Adsorption effects and mechanisms of phosphorus by nanosized laponite

• Published in: Chemosphere (Oxford) 2023-08, Vol.331, p.138684-138684, Article 138684
• Main Authors: Jia, Chonghao, Chi, Jialin, Zhang, Wenjun
• Format: Article
• Language: English
• Subjects: Adsorption; Clay; Density functional theory (DFT); Humans; Laponite; Minerals; Phosphate; Phosphates - chemistry; Phosphorus - chemistry; Transmission electron microscopy (TEM); Wastewater
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.138684

Phosphorus (P), an important macroelement for crops, may be lost into water systems by human activities and subsequently cause serious environmental problems such as eutrophication. Thus, the recovery of P from wastewater is essential. P can be adsorbed and recovered from wastewater using many natural, environmentally friendly clay minerals, however the adsorption ability is limited. Here we applied a synthesis nanosized clay mineral, laponite, to evaluate the P adsorption ability and molecular mechanisms of the adsorption process. We apply X-ray Photoelectron Spectroscopy (XPS) to observe the adsorption of inorganic phosphate onto laponite, and then measure the adsorption content of phosphate by laponite via batch experiments in different solution conditions, including pH, ionic species and concentrations. Then the molecular mechanisms of adsorption are analyzed by Transmission Electron Microscopy (TEM) and molecular modeling using Density Functional Theory (DFT). The results show that phosphate adsorbs to the surface and interlayer of laponite via hydrogen bonding, and the adsorption energies of the interlayer are greater than those of the surface. These bulk solution and molecular-scale results in a model system may provide new insights into the recovery of phosphorus by nanosized clay, with possible environmental engineering applications for P-pollution control and sustainable utilization of P sources. The adsorption of phosphorus by nanosized clay, laponite would provide a new perspective of P recovery in wastewater, with possible applications in environmental chemical engineering. [Display omitted] •We found a nanosized clay, laponite, exhibit high phosphorus adsorption ability.•The adsorption of phosphate by laponite is mediated by varied solution conditions.•Surface and interlayer of laponite could adsorption phosphate.•The adsorption of phosphorus by laponite is mainly mediated by hydrogen bonding.