Cardoso Rita M F, Cardoso Inês M F, da Silva Luís Pinto, Esteves da Silva Joaquim C G
Chemistry Research Unit (CIQUP), Institute of Molecular Sciences (IMS)-DGAOT, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre 697, 4169-007 Porto, Portugal.
Nanomaterials (Basel). 2022 Apr 4;12(7):1211. doi: 10.3390/nano12071211.
A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed—Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of −3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (kap in min−1): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (kapc in min−1) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (kap = 0.0097 min−1 and kapc = 0.012 min−1 (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.
开发了一种以铜（II）掺杂碳点（Cu-CD，以L-半胱氨酸和聚乙二醇（PEG）作为前驱体和钝化剂）为催化剂的催化臭氧化高级氧化工艺（AOP）用于处理纺织废水（温度T = 25°C，pH = 7）。分析了四种染料——甲基橙（MO）、橙II钠盐（O-II）、活性黑5（RB-5）和雷马素亮蓝R（RBB-R），以及印染行业的实际废水。具有显著催化臭氧化性能的Cu-CD通过一锅水热法成功合成，其尺寸为4.0 nm，电荷为−3.7 mV，荧光量子产率为31%。染料水溶液的褪色遵循表观一级动力学，速率常数如下（kap，单位为min−1）：MO为0.210；O-II为0.133；RB-5为0.177；RBB-R为0.086。在Cu-CD存在下，获得了以下表观一级速率常数（kapc，单位为min−1），且无催化剂时速率常数相应增加（%Inc）：MO为1.184（464%）；O-II为1.002（653%）；RB-5为0.709（301%）；RBB-R为0.230（167%）。氯化钠（浓度为50 g/L）的存在导致染料溶液褪色速率显著增加，这是由于臭氧与氯化物反应产生了其他自由基，如氯和氧化氯。考虑到所研究的实际纺织废水具有较高的碳酸盐浓度（>356 mg/L），这会抑制臭氧分解，无Cu-CD和有Cu-CD时的褪色一级速率常数（分别为kap = 0.0097 min−1和kapc = 0.012 min−1（%Inc = 24%））相对较小。显然，其表面覆盖有柔软且高度水合的焦糖化PEG涂层的Cu-CD加速了臭氧分解和染料吸附，提高了其降解效果。
