Reactive extraction of methanesulfonic acid from wastewater using trioctylamine.

Wastewater containing methanesulfonic acid (MSA) mainly originates from the production process of metal detergent, which also contributes significantly to environmental pollution. This study investigates the extraction of MSA from wastewater using trioctylamine (TOA). A thorough investigation was carried out into the factors that affect extraction efficiency, such as the type of extractant, phase ratio (O/A), temperature, stirring speed, and extraction time. An extraction efficiency of 96.1% was achieved using TOA at 25 °C, 1400 r·min, and an extraction time of 30 min. Various techniques including FT-IR, XPS, and high-resolution ESI-MS were employed to investigate the extraction mechanism. The results of different techniques revealed that the complexation between TOA and MSA occurred through ionic and hydrogen bonding interactions. Moreover, TOA was successfully regenerated through back-extraction with sodium hydroxide. The proposed extraction system is advantageous for eco-friendly engineering applications.