火山岩材料作为PRB介质修复铜污染地下水的研究

发布时间：2018-05-27 00:00

本文选题：火山渣 + 浮石　；参考：《兰州理工大学》2017年硕士论文

【摘要】：本研究以天然火山岩材料火山渣和浮石为研究对象,讨论了粒径、吸附时间、投加量、溶液p H、溶液初始浓度对火山渣和浮石去除地下水中Cu(Ⅱ)的性能影响。还提出了火山渣的最佳改性方法和条件,探讨了铁改性火山渣除Cu(Ⅱ)的最佳工艺条件,然后通过动态柱实验对两种可渗透反应墙(Permeable Reactive Barrier,PRB)填充介质修复Cu(Ⅱ)污染地下水的可行性进行评估,并探索出两种火山岩的再生方法和最佳的再生条件。本研究得出的主要结论如下:(1)火山渣和浮石的最佳静态除Cu(Ⅱ)工艺条件:在初始浓度为20mg/L时,选择火山岩的粒径为0.15~0.425mm(4~100目),固液比为8g/L,p H为6,反应时间为2h、震荡速度为200r/min时,火山渣和浮石对Cu(Ⅱ)有最佳的去除效果。火山渣和浮石对Cu(Ⅱ)的吸附更符合Langmuir等温吸附规律,火山渣和浮石吸附Cu(Ⅱ)的动力学过程均符合准二级动力学模型。(2)浮石对Cu(Ⅱ)的吸附效果优于火山渣,为了更好地满足应用要求,有必要对火山渣加以改性。经FeCl_3浸泡改性后的火山渣可以显著提高对水体中Cu(Ⅱ)的去除效果。最终选用2mol/L的FeCl_3作为火山渣改性剂,最佳固液比和改性时间分别为30:1和12h。静态吸附实验确定的铁改性火山渣除Cu(Ⅱ)的最佳工艺条件与浮石相同,相对于Freundlich模型,改性火山渣对Cu(Ⅱ)的吸附等温线更符合Langmuir等温吸附模型,表明铁改性火山渣对Cu(Ⅱ)的吸附以单分子层吸附为主,最大吸附量为2.524mg/g。改性火山渣对Cu(Ⅱ)的吸附符合准二级动力学模型,说明铁改性火山渣的吸附是以化学吸附为主。通过物相与表面形貌分析发现,改性后的火山渣表面铁氧化物的量显著增加,且含有更多的微孔和更大的表面积,可以提高火山渣对Cu(Ⅱ)的吸附性能。(3)不同流速的动态柱实验结果表明,流速较低时(0.3m L/min),浮石PRB对不同初始浓度Cu(Ⅱ)的去除率均在96%以上。改性火山渣PRB对Cu(Ⅱ)能实现92%以上的去除率。而当流速为0.5m L/min和1.0m L/min时,各反应柱随着处理时间的延长,去除率呈明显下降趋势。浮石PRB和铁改性火山渣PRB对初始浓度为10mg/L含Cu(Ⅱ)废水去除效果最好,出水均达到《地下水质量标准》III类标准限值。(4)不同初始Cu(Ⅱ)浓度条件下的动态PRB柱实验表明,浮石动态反应柱在不同浓度梯度下对Cu(Ⅱ)的去除效果要优于铁改性火山渣。与铁改性火山渣PRB相比,浮石PRB更能适应高流速(1.0m L/min)条件下对地下水中Cu(Ⅱ)的去除。(5)火山岩PRB在整个实验过程中运行效果良好,反应装置运行54d后,去除率仍能维持在85%左右,出水仍能满足《地下水质量标准》III类水质标准要求。可以将浮石和铁改性火山渣作为新型PRB反应介质应用于地下水原位除Cu(Ⅱ)的实践项目中。(6)盐酸浸泡再生效果要优于高温活化再生,最佳再生条件:盐酸浓度为0.3mol/L,再生时间为60min。经过5个周期的连续吸附/再生过程,改性火山渣和浮石对Cu(Ⅱ)的去除率仍可达到80%以上,充分说明再生的两种火山岩仍具有良好的除Cu(Ⅱ)能力。
[Abstract]:In this study, the effects of particle size, adsorption time, dosage, solution P H, solution initial concentration on the removal of Cu (II) in groundwater by volcanic slag and pumice were discussed. The optimum methods and conditions for the modification of the slag were also discussed. The best work of the iron modified volcano slag in addition to Cu (II) was discussed. The feasibility of two kinds of permeable reaction walls (Permeable Reactive Barrier, PRB) filled medium to repair the polluted groundwater of Cu (II) was evaluated by the dynamic column experiment, and the regeneration methods and optimal regeneration conditions of the two kinds of volcanic rocks were explored. The main conclusions of this study were as follows: (1) the best static of the crater and pumice. Cu (II) process conditions: when the initial concentration is 20mg/L, the particle size of the volcanic rock is 0.15~0.425mm (4~100 mesh), the solid to liquid ratio is 8g/L, the P H is 6, the reaction time is 2h, the shock velocity is 200r/min, the slag and the pumice have the best removal effect to Cu (II). The adsorption of volcanic slag and pumice to Cu (II) is more consistent with the regularity of Langmuir isothermal adsorption. The kinetic process of adsorption of Cu (II) by volcanic slag and pumice all conforms to the quasi two stage kinetic model. (2) the adsorption effect of pumice on Cu (II) is better than that of volcanic slag. In order to better meet the application requirements, it is necessary to modify the volcanic slag. The removal of Cu (II) in water can be significantly improved by the modified slag after FeCl_3 soaking. 2mol/L FeCl_3 is used as the modifier for the slag. The optimum solid to liquid ratio and the modification time are 30:1 and 12h. static adsorption experiments. The best technological conditions of the iron modified volcano slag are the same as that of the pumice. Relative to the Freundlich model, the adsorption isotherm of the modified crater to Cu (II) is more consistent with the Langmuir isothermal adsorption model. The adsorption of iron modified volcano on Cu (II) is dominated by single molecular layer adsorption. The maximum adsorption capacity is 2.524mg/g. modified volcano slag adsorption to Cu (II) in accordance with the quasi two stage kinetic model. It shows that the adsorption of iron modified volcanoes is mainly by chemical adsorption. By the analysis of the surface morphology and surface morphology, the iron oxide on the surface of the modified volcano slag is found. The adsorption properties of Cu (II) can be improved by increasing the amount of micropores and larger surface area. (3) the experimental results of dynamic columns at different velocities show that the removal rate of Cu (II) with different initial concentrations is above 96% when the velocity is lower (0.3m L/min). The modified volcano slag PRB can achieve more than 92% of Cu (II). When the flow rate is 0.5m L/min and 1.0m L/min, the removal rate of each reaction column decreases with the prolongation of the treatment time. The removal efficiency of the floating stone PRB and the iron modified volcano slag PRB is the best for the initial concentration of 10mg/L containing Cu (II) wastewater, and the effluent reaches the standard >III standard limit of the standard of the underground water quality. (4) different initial Cu (II) concentration The dynamic PRB column experiment under the degree condition shows that the removal effect of the pumice dynamic reaction column to Cu (II) under different concentration gradient is better than that of the iron modified volcano. Compared with the iron modified volcano slag PRB, pumice PRB can adapt to the removal of Cu (II) in the groundwater under the condition of high velocity (1.0m L/min). (5) the volcanic PRB is running during the whole experiment process. The effect is good, after the reaction device runs 54d, the removal rate can still be maintained at about 85%, and the effluent can still meet the standard of >III water quality standard of the standard of groundwater quality. It can be used as a new PRB reaction medium in the practice project of the groundwater in situ removal of Cu (II). (6) the regenerative effect of hydrochloric acid is better than the high temperature live. The optimum regeneration conditions are as follows: the concentration of hydrochloric acid is 0.3mol/L and the regeneration time is 60min. through 5 cycles of continuous adsorption / regeneration. The removal rate of Cu (II) by modified crater and pumice can still reach more than 80%, which fully indicates that the two kinds of regenerated volcanic rocks still have good ability to remove Cu (II).
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X523

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