A recent study has explored the use of algal biochar, derived from the microalga Cyanidioschyzon merolae, to tackle the problem of heavy metal leachate from mine tailings. This biochar is produced through hydrothermal liquefaction, resulting in a material capable of immobilizing metals such as copper, iron, and zinc. By using density functional theory (DFT) and laboratory experiments, researchers identified the molecular interactions that enable metal adsorption onto the biochar, highlighting cation-π interactions, complexation, and ion exchange as key mechanisms.

The study found that algal biochar has the highest affinity for copper ions, followed by iron and zinc. UV–Vis spectroscopy confirmed that metal-ion adsorption was not affected by solution pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, while thermogravimetric analysis indicated strong chemical interactions between the biochar and metal ions. These findings suggest that algal biochar can effectively trap metals, even under varying pH and temperature conditions.

The potential application of algal biochar in geopolymers containing mine tailings is particularly promising. Mine tailings, which are the waste byproducts of mining operations, pose significant environmental challenges due to heavy metal leachates. By incorporating algal biochar into construction materials such as bricks, concrete, and geopolymers, it is possible to immobilize these metals, thereby preventing contamination of soil and water.

This research underscores the role of algal biochar in promoting sustainability and environmental protection. By effectively reducing metal leachates, algal biochar enhances the viability of using mine tailings in construction, offering a low-carbon alternative to traditional building materials and contributing to resource conservation and pollution prevention.