污泥生物炭水热制备及其对染料脱色研究

发布时间：2018-01-04 11:25

本文关键词：污泥生物炭水热制备及其对染料脱色研究　出处：《东华大学》2017年硕士论文　论文类型：学位论文

【摘要】：吸附法和高级氧化法是处理染料废水常用方法。但传统的吸附工艺以活性炭作为吸附剂,成本较高,且饱和后活性炭需要高温再生。常用的高级氧化工艺Fenton法,会产生大量铁泥废弃物,且Fe~(3+)影响出水色度。针对上述问题,本论文选用城市污泥固体废弃物作为原料,采用水热法将过渡金属Co和Fe负载在污泥生物炭上,污泥生物炭/钴吸附材料和污泥生物炭/钴/铁类芬顿催化材料。采用X射线衍射、扫描电子显微镜、傅里叶红外、热重分析等多种表征手段对材料进行微观结构分析,同时选用刚果红作为染料废水检验材料的吸附和催化降解性能。通过研究,本论文得到以下结论:以单独污泥作为原料,采用水热法制备污泥生物炭。通过单因素实验,分别考察水热温度、水热时间、水热pH和固体污泥填充质量四个因素对污泥生物炭处理刚果红染料废水的影响,得出最优的水热条件为:水热温度:180℃;水热时间:3 h;水热pH:9;固体污泥填充质量:1 g。通过表征分析发现污泥经水热法处理后,有机质发生碳化,产生多孔的结构,提高了材料的比表面积,且热稳定性提高,表面含氧官能团减少导致亲水性减弱。为进一步提高污泥生物炭的吸附性能,本研究在制备污泥生物炭的过程中掺杂过渡金属钴元素,当钴掺杂量达到8 g/L时,掺钴材料的比表面积从污泥生物炭的42.651 m2/g提高到71.579 m2/g,对刚果红的去除率从42.8%提高到97.3%。同时研究吸附温度、pH、染料配水溶剂等对刚果红去除的影响。研究结果表明,材料对于刚果红的吸附属于放热反应,温度的升高会降低去除率,所以选择最优的吸附温度为25℃;酸性环境对去除率影响较小,但是当pH调节为碱性时,去除率降低,分析原因是OH~-与刚果红染料竞争吸附剂表面的活性位点;选用自来水模拟实际水体,会导致去除率降低,但去除率仅降低4.38%,分析主要原因是自来水中杂质占据活性吸附位点。探究吸附材料对与刚果红的去除机理,材料对于刚果红的吸附遵循二级动力学模型,说明该吸附属于化学吸附;材料对于刚果红的吸附等温线更符合Langmuir型等温吸附,说明该吸附过程属于单分子层吸附。基于以上研究,制备污泥生物炭/钴/铁类芬顿催化材料,用于处理高浓度刚果红染料废水。通过单因素实验,探究铁离子掺杂量、材料投加量、双氧水投加量、溶液pH对降解率的影响。掺杂4 mmol Fe~(3+)的复合材料的最优反应条件为:材料的投加量为1 g/L,双氧水的投加量为0.75 m L/L,反应体系的pH为3,此时刚果红的脱色率可达100%。SEM表征发现,Fe~(3+)的加入使得复合材料出现了直径为300nm的炭微球,炭微球结构均一。VSM表征分析发现,复合材料的饱和磁强度较单独加入钴材料有所提高,饱和磁强度为17.749 emu/g,这与XRD分析中Fe_3O_4的生成研究结果一致。说明Fe~(3+)的加入,有利于材料从溶液中的分离。XPS表征分析得知复合材料的主要元素组成为C、Fe、Co、O,这也证明了在水热反应条件下,污泥生物炭、钴元素、铁元素很好的结合到了一起,形成了结构优良的复合材料。研究复合材料对刚果红的去除机理,表明复合材料与H_2O_2构成类Fenton体系,产生具有强氧化作用的?OH,复合材料对刚果红的去除是吸附与高级氧化协同作用的结果。
[Abstract]:Adsorption and advanced oxidation treatment of dye wastewater is commonly used method. But the traditional adsorption process using activated carbon as adsorbent, high cost, and the saturated activated carbon needs high temperature regeneration. Advanced oxidation processes commonly used Fenton method, will produce a lot of waste iron mud, and Fe~ (3+) to solve the above problems affect the water chroma. In this paper, city sludge solid waste as raw materials by hydrothermal method, the transition metal Co and Fe load in the sludge biological carbon, biological carbon / cobalt sludge adsorption materials and sludge biological carbon / cobalt / iron Fenton catalytic material. By using X ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis a variety of characterization methods of material microstructure is analyzed, at the same time using Congo red as the adsorption and catalytic degradation performance test material of dye wastewater. Through the research, this paper gets the following conclusions: to separate the sludge for As raw materials, preparation of bio carbon sludge by hydrothermal method. Through single factor experiment, respectively. The effect of hydrothermal temperature, hydrothermal time, hydrothermal pH and solid sludge filling quality four factors of Congo red dye wastewater treatment sludge biochar, the hydrothermal conditions for optimal hydrothermal temperature: 180 degrees time: 3 h; hydrothermal; hydrothermal pH:9; solid sludge filling quality: 1 g. analysis showed that the treated sludge characterized by hydrothermal method, organic matter carbonation, produce porous structure, increase the surface area of the material, and improve the thermal stability, surface oxygen groups reduced hydrophilicity decreased. In order to further improve the adsorption performance of sludge biochar, transition metal doped cobalt process of the preparation of biological carbon sludge in the system, when the cobalt content reached 8 g/L, Co doped material specific surface area increased from 42.651 M2 /g sludge biochar to 71.579 m2/g, The Congo red removal rate increased from 42.8% to 97.3%. and pH, adsorption temperature, influence of dyes solvent on the removal of Congo red. The results show that the material for the adsorption of Congo red is an exothermic reaction, high temperature will reduce the removal rate, so the choice of the optimal adsorption temperature is 25 DEG C; acidic environment little effect on the removal rate, but when the pH control is basic, the removal rate is reduced, cause analysis is the active site of OH~- and Congo red dye competition on the surface of adsorbent; use tap water to simulate the actual water, will lead to the removal rate decreased, but the removal rate decreased by 4.38%, the main reason is the analysis of impurities in tap water occupy active adsorption sites to explore the mechanism of the removal. Adsorption materials and materials for adsorption of Congo red, Congo red follows two order kinetic model, indicating that the adsorption belongs to chemical adsorption; materials for adsorption of Congo red Temperature is more in line with the Langmuir isotherm, the adsorption process belongs to monolayer adsorption. Based on the above research, the preparation of bio carbon / cobalt iron sludge / Fenton like catalytic material, for the treatment of high concentration of Congo red dye wastewater. Through single factor experiment, explore the iron ion doping amount, material dosage, dosage of hydrogen peroxide plus, the effect of pH on the degradation rate. The doping of 4 mmol Fe~ (3+) optimal reaction conditions of composite materials is: material dosage is 1 g/L, the dosage of hydrogen peroxide is 0.75 m L/L, pH of the reaction system was 3, the rate of decolorization of Congo red 100%.SEM characterization Fe~, (3+) adding composite diameter carbon microspheres 300nm, carbon microspheres uniform structure characterization of.VSM analysis showed that the composite strength is adding saturated magnetic cobalt material increased, saturation magnetization of 17.749 emu/g, and the Fe_3O_4 in XRD analysis Generation of research results. The results showed that Fe~ (3+) to join, has separated from the characterization of.XPS solution in the analysis that the main elements of composite materials composed of C, Fe, Co, O for the material, it also proves that under hydrothermal condition, biochar, cobalt iron sludge, with very good together, forming a composite structure. The excellent removal mechanism of composite materials of Congo red, show that the composite materials composed of H_2O_2 with Fenton system, which has a strong oxidation? OH composite materials on the removal of Congo red adsorption and advanced oxidation synergistic results.

【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X788

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