Construction and demolition waste repurposed for heavy metal ion removal from wastewater: a review of current approaches

Over the past few decades, the world is facing critical water supply problems caused by the relentless increase of global human populations and the associated rise of anthropogenic activities. Heavy metals are among the main water pollutants which pose a great threat to human health. Hence, globally there has been a large amount of research devoted to investigating cost-effective and sustainable methods for removal of heavy metals from polluted water. One such area of interest is the utilization of construction and demolition waste (CDW) materials for the adsorptive removal of heavy metal ions (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sr, and Zn). This review focuses on the most current research for the use of CDW as an adsorbent. The different heavy metal ion removal mechanisms involved are also discussed. Further, this article documents the regeneration and reuse strategies for heavy metal treated adsorbents and the efforts to apply these materials in large-scale applications. Finally, the main research gaps are identified and future research directions suggested.