Biochar Enhanced Phytoremediation Application in Mine Tailings Contaminated by Heavy Metals

Mining activities has generated large amounts of mine tailings each year and these tailings usually contain high concentrations of heavy metal pollutants which not only cause serious damage to the local and surrounding soil ecosystems but also harm human health through the transmission of food chain. Phytoremediation is an environmentally friendly long-term effective and low-cost restoration method. However some tailing soil acidification low organic matter content poor water holding capacity and compaction make plant struggle to survive. Biochar is a soil conditioner. Its addition can promote plant growth by improving the physical chemical and biological properties of soil thus strengthening the ability of plants to repair the soil contaminated by heavy metals from tailings. This paper reviews how the physicochemical properties of biochar affect phytoremediation and summarized how the raw materials of biochar affect the physicochemical characteristics. Finally the future research directions are prospected.