似文献
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To evaluate the effect of vermiculite addition on composting food wastes from Korean households, food wastes were composted in three small bins to which different additives were added. The following three bins were employed: in Case I, only recycled compost was composted; in Case II, food wastes with recycled compost; and in Case III, food wastes with recycled compost and vermiculite. In the experiment performed for 30 days, it was confirmed that the supplementary addition of vermiculite to the composting mixture did not significantly improve the weight loss rate and the decomposition rate of food wastes. Due to dilution through the use of inorganic vermiculite, the vermiculite addition reduced the organic matter concentration of the composting mixtures. Vermiculite addition did not raise the pH value. Weight losses of roughly 70% were observed based on calculating moisture loss as well as dry food waste loss and not considering additives, while dry food waste loss was 29.4% and 35.8% with and without the addition of vermiculite, respectively. For these experiments, the major portion of the weight loss was the loss of water. The results indicate a need to differentiate between weight loss percentages and decomposition percentages, and a need to indicate if either of these percentages includes or excludes the mass of additives. 相似文献