Cleaning Up Metal Contamination after Decades of Energy Production and Manufacturing: Reviewing the Value in Use of Biochars for a Sustainable Future

Abstract

The lasting impact of ancestral energy production operations and global manufacturing has not only generated substantial CO2 emissions, but it has also led to the release of metal-based pollutants into Earth’s water bodies. As we continue to engineer, mine (coal and metals), and now bore into geothermal wells/fracking sites for alternative energy sources, we continue to contaminate drinking water supplies with heavy metals through infiltration and diffusion, limiting progress towards achieving Sustainable Development Goals 3 (Sustainable Development Goal 3: Good health and well-being), 6 (Sustainable Development Goal 6: Clean water and sanitation), 14 (Sustainable Development Goal 14: Life below water), and 15 (Sustainable Development Goal 15: Life on land). This review shows how the research community has designed and developed mesoporous biochars with customizable pore systems, as well as functionalized biochars, to extract various heavy metals from water sources. This article investigates how biochar materials (non-activated, activated, functionalized, or hybrid structures) can be adapted to suit their purpose, highlighting their recyclability/regeneration and performance when remediating metal-based pollution in place of conventional activated carbons. By utilizing the wider circular economy, “waste-derived” carbonaceous materials will play a pivotal role in water purification for both the developed/developing world, where mining and heavy manufacturing generate the most substantial contribution to water pollution. This review encompasses a wide range of global activities that generate increased heavy metal contamination to water supplies, as well as elucidates emerging technologies that can augment environmental remediation activities, improving the quality of life and standard of living for all.