Fast and effective arsenic removal from aqueous solutions by a novel low-cost eggshell byproduct

Developing alternative green solutions for local and correct recycling of eggshells waste (ES) are needed by the egg-processing industries. In this study, we proposed transforming ES into a novel low-cost chemical compound named hydroxyl-eggshell (ES-OH) and investigated its capacity for arsenic (As) removal from aqueous solutions. Laboratory experiments were conducted to investigate the effects of ES-OH doses, pH, kinetics, and isotherms on As removal efficiency. The kinetics study showed that ES-OH removed nearly all As from solution in less than 15 min. The pseudo-second-order model described the process, and the maximum As removal capacity predicted by the Langmuir isotherm model was 529 mg g^-1. Using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray detector (SEM-EDS), and X-ray diffraction (XRD), we found that the As removal mechanism by ES-OH was due to vladimirite precipitation, followed by weak electrostatic interactions between the precipitate and arsenate ions. Finally, after an economic analysis, we conclude that besides being a novel and economical income source, egg-producing companies might implement the ES-OH production process as a local environmentally-friendly way of recycling eggshells and reducing water As contamination.