Tandem type PRBs-like technology implanted with targeted functional materials for efficient resourceful treatment of heavy metal ions from mining wastewater

Abstract

The resource treatment of mine wastewater with low-concentrations heavy metal ions is desirable for the sustainability of the metallurgical industries, but is challenging. In this study, we developed a novel combined tandem type permeable reactive barriers-like (PRBs-like) technology with implanted targeted adsorbents to achieve the selective removal of metals from mining wastewater. In the continuous flow test, the PRBs-like enable the content of lead, arsenate and zinc ions in 790 mL of actual mine effluent to reach below the Chinese pollutant discharge standards for lead and zinc industries (GB2546-2010) within 6 h. The expected ability of the reactor benefits from the outstanding mass transfer of the three adsorbents, tannic acid based polymer (TABP), cerium oxide (CeO2) and zero-valent iron (ZVI), with capacities of 116.6, 87.5 and 61.8 mg g−1 for lead, arsenic and zinc ions at an equilibration time of 20 min. Noteworthy, TABP features a strong affinity for lead, as well as CeO2 for arsenate, which is favorable to the aggregation of a single species metal in the corresponding reaction partition. In addition, factors including different flow rates, pH and reaction media distances on the performance of PRBs-like were investigated, demonstrating excellent adaptability of the tandem reactor to the wastewater environment. And long-term experiments showed the high stability and efficiency of the operation of the reactor. The graded combined device and the targeted adsorbent were first integrated in this work to point out a high-efficiency pathway, which can recycle the heavy metals in mine wastewater.