Viability of zeolites obtained from hazardous aluminum industry waste for soil remediation

The effectiveness of two zeolites, type LTA and NaP (called ZA and ZB, respectively), synthesized using hazardous aluminium industry waste, was evaluated for the remediation of a soil polluted with metal(loid)s and polychlorinated biphenyls (PCBs). The influence of zeolite amendment on soil physicochemical properties and its associated phytotoxicity was also assessed. Batch experiments were conducted in a climatic chamber with zeolite doses of 0 %, 0.5 %, and 1 %. At 7 and 30 days, the availability of As, Fe, Ni, and Pb was determined. After 30 days of incubation, soil physicochemical characteristics, PCB concentrations, and phytotoxicity, were analyzed. Both zeolites induced a dose-dependent increase in soil pH—particularly notable for ZA at 1 %—and in electrical conductivity, although the latter remained within normal range for soils. While the two zeolites reduced metal(loid) availability in soil, they showed a different behavior. In this regard, ZA was more effective at immobilizing As and Ni, while ZB performed better for Pb. Regarding PCBs, soil incubation under our experimental conditions reduced the content of most of these contaminants, even in the control sample, probably as a result of biodegradation, and the addition of zeolites did not enhance this process. Thus, sustainable zeolites obtained from hazardous aluminum industry waste emerge as promising material for soil decontamination processes, thereby contributing to the principles of the circular economy. However, further studies combining zeolites with other agents are required to enhance the effectiveness of the treatment without adversely impacting soil properties.