Lead Release from Simulated Lead-Containing Jarosite Using Freeze–Thaw Cycling with EDTA
2023
Jun Peng | Yujun Shen | Hui Liu | Luhua He | Yangjin Wei | Xu Yan
Lead is the primary toxic element found in jarosite residue: it is necessary to synthesize simulated lead-containing jarosite residue (SLJS) to investigate its lead release behavior and predict the slag&rsquo:s stability and potential for secondary environmental pollution. This study explores the ion release behavior, leaching toxicity, and stability of SLJS during freeze&ndash:thaw cycles with EDTA (E-FTC). Experimental results demonstrate that the release of lead, iron, and sulfate from SLJS under E-FTC is contingent upon multiple factors, including solution pH, EDTA concentration, freeze&ndash:thaw cycles, freezing temperature, and freeze&ndash:thaw mode. Specifically, employing an EDTA concentration of 200 mM, a pH of 6, a freezing temperature of &minus:20 °:C, and 12 freeze&ndash:thaw cycles, the lead release reaches 15.1 mM, accounting for 94.9% of the total lead content, while iron is negligibly released, thus enabling effective separation of lead from iron. Subsequent to E-FTC, the exchangeable lead content exhibits a substantial reduction, accompanied by a marked increase in residual lead, resulting in a remarkable 98% reduction in leaching toxicity. Moreover, the equilibrium concentration of lead in the continuous stable leaching solution is 0.13 mg/L, significantly below the lead toxicity threshold (5 mg/L). Therefore, environmental stability can be greatly enhanced. This study presents a novel approach for the safe disposal of jarosite residue under mild conditions and at low temperatures, contributing to the broader field of environmentally sustainable waste management.
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