Sorbents derived from lignocellulosic waste materials: characterization and potential removal of surfactants, phenolic compounds, and nutrients from environmental aqueous solutions

Sorbent materials were prepared from two lignocellulosic materials, banana peelings (BP) and rice husks (RH). Scanning Electron Microscopy (SEM) studies revealed that sorbent from BP has a rough surface with structures of no definite shape and size, while RH sorbents showed smooth surface with regular patterns of structures. Fourier Transfrom Infrared (FT-IR) studies also revealed that both sorbents are rich in -OH, -C=O, -CH2 groups and traces of -C-O stretches. Batch sorption experiments were conducted to assess the surfactants, phenols, and nutrient (N and P) removal potential of the prepared sorbent materials under two initial pH conditions (6 and 9) for both surface and effluent water, and two salinity conditions (3 and 33 ppt) for surface water only. In general, both BP and RH derived sorbent materials showed potential in removing surfactants and phenols from surface waters. Removal of surfactants and phenols was observed to be significantly affected by salinity but not by the initial pH level. Sorption of the surfactants to the BP sorbents was observed to be favorable at slightly acidic pH of 6 and high salinity water (33 ppt). Phenol removal by BP and the RH-derived sorbents was not significantly affected by pH changes within the range of common environmental water levels. In contrast, the removal of phenol by both sorbent materials was significantly reduced at higher salinity concentration regardless of the pH level. Lastly, results suggest that the sorbent materials evaluated in this study showed minimal or no potential application as sorbents for reducing nutrient (N and P) concentrations in both surface and effluent waters.