Modified natural organic waste red kenaf straw as an oil sorbent for oil spill remediation

The oil contamination issue in water is becoming more and more serious. Consequently, it is imperative to develop advanced materials and methods to address the oil pollution issue in the environment. In this work, red kenaf straw, a type of the agricultural waste, was selected as the raw material, and the acid anhydride was utilized as an environment-friendly esterification reagent to facilitate the conversion of hydrophilic groups into hydrophobic groups through a modification reaction. The modified straw was turned into a high-performance oil sorbent with good hydrophobicity and lipophilicity. The effects of different esterification reagents, straw particle size, reaction time and reaction temperature during modification process on the properties of modified materials have been investigated. The structure of the sorbent was characterized by scanning electron microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Brunner-Emmet-Teller (BET), and X-ray diffraction (XRD). The oil-sorption capacity of the optimally modified straw product was nearly 100% higher than that of the raw straw whatever in pure oil system, oil-H₂O system or oil-NaCl solution mixed system. Additionally, the oil-absorbing mechanism and reusability were investigated. This study presents a novel methodology for transforming agricultural waste straw into valuable environmental remediation product. PRACTITIONER POINTS: An efficient bio-based oil absorbent preparation method was developed by method optimization. The environmentally friendly oil adsorbent synthesis process is economical, green, and safe. The sorption capacity of straw reached 8.09 g/g and can retain at a high sorption level after 5 cycles.