功能化生物炭缓解纳米颗粒毒性和膜污染及储能应用研究

发布时间：2018-01-02 21:30

本文关键词：功能化生物炭缓解纳米颗粒毒性和膜污染及储能应用研究　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：生物炭是生物质热解过程的固体副产物。近年来,生物炭在缓解全球变暖、改良土壤及去除污染物等方面得到了较为广泛的应用。本论文研究了生物炭对氧化铜纳米颗粒植物毒性的缓解作用与机理,探究了改性生物炭在膜生物反应器中对膜污染的缓解与机制,最后探索了重金属污染的生物质制备得到的生物炭在储能方面的应用。本研究旨在通过对生物炭与纳米颗粒、生物炭与微生物胞外分泌物的作用、以及生物炭的电子传递性能研究,拓展生物炭在环境和能源领域的新应用,促进废弃生物质的处置与资源回收。论文主要研究内容和结果如下:1.生物炭缓解氧化铜纳米颗粒(CuONPs)植物毒性机理:在小麦萌芽实验和水培生长实验中,研究了不同浓度的氧化铜纳米颗粒对植物生长的影响,分析了生物炭对氧化铜纳米颗粒植物毒性的缓解作用,并通过设计实验对其脱毒机制进行了验证。结果表明,生物炭对氧化铜纳米颗粒的植物毒性具有显著的缓解作用,在水培系统中添加3%的生物炭,可以完全消除高浓度(500 mg L-1)CuONPs对小麦生长的抑制,并降低小麦组织内的铜含量,降低毒性金属在作物内的富集。其脱毒机理主要包括生物炭对纳米颗粒释放铜离子的吸附,以及生物炭的空间阻隔作用,即植物根系表面吸附的生物炭减少了铜离子和纳米颗粒与植物的直接接触,降低纳米氧化铜的毒性。2.生物炭对膜生物反应器(MBR)膜污染的缓解作用与机制:研究了不同改性生物炭对MBR膜污染的影响,分析了不同类型的阻力与污泥性质的相关性,探索了生物炭的抗污机理。跨膜压差(TMP)测试结果显示碱洗生物炭、亲水性生物炭和活化生物炭的投加都能显著缓解膜污染。生物炭的添加能降低系统内的胞外聚合物(EPS)浓度和膜过滤阻力,其中,碱洗生物炭的添加主要降低膜的滤饼层阻力,而亲水性生物炭和活化生物炭的添加主要降低膜的滤饼层阻力和孔堵塞阻力。另外生物炭的亲水性有利于提高污泥的沉降性能,降低膜的滤饼层阻力,缓解膜污染。3.重金属污染生物质制备生物炭的储能应用探索:利用吸收和吸附镍的水葫芦生物质,通过快速热解和活化制备了 Ni,N掺杂的多孔碳材料,并比较了吸收和吸附镍对材料电化学行为的影响。结果表明,通过快速热解和活化水葫芦生物质制备的多孔碳材料具有良好的超级电容器性能,Ni对材料的电容器性能具有明显的促进作用,其中,在生长过程中吸收的Ni相对于吸附的Ni更能提高材料的电容性能。主要原因包括:在热解和活化过程中,吸收的Ni比原位吸附的Ni具有更有效的催化造孔作用;在生长过程中,Ni能促进水葫芦中氮的吸收,增加多孔碳的N掺杂量;并且吸收的Ni在材料中倾向于生成粒径更小的NiO颗粒,提高材料电容性能。
[Abstract]:Biochar is solid by-product of biomass pyrolysis process. In recent years, the biological carbon in the mitigation of global warming, soil improvement and removal of pollutants has been widely used. This paper studies the mitigation effect and mechanism of biochar on copper oxide nanoparticle toxicity in plants, explore the modified biological mechanism of carbon mitigation and membrane fouling in membrane bioreactor, and finally explore the biological activated carbon prepared by the heavy metal pollution in the application of biomass for energy storage. This study aims to biochar and bio carbon nanoparticles, and microbial extracellular secretions, and electron transfer properties of biochar, develop new biological applications carbon in the field of environment and energy, promote the disposal and recycling of waste biomass. The main research contents and results are as follows: 1. the biological carbon mitigation copper oxide nanoparticles (CuONPs) plant Toxic mechanism: in wheat germination experiment and hydroponic growth experiment, the effects of different concentrations of copper oxide nanoparticles on the growth of plants, analyzed the mitigation effect of biochar on copper oxide nanoparticle toxicity in plants, and verified by experimental design on its mechanism of detoxification. The results showed that the toxicity of biochar on plants copper oxide nanoparticles have significant mitigation effects of biochar in the 3% hydroponic system, can completely eliminate the high concentration (500 mg L-1) inhibited CuONPs on wheat growth, and reduce the copper content of wheat tissue, reduce the toxicity of metal enrichment in the crop. The detoxification mechanism mainly includes biological adsorption the release of copper ion on carbon nano particles, and biological carbon space barrier effect, namely the biological carbon adsorbed on the surface of plant roots to reduce the copper ions and nanoparticles and plant direct contact, reducing Na For the toxicity of.2. biological carbon meters copper oxide (MBR) membrane biological reaction to alleviate the effects and mechanism of membrane fouling: the influence of different modified biochar on MBR membrane fouling were studied, analyzed the relationship between the resistance and sludge properties of different types, explore the anti fouling mechanism of biological carbon (trans membrane pressure. TMP) test results show that the alkali washing of biochar, hydrophilic biological carbon and activated biochar addition can significantly alleviate membrane fouling. Biochar addition can reduce the extracellular polymers in the system (EPS) concentration and membrane filtration resistance, the alkali washing of biochar added to reduce the filter cake resistance membrane, hydrophilic biological carbon and activated biochar addition decreased the cake layer resistance and membrane pore blocking resistance. In addition, hydrophilic biochar is beneficial to improve the settling performance of sludge, reduce cake resistance, alleviate membrane fouling of.3. heavy metal pollution of biomass Preparation of biological carbon storage application: absorption and adsorption of nickel by water hyacinth biomass, fast pyrolysis and activation of Ni were prepared, the porous carbon materials doped with N, and compared the absorption and adsorption effect of nickel on the electrochemical behavior of materials. The results show that the super capacitor has good performance by fast pyrolysis porous carbon materials and activation of water hyacinth biomass preparation, Ni capacitor performance of materials has obvious role in promoting, the absorption in the process of growth of Ni relative to the adsorption of Ni can improve the performance of capacitor materials. The main reasons include: in the pyrolysis and activation process, the absorption of Ni in situ adsorption ratio Ni has more effective catalytic pore effect; in the growth process, Ni can promote the water hyacinth in nitrogen absorption, increase of N doping content of porous carbon; and the absorption of Ni particles to generate NiO tend to a smaller size in the material, Improve the performance of material capacitance.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X505

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