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摘要 [目的]研究无患子活性炭制备的最佳工艺及其对苯酚的吸附。[方法]以H3PO4为活化剂制备无患子残渣活性炭,通过正交试验对制备工艺进行优化,探讨浸渍比、活化温度、活化时间对活性炭亚甲基蓝和碘吸附值的影响。利用N2吸脱附试验、SEM,对活性炭的结构与性能进行表征。选取了投炭量、苯酚溶液pH、苯酚初始浓度、吸附温度为单因素,探讨其对苯酚吸附的影响。[结果]浸渍比为1∶1、活化温度为500 ℃、活化时间为60 min时,制备的活性炭对亚基蓝的吸附值为82 mg/g、碘吸附值为773 mg/g、BET比表面为738 m2/g、总孔容达0.669 2 cm3/g、平均孔径为3.625 7 nm。 活性炭在中性条件下对苯酚吸附效果最佳;低温有利于吸附,但温度的影响不大。[结论]所制备的活性炭具有良好的苯酚吸附效果。
关键词 无患子;活性炭;苯酚;吸附
中图分类号 S181.3 文献标识码 A 文章编号 0517-6611(2014)25-08724-04
Abstract [Objective] The research aimed to study the best preparation process of activated carbon with S. mukorossi residue and its adsorption capacity to phenol. [Method] The activated carbon was prepared with S. mukorossi residue by using H3PO4 as activator. The preparation process was optimized by orthogonal experiment, and the influences of the mass ratio of acid to material, activation temperature and time on adsorption values of methylene blue and iodine by activated carbon were discussed. The structure and property of activated carbon were characterized by N2 adsorptiondesorption experiment and SEM. Selecting activated carbon quantity, adsorption temperature, initial concentration and pH of phenol as single factors, their influences on phenol adsorption were discussed. [Result] The adsorption values of methylene blue and iodine by the activated carbon could reach 82 and 773 mg/g respectively at an impregnation ratio of 1∶1, an activation temperature of 500 ℃ and an activation time of 60 min. Meanwhile, the prepared activated carbon’s BET specific surface area was 738 m2/g; total pore volume was 0.669 2 cm3/g; average pore size was 3.625 7 nm. Under the neutral condition, adsorption effect of the activated carbon on phenol was the best. Low temperature was good for adsorption, but temperature had limited effects on adsorption. [Conclusion] The prepared activated carbon with S. mukorossi residue showed good results on adsorption capacity to phenol.
Key words S. mukorossi; Activated carbon; Phenol; Adsorption
活性炭是一种比表面积高、孔隙发达、吸附性能优异的含碳物质,广泛地应用于食品、环保、国防、医药等领域[1-4]。传统的活性炭原料主要是煤炭和木材,随着不可再生能源的日益枯竭,农林废弃物正被越来越多的学者们所研究。
无患子已被列入全国重要的能源树种,并在福建省泉港、建宁、德化等地发展种植无患子近1.33×104 hm2,规划种植6.67×104 hm2。无患子提取生物柴油原料后的残渣约占70%左右,残渣含有大量的纤维素,丢弃既破坏环境,又浪费资源。利用无患子残渣制备活性炭具有广阔的市场前景,也为无患子残渣的废物再利用找到新的出路。
苯酚是一种常见的高毒性难降解有机物。随着化工行业的迅速发展,含酚废水数量与种类也与日俱增,对水体造成了巨大的威胁[5]。含酚废水苯环结构稳定,不易分解,可生化性差,处理难度大,是当前环境领域研究的热点与难点问题[6]。
活性炭具有发达的孔隙结构和巨大的比表面积,在吸附水体中有机污染物,尤其是低浓度有机污染物得到了广泛的应用[7-8]。笔者以H3PO4为活化剂制备无患子活性炭,正交试验对制备工艺进行优化,探讨了浸渍比、活化温度、活化时间对活性炭亚甲基蓝和碘吸附值的影响,并对制备的活性炭结构与性能进行了表征;选取了投炭量、苯酚溶液pH、吸附温度、苯酚初始浓度为单因素,探讨其对活性碳吸附苯酚废水的影响。 3 结论
对于以无患子残渣为原料,H3PO4为活化剂制备的活性炭,并选取单因素探讨其对苯酚吸附的影响,得出以下结论:
(1)根据正交试验法,得出制备无患子活性炭的最佳工艺条件:活化温度500 ℃,活化时间60 min,浸渍比1∶1。在该工艺条件下,活性炭的亚甲基蓝吸附值为82 mg/g,碘吸附值为733 mg/g。
(2)在最佳工艺条件下,活性炭的BET比表面积为738 m2/g,孔容为0.669 2 cm3/g,平均孔径为3.625 7 nm。
(3)扫描电镜分析可知,H3PO4活化制备的活性炭表面粗糙,呈现凹凸不平的棉絮状并向内部延伸;活性炭有大小不一的孔洞,孔洞有的呈圆形,有的呈不规则形状。
(4)活性炭在中性条件下对苯酚吸附效果最佳;低温有利于吸附,但温度的影响不大,所制备的无患子活性炭具有良好的苯酚吸附效果。
参考文献
[1] 郝明明,王伟,王亮,等.杏核壳活性炭在枸杞油脱色中的应用[J].食品科技,2011,36(4):60-62.
[2] 金世宏.药用炭与尿毒清治疗慢性肾功能不全[J].临床医学,2009,29(25):105.
[3] 刘恩文.活性炭纤维的制备及在核生化防护服中的应用[J].国防技术基础,2008,8(5):55-58.
[4] YUAN J H,XU R K.The amelioration effects of low temperature biochar generated from nine crop residues on an acidic Ultisol [J].Soil Use and Management,2011,11(27):110-115.
[5] 房平,邵瑞华,任娟.活性炭对苯酚的吸附研究[J].炭素技术,2011,30(2):12-16.
[6] DOS SANTOS V L,MONTEIRO A S,BRAGA D T,et al.Phenol degradation by Aureobasidium pullulans FE13 isolated from industrial effluents[J].Journal of Hazardous Materials,2009,161(2/3):1413-1420.
[7] 刘通,孙贤波,刘勇弟.活性炭对生化出水中不同种类有机物的去除效果[J].环境化学,2009,28(3):369-372.
[8] ANU MATILAINEN,NIINA VIENO,TUULA TUHKANEN.Efficiency of the Activated Carbon Filtration in the Natural Organic Matter Removal [J].Environment International,2006,32(3):324-331.
[9] 方智利.磷酸活化褐煤制备活性炭的研究[D].昆明:昆明理工大学,2002.
[10] 辛勤.固体催化剂研究方法[M].北京:科学出版社,2004:364-367.
[11] 尤翔宇,杨杰,王云燕.苯酚在活性炭上的吸附模型[J].中国有色金属学报,2012,22(10):2924-2929.
[12] 王红斌,杨敏,陈毅坚,等.活性炭自水溶液吸附苯酚的热力学探讨[J].云南民族大学学报:自然科学版,2003,12(4):220-223.
[13] 肖成建.水溶液中痕量镅在容器壁上的吸附研究[D].绵阳:中国工程物理研究院,2005.
关键词 无患子;活性炭;苯酚;吸附
中图分类号 S181.3 文献标识码 A 文章编号 0517-6611(2014)25-08724-04
Abstract [Objective] The research aimed to study the best preparation process of activated carbon with S. mukorossi residue and its adsorption capacity to phenol. [Method] The activated carbon was prepared with S. mukorossi residue by using H3PO4 as activator. The preparation process was optimized by orthogonal experiment, and the influences of the mass ratio of acid to material, activation temperature and time on adsorption values of methylene blue and iodine by activated carbon were discussed. The structure and property of activated carbon were characterized by N2 adsorptiondesorption experiment and SEM. Selecting activated carbon quantity, adsorption temperature, initial concentration and pH of phenol as single factors, their influences on phenol adsorption were discussed. [Result] The adsorption values of methylene blue and iodine by the activated carbon could reach 82 and 773 mg/g respectively at an impregnation ratio of 1∶1, an activation temperature of 500 ℃ and an activation time of 60 min. Meanwhile, the prepared activated carbon’s BET specific surface area was 738 m2/g; total pore volume was 0.669 2 cm3/g; average pore size was 3.625 7 nm. Under the neutral condition, adsorption effect of the activated carbon on phenol was the best. Low temperature was good for adsorption, but temperature had limited effects on adsorption. [Conclusion] The prepared activated carbon with S. mukorossi residue showed good results on adsorption capacity to phenol.
Key words S. mukorossi; Activated carbon; Phenol; Adsorption
活性炭是一种比表面积高、孔隙发达、吸附性能优异的含碳物质,广泛地应用于食品、环保、国防、医药等领域[1-4]。传统的活性炭原料主要是煤炭和木材,随着不可再生能源的日益枯竭,农林废弃物正被越来越多的学者们所研究。
无患子已被列入全国重要的能源树种,并在福建省泉港、建宁、德化等地发展种植无患子近1.33×104 hm2,规划种植6.67×104 hm2。无患子提取生物柴油原料后的残渣约占70%左右,残渣含有大量的纤维素,丢弃既破坏环境,又浪费资源。利用无患子残渣制备活性炭具有广阔的市场前景,也为无患子残渣的废物再利用找到新的出路。
苯酚是一种常见的高毒性难降解有机物。随着化工行业的迅速发展,含酚废水数量与种类也与日俱增,对水体造成了巨大的威胁[5]。含酚废水苯环结构稳定,不易分解,可生化性差,处理难度大,是当前环境领域研究的热点与难点问题[6]。
活性炭具有发达的孔隙结构和巨大的比表面积,在吸附水体中有机污染物,尤其是低浓度有机污染物得到了广泛的应用[7-8]。笔者以H3PO4为活化剂制备无患子活性炭,正交试验对制备工艺进行优化,探讨了浸渍比、活化温度、活化时间对活性炭亚甲基蓝和碘吸附值的影响,并对制备的活性炭结构与性能进行了表征;选取了投炭量、苯酚溶液pH、吸附温度、苯酚初始浓度为单因素,探讨其对活性碳吸附苯酚废水的影响。 3 结论
对于以无患子残渣为原料,H3PO4为活化剂制备的活性炭,并选取单因素探讨其对苯酚吸附的影响,得出以下结论:
(1)根据正交试验法,得出制备无患子活性炭的最佳工艺条件:活化温度500 ℃,活化时间60 min,浸渍比1∶1。在该工艺条件下,活性炭的亚甲基蓝吸附值为82 mg/g,碘吸附值为733 mg/g。
(2)在最佳工艺条件下,活性炭的BET比表面积为738 m2/g,孔容为0.669 2 cm3/g,平均孔径为3.625 7 nm。
(3)扫描电镜分析可知,H3PO4活化制备的活性炭表面粗糙,呈现凹凸不平的棉絮状并向内部延伸;活性炭有大小不一的孔洞,孔洞有的呈圆形,有的呈不规则形状。
(4)活性炭在中性条件下对苯酚吸附效果最佳;低温有利于吸附,但温度的影响不大,所制备的无患子活性炭具有良好的苯酚吸附效果。
参考文献
[1] 郝明明,王伟,王亮,等.杏核壳活性炭在枸杞油脱色中的应用[J].食品科技,2011,36(4):60-62.
[2] 金世宏.药用炭与尿毒清治疗慢性肾功能不全[J].临床医学,2009,29(25):105.
[3] 刘恩文.活性炭纤维的制备及在核生化防护服中的应用[J].国防技术基础,2008,8(5):55-58.
[4] YUAN J H,XU R K.The amelioration effects of low temperature biochar generated from nine crop residues on an acidic Ultisol [J].Soil Use and Management,2011,11(27):110-115.
[5] 房平,邵瑞华,任娟.活性炭对苯酚的吸附研究[J].炭素技术,2011,30(2):12-16.
[6] DOS SANTOS V L,MONTEIRO A S,BRAGA D T,et al.Phenol degradation by Aureobasidium pullulans FE13 isolated from industrial effluents[J].Journal of Hazardous Materials,2009,161(2/3):1413-1420.
[7] 刘通,孙贤波,刘勇弟.活性炭对生化出水中不同种类有机物的去除效果[J].环境化学,2009,28(3):369-372.
[8] ANU MATILAINEN,NIINA VIENO,TUULA TUHKANEN.Efficiency of the Activated Carbon Filtration in the Natural Organic Matter Removal [J].Environment International,2006,32(3):324-331.
[9] 方智利.磷酸活化褐煤制备活性炭的研究[D].昆明:昆明理工大学,2002.
[10] 辛勤.固体催化剂研究方法[M].北京:科学出版社,2004:364-367.
[11] 尤翔宇,杨杰,王云燕.苯酚在活性炭上的吸附模型[J].中国有色金属学报,2012,22(10):2924-2929.
[12] 王红斌,杨敏,陈毅坚,等.活性炭自水溶液吸附苯酚的热力学探讨[J].云南民族大学学报:自然科学版,2003,12(4):220-223.
[13] 肖成建.水溶液中痕量镅在容器壁上的吸附研究[D].绵阳:中国工程物理研究院,2005.