Enhancing phosphate removal from wastewater using optimized fly ash adsorbents

• DOI: 10.1016/j.dwt.2025.101056
• Publication Date: 2025-02-11T22:43:16Z
• Authors: Kaicheng Zhou; Xuan Chen; Tao Ye; Pingan Pan; Doufeng Wu; Pengfei Sun; Xiaopeng Dong; Sanchuan Yu
• Keywords: Fly ash modification; Ecology; Environmental sustainability; Wastewater treatment; Environmental technology. Sanitary engineering; Phosphate adsorption; TD1-1066; QH540-549.5

Phosphorus pollution in aquatic ecosystems poses a significant environmental challenge, contributing to harmful algal blooms and hypoxic zones. This research capitalizes on modified fly ash (FA), traditionally seen as industrial waste, to efficiently remove phosphate from wastewater. Through precise modifications involving an optimized alkali-ash ratio and a specific calcination temperature of 600 °C, the developed FA-NaOH-7 adsorbent showcased enhanced physicochemical properties, with a surface area increased to 96.2 m2·g−1. Kinetic analysis affirmed that phosphate adsorption follows a pseudo-second-order model, predominantly through chemisorption mechanisms. The adsorption efficacy peaked at a pH of 2.5, where the FA-NaOH-7 demonstrated a phosphate removal efficiency of over 99 % within just 30 mins, highlighting its rapid action. The Langmuir adsorption isotherm confirmed a maximum adsorption capacity of 18.7 mg·g−1. Zeta potential measurements further elucidated that electrostatic attraction plays a crucial role in phosphate capture. This study not only underlines the effectiveness of utilizing modified FA for environmental remediation but also enhances phosphate removal strategies, transforming waste into a resource for sustainable environmental management.