Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany.
Department of Chemical and Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Sheffield, S1 3JD, United Kingdom; Faculty of Life Sciences, University of Bradford, Richmond Road, Bradford, BD7 1DP, United Kingdom.
J Environ Manage. 2022 Dec 15;324:116279. doi: 10.1016/j.jenvman.2022.116279. Epub 2022 Sep 25.
Phosphate shortages and the ensuing pressures on food security have led to an interest in processed sewage sludge as a substitute for commercial fertilisers. The presence of heavy metals in this nutrient source causes concerns around environmental release and pollution. This work builds towards a resin-in-pulp sludge detoxification process. It showcases the kinetic and thermodynamic adsorption capabilities of the ion-exchange resins C107E (carboxylic acid functionality), MTS9301 (iminodiacetic acid) and TP214 (thiourea), with respect to Cu(II), Fe(II), Pb(II) and Zn(II), within a simulated sewage sludge weak acid (acetate) leachate. The isotherms produced in this complex system were quite different to those generated when single metals were investigated in isolation, with desorption of lower affinity species clearly observed at higher equilibrium concentration values. Mixed-metal isotherm data were fitted to common two-parameter isotherm models and also a novel modified Langmuir model, which better accounted for the effects of desorption and competition. Kinetic data were also fit to common two-parameter models; results suggesting the system was likely film diffusion-controlled and followed pseudo-2nd-order kinetics. C107E displayed rapid adsorption of lead (t = 26 ± 3min), and significant uptake of all metals. MTS9301 showed high affinity for copper ions, with concurrent desorption of all the other metals, and also displayed the fastest kinetics (t = 14.1 ± 0.9, 130 ± 20, 25 ± 5 and 49 ± 6 min for copper, iron(II), lead and zinc, respectively). C107E and MTS9301 showed far slower adsorption for iron(II) than the other three metals, which invited the possibility of kinetic separations. TP214 had reasonable effectiveness in removal of copper, but poor affinity for all other metals. The greatest difficulty in modelling the multi-metal system was the two-stage trends observed in equilibrium experiments, as metal-proton exchanges become metal-metal exchanges. While not having the highest capacity, MTS9301 was recommended as the most appropriate resin for rapid and efficient removal of Cu, Pb and Zn from the acetate medium.
磷酸盐短缺以及由此对食品安全造成的压力，促使人们关注将经过处理的污水污泥作为商业肥料的替代品。这种营养源中重金属的存在引发了对环境释放和污染的担忧。本工作旨在开发一种浆内树脂污泥解毒工艺。它展示了离子交换树脂 C107E（羧酸官能团）、MTS9301（亚氨基二乙酸）和 TP214（硫脲）在模拟污水污泥弱酸（乙酸盐）浸出液中对 Cu(II)、Fe(II)、Pb(II)和 Zn(II)的动力学和热力学吸附能力。在这个复杂体系中生成的等温线与单独研究单一金属时生成的等温线有很大的不同，在较高的平衡浓度值下，明显观察到低亲和力物质的解吸。混合金属等温线数据符合常见的双参数等温线模型，也符合一种新的改进朗缪尔模型，该模型更好地解释了解吸和竞争的影响。动力学数据也符合常见的双参数模型；结果表明，该体系可能是膜扩散控制的，并遵循准二级动力学。C107E 对铅表现出快速的吸附（t=26±3min），并对所有金属表现出显著的吸收。MTS9301 对铜离子具有高亲和力，同时解吸所有其他金属，并且还表现出最快的动力学（t=14.1±0.9、130±20、25±5 和 49±6min，分别为铜、铁(II)、铅和锌）。C107E 和 MTS9301 对铁(II)的吸附速度远慢于其他三种金属，这使得实现动力学分离成为可能。TP214 在去除铜方面具有一定的效果，但对所有其他金属的亲和力较差。在多金属体系建模中最困难的是在平衡实验中观察到的两个阶段趋势，因为金属-质子交换变成了金属-金属交换。虽然容量不是最高，但 MTS9301 被推荐为从乙酸介质中快速有效去除 Cu、Pb 和 Zn 的最合适树脂。
