Studies on the adsorptive removal of cesium ions using Nigella sativa as an adsorbent and optimization with response surface modeling

The wastewater contaminated with radioactive wastes is more hazardous and has an adverse impact on ecosystems. One of the harmful species present in radioactive wastes is cesium. We are in need of adequate process for the removal of cesium to protect the environment. In recent years, the adsorption process has been adopted for the removal of contaminants from the waste stream. In this study, a new low-cost adsorbent synthesized from Nigella sativa (black cumin seed) has been employed for the removal of Cs(I) from the simulated wastewater. The adsorbent was characterized by scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction, and Fourier-transform infrared spectroscopy analysis. The simulated wastewater sample containing cesium ions was prepared and the adsorption studies were carried out. The process parameters such as initial solution pH, contact time, the dosage of adsorbent, and concentration of Cs(I) were examined and the percentage separation of Cs(I) and adsorption capacity of activated black cumin seed (BCS) were evaluated. The kinetic studies and adsorption isotherm studies were performed to analyze the experimental findings. The optimized parameters were evaluated using the Response surface methodology to analyze the maximum percentage removal of Cs(I) and adsorption capacity of activated BCS. The optimized values were compared with the experimental findings.