de Oliveira Igor Muniz, Docílio Pereira João Victor, da Silva Pereira Everton Carlos, de Souza Micaelle Silva, Cazetta Márcia Luciana, da Cruz Neto Claudiano Carneiro, da Silva Santana Victor Mancir, Araújo Pinto Victor Hugo, Rebouças Júlio Santos, da Silva Martins Dayse Carvalho, DeFreitas-Silva Gilson, Costa Denilson Santos, da Silva Vinicius Santos
Centro de Formação de Professores, Universidade Federal do Recôncavo da Bahia, 45300-000. Amargosa, Bahia, Brazil.
Centro de Ciências Exatas e Tecnológicas-Universidade Federal do Recôncavo da Bahia, 44380-000. Cruz das Almas, Bahia, Brazil.
ACS Omega. 2024 Jun 25;9(27):29516-29528. doi: 10.1021/acsomega.4c02132. eCollection 2024 Jul 9.
A heterogenized Mn(III) porphyrin-based catalyst was prepared for dye degradation. The new Mn(III) complex of 5,15-bis(4-aminophenyl)-10,20-diphenylporphyrin was immobilized, via covalent bond, in chloropropyl silica gel, generating the material (Sil-Cl@MnP) with a loading of 23 μmol manganese porphyrin (MnP) per gram of Sil-Cl. This material was used as a catalyst in degradation reactions of model dyes, a cationic dye [methylene blue (MB)] and an anionic dye (reactive red 120, RR120), using PhI(OAc) and HO as oxidants. The oxidation reactions were carried out after the dye reached adsorption/desorption equilibrium with the catalytic material, with a much higher percentage of adsorption being observed for the cationic MB dye (20%) than for the anionic RR120 dye (3%), which may be associated with electrostatic attraction or repulsion effects, respectively, with the negatively charged surface of the silica (zeta potential measurement for Sil-Cl@MnP, ζ = -19.2 mV). In general, there was a higher degradation percentage for MB than for RR120, probably because the size and charge of RR120 would hinder its approach to the MnP active species on the silica surface. With respect to the oxidant, the PhI(OAc)-based systems showed a higher degradation percentage than those of HO. It was observed that the increase in the oxidant concentration promoted a significant increase in the degradation of MB, with a degradation of approximately 65%. The efficiency of the catalyst was also evaluated after successive additions of the oxidant every 2 h, and it can be seen that the catalyst had no loss of efficiency, with a degradation percentage greater than 80% being observed after 8 h of reaction. The phytotoxicity of the products formed in the system was evaluated in a 1:23.5:188 molar ratio Sil-Cl@MnP: MB:PhI(OAc) was used. In these studies, phytotoxicity was found for the germination of lettuce seeds when the original solution was used without dilution; however, when diluted (10% V/V), the results were close to the positive and negative controls. Thus, the material obtained proved to be a potential candidate for application in the degradation reactions of environmental pollutants.
制备了一种基于异质化锰（III）卟啉的催化剂用于染料降解。5,15-双（4-氨基苯基）-10,20-二苯基卟啉的新型锰（III）配合物通过共价键固定在氯丙基硅胶中，生成每克硅胶负载量为23 μmol锰卟啉（MnP）的材料（Sil-Cl@MnP）。该材料用作模型染料降解反应的催化剂，使用PhI(OAc)₂和H₂O₂作为氧化剂，分别对阳离子染料[亚甲基蓝（MB）]和阴离子染料（活性红120，RR120）进行降解反应。氧化反应在染料与催化材料达到吸附/解吸平衡后进行，观察到阳离子MB染料的吸附百分比（20%）远高于阴离子RR120染料（3%），这可能分别与静电吸引或排斥效应有关，硅胶表面带负电荷（Sil-Cl@MnP的ζ电位测量值，ζ = -19.2 mV）。总体而言，MB的降解百分比高于RR120，可能是因为RR120的大小和电荷会阻碍其接近硅胶表面的MnP活性物种。关于氧化剂，基于PhI(OAc)₂的体系显示出比H₂O₂更高的降解百分比。观察到氧化剂浓度的增加促进了MB降解的显著增加，降解率约为65%。每2小时连续添加氧化剂后也评估了催化剂的效率，可以看出催化剂没有效率损失，反应8小时后观察到降解百分比大于80%。以1:23.5:188的摩尔比Sil-Cl@MnP:MB:PhI(OAc)₂评估了体系中生成产物的植物毒性。在这些研究中，当使用未稀释的原液时，发现生菜种子发芽存在植物毒性；然而，当稀释（10% V/V）时，结果接近阳性和阴性对照。因此，所获得的材料被证明是环境污染物降解反应应用的潜在候选材料。
