Removal of Cadmium from Contaminated Groundwater Using a Novel Silicon/Aluminum Nanomaterial: An Experimental Study

Cadmium (Cd) is a harmful element to human health and biodiversity. The removal of Cd from groundwater is of great significance to maintain the environmental sustainability and biodiversity. In this work, a novel low-temperature roasting associated with alkali was applied to synthesize an eco-friendly adsorbent using coal fly ash. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray fluorescence, and X-ray photoelectron spectroscopy were applied to analyze the physical and chemical characteristics of the adsorbent. The experiments show that a significant improvement in specific surface area and activity of adsorbent was observed in this study. The functional groups of Na-O and Fe-O were verified to be beneficial in the removal of Cd2+. The material capacity to adsorb Cd2+ was considerably improved, and the maximum uptake capacity was 61.8 mg g(-1) for Cd2+ at 25 degrees C. Furthermore, pH and ionic strength play critical roles in the adsorption process. The Langmuir and pseudo-second-order models can appropriately describe the adsorption behavior, and the enhanced adsorption ability of Cd2+ by modified coal fly ash was attributed to ion-exchange, co-precipitation, and complexation. Higher sorption efficiency was maintained after two regeneration cycles. These results offer valuable insights to develop high-performance adsorbent for Cd2+ removal.

Automated summary

A novel eco-friendly adsorbent was synthesized using coal fly ash, significantly enhancing the adsorption capacity for Cd2+. Functional groups of Na-O and Fe-O were found to be beneficial for the removal of Cd2+. The adsorption efficiency of the adsorbent remained high even after two regeneration cycles, showing potential for high-performance Cd2+ removal.