-
偶氮染料是纺织业中使用最多的一类染料 [1],具有难降解的特性。常见的处理方法包括物化法、化学法和生物法。物化法不能彻底降解污染物,化学法成本过高,生物法降解缓慢[2],因此限制了这些方法的应用。
次氯酸钠氧化法广泛用于降解废水中的污染物,并以污染物去除效率高、设备简单、经济性等优点而受到人们的重视。NaClO溶液的稳定性较差,大大降低了其氧化性的利用率。此外,采用NaClO直接氧化废水,会产生具有强致癌性的氯代有机物。增强NaClO的氧化性和消除氯代有机物对拓宽其在水处理中的应用极为重要。镍基催化剂能促进NaClO溶液的分解增强其氧化性,且以催化效果好、便宜等优点而备受关注[3]。NaClO在氧化镍的作用下生成具有极强活性的原子氧,迅速氧化废水中的污染物,从而达到去除COD和脱色的目的[4-5]。本课题组研发的NaClO催化氧化法能有效降解活性艳红K-2BP、酸性大红3R等偶氮染料,活性艳红K-2BP的脱色率在120 min达到94%以上[6],而酸性大红3R的脱色率在35 min达到90%以上。原子氧在脱色降解过程起了主导作用,因此未在染料降解产物中发现氯代有机物。
研究染料的分子结构与脱色性能之间的关系对废水的处理至关重要。染料种类繁多,结构各异,可以采用QSPR (quantitative molecular structure-properties relationships)法研究分子结构和脱色性能的关系。该方法简单易行,了解了分子结构信息,就可以分析和预测染料的理化性质或环境行为[7]。
本研究分别采用NaClO催化氧化法和NaClO氧化法脱色降解活性黄X-R废水,考察比较两种方法的脱色效果;比较催化氧化法对活性黄X-R和另外两种偶氮染料的脱色效果,在此基础上采用QSPR分析该方法处理不同染料效果存在差异的原因,进而指出其适用范围。本研究选择适当的染料分子结构描述符,通过线性回归法研究上述目标染料分子结构与NaClO催化氧化法对其脱色效果之间的关系。研究结果将为推广应用NaClO催化氧化法提供理论依据。
NaClO催化氧化法降解活性黄X-R废水和该方法的适用范围
Degradation of reactive yellow X-R wastewater by NaClO catalytic oxidation method and its application scope
-
摘要: 采用NaClO催化氧化法对活性黄X-R废水进行了脱色降解的系统研究,探讨了反应条件对脱色效果的影响,分析了染料的降解机理。结果表明,该方法对染料的脱色率不到50%,脱色率随着染料和有效氯浓度的增加而略微增大,随着初始pH的上升而减小,催化剂的投加对脱色率的影响甚微。NaClO氧化法的对比实验结果表明,NaClO的直接氧化在催化氧化降解过程中起了主导作用,原子氧的作用次之。自由基清除剂实验结果也证明了这一点。定量分析了活性黄X-R和另外2种偶氮染料的分子结构与NaClO催化氧化法对其脱色效果的关系(QSPR分析),结果表明,染料分子结构中磺酸基数目和无机性值与有机性值的比值对脱色率有较强的影响,磺酸基数目的影响尤为突出。NaClO催化氧化法更加适合于降解K型活性染料、含有磺酸钠盐的酸性染料和苯环染料,因为它们具有较强的耐氯牢度。采用XPS、XRD和SEM法对催化剂进行表征,结果发现其表层化学吸附氧的比例随着催化剂使用时间的延长略微减小,表层里含有β-NiOOH和β-Ni(OH)2,且牢牢附着在氧化铝小球表面,不易脱落造成二次污染。Abstract: The decolorization and degradation of reactive yellow X-R wastewater were systematically studied by NaClO catalytic oxidation method. The effects of reaction conditions on decolorization were discussed, and the degradation mechanism of the dye was analyzed. The results showed that the decolorization rate of the dye by this method was lower than 50%. The decolorization rate increased slightly with dye and available chlorine concentration, and decreases with initial pH. The addition of the catalyst had little influence on the decolorization rate. The comparative experiment results of NaClO oxidation showed that the direct oxidation of NaClO played a leading role, followed by atomic oxygen in the catalytic oxidation degradation process. The experimental results of free radical scavengers also confirmed this point. The relationship between the molecular structure of reactive yellow X-R and other two azo dyes and the decolorization effect of NaClO catalytic oxidation method (QSPR analysis) was quantitatively analyzed. The results showed that the number of sulfonic acid groups in dye molecular structure and the ratio of inorganic value to organic value had great influence on the decolorization rate, especially the number of sulfonic acid groups. NaClO catalytic oxidation is more suitable for degradation of K reactive dyes, acid dyes containing sodium sulfonate and benzene ring dyes, because they have stronger chlorine fastness. The catalyst was characterized by XPS, XRD and SEM. The results showed that the proportion of chemisorbed oxygen in the surface layer decreased slightly with the prolonging of catalyst service time, and β-NiOOH and β-Ni(OH)2 were contained in the surface layer, which was firmly attached to the surface of alumina beads and was not easy to fall off and cause secondary pollution.
-
Key words:
- nickel oxyhydroxide /
- sodium hypochlorite /
- catalytic mechanism /
- reactive yellow X-R /
- QSPR analysis
-
表 1 偶氮染料的去除率和分子结构描述符
Table 1. Removal rate and molecular structure descriptor of the azo dyes
染料名称
Dye name分子结构描述符
Molecular structure descriptor脱色率/%
Color removal rateA B C 活性艳红K-2BP 3 3.95 5 91.3 酸性大红3R 3 6.25 4 99.69 活性黄 X-R 2 3.14 4 39.3 表 2 分子结构描述符与去除率的线性回归方程
Table 2. Linear regression equation between molecular structure descriptor and removal rate
分子结构描述符
Molecular structure descriptor回归方程
Regression equationR2 F A =56.195A−73.09$ \omega $ 0.9836 59.815 B =15.958B+5.805$ \omega $ 0.6194 2.627 C =21.805C−17.725$ \omega $ 0.1481 0.174 表 3 催化剂表面元素的相对占比
Table 3. Relative proportion of catalyst surface elements
元素
Elements峰位置
Position结合能/eV
Binding energy相对含量/% Relative content 新制备的
催化剂
New catalyst处理过3000 min活性
艳红K-2BP的催化剂
Catalyst of K-2BP treated
for 3000 min处理过3000 min酸性
大红3R的催化剂
Catalyst of 3R treated
for 3000 min处理过3000 min活性
黄X-R的催化剂
Catalyst of X-R treated
for 3000 minNi Ni(OH)2,2p3/2 855.98 6.34 10.61 13.46 10.50 Ni Ni(OH)2,2p1/2 873.61 Ni NiOOH,2p3/2 861.86 3.92 4.84 5.95 4.43 Ni NiOOH,2p1/2 879.81 O O1s 531.40 87.67 83.08 78.46 83.83 S S2p 168.67 2.07 1.47 2.13 1.24 -
[1] 周宁, 宇秉勇, 宋红, 等. 染料工业废水产污情况分析 [J]. 染料与染色, 2018, 55(1): 54-61. ZHOU N, YU B Y, SONG H, et al. Analysis on the pollution of dye industrial wastewater [J]. Dyestuffs and Coloration, 2018, 55(1): 54-61(in Chinese).
[2] 武俐, 邰超, 王晴晴, 等. 负载型纳米Fe-Pd降解水溶性偶氮染料 [J]. 环境化学, 2012, 31(8): 1125-1130. WU L, TAI C, WANG Q Q, et al. Degradation of azo dye by resin-supported nano-iron/palladium [J]. Environmental Chemistry, 2012, 31(8): 1125-1130(in Chinese).
[3] 申晨, 梅华, 石晓鹏, 等. 镍基催化剂的改性及其提高NaClO氧化性能 [J]. 化学反应工程与工艺, 2010, 26(1): 47-51. doi: 10.3969/j.issn.1001-7631.2010.01.009 SHEN C, MEI H, SHI X P, et al. Improving the oxidation of NaClO by modified Ni-based catalysts prepared through immerse precipitation method [J]. Chemical Reaction Engineering and Technology, 2010, 26(1): 47-51(in Chinese). doi: 10.3969/j.issn.1001-7631.2010.01.009
[4] 吴正雷, 彭文博, 董凯, 等. 催化氧化-BAF工艺处理乙基麦芽酚废水研究 [J]. 广东化工, 2020, 47(11): 165-166,164. doi: 10.3969/j.issn.1007-1865.2020.11.069 WU Z L, PENG W B, DONG K, et al. The treatment of ethyl maltol wastewater by catalytic oxidation and biological aerated filter technology [J]. Guangdong Chemical Industry, 2020, 47(11): 165-166,164(in Chinese). doi: 10.3969/j.issn.1007-1865.2020.11.069
[5] 吴正雷, 彭文博, 董凯, 等. Ni基催化剂处理甲基橙废水动力学及机理研究 [J]. 当代化工, 2020, 49(5): 850-854. doi: 10.3969/j.issn.1671-0460.2020.05.024 WU Z L, PENG W B, DONG K, et al. Research on kinetics and mechanism of degradation of methyl orange wastewater catalyzed by Ni-based catalyst [J]. Contemporary chemical industry, 2020, 49(5): 850-854(in Chinese). doi: 10.3969/j.issn.1671-0460.2020.05.024
[6] 徐文英, 高浩阳. NiOx(OH)y/NaClO催化氧化体系对模拟印染废水中活性艳红K-2BP的降解脱色效果[J]. 环境工程学报, 2021, 15(3): 835-836. XU WY, GAO H Y. Degradation and decolorization of reactive brilliant red K-2BP in simulated printing and dying wasterwater by NiOx(OH)y/NaClO catalytic oxidation system[J]. Chinese Journal of Environmental Engineering, 2021, 15(3): 835-846 (in Chinese)
[7] 田长顺, 刘祖文. 偶氮染料分子结构与脱色性能的定量关系研究 [J]. 工业用水与废水, 2008, 39(4): 10-12. doi: 10.3969/j.issn.1009-2455.2008.04.003 TIAN C S, LIU Z W. Quantitative relationship between molecular structure of azo dyes and their decolorization performance [J]. Industrial Water & Wastewater, 2008, 39(4): 10-12(in Chinese). doi: 10.3969/j.issn.1009-2455.2008.04.003
[8] 李蕾, 夏思淝, 刘文利, 等. 气敏金属氧化物吸附氧负离子O2-, O-的研究[J]. 山东工业大学学报, 1994, 24(3): 287-290. LI L, XIA S F, LIU W L, et al. Investigation of adsorbed O2- and O- on the surface of gas sensing metal oxides[J]. Journal of Shandong University of Technology, 1994, 24(3): 287-290 (in Chinese).
[9] 唐玉朝, 尹汉雄, 黄健, 等. 零价铁活化过硫酸钠对偶氮染料4BS的脱色机理 [J]. 环境化学, 2018, 37(5): 1071-1078. TANG Y C, YIN H X, HUANG J, et al. Decoloration mechanism of azo dye 4BS by zero valent iron activated sodium persulfate [J]. Environmental Chemistry, 2018, 37(5): 1071-1078(in Chinese).
[10] 陈柏言. 冰中黑炭来源单线态氧的光化学生成[D]. 长春: 吉林大学, 2017. CHEN B Y. Photochemical production of singlet oxygen from black carbon in ice[D]. Changchun: Jilin University, 2017 (in Chinese).
[11] XU W Y, GAO H Y. Decomposition performance of hypochlorite on bead-type NiOx(OH)y catalyst: Improving applicability of catalysts [J]. Water Science and Technology, 2020, 82(5): 967-983. doi: 10.2166/wst.2020.402 [12] ZENG Q F, FU J, ZHOU Y, et al. Photooxidation degradation of reactive brilliant red K-2BP in aqueous solution by ultraviolet radiation/ sodium hypochlorite [J]. Clean, 2009, 37(8): 574-580. [13] 姬学敏. 花状氢氧化镍微球、二氧化钛及其复合物的制备、吸附与光催化性能研究[D]. 杭州: 浙江工业大学, 2016. JI X M. Preparation, adsorption and photocatalytic performance of flower-like Ni(OH)2 microspheres, TiO2 and its composite[D]. Hangzhou: Zhejiang University, 2016 (in Chinese).
[14] 王元刚, 刘诗雨, 赵建海, 等. 氢氧化镁混凝过程应用于活性黄X-R废水脱色研究 [J]. 环境工程, 2015, 33(7): 61-65. WANG Y G, LIU S Y, ZHAO J H, et al. Removal of color from reactive yellow X-R wastewater by magnesium hydroxide coagulation process [J]. Environmental Engineering, 2015, 33(7): 61-65(in Chinese).
[15] 王昶, 邱鸿雨, 李荣, 等. 蛭石类芬顿降解偶氮活性黄X-R染料的研究 [J]. 天津科技大学学报, 2019, 34(3): 49-54. WANG C, QIU H Y, LI R, et al. Degradation of azo dye reactive yellow X-R by using vermiculite as a Fenton-like catalyst [J]. Journal of Tianjing University of Science & Technology, 2019, 34(3): 49-54(in Chinese).
[16] DEROSA M C, CRUTCHLEY R J. Photosensitized singlet oxygen and its applications [J]. Coordination Chemistry Reviews, 2002, 233-234: 351-371. doi: 10.1016/S0010-8545(02)00034-6 [17] 黑木宣彦. 染色理论化学(陈水林译)[M]. 北京, 纺织工业出版社, 1957, 85-87. NOBUHIKO KUROKI. Dyeing theoretical chemistry (translated by CHEN S L) [M].Beijing:Textile Industry Press, 1957, 85-87.
[18] 陈荣圻. 活性染料染色牢度对策和固色剂的发展(二) [J]. 印染, 2016, 42(3): 51-54. CHEN R Q. Countermeasures for dyeing fastness of reactive dyes and development of fixing agents (2) [J]. Dyeing and Finishing, 2016, 42(3): 51-54(in Chinese).
[19] 李锦簇. 国内活性染料发展概况 [J]. 染料工业, 1985, 1: 1-7. LI J C. Development of reactive dyes in China [J]. Dyestuff Industry, 1985, 1: 1-7(in Chinese).
[20] 董亚荣, 王立栋, 金泥沙. 含活性染料印染废水生物降解脱色性能研究 [J]. 染整技术, 2016, 38(2): 54-57. doi: 10.3969/j.issn.1005-9350.2016.02.016 DONG Y R, WANG L D, JIN N S. Research on biodegradation and capability of decolorization of reactive dyeing wastewater [J]. Textile Dyeing and Finishing Journal, 2016, 38(2): 54-57(in Chinese). doi: 10.3969/j.issn.1005-9350.2016.02.016
[21] 徐向荣, 王文华. Fenton试剂与染料溶液的反应 [J]. 环境科学, 1999, 20(3): 72-74. doi: 10.3321/j.issn:0250-3301.1999.03.019 XU X R, WANG W H. The reaction of Fenton’s reagent and dye solution [J]. Chinese Journal of Environmental Science, 1999, 20(3): 72-74(in Chinese). doi: 10.3321/j.issn:0250-3301.1999.03.019
[22] YANG S X, FENG Y J, WAN J F, et al. Effect of CeO2 addition on the structure and activity of RuO2/γ-Al2O3 catalyst [J]. Applied Surface Science, 2005, 246(1-3): 222-228. doi: 10.1016/j.apsusc.2004.11.013 [23] 刘正. 绒球状β-氢氧化镍微米球的可控合成及其电化学性能 [J]. 合成化学, 2016, 24(10): 861-865. LIU Z. Synthesis and electrochemical properties of pompon-like β-Ni(OH)2 microspheres [J]. Chinese journal of synthetic chemistry, 2016, 24(10): 861-865(in Chinese).