开孔泡沫混凝土的制备及其吸附性能研究

发布时间：2018-06-12 08:23

本文选题：开孔泡沫混凝土 + 制备　；参考：《西南科技大学》2017年硕士论文

【摘要】：目前,含铬污水处理是我国面临的重大环境问题之一,多孔材料因具有特殊孔结构常被用于污水处理,而多孔材料孔结构的变化对其性能及应用有极大影响。泡沫混凝土因闭孔较多,很少被应用于污水处理。因此,制备具有开孔结构的泡沫混凝土,并研究其对模拟含铬污水中铬的吸附性能,为解决含铬污水处理提供一定的技术支撑,同时也为水泥基多孔材料功能化应用提供参考。本论文以普通硅酸盐水泥和发泡剂为主要原料,采用物理发泡方法,设计、制备400kg/m3开孔结构的泡沫混凝土。研究了水灰比、发泡剂稀释比例、泡沫掺量、泡沫密度和养护制度等因素对开孔泡沫混凝土孔结构的影响;并将开孔泡沫混凝土作为吸附剂,研究了其对模拟含铬废水中Cr(III)的吸附性能。通过改变吸附剂的投加量、吸附时间和吸附温度对其静态吸附性能的影响,同时研究了此过程的吸附动力学和热力学;通过改变吸附柱高度、溶液的初始浓度和流速对其动态吸附性能的影响,并进行了穿透曲线的拟合。研究结果表明,水灰比为0.35~0.55,发泡剂液浓度为2:70,泡沫掺量为11%和泡沫密度为36kg/m3~51 k g/m3时可制备出干密度为40 0k g/m3且开孔率在45%~59%的开孔泡沫混凝土;吸附试验表明:(1)静态吸附实验:吸附剂为0.3 g,吸附率可达9 8%,且该吸附过程符合准二级吸附动力学模型和Langmuir等温吸附模型。(2)动态吸附实验:含Cr(III)模拟废水的初始浓度为85 mg/L,溶液流速为7.5 m L/m i n,吸附柱高度为1 9 c m时,穿透时间为1 2 6 0 m in,吸附效率为81%。且该吸附行为符合Thomas模型和Yoon-Nelson模型,吸附过程中吸附剂外表面扩散和内扩散不是反应的速率控制步骤。
[Abstract]:At present, the treatment of chromium-containing wastewater is one of the major environmental problems in China. Porous materials are often used in sewage treatment because of their special pore structure, and the changes of pore structure of porous materials have a great impact on their performance and application. Foam concrete is rarely used in sewage treatment because of more closed pores. Therefore, the preparation of foam concrete with open pore structure and the study of its adsorption performance on chromium in simulated chromium-containing wastewater provide some technical support for the treatment of chromium-containing wastewater, and also provide a reference for the functional application of cement-based porous materials. In this paper, ordinary Portland cement and foaming agent are used as the main raw materials, the physical foaming method is used to design and prepare the 400kg/m3 open structure foam concrete. The effects of water-cement ratio, foaming agent dilution ratio, foam content, foam density and curing system on the pore structure of open-hole foam concrete were studied, and the porous foam concrete was used as adsorbent. The adsorption properties of Cr-III in simulated Cr-containing wastewater were studied. The adsorption kinetics and thermodynamics of the process were studied by changing the dosage of adsorbent, adsorption time and adsorption temperature, and the adsorption column height was changed. The influence of the initial concentration and flow rate of the solution on the dynamic adsorption performance was investigated and the penetration curve was fitted. The results show that when the water-cement ratio is 0.35 ~ 0.55, the concentration of foaming agent is 2: 70, the foam content is 11% and the foam density is 36kg/m3~51 k g/m3, the dry density is 400 k g/m3 and the porosity is 45%. The adsorption experiment shows that the static adsorption experiment: the adsorbent is 0.3 g, the adsorption rate can reach 9.8, and the adsorption process accords with the quasi-second-order adsorption kinetic model and Langmuir isothermal adsorption model .t2) dynamic adsorption experiment: Cr-III) simulates the initial wastewater. When the concentration is 85 mg / L, the flow rate of solution is 7.5 mL / ml, the height of adsorption column is 19 cm, The penetration time is 1 260 min and the adsorption efficiency is 81 mm. The adsorption behavior is in accordance with the Thomas model and Yoon-Nelson model. The external surface diffusion and internal diffusion of adsorbent are not the rate control steps in the adsorption process.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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