33 / 2023-04-29 19:16:43

Comparison of different iron sources for magnetic zero-valent iron engineered hydrochar preparation: Chromium removal insight and practicality assessment

Red mud, Copper slag, Magnetic engineered hydrochar, Hexavalent Chromium, Removal mechanisms.

The recycling of industrial solid by-products such as red mud (RM) and copper slag (CS) has become an urgent priority, due to their large quantities and in dangerous valuable elements. In this work, RM and CS were employed to fabricate hydrochar (HC) to prepare zero-valent iron modified carbonous materials, and conventional iron salts (IS, FeCl₃) was applied as comparison, fabricated HC labeled as RM/HC, CS/HC, and IS/HC, respectively. The physic-chemical properties of these adsorbents were comprehensively characterized. Further, chromium (Cr(VI)) removal performance was assessed (375.66, 454.74, and 337.19 mg/g for RM/HC, CS/HC, and IS/HC, respectively). Further, the influence of dosage and initial pH were tested, while isotherms, kinetics, and thermodynamics analysis were also conducted, to mimic the surface interactions. According to results, the higher capacity of iron contained by-products derived HC (RM/HC and CS/HC) could be attributed to the indigenous minerals contained in slags, such as Al, Ca, Si, etc. The stability and recyclability of these adsorbents also verified, while the practical feasibility was assessed by bok choy-planting experiment and economic assessment. This work offered evidence for the resource utilization and iron-contained wastes management as functional materials, which has sustainable implications for the control of heavy metal pollution.