Abstract:

The biomass-based copper-loaded activated carbon catalysts (Cu/AC) were prepared by precursor impregnation method. N₂-adsorption desorption and X-ray photoelectron spectroscopy, etc. were used to investigate their physicochemical properties. The catalytic performance of the Cu/AC prepared with various carbonization and activation conditions for the wet oxidation degradation of phenol were evaluated in a fixed-bed reactor. The results demonstrated that the Cu species on the surface of Cu/AC co-existed with Cu²⁺ and (Cu⁺+Cu⁰). As the carbonization temperature increased, more volatiles were generated during the carbonization process, in which Cu²⁺ was reduced to Cu⁺ and Cu⁰, thus the content of (Cu⁺+Cu⁰) increased, and the catalytic activity for phenol degradation was gradually improved. As the carbonization time increased, the content of (Cu⁺+Cu⁰) decreased, and Cu₂O and CuO were well incorporated into the carrier which led to the increase of the lattice oxygen. Therefore the catalytic activity increased firstly and then decreased. As the activation temperature and the activation time increased, the specific surface area of Cu/AC reached 1096.1m²/g with massive micropores generated, and a large amount of oxygen-containing functional groups were decomposed which oxidized the (Cu⁺+Cu⁰) formed during the carbonization process to Cu²⁺, meanwhile the lattice oxygen content increased. Hence, the catalytic activity increased as the activation temperature, while it increased firstly and then decreased as the activation time. In the catalytic wet oxidation of phenol, the Cu/AC catalyst exhibited good stability with low Cu leaching concentration. The optimum preparation conditions of Cu/AC were carbonization temperature of 800℃, carbonization time of 2h, activation temperature of 880℃, and activation time of 2h. The Cu/AC prepared under the optimum conditions achieved 98.5% phenol conversion and 91.1% COD conversion in 8.5h.

Key words: waste water, fixed-bed, biomass, catalytic wet oxidation, phenol, copper-loaded activated carbon

摘要：

采用前体浸渍法研制了生物质基载铜活性炭催化剂（Cu/AC），利用N₂-吸附脱附、X射线光电子能谱等技术对Cu/AC性质进行了表征，在固定床反应器中研究了不同炭化活化条件所得Cu/AC催化湿式氧化降解苯酚性能。结果表明：Cu/AC表面Cu物种以Cu²⁺和（Cu⁺+Cu⁰）共存。随着制备Cu/AC炭化温度的升高，炭化过程中产生更多的挥发分，促进Cu²⁺还原为Cu⁺和Cu⁰，（Cu⁺+Cu⁰）含量增大，Cu/AC降解苯酚催化活性逐渐升高；随着炭化时间延长，（Cu⁺+Cu⁰）含量下降，Cu₂O、CuO较好地并入载体使晶格氧含量增加，催化活性先升高后下降；随着活化温度升高和活化时间延长，Cu/AC比表面积达到1096.1m²/g并有大量微孔生成，大量含氧官能团分解将炭化过程中还原生成的（Cu⁺+Cu⁰）氧化为Cu²⁺，晶格氧含量增加，催化活性随着活化温度的升高而升高，随着活化时间的延长先升高后下降。催化湿式氧化降解苯酚过程中，Cu/AC具有良好的稳定性和低的Cu离子浸出浓度。Cu/AC的最优制备条件为炭化温度800℃，炭化时间2h，活化温度880℃，活化时间为2h，所得Cu/AC在反应8.5h时实现98.5%的苯酚转化率和91.1%的COD转化率。

关键词: 废水, 固定床, 生物质, 催化湿式氧化, 苯酚, 载铜活性炭