An effective way to utilize solid waste resources: The application of modified fly ash in removing Cu2+ and Pb2+ in wastewater

Abstract

The sustainable development of society requires the support of developed industrial production, which inevitably produces a series of industrial by-products, including heavy metal-containing wastewater and solid waste. Using solid waste to adsorb heavy metal ions in wastewater is a sustainable way. This not only reduces the environmental threat caused by solid waste accumulation, but also reduces the treatment cost of heavy metal ions in wastewater. In this study, fly ash was modified to prepare magnetic adsorbent (M-AT), which was used to adsorb Cu2+ and Pb2+ in wastewater. The results showed that M-AT has a good adsorption effect on Cu2+ and Pb2+ in wastewater. Its maximum adsorption capacity for Cu2+ and Pb2+ was 53.18 and 85.86 mg/g, respectively. Ion exchange and complexation reaction were major adsorption mechanisms of M-AT for Cu2+ and Pb2+, they played an important role in the adsorption process. M-AT maintained a good adsorption effect on Cu2+ and Pb2+ under different influence factors. This ensured that M-AT can be used in complex application environments. In addition, M-AT exhibited good reusability, its removal rate for Cu2+ and Pb2+ reached 50.21 % and 75.15 % after 5 adsorption–desorption cycles. And the removal rate of M-AT for Cu2+ and Pb2+ in domestic sewage treatment plant influent, tailings drainage, industrial wastewater was 82.80 %, 87.12 %, 85.12 % and 95.10 %, 91.20 %, 93.13 %, respectively. These results proved the feasibility of M-AT in treating Cu2+ and Pb2+ in wastewater. This study provides a new way for the resource utilization of fly ash. Applying solid waste to treat heavy metal-containing wastewater is a sustainable way to treat industrial waste.