去除焦化反渗透浓水有机污染物试验研究

发布时间：2018-05-17 07:24

本文选题：煤粉 + 焦粉　；参考：《中国矿业大学》2017年硕士论文

【摘要】：双膜工艺广泛应用于焦化废水深度处理过程,从废水中获得70%高品质出水的同时会形成30%的反渗透浓水(ROC)。ROC中有机物比系统进水高2-3倍,且通常为难生物降解的溶解性有机物。若未经妥善处理直接排放,将会对环境造成极大的危害。相比于吸附法,生物法和高级氧化法受水质影响比较大,处理效果不甚理想。活性炭等传统吸附剂存在价格昂贵、再生困难及污染物没有合理去向等缺点,导致吸附法未得到大面积推广运用。由此,本文试图寻找一种新型吸附剂去除反渗透浓水中有机污染物,确保使用成本降低以及吸附效率提高,促使吸附法在实践中得到更加广泛的应用。在文献回顾及理论分析基础上,选择煤粉、细焦粉和粗焦粉作为三类备选吸附剂。首先,采用三级静态吸附试验对三种吸附剂去除ROC中有机污染物的效果进行对比,确定较优吸附剂。其次,对选定的吸附剂进行吸附效果、吸附模型以及吸附性能的分析,为该吸附剂的工业应用提供理论指导。主要研究内容如下:对ROC进行水质分析。该污水呈浅黄色,离子含量较高,氯离子浓度为3347.81 mg/L,同时COD和UV254分别为219.00 mg/L和4.36。对吸附剂进行理化性质分析。采用激光粒度激光粒度仪、扫描电镜、傅里叶变换红外光谱、比表面测定仪分别对三种吸附剂的粒度组成、表面微观形貌、表面含氧官能团、比表面积、孔容和孔径分布进行分析。结果表明:-0.074 mm的颗粒分别在煤粉、细焦粉、粗焦粉中的比例占82.69%、69.68%、62.85%。细焦粉的孔隙结构比煤粉表面发达,表面粗糙度也是比煤粉和粗焦粉要大。煤粉、细焦粉及粗焦粉BET比表面积5.03 m2/g、24.82 m2/g及20.51 m2/g。吸附剂的选型与吸附性能研究。通过三级静态吸附试验得出,细焦粉、粗焦粉及煤粉对ROC中COD去除率可分别达到76.26%、74.06%及65.75%。建立静态吸附试验系统,得到细焦粉投加量、吸附时间、溶液pH值等因素对反渗透浓水中COD及UV254的去除效果和影响规律。研究表明,当试验条件为细焦粉投加量120 g/L、吸附时间10 min、溶液pH为7.56,对ROC中COD和UV254的去除率可达77.72%和86.22%,吸附后废水COD值为48.80 mg/L。探究溶液pH值对细焦粉孔隙结构及表面官能团的影响。与原细焦粉对比发现,经酸和碱处理后,细焦粉吸收峰、官能团的种类及孔隙结构均未发生明显变化。引入响应面试验得到函数方程,并对预测模型进行验证,结果表明该模型能够较好反映COD、UV254去除率。吸附剂的吸附特性研究。对比吸附前后细焦粉的表面官能团以及表面微观形貌的变化,考察细焦粉吸附反渗透浓水中有机污染物的动力学以及热力学特征。通过数据拟合发现,细焦粉对反渗透浓水中有机污染物的吸附动力学曲线符合准二级动力学方程;等温吸附线符合Freundlinch等温吸附方程。
[Abstract]:Dual-membrane process is widely used in the advanced treatment of coking wastewater. When 70% high quality effluent is obtained from the wastewater, 30% of the organic matter in ROC.ROC will be 2-3 times higher than the influent of the system, and it is difficult to biodegrade dissolved organic matter. If the discharge is not handled properly, it will do great harm to the environment. Compared with adsorption method, biological method and advanced oxidation method are greatly affected by water quality, and the treatment effect is not satisfactory. The traditional adsorbents such as activated carbon have some disadvantages such as high price, difficulty in regeneration and lack of proper direction of pollutants, which lead to the lack of extensive application of the adsorption method. Therefore, this paper tries to find a new adsorbent to remove organic pollutants in reverse osmosis (RO) concentrated water, so as to reduce the use cost and improve the adsorption efficiency, which will promote the application of adsorption method in practice. On the basis of literature review and theoretical analysis, coal powder, fine coke powder and coarse coke powder were selected as three kinds of alternative adsorbents. First, three kinds of static adsorption experiments were used to compare the effects of three adsorbents on the removal of organic pollutants from ROC, and the better adsorbents were determined. Secondly, the adsorption effect, adsorption model and adsorption performance of the selected adsorbent are analyzed, which provides theoretical guidance for the industrial application of the adsorbent. The main research contents are as follows: the water quality of ROC is analyzed. The wastewater is yellowish and has a high ion content. The concentration of chloride ion is 3347.81 mg / L, and the COD and UV254 are 219.00 mg/L and 4.36 mg/L, respectively. The physical and chemical properties of the adsorbent were analyzed. Laser particle size analyzer, scanning electron microscope, Fourier transform infrared spectroscopy (FTIR) were used to analyze the particle size composition, surface morphology, surface oxygen functional group and specific surface area of the three adsorbents, respectively. Pore volume and pore size distribution were analyzed. The results show that the proportion of% -0.074 mm particles in coal powder, fine coke powder and coarse coke powder is 82.699.68mm and 62.85mm, respectively. The pore structure of fine coke powder is more developed than that of coal powder surface, and the surface roughness is larger than that of coal powder and coarse coke powder. The specific surface area of coal powder, fine coke powder and coarse coke powder is 5.03 m2 / g, 24.82 m2 / g and 20.51 m2 / g respectively. Study on the selection of adsorbent and its adsorption performance. Through the three-stage static adsorption test, it is found that the removal rate of COD in ROC by fine coke powder, coarse coke powder and coal powder can reach 76.2674.06% and 65.75% respectively. The static adsorption test system was established to obtain the removal efficiency and influence law of COD and UV254 in concentrated reverse osmosis water by the addition of fine coke powder, adsorption time and pH value of solution. The results showed that the removal rates of COD and UV254 in ROC were 77.72% and 86.22%, respectively, when the dosage of fine coke powder was 120 g / L, adsorption time was 10 min, pH was 7.56, and the COD value of wastewater was 48.80 mg / L after adsorption. The effect of pH value of solution on pore structure and surface functional groups of fine coke powder was investigated. Comparing with the original fine coke powder, it was found that the absorption peak, functional group type and pore structure of the fine coke powder did not change obviously after acid and alkali treatment. The function equation is obtained by using response surface test and the prediction model is verified. The results show that the model can well reflect the removal rate of CODU UV254. Study on adsorption characteristics of adsorbent. The changes of surface functional groups and surface morphology of fine coke powder before and after adsorption were compared, and the kinetics and thermodynamics of adsorption of organic pollutants in concentrated water by reverse osmosis were investigated. It is found that the adsorption kinetics curve of fine coke powder for concentrated organic pollutants in reverse osmosis water accords with quasi-second-order kinetic equation and the isothermal adsorption line accords with Freundlinch isothermal adsorption equation.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X784

【参考文献】