Laboratório de Bioinorgânica e Catálise, Departamento de Química - Centro Politécnico, PO Box 19032, 81531-980 Curitiba/PR, Brazil; Centro de Estudos do Mar, Pontal do Paraná/PR - Universidade Federal do Paraná (UFPR), Brazil.
Laboratório de Bioinorgânica e Catálise, Departamento de Química - Centro Politécnico, PO Box 19032, 81531-980 Curitiba/PR, Brazil.
J Colloid Interface Sci. 2019 Apr 1;541:425-433. doi: 10.1016/j.jcis.2019.01.111. Epub 2019 Jan 28.
This paper reports the use of two layered hydroxide salts (LHS) (zinc hydroxide nitrate - ZHN - Zn(OH)(NO)·2HO, and zinc hydroxide chloride - ZHC - Zn(OH)Cl·HO) as catalysts for brilliant green (BG) organic dye bleaching, using hydrogen peroxide as oxidant. The LHS were prepared by precipitation reaction between an aqueous solution of zinc salts and an aqueous ammonia solution. The solids were characterized by powder X-ray diffraction (XRD), electron paramagnetic resonance (EPR), ultraviolet-visible electronic spectroscopy (UV-Vis) and Fourier-transform infrared spectroscopy (FTIR). The catalytic activity of the solids was investigated at temperatures of 25, 35 and 45 °C, using different molar ratios of oxidant:dye:Zn ions (present in the catalyst), in the absence and presence of ambient light. The kinetic aspect of the reaction was investigated considering that the reaction showed pseudo-first order behavior in relation to BG dye concentration. We propose a mechanism where superoxide radicals account for most of the bleaching taking place. The catalytic results obtained, along with the low cost and low toxicity of zinc compounds, establish ZHN and ZHC as novel catalysts for dye wastewater treatment, an area with constant demand for new methods and materials given its relationship with environmental equilibrium and human health.
本文报道了使用两种层状氢氧化物盐（LHS）（硝酸锌氢氧化物 - ZHN - Zn(OH)(NO)·2H₂O 和氯化锌氢氧化物 - ZHC - Zn(OH)Cl·H₂O）作为催化剂，用过氧化氢作为氧化剂，对亮绿（BG）有机染料进行漂白。LHS 通过锌盐的水溶液和氨水溶液之间的沉淀反应制备。通过粉末 X 射线衍射（XRD）、电子顺磁共振（EPR）、紫外-可见电子光谱（UV-Vis）和傅里叶变换红外光谱（FTIR）对固体进行了表征。在 25、35 和 45°C 的温度下，在不存在和存在环境光的情况下，使用不同的氧化剂:染料:Zn 离子（存在于催化剂中）摩尔比，研究了固体的催化活性。考虑到反应在 BG 染料浓度方面表现出准一级行为，研究了反应的动力学方面。我们提出了一种机制，其中超氧自由基占主导地位。考虑到锌化合物的低成本和低毒性，所获得的催化结果确立了 ZHN 和 ZHC 作为新型染料废水处理催化剂，该领域对新方法和新材料的需求不断，因为它与环境平衡和人类健康有关。
