Environmental Science and Pollution Research ( IF 5.8 ) Pub Date : 2020-09-24 , DOI: 10.1007/s11356-020-10925-7 Manviri Rani 1 , Uma Shanker 2
Release of colouring agents into the environment alarms the need to design a cheap, quick and safe process. Owing to environmental safety concern, synthesis of two metal hexacyanoferrates (MHCFs) based on cadmium (CdHCF) and manganese (MnHCF) was carried out using natural plant extract of Azadirachta indica and water as a solvent. Synthesized MHCFs were utilized for the removal of an acid dye (fuchsin acid, FA) and a xanthenes dye (rhodamine B, RB). The reactions were optimized at various conditions of dye concentration, catalyst dose, reaction pH, time and source of light. The MHCFs showed excellent results with both the dyes within very limited span of time (2 h). Consequently, 98% of FA and 97% of RB were degraded with 10 mg of CdHCF, at neutral pH and under sunlight. The degradation process followed the first-order reaction kinetics having t1/2 around 0.3 min. The MHCFs exhibited difference of only little percentage in degradation owing to a very slight difference between their surface areas (CdHCF: 54.1 m2 g−1; MnHCF: 49.7 m2 g−1). The synthesised nanocatalysts were stable as indicated by their higher negative zeta potential values. The adsorption of dyes was found to be maximum with CdHCF having Xm value 19.69 mg g−1 and 18.15 mg g−1 for FA and RB, respectively. Photocatalytic degradation involved the main role of hydroxyl radical as indicated by decline in activity of nanocatalyst in the presence of scavengers. All in all, this study presents highly active nanomaterials with higher surface area, stability and semiconducting properties under natural conditions.
中文翻译:
基于六氰合铁酸盐的纳米粒子对阳光驱动的有机染料快速光催化降解的见解
将着色剂释放到环境中警告需要设计一种廉价,快速和安全的工艺。出于对环境安全的考虑,使用印A(Azadirachta indica)的天然植物提取物合成了基于镉(CdHCF)和锰(MnHCF)的两种金属六氰合高铁酸盐(MHCFs)。和水作为溶剂。合成的MHCF用于去除酸性染料(品红酸,FA)和黄嘌呤染料(若丹明B,RB)。在染料浓度,催化剂剂量,反应pH,时间和光源的各种条件下对反应进行了优化。MHCF在极短的时间内(2小时)显示两种染料均具有优异的效果。因此,在中性pH和阳光下,使用10 mg CdHCF可以降解98%的FA和97%的RB。降解过程遵循一级反应动力学,该动力学在0.3 min左右具有t 1/2。由于MHCF的表面积之间非常微小的差异,因此它们的降解率差异很小(CdHCF:54.1 m 2 g -1 ; MnHCF:49.7 m 2g -1)。如其较高的负ζ电势值所示,合成的纳米催化剂是稳定的。发现对于CdHCF,其FA和RB的X m值分别为19.69 mg g -1和18.15 mg g -1时,染料的吸附最大。如清除剂的存在,纳米催化剂活性下降表明,光催化降解涉及羟基自由基的主要作用。总而言之,这项研究提出了在自然条件下具有更高表面积,稳定性和半导体特性的高活性纳米材料。