【作者】 张威；

【导师】 王鹏；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2007， 硕士

【摘要】 本文建立了以颗粒活性炭为催化剂微波诱导氧化工艺(Microwave Induced Oxidation Process,简称MIOP)和活性炭吸附-微波辐照活性炭再生工艺处理苯酚废水,并深入开展了相关基础研究。基于活性炭对有机污染物的吸附能力和对微波的强吸收能力,利用微波能量实现对有机物的分解和炭化。本文首先以苯酚废水为处理对象,建立了活性炭为催化剂MIOP工艺。通过实验确定了MIOP最佳处理条件,50ml浓度为68.5mg·L-1的苯酚溶液,溶液pH<9,活性炭用量2.0g,100W微波辐照10min,对其去除率为96%,苯酚浓度增大到420mg·L-1,去除率仍可达85%左右。活性炭经过6次重复使用后,对苯酚的去除率可保持在80%以上。反应动力学研究表明,该过程符合一级动力学规律,动力学常数k=0.3231min-1,半衰期t1/2=2.15min。通过对比实验和微波辐照前后溶液进行的紫外扫描分析可知,MIOP对苯酚降解彻底。以吉林某化工厂有机废水为处理对象,建立了活性炭吸附-微波辐照活性炭再生工艺。通过实验表明JX-206型果壳炭对废水处理效果最好,最佳吸附工艺条件:100ml废水,pH=3,加30g活性炭,作用2h达到吸附平衡,COD去除率为90.17%,活性炭经过9次重复使用后对废水COD去除率为80%左右。修正后的Freundlich吸附等温模型能更好地定量描述其吸附过程。活性炭再生的最佳工艺条件:功率为400W的微波辐照1.67min,活性炭表面为600℃,再生后活性炭碘值可达到900mg·g-1左右,活性炭燃烧的损失不足2%。在工艺研究的基础上进行了活性炭吸附-微波辐照活性炭再生工艺的相关基础研究。对不同条件下活性炭吸附苯酚的速率常数ka、吸附活化能E以及液相有效扩散系数Di进行了估算。利用Langmuir参数计算了吸附标准热力学函数△G 0、△H 0、△S0。结果表明,在pH5.35和pH10.30时,△G 0<0。但在低pH时,吸附速率常数大,吸附活化能小,有效扩散系数大,吸附量大,苯酚分子在活性炭表面呈直立取向,该过程放热较多,熵增较小。活性炭是很好的吸收微波物质,功率为600W的微波辐照2min,活性炭表面温度可达1000℃,含水率由54%降至15%。经验公式T=c1×exp(c2/t)可以近似定量描述活性炭在微波场内的升温过程。与辐照前活性炭相比,辐照后的活性炭表面pH值由4.82增加到6.82。活性炭比表面积、孔容积都增加了100%左右,且微波主要作用于直径小于5nm的活性炭孔。更多还原

【Abstract】 Microwave Induced Oxidation Process (MIOP) with Granular Activated Carbon (GAC) as catalyst and GAC adsorption-GAC regeneration under microwave irradiation were introduced into the treatment of phenol wastewater. Furthermore, corresponding theoretical investigation was performed. Upon the basis of adsorption of organic pollutants on GAC and intensive absorption of MV by GAC, organic pollutants were decomposed and carbonized under microwave irradiation.Firstly, this paper was concentrated on the treatment of phenole wastewater, MIOP with GAC as catalyst was established. Through the experiment it concluded that the removal rate of phenol was over 96% under the optimal treatment conditions: 50ml phenol wastewater of 68.5mgL-1; pH<9, GAC addition amount of 2.0g; 10min under MV of 100W. When phenol wastewater concentration was up to 420mg·L-1, the removal rate of phenol reached about 85%. After six times repeated utilization of GAC, the removal rate of phenol was still above 80%. Kinetics of phenol wastewater treatment was studied and the results showed that the process was fist-order kinetics reaction, the kinetics rate constant k= 0.3231 min-1, the half-life period t1/2= 2.15 min. It concluded that MIOP decomposed phenol completely from contrastive experiments and the ultraviolet spectra of phenol before and after MW irradiation.And then, aimed at organic wastewater of certain chemical plant in Jilin, GAC adsorption and GAC regeneration under microwave irradiation were established. Through experiment, it indicated that JX-206 fruit shell carbon was provided with the best wastewater treatement effect, the removal rate of COD was 90.17% and adsorption equilibrium was reached after 2h treatment under the optimal adsorption process: 1000mL wastewater; pH=3; GAC addition amount of 30.0g. After nine times repeated utilization of GAC, the removal rate of COD was still about 80%. Modified Freundlich adsorption isotherm model could be used to formulate the adsorption behavior of organic pollutants on GAC quantificationally. Iodine values of the regenerated GAC could reach about 900mg·g-1, the mass loss of GAC is less than 2% resulted from combustion under the optimal GAC-regenerated conditions: 1.67min under microwave irradiation of 400W; 600℃of GAC surface temperature.Based upon process research, the theory research of GAC adsorption-GAC regeneration under microwave irradiation was performed. Phenol adsorption kinetics rate constant ka, activation energy E and liquid effective diffusion coefficient Di of GAC adsorption under different conditions were estimated. Besides, standard free energy△G0、enthalpy△H0 and entropy△S0 of adsorption were calculated from Langmuir parameters. The results showed that when pH=5.35 and pH=10.30,△G0<0. However, the molecules of phenol may be adsorbed vertically, when pH was lower, ka, Di, adsorption amount and heat emission were higher, and E smaller. In this process the molecules of phenol may be adsorbed vertically, heat emission was higher, entropy enhancement lower. As result of intensive absoption of microwave by GAC, GAC surface temperature could reach to 1000℃, water- contained content increased from 54% to 15% under 2min MV irradiation of 600W. Moreover, temperature rising behavior could be described approximately quantificationally with experienced equation T=c1×exp(c2/t). Compared with GAC before microwave irradiation, after microwave irradiation pH of GAC surface increased from 4.82 to 6.82, the specific area and pore volume of regenerated GAC both increased 100%, microwave play a major role in GAC with pore less than 5nm.更多还原